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If the crew of an aircraft operating under FAR Part 121 and conducting an instrument approach determines, as they begin their descent from the MDA/DA/DH, that they will be unable to touchdown within the touchdown zone of the runway is a missed approach mandatory?

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  • $\begingroup$ @PaulOgilvie - The scenario in the question above allows for only a couple of seconds for the crew to make a decision whether to go missed approach or not. Certainly not enough time or the proper moment to be contacting ATC. Also, this is an issue for which the crew is solely responsible for making a decision. $\endgroup$ – 757toga Mar 21 '18 at 14:03
  • $\begingroup$ The first steps in any missed approach is to follow the runway heading, start climbing and announce a go around/missed aproach. There is enough time to contact ATC and they can tell you what they want. The Missed Approach procedure is one of them and is the default. The "couple of seconds" you talk about is deciding you're not going to land. $\endgroup$ – Paul Ogilvie Mar 21 '18 at 14:34
  • $\begingroup$ @PaulOgilvie - Thanks for you comment. But the question was specifically aimed at whether or not the crew was "mandated" to make a missed approach under the circumstances described. Your comment suggests that they have already made that decision. $\endgroup$ – 757toga Mar 21 '18 at 14:37
  • $\begingroup$ @PaulOgilvie - Again the question is not whether the crew could stop the airplane in the remaining runway if they elected to land. The question is whether or not the crew is "procedurally" or "legally" required to make a missed approach if they cannot touch down within the touchdown zone. $\endgroup$ – 757toga Mar 21 '18 at 14:42
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    $\begingroup$ @PaulOgilvie "You contact ATC and decide with them what to do". No, the pilot is flying the aircraft and decides if a missed necessary. ATC's primary responsibility is separation of aircraft. $\endgroup$ – Steve Kuo Mar 21 '18 at 18:15
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This is spelled out in 91.175(c), in particular

Operation below DA/DH or MDA. Except as provided in paragraph (l) of this section or § 91.176 of this chapter, where a DA/DH or MDA is applicable, no pilot may operate an aircraft, except a military aircraft of the United States, below the authorized MDA or continue an approach below the authorized DA/DH unless

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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

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    $\begingroup$ There is also a 121 specific rule on this, which pretty much says the same thing. $\endgroup$ – Lnafziger Mar 22 '18 at 19:11
  • $\begingroup$ @Lnafziger - can you be more specific about which 121 rule you mean? $\endgroup$ – 757toga Mar 23 '18 at 0:14
  • $\begingroup$ @757toga It's 121.651. $\endgroup$ – Lnafziger Mar 24 '18 at 0:41
  • $\begingroup$ @Lnafziger - that's it, thanks. For those reading this, the distinction between the pure part 121 rule and the general part 91 rule has to do with a greater limitation imposed on the 121 operator regarding what the weather report has to be prior to passing the FAF (or G/S intercept altitude). $\endgroup$ – 757toga Mar 24 '18 at 1:03
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Part 135 pilot: I think there is the practical and legal answer here. The legal answer is yes you must execute a missed approach. That's why the regulation specifically uses the word "continuously." If at any point you realize it's not going to work, you must go missed.

However, if this realization comes late in the flare and you make the determination that landing is the safer choice compared to going missed, then you should obviously land. You have to remember that missed approach procedures are NOT protected for climb gradient once you descend below the MDA/DH and this becomes dramatically more important the lower you are to the surface and the closer to the departure end you are.

A realistic example: Part 135 ops, you're flying a C208 into a shorter runway, lets say 3,000 feet. You realize that you will be unable to land in the touchdown zone due to a sudden wind gust which keeps you airborne during the flare. However, there is a high obstacle (rising terrain, cell phone tower, etc.) near the departure runway end. Depending on visibility and ceilings you may not be able to visually ensure obstacle clearance and can't be assured clearance based on the procedure alone. If you believe that you will make a safe landing due to having high landing distance available vs. landing performance margin, I would continue the landing rather than risk a CFIT. CFITs aren't survivable, but runway overruns usually are.

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  • $\begingroup$ Welcome to Aviation.SE! Nice first answer. In your first paragraph you refer to "the regulation". I guess you mean the quote from the other answer. We generally prefer answers to be standalone here, so could you add a quote from the regulation you refer to? $\endgroup$ – Bianfable Dec 12 '20 at 15:45

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