Q & A

Normals

Eddie sez:

Over the years I've probably got several thousands of questions on the web and, I am afraid to say, I hardly ever make a record of them. I know this because sometimes when I am researching an answer, I realize that I once answered the question before. If only I had captured it the first time! Well let's see if we can fix that.

I think I average five to ten "Eddie" emails every day and usually one or two questions. I try to answer everything but it quite often takes me a while. I think my record so far is two years to find an answer. I hope I can do better if you have a question for me. If you do, select the "Contacts" button on the top of the screen.

Some of this comes from the references shown below.

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Last revision:

2020-07-22

Cover Story:

2019-06-06

2019-04-28

2019-02-26

Most Recent Questions

Here are the most recent questions, this time around. I'll push these down below into alphabetic order the next time I update this page.

What if the entire organization is ignoring SOP?

Dear Eddie,

Are normal procedures as outlined in the AFM mandatory by the FARs in a part 91 operation? Even if the OEM is not really keeping the AFM up to date since the aircraft is an older model, or the OEM has arguably overlooked something?

[The reader provided specifical examples which have been redacted for privacy reasons.)

Signed, R. Fader
Fort Lee, New Jersey


Mr. Fader

Our team offers you the following penned by Larry, a very astute legal-minded professional aviator. I trust his judgment implicitly but I would like to add something up front.

I flew for a number of outfits in the Air Force that were allowed to operate as they saw fit and they often courted disaster while relying on luck to keep them safe. Sometimes that worked, sometimes it didn’t. I flew a version of the Boeing 707 (EC-135J) that relied on the manual of another variant (EC-135C) that came from a third (C-135B). All of this more than a decade after the aircraft were out of production. We ended up with a lot of undocumented systems and procedures and we flew the airplane the way the most experienced pilot in the squadron was taught. Every now and then a pilot would return and wondered why we were doing something against procedure and we figured out somebody along the way corrupted the process. That squadron crashed an airplane a few years after I left.

I don’t think we as pilots are good at improvisation. If you are making it up as you are flying, chances are you are going to make a mistake or overlook something that could make your life safer and easier. I encourage you to write these informal procedures into a form that makes them look like they came from the manufacturer and see if everyone involved is onboard with doing it the same way. Once you have buy in, I would run an all-hands accident investigation. The premise is to suppose the airplane in question crashed with a loss of all hands and took out some ground personnel too. (When I did this in the Air Force, I would say the airplane crashed into the base elementary school.) Now examine those procedures and hypothesize how well they would stand up to NTSB and public scrutiny.

Larry will draw the legal definitions for you, but he also points out that just because something is legal it may not be safe or prudent. I would like to add to that by saying the stakes are too high for “good enough” to be good enough. That’s my two cents. Larry’s follows.

Eddie


Thank you for your questions. You ask: “In general, are normal procedures as outlined in the POH/AFM mandatory by the FARs in a part 91 operation?” In my opinion, the short answer is no, adherence to the NORMAL procedures in the POH/AFM is not mandatory under the FARs for operations conducted under FAR Part 91. You then cite several examples of procedures contrary to the NORMAL procedures listed in the FAA-approved POH/AFM and ask if I would consider them as intentional non-compliance.

First, with respect to the POH/AFM being current and onboard the airplane, refer to 14 CFR §91.9 (b)(1) below:

§91.9 Civil aircraft flight manual, marking, and placard requirements.

(a) Except as provided in paragraph (d) of this section, no person may operate a civil aircraft without complying with the operating limitations specified in the approved Airplane or Rotorcraft Flight Manual, markings, and placards, or as otherwise prescribed by the certificating authority of the country of registry.

(b) No person may operate a U.S.-registered civil aircraft—

(1) For which an Airplane or Rotorcraft Flight Manual is required by §21.5 of this chapter unless there is available in the aircraft a current, approved Airplane or Rotorcraft Flight Manual or the manual provided for in §121.141(b); and

From the information you provided, it appears there is an FAA-approved, OEM provided POH/AFM onboard the airplane or airplanes you reference in your questions. (Note: The POH/AFM lists the serial number of the airplane to which it is assigned. If a manual does not indicate a specific aircraft registration and serial number, it is limited to general study purposes only.) If so, this complies with §91.9 (b) (1), provided the POH/AFM is current. However, you also state the “OEM is not really keeping the AFM up to date since the aircraft is an older model.” If the airplane’s OEM is no longer in business, and no other entity is responsible for the airplane model, then it is my opinion that the latest, most current manual commercially available specific to the airplane’s serial number would be meet the intent of the regulation. However, if the airplane’s operator is intentionally choosing not to purchase an available subscription update service or a more current manual from the OEM or other approved entity, and there is a more current POH/AFM available, then in my opinion the POH/AFM onboard would not meet the intent of §91.9 (b) (1).

(Note: 14 CFR Part 91 places primary responsibility on the owner or operator for maintaining an aircraft in an airworthy condition. The owner/operator of the airplane is responsible for its airworthiness, which in this case means ensuring a current, approved manual is onboard the airplane. However, §91.9 (b) (1) states that no person may operate the airplane unless there is available in the aircraft a current, approved Airplane or Rotorcraft Flight Manual. This places the responsibility on the person (or certificated pilot) operating the airplane to make sure the current manual is onboard.)

PINC, or procedural intentional non-compliance has traditionally meant willfully, intentionally, and deliberately operating contrary to standard operating procedures (SOPs), airframe manufacturer’s guidance, FAA guidance (e.g., AIM, Advisory Circulars, Handbooks, etc.) or FAA regulations. In the examples you cite above, although the operations appear legal at first blush, they are arguably contrary to published manufacturer’s guidance, SOPs, and accepted safety standards. In my opinion, they are classic examples of PINC or perhaps normalization of deviance.

In my experience, operations such as you describe go unchecked until FAA gets involved after an accident or incident. A noteworthy example is when FAA rescinded exemptions to the Collings Foundation after their deadly B-17 accident at Bradley (KBDL), 2 Oct 2019.

It is only then that such operations are looked at as to whether they are careless or reckless. Willful, deliberate, and intentional non-compliance with published guidance is not only foolhardy; it may be reckless. The NTSB has determined that “reckless” operation results from a deliberate or willful disregard of the regulations or accepted standards of safety so as to potentially or actually endanger the life or property of another. The examples you cite could potentially be reckless under 14 CFR §91.13 Careless or reckless operation, especially if such operations resulted in an accident or incident.

Furthermore, those who purposefully disregard published guidance, especially from the aircraft manufacturer, bear the burden of presenting a legally compelling alternative explanation for their deviations sufficient to overcome the inference of carelessness in the event of an FAA investigation. Otherwise, a finding of carelessness should be expected. And, although you did not mention the level of certificate you or others hold, keep in mind that NTSB has long held that an airline transport pilot must exercise those privileges with the highest degree of care and judgement.

In summary, although certain operations may be legal, they may not be safe or prudent. FAA maintains a webpage where such safety concerns may be submitted. (https://hotline.faa.gov/) Submission may be made by name or anonymously. I have used this avenue in the past with timely, effective results. The FAA inspector phoned and we spoke, the offending pilot was counseled by the inspector, and my identity was never revealed to the pilot.

I hope this information has been helpful and responsive to your questions.

Sincerely,
Larry, Code7700.com

Why do they keep making impossible approaches?

Dear Eddie,

We had a trip to Goodland, Kansas which has one runway long enough for our jet with an LPV on one end and an ILS on the other, so no worries. When I was learning to fly, I actually did my solo cross country to Goodland so it was a nostalgic trip for me. While thumbing through the approach plates, we found this gem:

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Photo: VOR Rwy 30, Renner Field / Goodland Muni (KGLD)
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It has been so long since I've flown a real VOR approach, I think I have forgotten how. I probably flew this very approach, back in the day. My question is how is this approach even possible? If you are flying a Category A aircraft and only need a half-mile visibility, how are you going to descend from 4,200 feet down to the runway at 3,654 feet if you aren't in a helicopter? I'm not mathematician, but if a normal glide path is 300 feet every mile, then how are you going to descend 546 feet in half that distance?

Signed, R. Fader
Fort Lee, New Jersey


Mister Fader,

This is a good one for discussion because it is more complicated than it appears.

If you don’t factor the approach lighting system:

The gradient would be arcsin( 546 / (1/2 of 5280) ) = 11.94° which is well above the TERPS limit for Cat A (5.7°). The real formula involves the curvature of the earth and is given in TERPS Chapter 2, Formula 2-6-4, but this is close enough. For Category D you are just over the 3.1° limit, but barely: arcsin( 583 / (2 * 5280) ) = 3.16°. Conclusion: the approach cannot be safely flown at minimums.

If you do factor the approach lighting system:

A typical MALSR starts 2,400’ from the runway threshold with the roll bar at 1,000’ prior. So if you consider everything, which you shouldn’t, the Category A gradient becomes arcsin( 546 / ((1/2 of 5280)+2400) ) = 6.22, still too high but close. If they installed a MALSR that was long enough to give you the necessary cues to descend to 100’ you would be okay, but those lights would need to be at 3,000 feet from the runway. Conclusion: unless they installed a longer MALSR, which I think is permissible, the approach cannot be safety flown at minimums.

They very well may have installed longer approach lights. I have seen installations where the lights were made as long as real estate would permit, and the minimums were constructed accordingly.

A more likely explanation would be what we called the “Sergeant Snuffy effect” when I went to USAF Instrument Instructor school. They would have us dissect approaches to explain how the approach was designed. Every now and then we would come up with one that could not be explained. The instructor said the USAF approaches were designed by Sergeant Snuffy, who wasn’t a pilot. He went to airspace school and didn’t pay strict attention every day in class. My conclusion: Sergeant Snuffy got out of the AF and started designing approaches for civilians.

I hope that helps. The obvious lesson, I am sure you already know, is that you have to figure these things out before you depart!

Eddie

How to Master an Airplane?

Dear Code 7700,

I would like advice on the best way to really master an airplane.

I’ve accumulated eight type ratings over the years including the GVI, but it looks like I’ll be flying the G450 and 550 for the foreseeable future. I’ve been doing that for several years now but feel I need to dig deeper. I’m always surprised at recurrent training of things I didn’t realize or have just forgotten. Just curious if you have a system or just always keep reading and reviewing.

Signed, R. Fader
Fort Lee, New Jersey


Mister Fader,

That is a pretty good question that I need to give a little thought to. In fact, let me ask my partners here for their answers and I will put it all together.

For me, the process of learning airplanes can be boiled down to a few points:

  • Adopt a “learn first, question second” attitude for areas where you don’t have any expertise. I learned that in year one during Air Force pilot training where the T-38 is so different than the T-37. But then when I became an instructor in the EC-135J (Boeing 707) I was amazed that some of our new pilots from the KC-135A (a similar looking airplane with a different wing and engines) insisted on flying the new airplane using the old airplane’s techniques. And that didn’t work. I think it pays to have an open mind in this situation.
  • Write everything down. When in class, try to write just enough to be able to recreate your notes later (this is important) but not to distract you from listening to what is being said. Then later that night, but no later than that, draw up a second set of notes to expand on the first set of notes. That allows you to fill in the details and reproduce everything in a more organized and legible fashion. One day later I can hardly read what I wrote in class. A week later, no chance. There is a drawing in the GV manual about the ground spoiler system that some instructors gave me credit for. I told them that I drew it from an older instructor’s chalk board drawing years before that took me three recurrent to get right. The original instructor has since passed away but somehow I got the credit because of my notes. The advent of cell phone cameras has been a game changer for me. After an instructor draws something particularly useful, I’ll ask permission to take a photo. Most instructors take this as a compliment.
  • Cross check everything. You should be able to categorize everything you get in a learning environment (classroom, simulator, airplane) into one of three categories: procedure, technique, hearsay. A procedure comes from the manufacturer’s manual or a government publication. It may or may not be true, but be careful about discounting it. A technique is an idea that improves upon a procedure, but sometimes long held techniques don’t transfer to the next airplane or could actually be ill advised but the fault in it hasn’t been discovered yet. Hearsay is just something someone said that is either good or bad, you just haven’t made that determination yet.
  • Evaluate sources. After a while you should become an educated shopper of information. I learned early on that the GV manual was excellent and that I could pretty much trust everything in it. I also learned early on that the G450 manual was filled with errors and not to be trusted. The same can be said of instructors. The majority of everything I learned at GIV initial at SimuFlite was wrong. In the GV, I learned that some FSI instructors were very sharp, others not so much.
  • Realize that “you don’t know what you don’t know.” Aviation is such a diverse and complex field that you cannot possibly know everything. We see that often when training someone for international operations. Just because it works from LAX to BOS doesn’t mean it will work from KBOS to EGLF.
  • And finally,

  • Be humble. I was once introduced before a speech as “a man who has forgotten more than most of us will ever know.” To that I said, “which means I have forgotten and that is a bad thing.” You have to constantly recover ground already taken, to use military jargon. Just because you had it down cold a year, a week, or even a day ago, doesn’t mean you know it today. As an Air Force instructor pilot a particularly humbling moment is the first time a former student teaches you something you taught him or her, but have since forgotten. The first time this happens it is embarrassing. The twentieth time it happens, it is just one more than the nineteenth. In other words, it is inevitable.

Those are just my off the cuff ideas on the subject. Let me ask three of the smartest pilots I know for their takes and I will get back to you.

Eddie


Mister Fader,

I wish there was a shortcut to “mastering an airplane” but like most things in life it only comes about through perpetual dedicated study and organization. I learned the organization bit from Eddie. I admired the way Eddie thoroughly researched a topic/system and recorded/documented it in such a way so as to be easily retrieved. I found preparing for G450 recurrent an overwhelming task because of the sheer volume of material to review. I wasn’t happy with FSI’s depth and I found Gulfstream’s manuals to be error filled monstrosities. My "short" G450 notes grew out of my desire to have a concise, accurate, appropriately deep study guide for Recurrent. Then my “long” G450/G550 notes grew out of my desire to “get straight” what I still didn’t fully understand. The DACU, for instance, probably consumed 10 hours of research before I felt I actually had it sorted out.

I’ve found the G150 to be different all together however. FSI’s recurrent manuals work just fine for studying and refreshing myself on the aircraft. After each recurrent I email myself and my coworkers anything new I learned. Before each recurrent I review my previous emails to refresh myself on the things that stood out to me from before.

One area I put a lot of effort into is dialing in maneuvers and exact callouts. I find developing my own reference material for this greatly helps because I’m able to precisely lay out what I should be doing/saying and then chair fly the maneuvers before sim sessions.

Best,

"The Beav"


Mister Fader,

Mastering the aircraft we are currently assigned to should be the ultimate goal of every pilot. That means knowing far more about the aircraft than what’s required/necessary to fly it safely from Point A to Point B. This is where being good enough at something is not enough if you can be better at it. Just like being better at something isn’t good enough if you can be the best...at it.

Like most other professional pilots I have accumulated my share of type ratings over the years. That has given me a chance to learn valuable lessons as to how to master the current aircraft. Perhaps the most important lesson I’ve learned, however, is that to master my current aircraft I have to intentionally forget the previous one. I personally have very limited excess brain capacity and couldn’t possibly master my current aircraft if I was actively trying not to forget my previous one.

So what next after we’ve made a decision to master the aircraft? Well, how we go about mastering an aircraft varies greatly from one person to the next. What works for me may or may not necessarily work for someone else. So what works for me?

  1. Notes: notes allow me to dissect complex systems into smaller and easier to understand components. Writing things down reinforces my understanding of the subject matter and make it easier to quickly and frequently review these subjects.
  2. Teach: there is no better way to master a complex subject than trying to teach it to someone else in the most simple of terms.
  3. Practice: “practice until you get it right. Then, keep on practicing until you cannot get it wrong.” You can practice at home sitting on a chair to visualize and verbalize procedures. Then take every opportunity to do the same while sitting in the cockpit.

Mastering anything takes time, commitment, effort, consistency, discipline, and organization. But here is the kicker: it’s a process that never ends…and should never end. There will always be something about the subject matter we are trying to master that we still don’t know, and that’s ok as long as we continue the learning process. There are no shortcuts.

Wally


Mister Fader,

Here are my gripes/suggestions:

  1. No schoolhouse I've been to has training manuals that are 100%, this is human and understandable. BUT, what bothers me is that for the price they charge, those training materials need to be on a revision cycle, whereby they are subject to peer review and new editions that incorporate all the corrections to the typos, just plain wrong information, and revisions from the manufacturer. I find this lacking at all the schoolhouses. At best, FSI Tucson would give you errata pages to go with your hardbound 604 pilot training guide. Talk about resting on your laurels...
  2. When I was at university, I found that having more than one textbook on one subject was invaluable. Something about how an author or authors explain a concept is so important with regards to whether you understand it or not. For example, once I got a Halliday and Resnick Physics textbook much of my confusion was cleared up. Similarly for Calculus. One time I saw a hydraulic schematic published by Canadair in a brochure, and thought this color coded diagram is worth a thousand words. Why didn't FSI do something like this? Presentation makes a huge difference.
  3. Instructors. I've found greatness, and get-by-ness. Not too many in-between. The pendulum swings. When hiring is strong, the good pilots get flying jobs. The bad pilots (or medical) teach.
  4. If you're on a 12 month recurrent cycle, try to read/study a system a month while on the road, this can help the overwhelming feeling you get on the first day of a 4 day recurrent.

Larry


Past Questions and Answers


AFM Electronic or Paper?

Dear Eddie,

I have heard many stories on this issue but I am trying to clear the air on this topic. Are part 91 operators on the G550 with worldwide operations required to carry a paper copy of the Airplane Flight Manual onboard at all times or can an operator just use the electronic version (IPAD) by Gulfstream in the Planebook app?

Signed, R. Fader
Fort Lee, New Jersey

Mister Fader,

I was on stage at this year’s NBAA IOC sitting next to two FAA inspectors, one of those in charge of this very thing. I got a question about this and said the only thing you must have paper versions of is the aircraft registration, the certificate of airworthiness, your license, and your medical. I looked at the Fed and said, “have I got that right?” He said, “I think so.” We also shared the stage with a French SAFA inspector who wasn’t shy about chiming in, but he simply nodded his head.

That being said, in our G450 we don’t have electronic versions of all the ASCs, so we keep paper versions of those. But other than that, we are paperless.

Eddie

Note: This answer can be found at: Paperless Oceanic.

Approach Categories?

Is your approach category based on your actual or your maximum certificated landing weight. To me the answer was always obvious but there are many who read 14 CFR 97.3 a different way, all based on a single comma. I think we have more than a few pilots out there flying the wrong approach category. They will tell you that I don't know what I am talking about. In 2013 the FAA settled the matter but haven't changed the regulation to remove the confusion. Don't be confused, read on.

More about this: Approach Categories.

Dear Eddie,

I read that you claim my approach category is based on my maximum landing weight but that isn't what they taught me at Brand X Simulator company, where all the instructors are experts. They tell me that if we did that in our Challenger, we wouldn't be able to fly into Aspen and nobody believes that. Besides, isn't what we are worried about the actual maneuverability of the aircraft? So if I am 10,000 pounds below maximum landing weight, shouldn't I be allowed to fly the approach category that fits that speed? I've read Part 97.3 several times and I think the maximum landing weight only applies to aircraft that do not have a VREF, which ain't me.

Signed, R. Fader
Fort Lee, New Jersey

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Photo: Circling at Hilo, Hawaii
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Mister Fader,

I have been wrestling with this issue for many years, but in 2013 the FAA finally cleared it all up. The bottom line is this: you must use the maximum certificated landing weight, even if you have a VREF.

Eddie

[14 CFR 97.3] Aircraft approach category means a grouping of aircraft based on a speed of VREF, if specified, or if VREF is not specified, 1.3VSO at the maximum certificated weight. VSO, and the maximum certificated landing weight are those values as established for the aircraft by the certification authority of the country of registry.

These categories are as follows:

  • Category A: Speed less than 91 knots
  • Category B: Speed 91 knots or more but less than 121 knots
  • Category C: Speed 121 knots or more but less than 141 knots
  • Category D: Speed 141 knots or more but less than 166 knots
  • Category E: Speed 166 knots or more

There are some who would argue that maximum certificated weight only applies to 1.3VSO based on the placement of a comma in the regulation. The debate raged on for decades but the FAA finally provided some clarity in 2013:

[14 CFR 97.3 Interpretation]

  • This memorandum is in response to your request for legal interpretation on the meaning of "aircraft approach category" as defined 14 C.F.R. § 97.3 dated September 24, 2012. Specifically you ask if the phrase "maximum certificated landing weight" as used in § 97.3 applies to aircraft grouped by speed of VREF. The answer to your question is "yes" the phrase "maximum certificated landing weight" applies to both aircraft grouped by speed of VREF as well as aircraft grouped by 1.3 VSO.
  • In 1972 the FAA implemented the U.S. Standard for Terminal Instrument Procedures (TERPS). The TERPS rule changed the way the FAA defined aircraft approach categories from one based on the number of engines to new criteria based on stall speed in landing configuration or aircraft weight. Specifically "aircraft approach category" was defined as a "grouping of aircraft based on a speed of 1.3 VSO (at maximum certificated landing weight) or on maximum certificated landing weight." See 32 Fed. Reg. 13909,13911-12 (Oct 6, 1967); 32 Fed. Reg. 6938, 6939 (May 5, 1967). Section 97.3 was amended later to remove the option for basing aircraft approach categories strictly on maximum certificated landing weight. See 44 Fed. Reg. 15659 (Mar. 15, 1979). The only remaining way to make this determination was "1.3 VSO (at maximum certificated landing weight)." Id.
  • In 1996 the FAA proposed replacing "1.3 VSO" with "VREF" in the definition of "aircraft approach category" in § 97.3. See 61 Fed. Reg. 1260, 1263 (Jan. 18, 1996). The proposed definition specified that aircraft would be grouped "based on a speed of VREF at the maximum certificated landing weight." Id. at 1268. After additional review, the FAA determined that application of the VREF standard "to aircraft certificated using VS could cause confusion for users of the airspace system and that some airplane flight manuals would not be consistent with the new VREF terminology. See 67 Fed. Reg. 70812, 70822 (Nov. 26, 2002). Therefore, the FAA revised § 97.3 in the final rule to "continue to reference 1.3 VSO for use in those cases where VREF is not specified." Id.
  • The regulatory history demonstrates that the FAA intended the "maximum certificated landing weight" qualifier to apply to aircraft for which either VREF or 1.3 VSO are used to determine approach category. The new VREF standard as proposed in 1996 required "maximum certificated landing weight" to be part of the determination. The FAA revised the final rule so that aircraft approach categories could still be determined using the existing "1.3 VSO at maximum certificated landing weight" standard in addition to the VREF standard proposed in the NPRM. The preamble to the final rule contained no discussion of removing the reference to maximum certificated landing weight for the VREF standard proposed in the NPRM. We therefore conclude that for aircraft grouped by speed of VREF aircraft approach category must be determined using speed of VREF at the maximum certificated landing weight.

CAS Message Stack (Bottom of Top Priority Color First)

I've been hearing this since the first airplane I flew with a Crew Alerting System (CAS): Go to the bottom message of the highest priority CAS color, and there's your problem. I don't think it has ever been true, despite all the simulator instructors who have told you otherwise. This question has been added to: Immediate Action!

Dear Eddie,

I am in recurrent right now and our instructor said we should always look to the "bottom of the top" in our CAS message stack when deciding what checklist to run. If you have a stack of reds, ambers, and blues, look at the bottom red message. If you have a stack of ambers and blues, look to the bottom amber message. That way you will always find the cause of the problem. It worked in the simulator so maybe that's the way to go. Maybe you should add it to your rules of thumb.

Signed, R. Fader
Fort Lee, New Jersey

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Photo: Example message stack, from a G550
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Dear Mister Fader,

I can't answer for all airplanes but that rule of thumb doesn't work in many Gulfstreams. Look at the photo of a message stack from an electrical problem in a Gulfstream G550. The top stack is amber and the bottom of that stack says "Main DC Volts" above a long stack of blue CAS messages. If you go to the G550 QRH (page MB-43), you are told to reduce loads, end of checklist. So you have to complete the flight without the rest of that stuff in blue. But if you think the problem through and first attack the blue "L BPCU Fail" message, which tells you the Bus Power Control Unit has a problem. That checklist tells you to press the RESET button, and you get everything back.

So, Mister Fader, that would not be a good rule of thumb, at least not in a Gulfstream.

Eddie

Cost Index

Dear Eddie,

I had a question for you on Cost Index. With the new NAT bulletin allowing us OWAFS, it says you can fly Cost Index. Now I know your FMS will give you your most practical speed for fuel efficiency but I like to be able to calculated things myself if able. Was wondering if you had a formula for cost index speed?

Signed, R. Fader
Fort Lee, New Jersey

Mister Fader,

Eddie

Selecting an en route altitude and speed greatly impacts the amount of fuel burned, but there are other costs that may outweigh the price of Jet-A.

The major airlines have long recognized this and that’s why some airline flight management computers (FMC) incorporate a Cost Index (CI) as a perfor-mance initialization input. Boeing defines CI as the time cost of the airplane divided by the fuel cost. The time cost includes the crew, maintenance programs and just about everything else that is paid for by the hour. If the fuel is more expensive than everything else, it pays to slow down. If the “everything else” is more than the fuel, you may want to speed up. Few business aircraft FMCs have CI entries, but you can figure this out on your own.

Consider a Gulfstream G450 cruising at 37,000 ft. in a 100-kt. headwind starting at 70,000 lb. gross weight under ISA condi-tions. The crew know LRC will be Mach 0.80 but are wondering if the owner will see an improved bottom line if they fly Mach 0.03 slower, or even Mach 0.03 faster.

“It depends,” is the right answer. But it depends on more than just what the aircraft’s design engineers thought; rather it de-pends on what the company accountant thinks. You won’t find the following equation in any aeronautical or pilot texts, but it might help answer the question, “How fast do you want to fly?”

In this equation:

D — Distance to cruise (nm, since the climb and descent fuel will be about the same, we consider only the cruise portion)

TAS — True air speed during cruise (kt.)

WF — Wind factor (kt., positive numbers for headwinds, negative for tailwinds)

FF — Fuel flow (pounds per hour), average in cruise

FC — Fuel cost ($ per gallon)

FD — Fuel density (pounds per gallon)

VA — Variable airframe costs ($ per hour)

VC — Variable crew costs ($ per hour)

VE — Variable engine costs ($ per hour)

Total Cost = ( D TAS-WF ) X ( FF X FC FC + VA + VC + VE )

To compute the answer, values must be inserted. Are the pi-lots paid hourly or by salary? A salaried crewmember doesn’t add to variable costs and so that expense does not lend to any incentive to fly faster. Are any of the maintenance programs billed by flight hour? Some aircraft maintenance programs are fixed rate to a certain level of activity and then add per hour charges, while others count every hour from the first at one hourly rate. Is the aircraft on a lease program, and billed by flight time as opposed to calendar time? All of these vari-able costs can amount to $3,000 or more for a typical business jet and may overwhelm the cost of fuel, making it financially advantageous to burn more Jet-A to reduce total flight time.

Mach No Variable Costs $1,000 Variable Costs $2,000 Variable Costs
0.77 $12,035 $20,828 $38,413
0.80 $12,278 $20,648 $37,389
0.83 $13,245 $21,233 $37,207

Meanwhile, the cost of fuel is always a factor. At $1.00 per gallon there are usually incentives to fly fast. But at $5.00 per gallon? Not so much!

For the sake of our example, let’s say it is an ISA day, the fuel costs $3.00 per gallon and has a density of 6.5 gal. per pound. The first hour fuel burn at Mach 0.77 will be 2,996 lb.; at Mach 0.80 it will be 3,178 lb.; and at Mach 0.83 it will be 3,593 lb. The speed up/slow down question depends entirely on those variable costs:

These numbers can be fine-tuned by adjusting fuel burn rates on an hourly basis, but for demonstration purposes the conclusion in this example is clear: It doesn’t pay to fly faster until the vari-able costs exceed the cost of the increased fuel burn.

In other words, when fuel costs are low, there’s a strong incentive to fly faster. Conversely, when fuel costs are high, there’s a strong incentive to fly slower. Similarly, as variable costs increase, the incentive to fly fast increases.

Note: This answer has been added to: Engineering.

Driftdown, "Really!"

This question has been added to: Oceanic Contingencies

Dear Eddie,

Your latest oceanic contingencies article got me to thinking more about the process. Essentially one is supposed to turn off the track and slow to drift down speed and continue in the same direction until descending below FL290 before making the turn back to your alternate.

I dug into the flight manual performance section regarding single engine procedures. Average numbers for our plane at weights and altitude near the single engine ETP point: 220 IAS, 380 TAS and a 300 fpm descent rate. Assuming no wind and starting from FL350, it would take about 22 minutes and 140 NM to get below 290. Then another 22 minutes not including the turn to get abeam the point at which the engine failed in the first place. Roughly 45 minutes spent before making headway to your landing. This seems counter intuitive and I was hoping for your insight.

Signed, R. Fader
Fort Lee, New Jersey

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Photo: Oceanic crossing tracks "Safe Zone" procedure
Click photo for a larger image

Dear Mister Fader,

It is counterintuitive in many more ways than just the safety of your airplane. In the North Atlantic, especially, you have the safety of everyone around you to worry about. In the days before the skies became so crowded, the answer was to indeed drift down according to your aircraft’s best ability so as to milk every last forward mile possible. But these days, doing that could endanger other airplanes. Is it morally right to endanger an airliner filled with hundreds of people to improve the odds for the ten or so sitting behind your cockpit? But we do have greater communications and surveillance as well as TCAS to help out.

So, all that being said, here is my plan. I try to allow for enough fuel to keep a proper offset until above or below the tracks. If it happens, I’ll be communicating with the air traffic service unit and trying to get the best drift down I can, but I won’t do that unless I have clearance. This means you cannot be content with having just enough ETP fuel to make your destination. Here is some food for thought: The Great Escape.

Eddie

En Route Timing

This question has been added to: Oceanic Departure

Dear Eddie,

We were flying in Australian airspace the other day when center asked us to cross the next waypoint at a certain time. How do you do that? We couldn't find anything in the FMS to help us.

Signed, R. Fader
Fort Lee, New Jersey

Dear Mister Fader,

I've never used an FMS that does this automatically. You simply have to look at the ETA your FMS gives you and adjust your speed or your route until the ETA is correct. Of course this is easier said than done.

When speeding up your options are limited by the top speed your aircraft will do and this can be limited by your VMO, MMO, or other constraints such as turbulence or the airplane's RVSM limitations. This, of course, means there could be some math involved. I'll go through the math, but if you just want the procedures, look at the "Rules of Thumb" given.

Eddie

When en route, making pure, brute force changes to airspeed is usually the first option when adjusting.

Speed of sound = 573.8 nm/hour (above 36,000 feet)

M = TAS 573.8

Which means:

TAS = M * 573.8

It is helpful to know in advance how much speed you can gain by going as fast as you would normally want versus your normal cruise Mach, as well as how much you can lose my slowing as much as you would be comfortable doing at altitude. Say, for example, you normally cruise at M 0.80 and are willing to fly as fast as M 0.83.

TAS at M 0.80 = 0.80 * 573.8 = 459  nm/hr TAS at M 0.83 = 0.83 * 573.8 = 476  nm/hr

So that means we can cover the distance traveled in an hour at the original speed (459 nm/hr) more quickly:

time = distance velocity = 459 476 = 0.9643  hr

Multiplying by 60 converts that to minutes:

time = 0.9643  hours * 60  minutes/hour = 58  minutes

So speeding up by M 0.83 covers the same distance originally flown in 60 minutes in a time of 58 minutes. I'll leave the math up to you, but slowing down by M 0.03 will take 62 minutes.

You can do the same thing for other increments, if your aircraft allows it. Say, for example, you want to be able to speed up to M 0.85 or slow down to M 0.75. You will find that will gain or lose you 4 minutes.

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Timing: You can gain or lose two minutes by speeding up or slowing down by M 0.03

It is easier to lose time than gain it, obviously. To lose 2 minutes at lower altitudes you can make a standard rate 360 degree turn. At higher altitudes, you may have to settle for a half-standard rate because of bank angles, but that loses you 4 minutes.

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Photo: A 360° turn
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Timing: A standard rate 360 degree turn loses 2 minutes, a half-standard rate 360 degree turn loses 4 minutes.

For larger losses, a timing triangle can be used by flying 60 degrees off heading by the amount of time to be lost, then 60 degrees in the opposite direction, then 60 degrees back on course.

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Photo: A timing triangle
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Timing: A 60 degree turn off course for time t followed by a 60 degree turn back to course for time t and a 60 degree turn back on course will add time t to the en route ETE.


EVS Low Visibility Approach: Where do I look?

Dear Eddie,

I am just getting comfortable with the Heads Up Display (HUD) and Enhanced Flight Vision System (EFVS) on my airplane but it seems the pilot in the right seat, without a HUD or EFVS, always seems to spot the runway before me. When we go to the simulator, the instructor says maybe I need new glasses or I just don't know where to look. But I don't need new glasses and the instructor doesn't have any good hints on where to look. Where should I be looking when on an approach at miniumums using EFVS?

Signed, R. Fader
Fort Lee, New Jersey

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Photo: A shot from a G500 EVS approach at ILS minimums, from Eddie's G500 initial training.
Click photo for a larger image

Mister Fader,

When using a HUD we tend to focus on the Flight Path Vector (FPV) which should be right at our touchdown zone. But the minimums for the approach are based on the approach lights, which will be well short of the runway. I took a photo while in training flying into Savannah, Georgia, Runway 10, with the visibility at minimums. The DA is 230 feet and, looking at the top right altimeter, you see we are at 240 feet, ten feet to go. Looking at the FPV (The circle with the wings and tail) we don't see anything from the infrared EFVS because there are no lights on the touchdown zone for this runway. But this runway has MALSR and you can just barely see them if you drop your eyes down along the centerline drawn in the HUD. That centerline is seven broken lines from short of the EFVS image toward the runway. Look right under the top broken line and you will see the roll bar from the MALSR. Spotting that allowed me to take it another 100 feet by which time the PM spotted the runway and we landed.

You didn't mention what kind of airplane but I think the best advice is to have the airplabne coupled or very stable, make sure you are on glide path, and as you get closer to minimums pick up a scan of where you expect to see approach lights.

Eddie

Note: This answer has been added to: Minimums.

Fuel Quantity Update in the FMS?

This question has been added to: Trip Planning

Dear Eddie,

What’s the story behind the following Cruise checklist item in my Gulfstream: FMS Fuel Quantity....UPDATE?

I’ve heard that someone complained to GAC about consistently seeing a fuel quantity disparity between the FMS and the gauge so GAC simply added this item to the checklist. It’s there any truth to that or is that a myth??

Signed, R. Fader
Fort Lee, New Jersey

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Photo: G450 Fuel Quantity PERF INIT page
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Dear Mister Fader,

No that step is an important part of how you detect a fuel leak. The FMS performance computer is constantly monitoring how much fuel the engines should be burning to produce that number. You check it and reset it on level off and, I think, you should repeat that every hour. If there is a wide discrepancy, you should suspect a fuel leak.

Few Gulfstream pilots really understand how to do this. It becomes especially difficult when you take on large amounts of fuel. After you level off the fuel the FMS thinks you have could be several hundred pounds high or low depending on the starting temperature of the fuel and, therefore, its density. Who is right? They both are. The FMS gave you a more accurate idea of how much fuel was burned, the fuel gauge gives you a more accurate idea of how much fuel you have. It is important to understand both concepts. Now you want to reset the FMS so it again agrees with the gauge. Your SOP should tell you to repeat that process every hour. As the flight progresses, the disagreement should get smaller and smaller.

So how does this help with a fuel leak? Let’s say you develop a small fuel leak somewhere in the system, it really doesn’t matter where. But for some reason you are losing 1,000 lbs every hour. Let’s say this leak develops on hour 3 of an 8 hour oceanic crossing from White Plains to Rome. Chances are you will catch it since you make these checks against your master document. Now let’s say it happens on hour 3 of an 8 hour flight from Cape Town to Rome and you aren’t doing this master document hourly check. If you noticed the FMS was off by 300 lbs on level off (not unusual) and never checked it again you could be at risk. Now let’s say the leak starts right after level off and you are down 1,000 the first hour, 2,000 the second hour, and so on. By the time you might notice, it may be time to put the airplane down promptly in a location you would rather avoid. But if you checked at hour 2 and noticed you were down 1,000 lbs, you would be warned that something isn’t right.

Eddie

Gulfstream G450/G550/G650 Sea Level Pressurization?

Dear Eddie,

We have a passenger that is requesting that we keep the aircraft cabin at sea level for a 1.5 hour flight. I have done this in the past, but I wanted to pick your brain on what technique you would use. The G650 pressurization system is just not one of those systems that we spend a lot of time experimenting with, it just always works. This is a fairly important request and I would prefer not to mess it up.

Signed, R. Fader
Fort Lee, New Jersey

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Photo: Cabin Pressure System Semi-Automatic, G650 example
Click photo for a larger image

Mister Fader,

You basically start by switching to SEMI and programming in the desired cabin altitude. The window will show you the maximum available airplane altitude on the left as you rotate the right figure to show your desired cabin altitude. You also need to put in the landing field elevation and the field elevation's current altimeter. For taxi out the system will go from LANDING to FLIGHT automatically as well as to LANDING during descent. This surprises many in the G450 and G550 because there are a few errors in the operating manual, but I’ve done this a few times. Because this question seems to come up regularly, we took a short video: G450 Descent with Pressurization in SEMI mode. Note that as we reach 1,000 ft below cruise altitude, the system makes the switch. As you can see from the G650 AOM extract shown here, the G650 manual lays it out explicitly. Generally speaking, you can get up into the middle twenties and maintain a sea level cabin.

Eddie

Note: this answer has been added to: G450 Pressurization System.

Landing Distance Available Confusion?

This question has been added to: Runway Data

Dear Eddie,

I tried to research this on my own with the help of your website and pulling down the general pub of Jeppesen pub but it went nowhere. Can you explain why the KSJC 10-9A lists displaced threshold distance (8463’) but note 5 states a LDA of 7614’? Our operation procedures has us insert the 8463’ in the HUD but it seems that may be erroneous. Any reference is kindly appreciated.

Signed, R. Fader
Fort Lee, New Jersey

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Photo: Extract, San Jose (KSJC) Jeppesen 10-9A page, 5 Oct 2018
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Dear Mister Fader,

The problem is not everything gets labeled on the airfield diagram. So at KSJC Runway 30L/12R you have an 11,000’ runway with some displaced threshold on both ends and what is unclear is how much of the opposite end displaced threshold is considered available as a stopway. The end result for us pilots is that the distances don’t always add up. San Jose isn’t alone in this. I’ve called various airport managers up about this and have been surprised that quite often they don’t know. I called airport operations at San Jose and they were very helpful.

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They sent the Airport Layout diagram. Everything adds up to within a foot now. The plan lists TODA = 11,000, ASDA = 10,152, LDA = 7,614, and Displaced Threshold = 2,537.

Doing the math, LDA = ADSA - DT = 10,152 - 2,537 = 7,615.

And, Landing Distance Beyond Threshold = TODA - DT = 11,000 - 2,537 = 8,463.

The difference between ASDA and TODA, in this case, is a stopway. It appears this runway has a 8463 - 7615 = 848’ stopway.

All of that brings us back to your original question: how much landing runway can you plan on? In this case, the shorter number is LDA which the ICAO says is “The length of runway which is declared available and suitable for the ground run of an aeroplane landing.” (Annex 14, Vol 1, Definitions) and the FAA says is “The runway length declared available and suitable for a landing airplane.” (AC 150/5300-13). This number does not include the stopway.

But what about the longer number? The landing distance beyond threshold does include the stopway. So what is a stopway? The ICAO says it is “A defined rectangular area on the ground at the end of take-off run available prepared as a suitable area in which an aircraft can be stopped in the case of an abandoned take off.” (Annex 14, Vol 1, Definitions) and the FAA says it is “An area designated by the airport beyond the takeoff runway able to support the aircraft during an aborted takeoff.” (14 CFR 1.1). So it is suitable or able, but not available. So it looks like the shorter number is the answer.

Eddie

Mysterious procedures from left field (EASA altimeter setting)?

This question has been added to: Altimeter Settings

Dear Eddie,

I was flying on a G650 recently and the pilot I was flying with did something interesting and I'm hoping you may enlighten me on, based on your knowledge/experience (I did review your code7700 page on altimeter procedures). Departing from Tokyo (TA=14,000 & TRL=FL140) we got cleared to FL190 when we were at around 4,000'. This pilot went ahead and selected 1013 on his altimeter. I have always waited until I was approaching the TA to set STD (29.92/1013). We discussed this at length but the bottom line is that he flies in Europe and he said the "standard" is now to set 1013 when you get cleared to a flight level; also that this is the "EASA standard" now. What say you?

Signed, R. Fader
Fort Lee, New Jersey

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Photo: QNE/QNH/QFE, from Altimeter Settings

Dear Mister Fader,

Unless something has changed since the last publication of EASA Air OPS, I don’t think that is right. AMC2 SPA.RVSM.105 says:

Emphasis should be placed on promptly setting the sub-scale on all primary and standby altimeters to 1013.2 hPa / 29.92 in Hg when passing the transition altitude, and rechecking for proper altimeter setting when reaching the initial cleared flight level."

I did a word search through the entire manual for “altimeter”, “transition altitude” , and “transition level” and did not come up with anything contrary to that. Besides, it sounds like a lousy technique. When climbing you always have the possibility of being asked to level off at a lower altitude below the transition altitude, and you will need the QNH to do that. On the other hand, if you are cleared below the transition level during descent I think it is a good technique to dial in the QNH so you don’t forget it. If you are given an intermediate level off above the transition level, one button press on most altimeters gets you back to QNE.

There is some debate about what the United Kingdom AIP has to say about this: "The vertical position of aircraft at, or below, any Transition Altitude will normally be expressed in terms of Altitude. The vertical position at, or above, any Transition Level will normally be expressed in terms of Flight Level. When descending through the Transition Layer the vertical position will be expressed by pilots in terms of Altitude, and when climbing in terms of Flight Level." Some pilots interpret "expressed" to mean "used." I called London Center and the controller asked around to be sure. They all agreed that you should not change from Altitude to Flight Level until you are reasonably assured you will be climbing above the Transition Level. Just like everyone else does it.

Please note that not everyone agrees with me on this. If you look at https://www.skybrary.aero/index.php/Transition_Altitude/Level you will see the opposite opinion. Skybrary has very impressive credentials and you may choose to go with them. In my view, if their opinion carried enough weight, they would convince the ICAO or EASA to put their chosen techniques into writing somewhere official.

Whenever I hear something that surprises me I’ll say just that ("I did not know that!") and ask where I can find that in writing. I even did this when I was a young second lieutenant copilot in the Air Force where older (higher ranking officers) didn’t appreciate being questioned. “Gee sir, I didn’t know that! It looks like I need to get into the books! Where can I find that published so I can study some more?”

I hope that helps,

Eddie

On Course or Established?

More about this: http://code7700.com/ils.htm#oncourse

Dear Eddie,

When can I consider myself “on course” or “established” for an approach? Everyone says just wait until the CDI is “off the wall” and you will be okay. I want to descend as soon as possible but how can I be sure I have obstacle clearance?

Signed, R. Fader
Fort Lee, New Jersey

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Photo: Proceeding Direct, from AFM 51-37.
Click photo for a larger image

Mister Fader

I flew my first ILS looking at a course indicator and was told the same thing: I could consider myself on course when the CDI came "off the wall."

On a procedure turn, for example, it was okay to descend to the inbound altitude once the CDI was no longer fully deflected.

Years later I adopted a "centered or nothing" attitude, thinking I was better than a nearly fully deflected needle.

But it begs the question, do we have the required obstacle clearance when the needle just comes off the wall. If not, what about one dot?

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Photo: Localizer final trapezoid, from Eddie's notes.
Click photo for a larger image

FAA Handbook 8083-15B, Instrument Flying Handbook, says one-quarter scale deflection means the airplane is aligned with the runway and full-scale deflection shows when the aircraft is 2.5° either side of centerline.

You cannot come up with a one size fits all rule about what full scale CDI deflection means. But doing the math, there are times when the needle comes off the wall a little early. I show that math on this website page: http://code7700.com/ils.htm#oncourse

So full scale is too much, waiting until the needles are centered can leave you too high for the procedure. But the FAA guidance is ambiguous. I think you should look at the ICAO Regs on this, ICAO Doc 8168, Procedures for Air Navigation Services, or PANSOPS, to be specific.

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Photo: ICAO "On Course," from ICAO Doc 8168.
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That regulation says the tracking tolerance of the localizer/azimuth is much more narrow than for non-precision approaches and gives us the worst case scenario. In that scenario, “half scale deflection” keeps you in the protection area.

So in my opinion, that’s a good time to consider yourself on course or established: half scale deflection.

Eddie

Half of What Wind and All of What Gust?

More about this: Landing.

Eddie,

We all know we have to add half the wind and the full gust increment to our approach speeds. But do you add half the wind, or half the headwind?

Signed, R. Fader
Fort Lee, New Jersey

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Photo: Crosswinds, MROC, 21 Feb 2012, Bernal Saborio
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Mister Fader,

This has vexed me for a long time, but there is a more important question. But first, to answer your question. It depends on your manufacturer. Most simply state the wind itself, they don't want you doing the headwind component. Gulfstream, for example:

[G450 Airplane Flight Manual §5.11] If gusty wind conditions are present, add ½ of the steady state wind plus the full gust value to a maximum additive of 20 knots (VREF + 20). VREF will still be the target speed at the threshold.

Bombardier aircraft have a similar statement.

The other method is used by Boeing, in the 737NG, for example:

[Boeing 737 GN FCTM, p. 1.11] If the autothrottle is disconnected, or is planned to be disconnected prior to landing, the recommended method for approach speed correction is to add one half of the reported steady headwind component plus the full gust increment above the steady wind to the reference speed. The minimum command speed setting is VREF + 5 knots.

Dassault has a similar method and they have an even better explanation:

[F900EX CODDE2, ] Approach speed (VAPP) is the result of: VREF + wind correction. For wind correction (maximum 20 kt): apply half headwind + full gust increment. COMMENTS: The gust value should be taken into account whatever the wind direction is. For example for RWY 18, wind 120/20G30 given by the ATC: the steady state headwind component is 10 kt (crosswind component is 17 kt) and the full gust is 10 kt so the wind correction should be 15 kt (which is less than 20 kt).

So the technical answer depends on your aircraft manuals, but I think the right answer, the one that takes physics into consideration, has more to do with my bigger concern: stall speeds and stopping distance.

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Photo: Landing flare energy, from Eddie's notes.
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Most aircraft use a VREF that is 1.3 times the stall speed, though some aircraft get as low as 1.23. You might think that 30 or 23 percent above stall speed is ample, but keep in mind the airplane has a downward vector which is aimed usually 3 degrees along the acceleration of gravity. You will need energy to stop that acceleration and that energy comes from your forward velocity. As you pull back on the yoke or stick, you are trading excess airspeed for a decreased downward vector.

Here's where it gets tricky. Your landing distance is more than likely based on touching down at VREF. Some manufacturers are explicit about this. Even though they want you to make the wind additive, they want you landing at VREF.

So let's say you do that. You are just a few feet off the ground at VREF and your negative gust hits. Now you have less energy to flare. Or lets say the positive gust hits. Now you are too fast for your landing data. What to do?

If I were writing the manual, I would recommend using half the headwind component plus all the gust, and then I would base my landing distance performance number on the highest possible touchdown speed. My AFM only provides for a 10 knot additive when computing landing distances and in a typical scenario that adds between 15 and 25 percent to my landing distance. If I know my required landing distance is more than 3/4 of the available runway, I know I will have to worry about the gust additive and perhaps find someplace else to land.

In the case of the G450, the Operational Information Supplement (G450-OIS-02), Table 45c give us an idea about how much runway is needed for each 10 knots of VREF additive: 11%.

Eddie

Nice C052 LOA, RNP(APCH) to fly into Nice, France

Dear Eddie,

I have a question regarding a new requirement at LFMN requiring RNP APCH specifications starting on March 1st, 2019. My operation has not received the C052 LOA yet and with this new requirement I'm not sure without it that I'm able/legal to do so. I've began the process of applying with the local FSDO but have an upcoming trip. You've touched on this topic to some extent and wondered what your thoughts are on the requirement at Nice and operations with/without C052.

Thanks for any insight you can provide.

Signed, R. Fader
Fort Lee, New Jersey

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Click photo for a larger image

Mister Fader,

If you are Part 91 I’m not sure you need C052 but you definitely need to make sure you have the RNAV A (GNSS) Rwy 04 and RNAV D (GNSS) Rwy 22 approaches available in your database and, to avoid a meeting after you land, be able to fly them if assigned. Ops.Group is reporting that aircraft are being stopped on the ramp and being asked for proof these approaches are loaded, and if not, they are filing violations.

C052 is available for Part 91 operators who need to prove to a foreign operator the authorization, but I haven’t heard France is asking for that. If you are a commercial operator get C052. If not, at least bring proof you’ve been trained. So that is my uneducated opinion. To get more educated, I contacted the good folks at temps-reel-nice-bf@aviation-civile.gouv.fr directly and here is what they said:

To answer your question, if the crew and the aircraft are able to fly the RNP (APCH) approaches specified in the AIC 33/18 [RNAV (GNSS) A, RNAV (GNSS) Y or Z and RNAV (GNSS) D], you don't need to get written authorization prior to fly to Nice."

Also note that the AIC that announced this (AIC 29/18) has been replaced by AIC 33/18. Make sure you are compliant with AIC 33/18 and make sure you have the correct approaches loaded in your FMS. I hope this works for you.

Eddie

Panel Cross Hairs?

Some questions seem silly but end up actually being useful. I wrote originally, "Why do you need to know this? You don't." But then someone pointed out that if you press gently on the crosshair you could reseat a broken connection. You (meaning me) are never to old to learn.

Dear Eddie,

I have been wondering about those little plus signs on my instrument panels, some people call them cross hairs. Why are they there. What are they for? Why do I, as a pilot, need to know about them?

Signed, R. Fader
Fort Lee, New Jersey

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Photo: Example panel, front
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Dear Mister Fader,

I've seen these from various manufacturers, including Gulfstream. If you remove the panel and look on the back side, you will see an electrical connector. The cross hair appears to mark where that connection is, presumably for the lights of the panel. Why do you need to know this? If you lose panel lighting you might try gently pressing on the crosshair. It could reseat that connection.

Eddie

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Photo: Example panel, back
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PANS OPS versus TERPS?

You know that when the approach plate says "PANS OPS" you aren't going to be flying a classic U.S. procedure turn the way you learned in the U.S. during instrument flight training. But sometimes when you are in a foreign country you see "TERPS" on the approach plate. Now what?

More about this: Course Reversals.

Dear Eddie,

My particular question is in regards to ICAO procedures. In general in the US we use FAA procedures and in non US areas use ICAO procedures. So at a field like Bagram in Afghanistan what procedures are actually in place when you fly a full procedure, ICAO or FAA? It seems unclear, most people I ask aren’t entirely sure and have flown in and out of there countless times which means clearly it isn’t that big a deal which isn't the best argument when flying expensive aircraft. So Bagram it would appear was TERPS'd by the US I would think yet it is a foreign country who has their own AIP but on the surface since FAA and ICAO use different TERPS criteria it would make sense to fly it based on who TERPS'd it. Either way it’s extremely confusing because there are good arguments to use FAA procedures and good arguments to use ICAO procedures so what is the correct answer?

Signed, R. Fader
Fort Lee, New Jersey

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Photo: Bagram, Afghanistan (OAIX) ILS or LOC DME Rwy 03R, Jeppesen 11-1, 15 Jun 18
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Mister Fader,

You are quite right, it is confusing. When I was in the Air Force we taught that seeing "TERPS" on the approach plate meant you flew U.S. procedures, period. We believed there were two choices: TERPS and PANS OPS. But it is more complicated than that.

Bagram does indeed say TERPS on the chart and given that most of the traffic in and out of there is the U.S. military, I think flying a TERPS procedure entry would be a safe bet. In countries where the U.S. has a strong presence, the answer can be airport specific. Take a look at two airports in Germany, for example.

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Photo: Ramstein, Germany (ETAR) ILS or LOC Rwy 08, Jeppesen 11-1, 17 Nov 17
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Ramstein Air Base is a U.S. Air Force installation which primarily serves U.S. aircraft. The place on the chart we are used to seeing TERPS says "MIPS" which means "Military Instrument Procedures Standardization." MIPS is taken from a NATO supplement to ICAO Document 8168-OPS/611 Volume II. Confused? Well fly a little further east . . .

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Photo: Munich, Germany (EDDM) ILS or LOC Rwy 08L, Jeppesen 11-1, 26 Oct 18
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So in the same country you have two different approach types. The German AIP is silent on this subject which leads you to believe everything, everywhere is in accordance with PANS OPS and you will be entering the procedures in accordance with ICAO Doc 8168. But there is an agreement in place between Germany and the U.S. military that provides an exception. The only place we civilians can see that in writing is in the Jeppesen ATC pages for Germany, which state:

[Jeppesen Airways Manual, ATC, Europe, Germany] Instrument approach procedures for civil airports are based on the PANS-OPS, Document 8168. Instrument approach procedures for military aerodromes are based on the United States Standards for Terminal Procedures (TERPS) or based on Military Instrument Procedure Standardization (MIPS).

I imagine there is a similar agreement with Afghanistan but I haven't seen it anywhere. Jeppesen has this:

[Jeppesen Airways Manual, ATC, Middle East, Afghanistan] Instrument approach procedures are based on the United States Standards for Terminal Procedures (TERPS) and on the PANS-OPS, Document 8168.

The word "and" is a bit misleading: is it TERPS or PANS-OPS? Your approach says TERPS and I think that is a good assumption. I agree with you that it makes sense to fly U.S. TERPS procedures when flying an approach procedure that says that. But you have a leg up in that you seem to understand both. So if you are about to start a course reversal which is depicted as a procedure turn (or the other way around) and the TERPS answer is different than the PANS OPS answer, I would simply ask. “We are about to turn right to begin the procedure turn, does that check with your expectations?” The worst thing they can do to you is laugh and call you names. That is a small price to pay for clarity.

Plotting the Hawaii "Romeo" Routes?

More about this: Plotting

Dear Eddie,

Please settle a bet for us. We fly from California to Hawaii almost every other week and have all the Romeo Routes memorized. We all agree that we need to plot over the North Atlantic because those tracks change twice a day. But the Hawaii tracks have been set in stone as long as any of us can remember. So we think there is no need to plot when flying the fixed tracks between California and Hawaii. And that also means we don’t have to do the ten-minute post position plot either. That’s right, isn’t it?”

Signed, R. Fader
Fort Lee, New Jersey

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Photo: Plotting Required, from 8900.1, Vol 4, Ch 1, ¶4-80
Click photo for a larger image

Mister Fader

No, that’s not right. Just because the route doesn't change on a daily basis doesn't mean you or your FMS will not make mistakes. The distance between ground-based navigation aids between California and Hawaii far exceeds those required by FAA Order 8900.1, Volume 4, Chapter 1, Paragraph 4-80.A, which says you must plot.

What the regulation says is that, “Plotting procedures are required for all turbojet operations where the route segment between the operational service volume of ICAO standard ground-based navigational aids exceeds 725 NM.” If you are flying a turboprop, the distance decreases to 450 nautical miles.”

So what is the service volume on an ICAO standard ground-based navigational aid? Depending on your altitude, that can be anywhere from only 25 nautical miles for an NDB or up to 130 nautical miles for a VOR.

So, as a rule of thumb, I’ve always plotted if I was further than 800 nautical miles from the nearest usable VOR.

That same regulation, by the way, also specifies the 10-minute post position plot, so the same rule applies. You do need to do a post position plot.

Eddie

How long does it take to reboot a Gulfstream?

Dear Eddie,

I fly a Gulfstream G650 and now and then have to "reboot" when the aircraft doesn't power up correctly. I heard that all you have to do is bring the airplane down to a no powewr state, count to ten, and then bring it back up. I've also heard 5 minutes, 10 minutees, and 12 minutes. What's the real answer?

Signed, R. Fader
Fort Lee, New Jersey

Mister Fader,

I've heard all those numbers too. The "official answer" is 15 minutes. This from a recent Gulfstream Journal which I'll cut and paste.

Eddie

[The Gulfstream Journal, 7/19/2019]

G350™/G450™/G500-5000™/G550™/G650™/G650ER™ (ATA 24): Recommended Minimum Power Down Time

By Jeremy Kelly, Customer Support Avionics/Electrical Group

Certain scenarios arise where aircraft power will need to be cycled. This is mainly done to assist in isolating Crew Alerting System (CAS) messages or other faults and verify if the failures are hard failed (non-resettable) or if they clear. The most accessible information for pilots will be from the Airplane Flight Manual (AFM), which gives a reference of 1 minute for power down. If the message persists, Technical Operations will, most often, be brought into the loop to provide additional support.

Tech Ops’ recommendations go deeper into the technical functionality of the different aircraft systems to better isolate the issue. One of the more common recommendations is to completely power down the aircraft for a MINIMUM of 15 minutes. The reason for the difference in time, lies in the sub-functions of different systems, specifically related to “keep alive” power. Keep alive power, either from batteries or capacitors, allows the system to absorb power interruptions or provide additional power to complete essential tasks after aircraft power has been removed. So, powering the aircraft before the capacitors have fully discharged or the systems have fully shut down means those specific functions will not actually reboot as intended.

The most notable system this applies to is the Central Maintenance Computer (CMC). The CMC specifically has keep alive power applied to it for an additional 12 minutes after all aircraft power has been removed. This is to allow the CMC to finish recording the Fault History Data Base (FHDB), Aircraft Condition Monitoring Function (ACMF), and additional data logs. The CMC is a large part of CAS message generation and display. Knowing this information, Tech Ops will recommend power be removed completely for 15 minutes.

The addition of 3 minutes is to ensure the 12 minutes have completely elapsed and all systems have powered down to eliminate any human errors in time keeping. Powering down the aircraft for a full 15 minutes ensures the CMC will power down completely. This provides a complete reset of the CMC and all software functions.

This data is extremely valuable to Tech Ops, as it will determine if the fault is a hard fault or is resettable. These two options tend to drive troubleshooting techniques in very different ways. Power cycling for 15 minutes ensures the Tech Ops Specialist is optimizing troubleshooting techniques for your specific scenario, based on the data provided.

Note: This answer has been added to: G450 Avionics.

RNP AR vs. Regular Old RNAV and/or RNP Approaches

Dear Eddie,

One more thing about RNP(GNSS), RNAV(RNP), and other such approaches that may or may not require special authorization. How can we tell the difference between one that does and one that does not require special authorization. Remember, back in the day, when they called them SAAAAAAAAR approaches? Life was so simple back then.

Signed, R. Fader
Fort Lee, New Jersey

Mister Fader,

I do remember those Special Aircraft and Aircrew Authorization Required (SAAAR) approaches and it was easier to identify them back then. They should be called RNAV(RNP) approaches these days, but standardization takes years for some of these things. Regardless, if special authorization is required, the approach is supposed to say so:

[ICAO Doc 9613, ¶6.2.5.1] The State AIP should clearly indicate that the navigation application is an RNP AR APCH procedure and that specific authorization is required. If distinct approvals are required for specific RNP AR APCH procedures or aerodromes, this requirement should be clearly identified by the State (see paragraph 6.3.2.2).

[ICAO Doc 9613, ¶6.3.2.2] Any operator with an appropriate operational approval may conduct RNP AR APCH instrument approach procedures, in a similar manner that operators with the proper authorization may conduct CAT II and CAT III ILS operations. This authorization may be in the form of a single approval for all RNP AR APCH procedures within a State, separate approvals for each RNP AR APCH procedure, or a combination of these methods (for example, State-wide approval for all procedures except those in highly challenging operational environments).

So here is how it should be done:

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Photo: Queenstown, New Zealand (NZQN) RNAV(RNP) Z Rwy 05, Jeppesen 12-20
Click photo for a larger image

Notice the first note, "FOR OPERATORS WITH CAANZ RNP-AR APPROVAL ONLY." Here is another approach to the same airport without the note:

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Photo: Queenstown, New Zealand (NZQN) RNAV(GNSS) G Rwy, Jeppesen 12-2
Click photo for a larger image

So that is how it is supposed to be done.

Eddie

Servicing Hydraulics on the Road (G450)

Dear Eddie,

I was on the road with my trusty G450 when the right hydraulic system synoptic showed us at 0.6 gallons, a bit low. Since it was so close to the "low" mark on the synoptic we decided to look at the actual mark on the reservoir piston after we landed. But there was nothing to see. We ended up flying home like that and got a "right hydraulic quantity low" CAS message just before landing. Our mechanics said we should have serviced it. But we were never taught how. Please teach us.

Signed, R. Fader
Fort Lee, New Jersey

Mister Fader,

As luck would have it, I was in the exact same situation a while back and I had never been trained either. We called in a local mechanic with GIV experience but he said the system was fine, since the digital readout in the aft equipment said the system was full. So he was no help. You may have noticed that the reservoir sits on its side and you may have heard that it takes "bootstrap" pressure to keep the reservoir properly pressurized. What that means to us pilots is that the engine has to be running to get a proper quantity indication. (Your mechanic can hook up an external source of pressure from a contraption known as a "mule" for some reason.) I took a few photos to communicate with our mechanic. Here is what we saw before we shut the engines down:

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Photo: G450 Right hydraulic system low synoptic, Eddie's aircraft
Click photo for a larger image

So we shut the engines down and looked at the reservoir indicator:

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Photo: G450 Right hydraulic system reservoir piston, unpressurized, Eddie's aircraft
Click photo for a larger image

I thought I could at least get a sense of the quantity but there is no indicator in sight. Turns out it was full scale to the right, since all that fluid was no longer pressurized. So next step was the digital readout:

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Photo: G450 aft equipment hydraulic reservoir indicator, left, Eddie's aircraft
Click photo for a larger image

It is the same indicator you use when servicing engine oils, except you select "HYD" instead. Unlike the oils, you only see one side at a time and the system defaults to the left. You need to push the "SELECT" switch up once to get the right system:

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Photo: G450 aft equipment hydraulic reservoir indicator, right, Eddie's aircraft
Click photo for a larger image

So, as you can see, it shows the right system at 0.95 gallons and "HI" which I assume means the quantity is registering at higher than that. But we know this is unpressurized. So I started the right engine and the quantity knocked down to 0.7 gallons, low but higher than what we saw in the cockpit. The reservoir piston showed us almost full:

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Photo: G450 Right hydraulic system reservoir piston, pressurized, Eddie's aircraft
Click photo for a larger image

Our mechanic emailed us the applicable sections from the maintenance manual: (I am only showing the applicable portions)

[G450 MM, §12-15, ¶1.B3] Servicing reservoir with onboard replenisher

(3) Apply 3000 psi of hydraulic power to applicable system.

(4) Rotate selector valve (3) to applicable hydraulic system.

(5) On ground service panel (7) select GND SVC BUS SW (6) to ON.

(6) Hold replenisher pump switch (4) to ON until reservoir gage (2) indicates FULL. NOTE: Do not overfill reservoirs (Max capacity is 3.66 gallons, full is 2.75 gallons left system, 0.8 gallon right system).

(7) Rotate selector valve (3) to OFF.

(8) . . . (9)(c)

(9) (d) Repeat Step 1.B3.(3) thru Step 1.B3.(7) and service reservoir until cockpit indicator indicates FULL.

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Photo: G450 aft equipment hydraulic replenishing panel, Eddie's aircraft
Click photo for a larger image

Our mechanic explained that the digital reservoir indicator in the aft equipment bay is not temperature compensated and that is why the manual requires you to judge using the cockpit indicator. So I had the other pilot in the cockpit running the engine and watching the synoptic. I selected "Right" from the reservoir handle, lifted the red guarded switch and added fluid until I saw 0.8 gallons. I ran to the cockpit and found the synoptic had only gone to 0.6 gallons. We agreed that I would go back and add fluid until the other pilot saw 0.8, at which point he would move the elevator back and forth. I would see the cables move (they are on the left side of the airplane) and stop the refill. And that is exactly what happened. The digital readout in aft equipment read 0.95 but the cockpit synoptic read 0.8 gallons. When you are done, make sure all the handles and switches are back to their original "off" and guarded positions.

The next flight, all was better:

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Photo: G450 hydraulics synoptic, the next flight, Eddie's aircraft
Click photo for a larger image

If you want to do this, I recommend you have your mechanic give you some hands on training and then document the fact you had been trained.

Eddie

Note: this item has been added to: G450 Hydraulics System.

Threshold Crossing Height on a Smaller Airplane at a Smaller Airport

Dear Eddie,

I enjoyed your Business & Commercial Aviation magzine article Staying on Glidepath but it brought to light something we in our flight department have been doing. We operate a Pilatus PC-12 out of [airport name redacted] and find it necessary to aim for 300' down the runway to make the 4,000 foot landing distance more comfortable. There are no obstacles on approach and we only do this "short field" technique at this airport. We follow all the rules in our manual and even add the extra 15% the FAA tells us to, just to be safe. Why do we have to use a 1,000 foot TDZ when were are considerably smaller that a Boeing 737?

Signed, R. Fader
Fort Lee, New Jersey

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Photo: Figure: 100 fpm flare technique, from Eddie's notes.
Click photo for a larger image

Mister Fader,

I notice that [airport name redacted] has a 3.00° PAPI based on a 20’ TCH. Doing the math, that intersects the runway at 381’, very close to your 300’ TDZ.

So can you do it? Yes, physically you can. But there are some more considerations.

I believe your aircraft was certified under Part 23, but maybe it is Part 25. Either way that means it was certified using a 50’ TCH. But just because it was certified that way doesn’t mean you have to fly it that way. But if you bend anything, it will be cited against you.

So what does constrain the pilot on a day-to-day basis? I believe it is the operating manual or handbook, depending on what you have. On some aircraft the manufacturer’s landing procedure will specify but on most you need to look at the performance section. So that is the first question you have to ask: does Pilatus mandate a TCH?

And that leads to the second question: just because the manufacturer defines a landing distance based on that TCH, why does the pilot have to do that? If you are operating from an uncontrolled airport without any kind of instrument approach, you might be able to argue dipping below a normal glide path is okay. If there is any kind of published glide path, you might get in trouble for going below it. 14 CFR 91.129(e)(3) says you have to maintain a glide path above a VASI. But you have a PAPI. So you could argue going below the PAPI is okay. But again, if you bend anything it is another thing for the Feds to hang around your neck.

So, bottom line: If your manuals don’t mandate a higher TCH and you stay above the PAPI, I think you are probably okay to cross the fence at 20’ and touchdown around 380 feet. If your manuals do specify something else, you need to think long and hard about deviating. But it sounds like you are putting in a lot of thought now. I recommend you document your decision making process and remember that these rules change at other airports. You shouldn’t, for example, dip below a glide slope aimed at the 1,000’ TDZ.

Eddie

Note: This answer has been added to: Aim Point vs. Touchdown Point.

Visual Descent Points for "Impossible" Approaches

This question has been added to: Visual Descent Points

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Photo: KVNY VOR-B, Jeppesen KVNY 13-2, 4 Nov 16
Click photo for a larger image

Dear Eddie,

The Van Nuys RWY 16R ILS is out of service for a while and we are now being issued the VOR-B when the weather is good, the VOR-A when it isn't. ATC will not approve a Circle Maneuver East of the airport because of KBUR ILS Rwy 8 Arrival flow / KBUR Rwy 15 Departure flow (Aircraft make climbing right turn towards KVNY). The airport is extremely difficult to find and especially so at night as you are not lined up with a runway and you are also not looking directly at the airport. I am flying a Challenger 605, which is Category D for Circling.

So for the VOR-B, the VDP is 3.2 NM and my target VS is 1,226 ft / min or call it 1,300 ft / min. Thus, if I do not see the runway before ZEXUG I am going to have to go missed and ask for the VOR-A or ILS RWY 8 KBUR VOR-B.

I am concerned about pilots wanting to make it work from the VOR-B and being even more encouraged to do so with the circling limitations. This combined with a shortened runway makes me feel like too fast, too steep, diving approach, with long landing on a now shortened runway will result in an over run accident soon.

Thanks.

Signed, R. Fader
Fort Lee, New Jersey

Dear Mister Fader,

You are right to be concerned, this looks like a bad situation at night or when the visibility goes down. First of all, as depicted, the approach cannot be flown on centerline with any hopes of being stable. When faced with such an approach, I like to draw out the "planned" descent rates. The person who drew the approach planned it just to get it done within the letter of any law that can be found in TERPS. Here is an example where "just because it is legal doesn't make it safe."

The only thing on this drawing you cannot get from the approach plate is the distance from the VOR to the touchdown zone (TDZ). I plotted that using GoogleEarth and got 0.6 nm.

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Photo: KVNY VOR-B, An unstable approach from minimums
Click photo for a larger image

As you can see from my drawing, You are much higher than a stable approach. This is what I call a "Flounder Approach." That comes from the movie "Animal House" where Bluto tells a pledge named Flounder, "Face it Flounder, you screwed up. You trusted us!"

To illustrate the math, I'll work out the first part of Option 1 for you right here. The altitude to lose is 3,580 - 2580 = 920 feet. The distance to lose that is 2.5 nm. So the required descent rate is (920 feet) / (2.5 nm) = 368 ft/nm. From your letter I gather you were doing the approach at 130 KTAS, so you will need a vertical velocity of (130 nm/hr) (368 ft/nm) (1 hr / 60 min) = 797 ft/min. Here is how it looks:

  • Option 1 (As published) PURSY to ZEXUG — 368 ft/nm (797 ft/min),
    then ZEXUG to TDZ — 574 ft/nm (1,244 ft/min)
  • That descent rate just 3 miles from touchdown is unsafe!

  • Option 2 Spot runway at PURSY, intercept 3° Glide Path at ZEXUG — 684 ft/nm 1,482 ft/nm)
    then 3° glide path — 318 ft/nm (689 ft/min)
  • Shoving the nose over for nearly 1,500 fpm at 5 nm might not be too bad, but it isn't good.)

  • Option 3 Spot runway at PURSY, fly to TDZ — 482 ft/nm (1,044 ft/nm)

In my opinion, if you haven't spotted the runway by PURSY, you should go around. If you do spot the runway at PURSY or sooner, you should maneuver east to pick up the ground track of the ILS and pick up a 3° glide path as soon as possible. You could even pick up a 3.5° glide path (as published for the ILS), the math is the same except that instead of descending at 318 ft/nm, you will be descending at 371 ft/nm.

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Photo: KVNY VOR-A, Jeppesen KVNY 13-1, 4 Nov 16
Click photo for a larger image

You mentioned the VOR-A as the low ceiling option. It could be that if you cannot spot the runway from that direction it is a nonstarter. But if you can, it may actually offer a better chance at a stable approach. The key point to remember is that you want to roll out on final 1.57 nm from the touchdown point to provide a stable approach at 500 feet AGL. Doing the math, you need to start down about a quarter of the way through the turn. I don't expect anyone to go through all this math, but you just need to envision that your target on rollout is 500' AGL.

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Photo: Circling KVNY from VOR-A to Runway 16R, the math
Click photo for a larger image

So if this was a day approach underneath a distinct ceiling with good visibility, the VOR-A could be a good option. But notice that the approach's viability minimum of 3 statute miles is only 2.6 nautical miles and I compute that you need to begin your turn at 2.75 nautical miles. I would be very tempted to bypass all this and head for Burbank.


14 CFR 97, Title 14: Aeronautics and Space, Standard Instrument Procedures, Federal Aviation Administration, Department of Transportation

14 CFR 97.3 Interpretation, AFS-400, 2013

Aeronautical Information Manual

Air Force Manual (AFM) 51-37, Instrument Flying, 1 December 1976

Air Force Manual (AFM) 51-40, Air Navigation, Flying Training, 1 July 1973

Boeing 737 NG Flight Crew Training Manual, Revision 12, June 30, 2013

Dassault Falcon 900X Crew Operational Documentation for Dassault non EASy (CODDE), Original, March 26, 2010.

FAA-H-8083-15, Instrument Flying Handbook, U.S. Department of Transportation, Flight Standards Service, 2001.

FAA Orders 8400 and 8900

Gulfstream G450 Airplane Flight Manual, Revision 35, April 18, 2013

Gulfstream G450 Maintenance Manual, Revision 18, Dec 12, 2013

ICAO Doc 8168 - Aircraft Operations - Vol I - Flight Procedures, Procedures for Air Navigation Services, International Civil Aviation Organization, 5th edition, 2006

ICAO Doc 9613 - Performance Based Navigation (PBN) Manual, International Civil Aviation Organization, 2008

United States Standard for Terminal Instrument Procedures (TERPS), Federal Aviation Administration 8260.3B CHG 25, 03/09/2012