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Scenario A: I started the takeoff roll and then noticed another aircraft is crossing the runway in front of me, how could I determine what is the best avoidance maneuver, like full braking to abort the takeoff? Or proceed take off and leave the ground before the collision? Or change the aircraft heading just like a car driver to avoid the traffic, in which my aircraft could probably rushed out of the runway?

Scenario B: I am holding on the runway and ready for takeoff and another aircraft is on the final to land, should I initiated takeoff ASAP or exited the runway? If I initiated the takeoff and the landing aircraft also take avoidance action and do a go around, will things getting worse since we may collide in air?

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  • $\begingroup$ Which type of aircraft (general aviation single engine or big heavy jet) do you have in mind when asking your question? Also - controlled or uncontrolled field? $\endgroup$
    – Chris
    Sep 10 '19 at 8:36
  • $\begingroup$ I am in a controlled field, will there be difference for a GA aircraft and a commercial aircraft? $\endgroup$
    – VvV
    Sep 10 '19 at 8:40
  • $\begingroup$ In both of those cases, the last thing I would try to do is takeoff. $\endgroup$
    – acpilot
    Sep 11 '19 at 20:39
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Scenario A: It all boils down to remaining distance available until impact and aircraft performance.

  • If you are in a commercial airliner you normally only have the option to abort. Your take-off performance calculation is normally optimized for the minimum power to get off the ground while staying safely within all applicable limits. Saves fuel and engine maintenance in the longterm. So you'll need most of the runway to get off the ground safely. Therefore no way to get airborne early (mass takes time to accelerate) and fly over the intruder.
  • If you are in an GA aircraft, things look a bit different at first glance but your chances of stopping before hitting the intruder are way better than gambling that your performance is good enough to fly over the intruder. Why? Lower mass and lower speeds. Normally you don't need the whole runway to get airborne which might lead to your thinking "I can get airborne and fly over him". There is just no reasonable way to make this judgement. So just try to stop, your stopping distance will be way shorter than what you are used to when you land as you are way slower.

In any case: your safest decision is to abort the take-off, slam on the brakes and, if your relative bearing to the intruder aircraft remains steady, it's time to head for the grass. Better a damaged gear than a collision.

Rule of thumb: If the aircraft owner can yell at you why you have damaged his aircraft it has been a good day. It means you are still alive.

Scenario B: Don't move. If the controller and the pilot of the approaching aircraft didn't notice and/or verbalize it on the radio make a radio transmission to give them a heads up. Something like "Bonanza 5545Y is holding position on runway 09." This might alert the approaching traffic as well as the controller.

To bring your example to the extreme and the approaching traffic doesn't go-around and gets uncomfortably close to you and you are under the impression you are in imminent danger get off the runway and, time permitting, make a radio transmission along the lines "Traffic approaching runway 09, runway is blocked, go-around, I say again, runway 09 is blocked, go-around." You can't out-accelerate him so vacate the runway. If you try to get airborne ahead of him there will be two aircraft with inadequate separation in a very dynamic environment. Try to keep it simple for everybody.

While I might get flamed here for non-standard phraseology even the FAA/your-governing-body-of-choice mandates that you should do everything that you deem helpful in this moment to avoid an accident.

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    $\begingroup$ There is also the possibility that the approaching aircraft will decide to land anyway but touch down further down (being highly irresponsible when doing so). So it is still much safer to stay stationary at the start of the runway. $\endgroup$
    – ratchet freak
    Sep 10 '19 at 13:12
  • $\begingroup$ If the aircraft takes no avoidance maneuver and proceed with the landing, what is the better avoidance maneuver for me, holding position on the runway or starting takeoff roll ASAP or try to exit the runway? $\endgroup$
    – VvV
    Sep 10 '19 at 14:10
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    $\begingroup$ @VvV Aircraft should be crossing the threshold at 50 ft, so unless you're in an airliner, they should clear you easily. $\endgroup$
    – StephenS
    Sep 10 '19 at 16:31
  • $\begingroup$ @StephenS Then what if I already started the takeoff roll, execute a takeoff abortion or speed up to leave the runway? $\endgroup$
    – VvV
    Sep 12 '19 at 23:43
  • $\begingroup$ @VvV There are so many variables, it's hard to say. $\endgroup$
    – StephenS
    Sep 13 '19 at 5:26
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In Scenario A there is no obvious answer. You take whatever action is necessary to avoid a collision. If this were a controlled airfield there would be questions raised to the ground controller. If not, similar questions would be directed at the pilot entering a runway without notifying anyone. Even at a completely deserted airfield without any form of station any pilot entering a runway would announce it on a radio beforehand just in case!

Scenario B can be a little more specific, and is a situation that occurs reasonably often at small airfields - less so at large controlled airports. Assuming you've not just busted onto the runway, ignoring traffic on final approach you probably have priority over the approaching aircraft. But if you're a large airliner and/or at a controlled airfield its hugely unlikely you've been cleared to enter the runway to line up if something is on final approach.

If this does happen:

  • an airliner would follow a missed approach procedure, which would take them well out of the way of the departing aircraft
  • a light aircraft would perform a similar manoeuvre but commonly known as a "go around". This involves positioning so that the pilot can keep eyes on the departing aircraft, for example flying just to the right of the runway at circuit height.
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    $\begingroup$ Scenario B happened in real life with an airliner taking off while another was on final approach (the second half): ATC gave a go around with an immediate turn to de-conflict the two aircraft. $\endgroup$
    – TemporalWolf
    Sep 10 '19 at 19:07
  • $\begingroup$ Happened to me personally. Was short final at Buttonville, one of Canada's busiest airports in the 90's, and I'm listening to the controller talk to the guy lining up for takeoff. Imagine my surprise when he gives him clearance when I'm about 1000 yd back. Took me about 5 seconds to realize there was no way he was getting out in time. "FFH in the go around". I was equally disappointed about the post-GA instructions - I knew there was a guy climbing into me but couldn't see him and the tower didn't say a thing. So I had to take it on my own to do a short circuit. $\endgroup$
    – Maury Markowitz
    Sep 15 '19 at 14:18
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A) I would reject the takeoff as (I assume this is a light GA aircraft) the stopping distance is likely to be short, more specifically shorter than the distance required to continue takeoff. If you are at or very close to rotation speed it might be better to continue.

B) You should stay put. The runway is occupied and the other aircraft should go around. If he chooses to land, it is easier to avoid stationary plane. Worst case scenario is that you commence takeoff at the same time he goes around.

In both cases you and/or the other aircraft have already messed up so be vigilant out there.

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  • $\begingroup$ What if I already started the takeoff roll and the other aircrafts proceed with the landing? Should proceed my taking off maneuver is better than holding position? $\endgroup$
    – VvV
    Sep 13 '19 at 0:00

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