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I have read about the missed-SFO-accident and watched the 2:22 movie. I want to ask about going-around (or canceling takeoff) when the pilot is fully aware of an emergency that the tower is not (or is late at acting).

According to the reconstruction of the real missed-accident done by the news:

  • Air Canada pilot was on final cleared to land, but instead heading to taxiway for reason that will be explained after FAA & TSB investigations
  • Tower did not notice and did not complain, clearance was still ok
  • Pilot double-checked with tower because he saw lights on the ground
  • Tower double-confirmed clear to land
  • Other pilot on queue said "where is this guy going?"
  • Tower requested go around
  • Air Canada flight crew initiated go around.

The order of the last two events is currently not clear and subject to investigation.

In the movie both ingoing and outgoing pilots are scared by the sight of each other but ATC Dylan doesn't command action until the last moment, while clearance to land and take off is still granted for both.

It is clear that in the movie ATC has failed and pilot(s) are aware of a real danger that affects the safety of flight operation.

Like a driver sighting an animal on the road and braking (or worse moosing) without calling the police first. I am no pilot, I understand that flight is definitely different from driving. And I also enjoyed my time on MSFS virtual flight school. I said the above because I know it could be disappointing for experienced pilots.

I want to ask for my culture/curiosity: when a pilot is cleared to takeoff/land but sees a legitimate reason to cancel the maneuver (e.g. stop/go around), can he simply advise the tower that he is doing that or must continue as earlier instructed? AFAIK when an indicator indicates failiure at < 80kt speed the pilot can immediately cancel takeoff, otherwise is required to continue.

My idea is that the Air Canada pilot could have told the tower something like "we are now fully thrusting and going around because I am not sure about the safety of this landing, please give me further instructions for looping" by his initiative.

This is allowed in the MSFS simulation (you can open virtual ATC radio and announce missed approach even a few feet above ground, they will tell you how to loop over the circuit asap). Is it allowed in reality, or do pilots need a clearance to go around?

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    $\begingroup$ What makes you say ATC failed? The pilot lined up for a taxiway instead of the runway, that's not exactly the towers fault. $\endgroup$ – J. Hougaard Jul 20 '17 at 12:09
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    $\begingroup$ As far as I know, it is not clear weather the pilot initiated a go-around before of after the ATC instruction, this is subject to investigation. Also I don't see from the evidence currently available that ATC has failed as you say. It is the responsibility of the pilot to line up for the correct runway. $\endgroup$ – DeltaLima Jul 20 '17 at 12:28
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    $\begingroup$ @J. Hougaard: By the pilot's last radio call, he clearly thought something was wrong, and asked ATC for clarification. Although the primary responsibility is with the Flight Crew, ATC had a clear opportunity to assist, and failed to do so. I'd say that controller was not operating at 100% on that particular call. $\endgroup$ – abelenky Jul 20 '17 at 13:57
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    $\begingroup$ Please note that questions about accidents (or even near accidents) where an investigation is on-going are not allowed to be asked (directly about the specifics of the accident). In this case, it would seem you have asked a generalized enough question to remain on topic, so well done. $\endgroup$ – CGCampbell Jul 20 '17 at 15:51
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    $\begingroup$ @DeltaLima According to Avherald, they had already overflown the other traffic just before Tower called the go-around. $\endgroup$ – reirab Jul 20 '17 at 20:10
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No, and this applies to any pilot, not just an airliner pilot. After the pilot has been cleared to land (or even if you're landing at your own discretion at an untowered airport), he can decide to go around instead of landing if he's dissatisfied with the approach for any reason.

The pilot might need to abort the landing for reasons the tower can't possibly know about, such as a gear unsafe indication, failing to achieve a stabilised approach, not making visual contact with the runway, or some distraction within the cockpit. And even in the case of a reason the tower should be able to tell - such as another aircraft infringing the runway, lining up on the wrong runway by accident, or birds on short final - the pilot must still go around if he thinks it's not safe to land, without waiting to be told.

The same applies to taking off. Even after being cleared to take off, the pilot must not take off if he thinks it is not safe to do so, even if it's for a reason the tower should know about, such as a runway obstruction or a take-off clearance on a crossing runway.

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    $\begingroup$ I usually think of it like this "Cleared to land" means your allowed to land, not that you must. In fact all airport diagrams that I have seen have a "go around" "path" on them, with instructions on how to wait to be re-inserted in the "landing queue". Same with "Cleared for Takeoff", you don't have to take off, you can just sit there for 45 mins. That's pretty rude, and I'm sure it will cause other issues. But the clearance only means you can, not that you have to. $\endgroup$ – coteyr Jul 20 '17 at 17:50
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    $\begingroup$ @coteyr If you try to sit there for 45 minutes you'll certainly be asked to vacate the runway! And on the "diagrams" you've seen you've noticed the missed approach procedure, which is for instrument traffic only: it's designed to assure terrain clearance even if you can't see anything on the climb-out. $\endgroup$ – Dan Hulme Jul 20 '17 at 18:56
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    $\begingroup$ @DanHulme Of course you will be "asked" to clear the runway, but if you need a tow truck and a fire crew to do that safely, you are quite entitled to ask for them and stay where you are! A request is not a command. ATC isn't in command of the plane - you are. $\endgroup$ – alephzero Jul 20 '17 at 22:23
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    $\begingroup$ @alephzero That is a very different situation. Nothing rude here. $\endgroup$ – Vladimir F Jul 22 '17 at 8:29
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The pilot of an aircraft is responsible for the safety of the flight. If he wants to go around or cancel takeoff, he can and will just do so. The purpose of ATC is to provide a service to help the pilots, not to tell them how to do their job. More technically speaking, when a flight is cleared for an approach, they are also automatically cleared to fly the associated missed approach.

The Air Canada pilot did not notice he was lined up for a taxiway before the pilot on the ground said so. Because the taxiway is parallel to the runway, this would have been very hard to see from the tower. The tower did nothing wrong, since they cleared the flight to land on the empty runway. It's hard to say why the pilot lined up for the taxiway instead.

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    $\begingroup$ Of course. It will be the investigator's duty to clarify $\endgroup$ – usr-local-ΕΨΗΕΛΩΝ Jul 20 '17 at 12:19
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    $\begingroup$ This is a great point - the pilot is the one responsible for all of the things. $\endgroup$ – Wayne Werner Jul 20 '17 at 21:03
  • $\begingroup$ I can buy that the offset might be hard to distinguish visually, but wouldn't it be clearer on a radar screen? $\endgroup$ – E.P. Jul 21 '17 at 0:02
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    $\begingroup$ @E.P. Not when the runway and taxiway are so close and exactly parallel. $\endgroup$ – J. Hougaard Jul 21 '17 at 4:54
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If a pilot decides to go-around for any reason, he can intiate a missed approach without making any radio call.

There is a good reason for this. The decision will usually be made late in the approach, either because the decision height has been reached without visual contact, the approach has become unstable, or some other safety issue has arisen. All these situations require immediate action by the flight crew. However, it may not be possible to contact ATC at this point. The frequency may blocked by other people speaking or the pilot may simply be too busy to make the call until his aircraft is safely established in the climb.

That is why there is a standard missed-approach procedure specific to each individual runway at major airports. This will have been designed to ensure separation from other traffic should a go around be required. In multi-crew operations the pilots will have briefed the missed-approach procedure before arrival, so both will have a clear understanding of what needs to happen without having to scrabble around the approach charts. For example, the standard missed approach might require a straight-ahead climb to 3,000ft and then a right turn to take up the hold over a navigation beacon.

If ATC sees that the aircraft is going around before a radio call is made (as is often the case) they know the crew will carry out the standard missed approach procedure unless advised otherwise. The crew will then call at the first opportunity to confirm the go around and give their intentions.

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  • $\begingroup$ Exactly like when I sim-fly over major airports. Charts report the decision height and the climb required for a missed approach $\endgroup$ – usr-local-ΕΨΗΕΛΩΝ Jul 20 '17 at 14:41
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    $\begingroup$ On the flip side, would towers be expected to withhold landing clearance any time the go-around path was not clear, so that clearance to land would always imply that both paths were clear? $\endgroup$ – supercat Jul 21 '17 at 18:56
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    $\begingroup$ @supercat You should ask that as a new question, so that everyone can see it and answer. (The short answer is yes, but there are special cases.) $\endgroup$ – Dan Hulme Jul 22 '17 at 9:42
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A pilot does not need to get clearance for a go-around. Seconds can make the difference between safety and disaster, once a pilot recognizes a situation where a go-around is required they are expected to initiate the maneuver immediately. Once the pilot has established a positive rate of climb and followed the immediate go-around actions they will then contact ATC and inform them they have gone around.

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A clearance gives the pilot permission to do it, but the pilot is not required to do it. Moreover, a go-around, or missed approach, can be executed at the pilot's discretion whenever he or she is not comfortable about anything.

I have some flying experience myself and I have executed go-arounds for all kinds of reasons, some not serious at all. I have also aborted takeoffs before for several reasons. In neither of these cases did I ever request permission. The general rule is "if in doubt, go around."

A pilot tells ATC that he or she is executing a missed approach (only after you have dealt with more serious matters), they don't ask for permission.

On approach to land, the crew usually also prepares to go around, just in case they need to. Pilots study the missed approach procedures for an airport and are ready to execute them whenever needed.

Furthermore, a pilot can disobey an ATC instruction, if obeying the instruction would jeopardise the safety of the flight.

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