Line Up and Wait - Impatiently

[flashcrash]

Anyone have access to a recording of the ATC instructions? Perhaps they were specifically told to line up behind the A320?

Malaysia A350 With Impatient Pilots Enters Heathrow Runway - One Mile at a Time

[Gabriel]

Why does the A350 keep crawling forward?

[flashcrash]

Indeed. I know the FAA permits multiple-LUAW subject to a bunch of conditions (daylight operations only, runway must be exclusively for take-offs, both aircraft have to be visible from the tower at all times, local assist must be staffed without overlap with non-local control etc.). But this is the UK. The ICAO does have a multiple line-ups procedure but it's only applicable when the aircraft enter the runway at different points: “Line-ups instructions may be issued to more than one aircraft at different points on the same runway …”.

From ICAO's perspective, two aircraft entering the runway in sequence at the same point of entry would be considered a conditional clearance (e.g. A350 line up and wait behind departing A320. You are number 2 for departure). But wait clearly means wait. It doesn't mean keep crawling forward.

Maybe ATC gave them some kind of conditional take-off clearance as well ("... cleared for takeoff after A320 departs the runway", assuming that phraseology is allowed), which would have left the Malaysian pilots thinking they could keep moving forward while their engines spooled up?

[davepotter]

He was just very keen. The instruction would of been, 'Behind the departing Airbus, line up and wait 27 right behind'. He did as he was told albeit a tad closer than what is common. The PIC is responsible for adhering to the ATC instruction in a safe manner.

[kent olsen]

So some 50 years ago I'm flying for a little commuter in a C-402. We de-iced the plane with a a big broom, quickly loaded the passengers and taxied out. Landing on 34R and departing on 34L. You had to cross the right for the left departure. Great now it really starts to snow. Well I'm behind a DC-10 sitting parallel with the landing runway. We will cross the landing runway and immediately takeoff from 34L. Great , more snow. So I call the captain of the NW DC-10 and ask if I can pull up behind his Starboard (#3) engine and let his exhaust keep me snow free, just don't had power to that engine as he makes the 90 deg right turn to cross over to 34L. He said " no problem, I'll stay at idle for you, boy I wish I could do that". Kept me snow free and I followed him across to 34L and departed shortly after him.

[Gabriel]

So some 50 years ago I'm flying for a little commuter in a C-402. We de-iced the plane with a a big broom, quickly loaded the passengers and taxied out. Landing on 34R and departing on 34L. You had to cross the right for the left departure. Great now it really starts to snow. Well I'm behind a DC-10 sitting parallel with the landing runway. We will cross the landing runway and immediately takeoff from 34L. Great , more snow. So I call the captain of the NW DC-10 and ask if I can pull up behind his Starboard (#3) engine and let his exhaust keep me snow free, just don't had power to that engine as he makes the 90 deg right turn to cross over to 34L. He said " no problem, I'll stay at idle for you, boy I wish I could do that". Kept me snow free and I followed him across to 34L and departed shortly after him.

Air Florida tricks.

[Gabriel]

Indeed. I know the FAA permits multiple-LUAW subject to a bunch of conditions (daylight operations only, runway must be exclusively for take-offs, both aircraft have to be visible from the tower at all times, local assist must be staffed without overlap with non-local control etc.). But this is the UK. The ICAO does have a multiple line-ups procedure but it's only applicable when the aircraft enter the runway at different points: “Line-ups instructions may be issued to more than one aircraft at different points on the same runway …”.

From ICAO's perspective, two aircraft entering the runway in sequence at the same point of entry would be considered a conditional clearance (e.g. A350 line up and wait behind departing A320. You are number 2 for departure). But wait clearly means wait. It doesn't mean keep crawling forward.

Maybe ATC gave them some kind of conditional take-off clearance as well ("... cleared for takeoff after A320 departs the runway", assuming that phraseology is allowed), which would have left the Malaysian pilots thinking they could keep moving forward while their engines spooled up?

Actually, I meant why do they keep crawling forward after lining up and after the A320 already started their take-off roll, thus trading useful runway ahead for useless runway behind. It's not just "while the engines spool up", as they would have to wait several times the spool-up time until they have enough separation to start the take off roll. Just a normal take-off roll to lift-off takes 30 ~45 seconds. Spool up time takes what? 10 seconds top? And then they are going to be waiting 20 ~35 seconds with take-off thrust set and brakes applied?

[Evan]

Your classic runway rage. Loom large in the rear-view mirror and the traffic in front of you will let you pass. Except that the A320 lacks a rear view mirror and there is no passing lane on the runway (yet). Soon airliners will be required to have horns and brake lights...

[BoeingBobby]

Air Florida tricks.

And how did that work out for Air Florida?? This guy is a legend in his own mind!
There is always at least one in every company that I have ever flown for.

[Gabriel]

And how did that work out for Air Florida??

That was precisely my point.

[BoeingBobby]

That was precisely my point.

That was my point exactly!

[3WE]

That was preciselyexactly my point..

Shall we not_forget that someone had the anti ice in the onuff position, that the power lever setting was way short of max, that the high-carbon quadrupleglute TOPMS detected acceleration problems, and that ATC gave a squeeze play departure in ‘wonderful’ weather.

Not sure that DC-10 exhaust adequacy was the primary factor here.

As to Kent’s admission to something Evan might frown upon, I’d ask Kent a very black and white question…Were the wings/tail clear, or weren’t they?

[Gabriel]

Shall we not_forget that someone had the anti ice in the onuff position, that the power lever setting was way short of max, that the high-carbon quadrupleglute TOPMS detected acceleration problems, and that ATC gave a squeeze play departure in ‘wonderful’ weather.

And the stall that was not avoided/recovered, of course.

Not sure that DC-10 exaust adequacy was the primary factor here.

Nobody said it was. But in any event, the Air Florida trick did not work for Air Florida, as it kept neither the wings nor the engines clear of ice.

[flashcrash]

But in any event, the Air Florida trick did not work for Air Florida, as it kept neither the wings nor the engines clear of ice.

In fact, bringing the aircraft close to the engine exhaust from the preceding DC-9 genuinely made matters worse because, to your point, the resulting slush created by the warming quickly refroze on the leading edge of the wings before the takeoff roll started. So, while it wasn't the primary cause of the accident, the crazy attempt at DIY de-icing by the Air Florida pilots was genuinely a contributing factor. From the final report:

"The Safety Board believes that the heat of the exhaust gases may have turned snow, which otherwise might have blown off during takeoff, into a slushy mixture ... the captain's actions to position the aircraft in the area of heated exhaust gases of the preceding aircraft may have contributed to this accident ... the action to taxi close to the aircraft ahead [is] an example of the captain's lack of awareness of, or disregard for, the contents of the flight manual." (page 61).

[Evan]

And the stall that was not avoided/recovered, of course.


Nobody said it was. But in any event, the Air Florida trick did not work for Air Florida, as it kept neither the wings nor the engines clear of ice.

You can’t teach an old dog not to do tricks. The new dogs however…