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Final Report: April 2018 737 high speed aborted TO

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Final Report: April 2018 737 high speed aborted TO

Old 27th Jan 2021, 17:18
  #41 (permalink)  
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I didn't mix AIRBUS but somebody wrongly quoted Airbus FCTM I just posted the correct version. Airbus also doesn't recommend reject after V1.
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Old 27th Jan 2021, 17:27
  #42 (permalink)  
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In the present case reject wasn't necessary but having decided to do it it should have been executed properly without wasting precious moments on any trouble shooting. In general if you cannot rotate even with proper procedure then reject is the only answer whatever the result.
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Old 27th Jan 2021, 18:30
  #43 (permalink)  
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I was going to shut up, but I just can't. This is addressed to no one in particular, but to some of the arguments which have been presented here.

Every procedure, whether designed by the manufacturer or your company, is based on the assumption that a conscious mind operates your brain, and that said mind is capable of understanding and reacting to situations correctly, and making optimal if not the best decisions to give everyone on board the best chances of making it in one piece. If that weren't the case, there would be no pilots.

This whole "go-minded" stuff was not caused by horrible takeoff overrun accidents that killed everyone on board. Yes, people have tragically died in overruns (mostly on landing) and it is not something to take lightly. However, you have 1000 times more chances of dying in a LOC accident while in the air. The actual origins of these procedures are the following: X, Y, Z aviation safety people examined a series of aborted takeoff above V1 incidents (many not resulting in overruns mind you!) and figured out that most of these were perfectly flyable aircraft, and that the takeoff was aborted for some insufficient reason that in the heat of the moment seemed critical to the crew. Conclusion: there is statistically very rarely a valid reason to reject the takeoff after V1, so it makes sense numbers-wise to "force" pilots to press ahead, because much more people risk to lose their lives if we continue to allow these frivolous rejected takeoffs than the 200 lives we're going to save when once in a blue moon there is actually a valid reason to attempt to stop. Or, more cynically, it could be about tyre costs. Realistically, it's probably a bit of both.

Let's take an example where the runway is too short to stop once you've passed V1 and the overrun is guaranteed - which again is not always the case. Now think about it. What offers your passengers the best chance of survival? Driving into the forest at the end of the runway while slowing down? Or nosebombing the same forest from the air because you took off with your wing on fire like a dumbass? And it doesn't even have to be something as dramatic as a fire chewing off bits of airfoil. Anything that would cause an aircraft to refuse to fly is a great reason to stop, no matter the speed. Same if you suspect possible imminent structural failure (wing on fire example). For the life of me, I can't figure out why you would try to power your way through that.

Obstacles at the end of the runway and to the sides are a concern, of course, but you should already be aware of these things before you even report for duty. It is your job to know the aerodrome and have plans in case something goes wrong. Where are the obstacles in case of an overrun? Where can I go? If I have a dual engine failure, where can I go? If I'm already in the air, where can I put her down to give us the best chances? If you're thinking about these things during a takeoff run, you are late. This is no time to discover the layout of the airport. The homework should have been ready from before.

Making the correct decision within seconds is what saves lives or elevates them from this earthly plane in a violent manner. And despite what you might think, there is no procedures and no checklist for decision-making. That burden lies squarely on your shoulders. Try to get used to it.
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Old 27th Jan 2021, 19:18
  #44 (permalink)  
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Originally Posted by Stuka Child View Post
And despite what you might think, there is no procedures and no checklist for decision-making.
Excellent post, Stuka Child. This is the very reason why my alarm clock is set at 5:00 tomorrow morning because no one invented a device yet that could do that for me.
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Old 28th Jan 2021, 05:36
  #45 (permalink)  
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We are but mere mortals some just more then others.

Captain Sullenberger and Captain Haynes come to mind.

We will all be judged by our decisions.
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Old 28th Jan 2021, 05:58
  #46 (permalink)  
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The number of people who think it’s ok to reject take off above v1... What am I reading here?! Unless you lost a wing or something after V1 you go. Period.
Some guys survived miraculously car accidents without wearing a seat belt. Does that mean it’s the right thing to do? Certainly not cause it’s undeniable that wearing the seat belt is safer overall.
Originally Posted by ManaAdaSystem View Post
You pass V1, start to rotate and nothing happens. What do you then?.
We did that in the sim. Toga and rotate using the trim wheel

Edit: Nice Post Stuka Child!

Last edited by pineteam; 28th Jan 2021 at 06:14.
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Old 28th Jan 2021, 06:42
  #47 (permalink)  
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Some posters need to have a bit of a chat with their Check Captain about this issue at their next License Renewal sim. session.
Of course if ,in fact , they ever do one............
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Old 28th Jan 2021, 10:05
  #48 (permalink)  
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We are discussing a takeoff that was rejected for a wrong reason and not even correctly executed. There are hardly any accidents that required split second decision. In takeoff incidents wrong decision is the major cause. So let's not go overboard. Most accidents are caused by incorrect handling of straightforward procedures without any time constraint. After V1 only at Vr one will know whether aircraft will get off with only option of trying other side or stabilizer. If it doesn't then you reject and accept the result. But for this one in million hours possibility you cannot throw the standard procedure of being go minded out of the window.
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Old 28th Jan 2021, 10:25
  #49 (permalink)  
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Pinetree & George, thank heavens. Thought I was on my own there ! Trust some of these posters are not pilots. I doubt that any professional, trained and practiced pilot would even contemplate stopping after V1.As I said before, keep the discussion in the classroom please. Out in the tough world, it is a no brainer. Boeing seem to agree. Airbus seem to agree. I got through 40 years of sim tests where if I continued after V1 but pleaded that I was "thinking outside of the box" I would have been granted a bit of re-education. Persisting in the dangerous delusion would have resulted in job termination. Quite rightfully so.
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Old 28th Jan 2021, 11:46
  #50 (permalink)  
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I would agree with all of that, except for the first part of the first sentence. Boeing are quite clear in the QRH, that:

Above 80 knots and before V1, reject the takeoff for any of the following:
  • any fire or fire warning
  • engine failure - confirmed by two parameters
  • blocked runway
  • take-off configuration warning
  • control malfunction
  • predictive windshear warning
  • if the airplane is unsafe or unable to fly.
That’s a cut and paste from the 737-800 QRH at the airline I currently fly from. The decision to stop was for a correct reason, if it was taken before V1, but the problem was in the execution, and that shouldn’t have been an issue because there are four simple steps in the initial RTO which any B737 captain should have engraved in their muscle memory, should review in the before take-off emergency brief, and be mentally rehearsing throughout the take-off role.

However, looking at the report, it would seem that despite what was written in the tech log the decision to reject was almost certainly taken above V1, and the process was slowed down further by attempting to fault find. Those were both errors which shouldn’t have happened, but in defence of the crew involved I wonder how much is due to the way simulator training is conducted. I’ve been flying the 737 for fifteen years, so nowhere near as long as some of the posters here. I’ve flown it for five airlines, so I’ve done about 26 recurrent checks and five OCC’s, three of which were excellent and covered virtually the whole type rating course, one of which included the type rating so was even better (that was the first one, obviously), and one of which was two sim sessions then a proficiency check, so wasn’t quite as good. But in every OCC except the initial type rating, and in every training or checking event, at five different airlines, every RTO has been for a fire or engine failure, and every RTO has been conducted with either 125 or 75 metres visibility, and every RTO has been initiated by a failure or fire two or three knots below V1 and every EFATO has been initiated 2 or 3 knots above V1 because the instructor or examiner has set that on the touch screen on their IOS because they either want you to stop or they want you to go, and don’t want some grey area right in the middle, exactly at V1 where in a non EFIS aircraft the width of the ASI needle can lead to discussion.

Not once, in any of those events, has the RTO been performed when taking off from a wet runway, in the dark, knowing that if we get airborne then at four hundred feet the LNAV is going to command an immediate right turn and we are then going to climb on a 4 DME arc around the Kathmandu VOR with the flaps out until we get to about three thousand feet above the airfield, which is going to take forever if we lose an engine, and we are going to climb to about twelve thousand feet to get across the foothills of the Himalayas to our take off alternate which is a dreadful sh*thole in India, and knowing that if we had a major control malfunction or a fire that wouldn’t go out then if we can’t get to that sh*thole our only option is, if we’re lucky and have the approval is to fly fourteen miles from Kathmandu and then return flying a curving RNP/AR approach through a narrow valley, or even worse, without the approval, fly a steep VOR approach where once you get to 4 DME and you’re visual, in the dark, in your burning or barely controllable aeroplane you are going to increase the rate of descent to get down onto the three degree PAPI slope for the visual landing, and if in the stress of all that, which you have never practised even in your Cat C training you get it wrong and have to go around then you are going around towards high ground where the MSA reaches 28,000 feet within 25 miles of the airfield.

Having been to Kathmandu many times, despite knowing that we stop below V1 and at or above V1 we go, I’m not sure, what I would have done, without the value of hindsight and a thread on prune to learn from, If I’d been in the left hand seat of that aircraft and had got a configuration warning at or slightly above V1, except I hope I wouldn’t have tried to find out if it was real, in the same way as we don’t try to find out if a fire warning is real, or a wind shear warning is real, we just assume it is and react. I’m probably going to get flamed for this by the pundits, but after thirty five years of flying for a living I’ve learned that it’s easy to sit in the back of a simulator or in an armchair and pontificate, but we weren’t there, and we shouldn’t vilify someone for a mistake which at some point in our careers, before we knew everything from reading prune, we could have made ourselves.
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Old 28th Jan 2021, 12:02
  #51 (permalink)  
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Excrab , great post. ( Not being sarcastic! )
I have been to Kathmandu ( and Lukla ! )
I feel your pain.
But its your job.
That’s what you’re paid for.
When you do your flight planning , pre-flight briefing etc. and line up on the runway and press TOGA you should have a pretty comprehensive mental image of what you are going to do.
And be confident about it.
If you don’t you are in the wrong game.
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Old 28th Jan 2021, 12:22
  #52 (permalink)  
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The Malaysian AAIB report agreed with the captain’s declaration to reject the takeoff was well taken since the captain said it was unsafe to continue considering the airport surrounding terrain and bad weather.

That said, some would argue the sound of the configuration warning at V1 was so inconsequential that a continued takeoff was a safer option than a high speed abort beyond V1 on a wet runway.

The Boeing report at Appendix 5 of the AAIB investigation made the following observations of the conduct of the abort. The aircraft had already passed the V1 of 141 knots when the captain initiated the abort. The QAR indicated the abort commenced ten knots after V1 – namely 151 knots which put the aircraft further down the runway which was already wet. The maximum speed reached was 154 knots before reducing. That is 13 knots beyond V1

The captain immediately overrode the RTO feature by using manual braking as the auto brakes actuated. The RTO feature applied instant 3000 PSI but this was reduced to 800 PSI the instant the captain applied manual braking. It gradually increased to 3000 PSI over the next 20 seconds. . Full reverse was not used.

Boeing stated: “During RTO, reverse thrust, wheel brakes and autobrake were used; however not to their maximum capability. Reverse detent was used instead of maximum reverse which would have been expected on a wet runway and commanded brake pressure was reduced from the autobrake applied brake pressure of 3000 PSI to 800 PSI and gradually increased back to maximum brake pressure over 20 seconds.”

To an informed observer it would appear the decision by the captain to abort beyond V1 was more a panic move rather than a fully considered decision of all the circumstances. If, as the captain stated, a takeoff configuration warning occurred as the aircraft passed V1, there is little doubt that there would have been a WTF moment startle factor and a momentary delay before he elected to continue the takeoff or reject.

It is doubtful if the captain at the time of the takeoff configuration warning, would have found the time to consider terrain and weather before making an informed decision. More likely he made a snap decision to abort. But why stop?

The fact he dithered with the speed brake handle after V1 would indicate he was caught by surprise while still accelerating. Maybe he hoped it would stop the configuration warning which was distracting. When the noise didn't stop he then instinctively initiated an abort because he didn't know what else to do.

Regardless of his handling errors during the abort which would suggest a degree of technical incompetency, it would appear that to the casual observer there could be only one reason for his action to abort beyond V1.

The captain’s considered on the spot opinion that the aircraft may not fly in terms of possible handling difficulties and unknown gradient of climb.

Or: A startle or WTF factor so strong that standard operating procedure as espoused by the aircraft manufacturer in the flight manual was overridden by the captain's primeval desire to stay on the ground regardless of stopping performance considerations. In other words a panic driven abort which fortunately caused no casualties. What do readers think?

Last edited by sheppey; 28th Jan 2021 at 12:59.
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Old 28th Jan 2021, 12:34
  #53 (permalink)  
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Reading this thread, I still get the impression, that a lot of pilots really do not understand the definition of V1 and how it relates to an abandon take off. I am sure someone on here can quote verbatim the definition. But for a start brakes should (already) be fully applied AT the V1 speed in the event of an abandon.
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Old 28th Jan 2021, 14:26
  #54 (permalink)  
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My understanding from the FAA rules is that V1 is either the maximum speed at which the RTO manoeuvre can be initiated, or the minimum speed at which a take off can safely be continued in the event of an engine failure. As we are talking about the stop
case here this means that at V1 we should be (in the 737) 1. Disconnecting the auto-throttle 2. Retarding the thrust levers 3. Deploying the speed brakes and 4. Deploy Max reverse thrust. As we carry out the second action the auto brakes kick in. So max braking will not be already applied at V1.
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Old 28th Jan 2021, 15:37
  #55 (permalink)  
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Yes, V1 is not the moment to start applying an RTO. When V1 is called by PM, it is already too late to begin a safe RTO - hence, many SOPs have the PIC removing their hands from the thrust levers as soon as V1 is called.

The actions of an RTO must already have been started by the time V1 is called - otherwise one must continue. What those actions are will vary between aircraft types.

Only in extremis should a stop be attempted after V1 - a catastrophic loss of control or airframe damage or separation etc.

PS, great post #50 exrab

Last edited by Uplinker; 28th Jan 2021 at 15:48.
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Old 28th Jan 2021, 17:17
  #56 (permalink)  
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The origins of 'go minded' are from work on the FAA Takeoff Training Safety Aid circa 1992-94 AC120-62. At a similar time the definition of V1 was harmonised world wide; the FAA had to 'add' time for recognition used elsewhere, and redefine with 'first action'.

Some US operators had difficulty with this, resorting to 'procedural' adjustment - calling V1 slowly, or starting 5 kts before the decision speed.
Within this, the hypothetical cases appeared without due consideration of requirement or risk; also the Unions promoted 'Except', more for legal cover than safety or practicality. The result was a legacy of indecision and inaccuracy imposed on the world via FAA and Boeing / Douglas.
In later years Airbus have provided balancing views in a range of safety publications (no 'except' in their drill?)

An ideal procedure is a simple If-Then.
There are a few time-critical events requiring 'automatic' pre-conscious action with little need for situation assessment: 'Pull Up', 'Wind-shear', 'Descend'.
Conversely RTO is one, if not the only time-critical situation which requires situation assessment before acting.
The situations for 'automatic' action are defined by technical systems (EGPWS, TCAS).
RTO situations are defined by 'people', individual perception and assessment, judgement of 'failure', in a time limited period, with inherent bias of human thought.

We construct RTO situations in our head at the particular moment; our interpretation of reality.
How we 'create' these situations is the dominant factor in modern RTOs. Yet increasingly our minds are cluttered with inappropriate knowledge, ill-informed hypothesis and wild supposition from others. The unbalanced fears from extreme situations or outcome, or risk, will resurface from memories biasing our thoughts in those rare and surprising situations where the clarity of If-Then is required.

Dispel hypothesis with fact, validate assumptions, check regulations, and rationally evaluate risk. These with a 'go mindset' will help judge and choose an appropriate action.

No choice is perfect, but it should at least be well considered based on prior understanding and knowledge; then doing what is perceived to be correct, at the time, for 'your' situation, no one can rationally judge otherwise - because they were not there.
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Old 28th Jan 2021, 17:29
  #57 (permalink)  
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Thanks for the love

No one is saying it's ok to reject after/above V1, but it is an indisputable fact that in some rare cases this is exactly what one must do. I can name you off the top of my head accidents with heavy loss of life, or death of everyone onboard, where the correct action was to stop and take the overrun if needed, but the go-minded captain went...and came right back down in a big fireball.

Miraculous escapes from car accidents are not exactly the best comparison. Aborted takeoffs above V1 are a relatively common occurrence despite what is being suggested on these fora, and the VAST MAJORITY of them end with no major damage to the aircraft, let alone hull losses or fatalities.

If anyone would like to see some numbers to compare fatalities from RTOs above V1 vs loss of control immediately after takeoff, I would be more than happy to pull them up and compile them for your viewing pleasure.

PPRuNe is a funny place. Operate outside of procedures (or on the thin grey line) and keep everyone alive, you are pilloried. Do something really stupid and kill everyone, you become a martyr - "oh don't blame the pilots" and all that hoo-hah.
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Old 28th Jan 2021, 18:27
  #58 (permalink)  
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Originally Posted by B2N2 View Post
We are but mere mortals some just more then others.

Captain Sullenberger and Captain Haynes come to mind.

We will all be judged by our decisions.
In the cases of these examples, the decisions were made long before, and habitually, before the famous incidents. Decisions which demonstrated their professionalism and preparing them as well as could be done for those brief and perhaps singular events that defined their long careers.
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Old 29th Jan 2021, 01:15
  #59 (permalink)  
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Stuka, I'd like to see that.
Years ago, Boeing did a study of exactly that (aborting above V1 vs. continuing) and concluded just the opposite. The percentage of aborts above V1 which resulted in "catastrophic" outcomes was quite high (catastrophic being hull loss and/or multiple fatalities), where as cases where the aircraft was "unflyable" were extremely rare.
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Old 29th Jan 2021, 02:40
  #60 (permalink)  
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You’re making it up.
Spot the Flight Sim. driver.
td is correct.
Put up the numbers or shut up.
Oh , but thats right , they don’t exist.
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