Low Visibility at Night

Photo: Jackson Hole, WY at minimums, from Eddie's cockpit.

Eddie Sez:

You got to know your limitations, to be sure, and minimums are certainly a limitation. You probably have the ones that you see on a daily basis memorized. The rest? Carry a cheat sheet in your wallet, one of these days it will come in handy.

What follows are quotes from the relevant regulatory documents, listed below. The operations specifications come from a former life of mine, you will have to reference your own if you are operating under 14 CFR 135. I've also thrown in a few comments in blue when it comes to 14 CFR 91 takeoff minimums.


14 CFR 1.1, General definitions

Alternate airport means an airport at which an aircraft may land if a landing at the intended airport becomes inadvisable.

Ceiling means the height above the earth's surface of the lowest layer of clouds or obscuring phenomena that is reported as "broken", "overcast", or "obscuration", and not classified as "thin" or "partial".

Flight visibility means the average forward horizontal distance, from the cockpit of an aircraft in flight, at which prominent unlighted objects may be seen and identified by day and prominent lighted objects may be seen and identified by night.

Nonprecision approach procedure means a standard instrument approach procedure in which no electronic glide slope is provided.

Precision approach procedure means a standard instrument approach procedure in which an electronic glide slope is provided, such as ILS and PAR.


14 CFR 91

Fuel Requirements for flight in VFR conditions [§91.151]

(a) No person may begin a flight in an airplane under VFR conditions unless (considering wind and forecast weather conditions) there is enough fuel to fly to the first point of intended landing and, assuming normal cruising speed—

(1) During the day, to fly after that for at least 30 minutes; or

(2) At night, to fly after that for at least 45 minutes.

Fuel requirements for flight in IFR conditions [§91.167]

(a) No person may operate a civil aircraft in IFR conditions unless it carries enough fuel (considering weather reports and forecasts and weather conditions) to—

(1) Complete the flight to the first airport of intended landing;

(2) Except as provided in paragraph (b) of this section, fly from that airport to the alternate airport; and

(3) Fly after that for 45 minutes at normal cruising speed or, for helicopters, fly after that for 30 minutes at normal cruising speed.

(b) Paragraph (a)(2) of this section does not apply if:

(1) Part 97 of this chapter prescribes a standard instrument approach procedure to, or a special instrument approach procedure has been issued by the Administrator to the operator for, the first airport of intended landing; and

(2) Appropriate weather reports or weather forecasts, or a combination of them, indicate the following:

(i) For aircraft other than helicopters. For at least 1 hour before and for 1 hour after the estimated time of arrival, the ceiling will be at least 2,000 feet above the airport elevation and the visibility will be at least 3 statute miles.

Destination Alternate Not Required [§91.167]

If there is an IAP and weather for ETA +/- 1 hour is at least 2,000 and 3

Takeoff Minimums

It may come as a surprise to some that there are no takeoff weather minimums for 14 CFR 91 operations, most of the time. It may come as a surprise to others that there are takeoff weather minimums for 14 CFR 91 operations, some of the time. This topic can set some pilots on edge. I get hundreds of emails and letters to the editors of various magazines that I've written for and 99 percent of them are very nice, constructive, and complimentary. There are a few, however, that start with the name calling and go downhill from there. This is a topic that brings out that kind of ugliness. (Feel free to add to it by clicking "Contact Eddie" below. Go ahead, I've got pretty thick skin.

[FAA-H-8083-16, p. 1-8.] Aircraft operating under 14 CFR Part 91 are not required to comply with established takeoff minimums. Legally, a zero/zero departure may be made, but it is never advisable. If commercial pilots who fly passengers on a daily basis must comply with takeoff minimums, then good judgment and common sense would tell all instrument pilots to follow the established minimums as well.

This makes a certain segment of the professional pilot class very happy and it enrages others. What about 14 CFR 91, §91.175?

[14 CFR 91, §91.175(f)]

(f) Civil airport takeoff minimums. This paragraph applies to persons operating an aircraft under part 121, 125, 129, or 135 of this chapter.

(1) Unless otherwise authorized by the FAA, no pilot may takeoff from a civil airport under IFR unless the weather conditions at time of takeoff are at or above the weather minimums for IFR takeoff prescribed for that airport under part 97 of this chapter.

(2) If takeoff weather minimums are not prescribed under part 97 of this chapter for a particular airport, the following weather minimums apply to takeoffs under IFR:

(i) For aircraft, other than helicopters, having two engines or less—1 statute mile visibility.

(ii) For aircraft having more than two engines—1/2 statute mile visibility.

(iii) For helicopters—1/2 statute mile visibility.

(3) Except as provided in paragraph (f)(4) of this section, no pilot may takeoff under IFR from a civil airport having published obstacle departure procedures (ODPs) under part 97 of this chapter for the takeoff runway to be used, unless the pilot uses such ODPs.

(4) Notwithstanding the requirements of paragraph (f)(3) of this section, no pilot may takeoff from an airport under IFR unless:

(i) For part 121 and part 135 operators, the pilot uses a takeoff obstacle clearance or avoidance procedure that ensures compliance with the applicable airplane performance operating limitations requirements under part 121, subpart I or part 135, subpart I for takeoff at that airport; or

(ii) For part 129 operators, the pilot uses a takeoff obstacle clearance or avoidance procedure that ensures compliance with the airplane performance operating limitations prescribed by the State of the operator for takeoff at that airport.

Yes this appears in Part 91, but no, it does not apply to Part 91 operations. But it is more complicated than that.

[14 CFR 97, §97.1 Applicability]

(a) This part prescribes standard instrument approach procedures to civil airports in the United States and the weather minimums that apply to landings under IFR at those airports.

(b) This part also prescribes obstacle departure procedures (ODPs) for certain civil airports in the United States and the weather minimums that apply to takeoffs under IFR at civil airports in the United States.

If you fly IFR you are operating under Part 97 and the "weather minimums that apply to takeoffs under IFR at civil airports in the United States" apply to you.

[14 CFR 97, §97.20(a)] This subpart prescribes standard instrument approach procedures and takeoff minimums and obstacle departure procedures (ODPs) based on the criteria contained in FAA Order 8260.3, U.S. Standard for Terminal Instrument Procedures (TERPs), and other related Orders in the 8260 series that also address instrument procedure design criteria.

The Standard Instrument Departure (SID) or Obstacle Departure Procedure (ODP) is prescribed by 14 CFR 97, which applies to all U.S. pilots flying under Instrument Flight Rules. Like it or not, if an airport lists takeoff minimums, they apply to you. If a U.S. airport does not list any takeoff minimums and your operation doesn't have takeoff minimums, you are good to go. (Foolish, but legal.) No what about internationally?

[ICAO Annex 6, Part II, ¶2.2.2.2.] The pilot-in-command shall not operate to or from an aerodrome using operating minima lower than those which may be established for that aerodrome by the State in which it is located, except with the specific approval of that State.

Part II of ICAO Annex 6 applies to general aviation aircraft. Part I applies to commercial operators and has a similar statement in ¶4.2.8. So when flying internationally, your takeoff minimums are as set by the host nation.

Approach Minimums [§91.175]

(a) Unless otherwise authorized by the FAA, when it is necessary to use an instrument approach to a civil airport, each person operating an aircraft must use a standard instrument approach procedure prescribed in part 97 of this chapter for that airport.

(b) For the purpose of this section, when the approach procedure being used provides for and requires the use of a DA/DH or MDA, the authorized DA/DH or MDA is the highest of the following:

(1) The DA/DH or MDA prescribed by the approach procedure.

(2) The DA/DH or MDA prescribed for the pilot in command.

(3) The DA/DH or MDA appropriate for the aircraft equipment available and used during the approach.

(c) Operation below DA/ DH or MDA. Except as provided in paragraph (l) of this section, where a DA/DH or MDA is applicable, no pilot may operate an aircraft below the authorized MDA or continue an approach below the authorized DA/DH unless —

(1) The aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers, and for operations conducted under part 121 or part 135 unless that descent rate will allow touchdown to occur within the touchdown zone of the runway of intended landing;

(2) The flight visibility is not less than the visibility prescribed in the standard instrument approach being used; and

(3) Except for a Category II or Category III approach where any necessary visual reference requirements are specified by the Administrator, at least one of the following visual references for the intended runway is distinctly visible and identifiable to the pilot:

(i) The approach light system, except that the pilot may not descend below 100 feet above the touchdown zone elevation using the approach lights as a reference unless the red terminating bars or the red side row bars are also distinctly visible and identifiable.

(ii) The threshold.

(iii) The threshold markings.

(iv) The threshold lights.

(v) The runway end identifier lights.

(vi) The visual approach slope indicator.

(vii) The touchdown zone or touchdown zone markings.

(viii) The touchdown zone lights.

(ix) The runway or runway markings.

(x) The runway lights.

(d) Landing. No pilot operating an aircraft may land that aircraft when —

(1) For operations conducted under paragraph (l) of this section, the requirements of (l)(4) of this section are not met; or

(2) For all other part 91 operations and parts 121, 125, 129, and 135 operations, the flight visibility is less than the visibility prescribed in the standard instrument approach procedure being used.

(l) Approach to straight-in landing operations below DH, or MDA using an enhanced flight vision system EFVS). For straight-in instrument approach procedures other than Category II or Category III, no pilot operating under this section or §121.651, 125.381, and 135.225 of this chapter may operate an aircraft at any airport below the authorized MDA or continue an approach below the authorized DH and land unless —

(1) The aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers, and, for operations conducted under part 121 or part 135 of this chapter, the descent rate will allow touchdown to occur within the touchdown zone of the runway of intended landing;

(2) The pilot determines that the enhanced flight visibility observed by use of a certified enhanced flight vision system is not less than the visibility prescribed in the standard instrument approach procedure being used;

(3) The following visual references for the intended runway are distinctly visible and identifiable to the pilot using the enhanced flight vision system:

(i) The approach light system (if installed); or

(ii) The following visual references in both paragraphs (l)(3)(ii)(A) and (B) of this section:

(A) The runway threshold, identified by at least one of the following:

( 1 ) The beginning of the runway landing surface;

( 2 ) The threshold lights; or

( 3 ) The runway end identifier lights.

(B) The touchdown zone, identified by at least one of the following:

( 1 ) The runway touchdown zone landing surface;

( 2 ) The touchdown zone lights;

( 3 ) The touchdown zone markings; or

( 4 ) The runway lights.

(4) At 100 feet above the touchdown zone elevation of the runway of intended landing and below that altitude, the flight visibility must be sufficient for the following to be distinctly visible and identifiable to the pilot without reliance on the enhanced flight vision system to continue to a landing:

(i) The lights or markings of the threshold; or

(ii) The lights or markings of the touchdown zone;

(5) The pilot(s) is qualified to use an EFVS as follows —

(i) For parts 119 and 125 certificate holders, the applicable training, testing and qualification provisions of parts 121, 125, and 135 of this chapter;

(ii) For foreign persons, in accordance with the requirements of the civil aviation authority of the State of the operator; or

(iii) For persons conducting any other operation, in accordance with the applicable currency and proficiency requirements of part 61 of this chapter;

Alternate Airport Weather Requirements [§91.169]

With IAP: 600'/2 precision, 800'/2 non precision at ETA Without IAP: ceiling and vis to allow descent from MEA, approach and landing under basic VFR.

These provisions can be confusing. At minimums you could call "landing," "continue," or "go around." Why? See Eddie's answer to a reader, below.


14 CFR 135

Takeoff Alternate Required [§135.217]

If weather above takeoff minimums but below authorized IFR landing minimums must have an alternate airport within 1 hour's flying time (at normal cruise speed in still air) of the departure airport.

Destination Alternate Not Required [§135.223]

If there is an IAP AND Weather for ETA +/- 1 hour at least 1,500' ceiling above lowest circling MDA or if no circling at least 1,500' above lowest minimum or 2,000' above airport elevation whichever higher AND Visibility at least 3 miles or 2 miles more than lowest applicable mins, whichever greater.

Destination Requirements Prior to Takeoff [§135.219]

Cannot takeoff IFR unless latest weather reports or forecasts indicate weather at destination for ETA will be at or above authorized landing minimums.

Takeoff Minimums [§135.225]

As provided in Part 97 or Ops Specs, if none then 1 sm visibility for 2 engine aircraft, if straight-in approach available then at mins for that approach.

Takeoff Minimums (C057)

1 sm or RVR 5000 (standard). If no published takeoff mins then may use standard or ops specs. If published min is greater than standard and no alternate procedure is not prescribed cannot use lower than standard.

Takeoff Minimums (C079)

When takeoff minimums are less than standard can use:

Approach Minimums [§135.225]

May not begin an IAP unless the airport has an approved weather facility and the latest weather is above minimums. Eligible on-demand may begin the IAP without an approved weather facility provided the alternate has one and have an approved altimeter setting. If weather goes below after beyond the FAF, may continue.

Approach Minimums (C053 and C074)

Touchdown zone (TDZ) RVR reports, when available for a particular runway, are controlling for all approaches and landings on that runway. The mid RVR and rollout RVR reports (if available) provide advisory information to pilots. The mid RVR report may be substituted for the TDZ RVR report if the TDZ RVR report is not available.

Approach Minimums (C054)

If weather less than 3/4 sm or RVR 4000, must have precision runway instrument marking or centerline lights and must have 15% additional runway over landing field length.

Alternate Airport Weather Requirements [§135.221]

Weather reports/forecasts above authorized mins at ETA.

Alternate Airport Weather Requirements (C055)

With at least one operational nav facility providing a straight-in nonprecision or circling: add 400' HAT/HAA and 1 sm vis. With at least two operational nav facilities providing straight-in approaches to a different runway: add 200' to higher HAT and 1/2 sm to higher vis minimum.


Cheat Sheet

These minimums will be modified by individual company rules and operations specifications.

Prior to Flight

Prior to Takeoff

Prior to Approach

General definitions

Ceiling means the height above the earth's surface of the lowest layer of clouds or obscuring phenomena that is reported as "broken", "overcast", or "obscuration", and not classified as "thin" or "partial".

Flight visibility means the average forward horizontal distance, from the cockpit of an aircraft in flight, at which prominent unlighted objects may be seen and identified by day and prominent lighted objects may be seen and identified by night.

Downloadable Cheat Sheet

For a downloadable cheat sheet: Click Here.


Eddie's Mailbox

Hello Eddie,
I was asked by a friend and ex-colleague the other day what our company procedure was for the “minimums” call on an approach to which I responded either, “landing” or “go-around” which is pretty much how I have been indoctrinated during my career. But I have heard on the odd occasion (when we’ve used contractors or when I’ve contracted for different outfits) of procedures that call for a “Continue” call instead and I was wondering what your thoughts are on this subject? My friend is an advocate of the latter procedure.

Best regards,
Avid Reader

Dear Avid,
The “continue” call comes from the provisions of 14 CFR 91.175 which says you can go below DA but no lower than 100 feet above touchdown zone elevation if you see the approach light system, and then may continue to land if you see the red terminating bars or the red size row bars or other parts of the runway that are listed in that paragraph.
So, for example, if you are flying an ILS with a 200’ DA and spot the approach lights (but not the red terminating or side row bars) and do not see the anything else, you can continue to 100’. The pilot should say “continue” to let the other pilot know what is going on. Then if the pilot spots the threshold or anything else listed in that paragraph, the pilot says “landing.” If no other required items are seen by 100', then even though you had seen a portion of the approach lights, the call is “go around.”
Eddie


References

14 CFR 1, Title 14: Aeronautics and Space, Definitions and Abbreviations, Federal Aviation Administration, Department of Transportation

14 CFR 91, Title 14: Aeronautics and Space, General Operating and Flight Rules, Federal Aviation Administration, Department of Transportation

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

14 CFR 135, Title 14: Aeronautics and Space, Operating Requirements: Commuter and On Demand Operations and Rules Governing Persons on Board Such Aircraft, Federal Aviation Administration, Department of Transportation

FAA-H-8083-16A, Instrument Procedures Handbook, U.S. Department of Transportation, Federal Aviation Administration, 2015

ICAO Annex 6 - Operation of Aircraft - Part 2 General Aviation, International Standards and Recommended Practices, Annex 6 to the Convention on International Civil Aviation, Part II, July 2008