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Missed Approach

Instrument Procedures

In most of my operational squadrons we used to joke, "A pro never takes it around," always preaching just the opposite. But if that is really the case, having flown in some pretty rotten weather over the years, why is it that I've only really had to go missed a handful of times?

We do this routinely in the simulator but in real life it can come as a shock:


 

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Basic Instrument Procedures

[Instrument Flying Handbook pg. 10-22]

  • A missed approach procedure is formulated for each published instrument approach and allows the pilot to return to the airway structure while remaining clear of obstacles. The procedure is shown on the approach chart in text and graphic form. Since the execution of a missed approach occurs when your cockpit workload is at a maximum, the procedure should be studied and mastered before beginning the approach.
  • When a MAP is initiated, a climb pitch attitude should be established while setting climb power. You should configure the aircraft for climb, turn to the appropriate heading, advise ATC that you are executing a missed approach, and request further clearances.
  • If the missed approach is initiated prior to reaching the MAP, unless otherwise cleared by ATC, continue to fly the IAP as specified on the approach plate to the MAP at or above the MDA or DA/DH before beginning a turn.
  • If visual reference is lost while circling-to-land from an instrument approach, execute the appropriate MAP. You should make the initial climbing turn toward the landing runway and then maneuver to intercept and fly the missed approach course.
  • Pilots should immediately execute the missed approach procedure:
    1. Whenever the requirements for operating below DA/DH or MDA are not met when the aircraft is below MDA, or upon arrival at the MAP and at any time after that until touchdown;
    2. Whenever an identifiable part of the airport is not visible to the pilot during a circling maneuver at or above MDA;
    3. When so directed by ATC.
  • The missed approach procedures are related to the location of the FAF. When the FAF is not located on the field, the missed approach procedure will specify the distance from the facility to the MAP. The airport diagram on the IAP shows the time from the facility to the missed approach at various groundspeeds, which you must determine from airspeed, wind, and distance values. This time determines when you report and execute a missed approach if you do not have applicable minimums. Missed approach instructions will be provided prior to starting the final approach of either an ASR or PAR approach.

Things have gotten better with modern day flight management systems, you just need to make sure the FMS is programmed to do what you want and what ATC expects. If you are doing an approach that has a simultaneous approach to a parallel runway, there is an excellent chance the published missed approach procedure is not what is in your box. Realize too that your first turn following a circling approach may not necessarily be toward the approach runway when flying internationally.

See U.S. FAA versus ICAO Differences for more about this.

Reasons for Executing a Missed Approach

[Instrument Procedures Handbook pg. 5-29]

  • Many reasons exist for executing a missed approach. The primary reason, of course, is that the required flight visibility prescribed in the IAP being used does not exist or the required visual references for the runway cannot be seen upon arrival at the DA, DH or MAP. In addition, according to Part 91, the aircraft must continuously be 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 135, unless that descent rate will allow touchdown to occur within the touchdown zone of the runway of intended landing. [Figure 5-20] CAT II and III approaches call for different visibility requirements as prescribed by the Administrator.
  • Once descent below the DA, DH, or MDA is begun, a missed approach must be executed if the required visibility is lost or the runway environment is no longer visible, unless the loss of sight of the runway is a result of normal banking of the aircraft during a circling approach. A missed approach procedure is also required upon the execution of a rejected landing for any reason, such as men and equipment or animals on the runway, or if the approach becomes unstabilized and a normal landing cannot be performed. After the MAP in the visual segment of a non-precision approach there may be hazards when executing a missed approach below the MDA. Any missed approach after a DA, DH, or MAP below the DA, DH, or MDA involves additional risk until established on the published missed approach procedure course and altitude.

Just because you can see the runway doesn't mean you can land on that runway.

See Stabilized Approach for more about this.

Required Obstacle Clearance

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Figure: Climbing or Missed Approach Required Obstacle Clearance, from TERPS Chap. 2, ¶ 202b.

[Aeronautical Information Manual ¶5-4-21.b.] Obstacle protection for missed approach is predicated on the missed approach being initiated at the decision altitude/height (DA/H) or at the missed approach point and not lower than minimum descent altitude (MDA). A climb gradient of at least 200 feet per nautical mile is required, (except for Copter approaches, where a climb of at least 400 feet per nautical mile is required), unless a higher climb gradient is published in the notes section of the approach procedure chart. When higher than standard climb gradients are specified, the end point of the non−standard climb will be specified at either an altitude or a fix. Pilots must preplan to ensure that the aircraft can meet the climb gradient (expressed in feet per nautical mile) required by the procedure in the event of a missed approach, and be aware that flying at a higher than anticipated ground speed increases the climb rate requirement (feet per minute). Tables for the conversion of climb gradients (feet per nautical mile) to climb rate (feet per minute), based on ground speed, are included on page D1 of the U.S. Terminal Procedures booklets. Reasonable buffers are provided for normal maneuvers. However, no consideration is given to an abnormally early turn. Therefore, when an early missed approach is executed, pilots should, unless otherwise cleared by ATC, fly the IAP as specified on the approach plate to the missed approach point at or above the MDA or DH before executing a turning maneuver.

[TERPS Chap. 2, ¶ 202b.] Climbing on departure or missed approach. The concept of providing obstacle clearance in the climb segment, in instrument procedures, is based on the aircraft maintaining a minimum climb gradient. The climb gradient must be sufficient to increase obstacle clearance along the flightpath so that the minimum ROC for the subsequent segment is achieved prior to leaving the climb segment (see figure 1-3). For TERPS purposes, the MINIMUM climb gradient that will provide adequate ROC in the climb segment is 200 ft/NM.

(1) The obstacle evaluation method for a climb segment is the application of a rising OCS below the minimum climbing flightpath. Whether the climb is for departure or missed approach is immaterial. The vertical distance between the climbing flightpath and the OCS is ROC. ROC for a climbing segment is defined as ROC = 0.24 CG. This concept is often called the 24% rule. Altitude gained is dependent on climb gradient (CG) expressed in feet per NM. The minimum ROC supplied by the 200 ft/NM CG is 48 ft/NM (0.24 × 200 = 48). Since 48 of the 200 feet gained in 1 NM is ROC, the OCS height at that point must be 152 feet (200 - 48 = 152), or 76% of the CG (152 ÷ 200 = 0.76). The slope of a surface that rises 152 over 1 NM is 40 (6076.11548 ÷ 152 = 39.97 = 40).

(2) Where an obstruction penetrates the OCS, a nonstandard climb gradient (greater than 200 ft/NM) is required to provide adequate ROC. Since the climb gradient will be greater than 200 ft/NM, ROC will be greater than 48 ft/NM (0.24 X CG > 200 = ROC > 48). The nonstandard ROC expressed in ft/NM can be calculated using the formula: (0.24 h) ÷ (0.76 d) where "h" is the height of the obstacle above the altitude from which the climb is initiated, and "d" is the distance in NM from the initiation of climb to the obstacle. Normally, instead of calculating the nonstandard ROC value, the required climb gradient is calculated directly using the formula: h ÷ (0.76d).

[TERPS Chap. 2, ¶ 202d.] In the case of a missed approach procedure, the climbing flight path starts at the height of MDA or DA minus height loss. The OCS starts approximately at the MAP/DA point at an altitude of MDA/DA minus the final segment ROC and adjustments. Therefore, the final segment ROC is assured at the beginning of the OCS, and increases as the missed approach route progresses. The OCS is applied until at least the minimum initial or en route value of ROC is attained, as appropriate.

No, you don't need math to fly a missed approach. The point here is that there isn't a lot of obstacle clearance and the sooner you climb, the better. While you must follow the ground track of the approach until the missed approach point, nothing precludes you from making an earlier climb.

Course or Heading?

Is the initial direction from the missed approach point a heading or a course? Generally speaking it is a course. Both U.S. and ICAO rules require you follow the final approach course until the missed approach point and then assume you follow the missed approach instructions literally. The word "heading" may be specified, in which case you fly a heading. Otherwise, do as the instruction says. None of the available references spell any of this out, but if you study them you should (I hope) come to the same conclusion. A few examples might help.

The Regulations

[FAAH-8083-16B, p. 4-41] The missed approach course begins at the MAP and continues until the aircraft has reached the designated fix and a holding pattern has been entered. [Figure 4-24] In these circumstances, ATC normally issues further instructions before the aircraft reaches the final fix of the missed approach course. It is also common for the designated fix to be an IAF so that another approach attempt can be made without having to fly from the holding fix to an IAF.

[AIM, ¶5-4-21.c.] If visual reference is lost while circling−to−land from an instrument approach, the missed approach specified for that particular procedure must be followed (unless an alternate missed approach procedure is specified by ATC). To become established on the prescribed missed approach course, the pilot should make an initial climbing turn toward the landing runway and continue the turn until established on the missed approach course. Inasmuch as the circling maneuver may be accomplished in more than one direction, different patterns will be required to become established on the prescribed missed approach course, depending on the aircraft position at the time visual reference is lost. Adherence to the procedure will help assure that an aircraft will remain laterally within the circling and missed approach obstruction clearance areas.

[ICAO Doc 8168, Vol 1, ¶6.2] The initial phase begins at the MAPt and ends at the start of climb (SOC). This phase requires the concentrated attention of the pilot on establishing the climb and the changes in aeroplane configuration. It is assumed that guidance equipment is not extensively utilized during these manoeuvres, and for this reason, no turns are specified in this phase.

[ICAO Doc 8168, Vol 1, ¶6.3] The intermediate phase begins at the SOC. The climb is continued, normally straight ahead. It extends to the first point where 50 m (164 ft) obstacle clearance is obtained and can be maintained. The intermediate missed approach track may be changed by a maximum of 15° from that of the initial missed approach phase. During this phase, it is assumed that the aircraft begins track corrections.

[ICAO Doc 8168, Vol 1, ¶6.4] The final phase begins at the point where 50 m (164 ft) obstacle clearance is first obtained (for Category H procedures, 40 m (131 ft)) and can be maintained. It extends to the point where a new approach, holding or a return to en-route flight is initiated. Turns may be prescribed in this phase.

[TERPS Chap. 2, ¶ 2-8-2.] Wherever practical, the missed approach course should be a continuation of the FAC [Final Approach Course]. Turns are permitted, but should be minimized in the interest of safety and simplicity.

A Few Examples

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Photo: Instrument approach chart legend, FAA 17229, 29 Mar 2018

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The FAA instrument approach chart legend isn't helpful, only indicating that the dashed line is the missed approach.

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Photo: KLAX ILS or LOC RWY 6L, FAA SW-3, 21 Jun 2018

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In this example, any missed approach begun before the missed approach point should be flown using the localizer course guidance, climbing immediately to 600 feet. Once passing the missed approach point, if not yet at 600 feet, I would continue on the outbound track (the course, not the heading) until reaching 600 feet, at which point the left turn can be started. I've heard an argument that the initial missed approach is made with a heading, but don't buy this. The instruction does not say to fly a heading.

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Photo: KLAX ILS or LOC RWY 24R, FAA SW-3, 21 Jun 2018

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In this example, any missed approach begun before the missed approach point should be flown using the localizer course guidance, climbing immediately to 2000 feet. Once passing the missed approach point, I would take up a 251° heading until intercepting the LAX 260° radial, which I would follow to the RAFFS intersection. Why a heading this time? Because the instruction says so.

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Photo: Missed approach course chart legend, Jeppesen Airways Manual, Chart Legend, p. 136.

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It is easy to place too much weight on the Jeppesen Airways Manual chart legend, it might be an over generalization. But it is a data point and it says "course" when addressing the missed approach.

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Photo: EGSS ILS DME or LOC RWY 04, Jeppesen Airways Manual, EGSS 31-1.

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In this example I would fly the course guidance to the missed approach point, then the course using available course guidance to the D2.0 turn point. With a modern avionics suite, this should be automatic. Flying an airplane with raw data only, I would correct the heading after the missed approach point with any known wind drift to attempt to fly the course accurately.

Smoothness

It is a ridiculous question but it comes up now and then, should you fly a missed approach smoothly? In my view it is one of the few times you need to be very abrupt and deliberate. The throttles go forward and the nose comes up as quickly as makes sense for your airplane. If you have to be gentle with the engines to prevent a compressor stall, for example, by all means do that. If your wing is so critical that going from a 3° glide path to a Go Around pitch risks a stall, well don't do that. But in general, a missed approach is a very abrupt maneuver.

In a Gulfstream G450, for example, the engines are controlled electronically and they will accelerate as quickly as they can. Pressing the Takeoff / Go Around (TO/GA) button on either yoke causes the flight director to pitch up and the engines to accelerate. We recently flew down to minimums at Atlanta Peachtree Dekalb (KPDX), saw nothing, and executed the missed approach as quickly as possible. Was it rough on the passengers? Well, EFOQA recorded the entire event:

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Photo: A missed approach executed abruptly, from Eddie's EFOQA report

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As you can see, the resulting aircraft performance wasn't abrupt at all. My advice: go missed approach as if your are in immediate threat of hitting something. (Because you are.) They will be concerned enough in back from the novelty of the situation, your smoothness on the controls and throttles aren't going to change that.

References

Aeronautical Information Manual

FAA-H-8083-16B, Instrument Flying Handbook, U.S. Department of Transportation, Flight Standards Service, 2018.

ICAO Doc 8168 - Aircraft Operations - Vol I - Flight Procedures, Amendment No. 3, Procedures for Air Navigation Services, International Civil Aviation Organization, 5th edition, 2006

United States Standard for Terminal Instrument Procedures (TERPS), Federal Aviation Administration 8260.3B CHG 19, 5/15/02

Revision: 20180624
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