Final Report: April 2018 737 high speed aborted TO
 

And he was an IP !

Strange. Maybe I missed it but as I read it, there was no record on the FDR of T/O Config Warning.

However the crew stated that the T/O Warning came on at around V1. The PIC then wasted a couple of valuable seconds dicking around with the speed brake handle to ensure it was in the detent and to no avail before initiating an RTO. Some people refuse to believe the numbers and think they know better, I guess.

Page one: the purpose of the report is not to apportion blame!!

Well, the Malaysian AAIB seems to think the decision was well taken. I don't know Boeing's blurb but Airbus states that an RTO may still be initiated above V1 if there is a very strong indication that the aircraft is unsafe to fly. If there was any chance the performance was drastically reduced out of KTM I'd say that was a fair stop! Yes, 'dicking around with the speed brake handle' wasted a quite a few stopping yards and full stopping potential was not apparently realised; but there is a thing called 'startle' and it happened at a local time that, for me at least, is a low performance hour.

No FDR data (CB not pulled) only QAR data. Boeing says:
"... the take of parameter present in the QAR data would not have been triggered. The S651 switch (Speed brake handle stowed switch, BDA) signal is provided to the proximity sensor electronics unit (PSEU) which then provides outputs for the takeoff config lights and aural warning module. The takeoff config warning parameter recorded by the QAR is sourced from the flap-slat electronics unit (FSEU)."
So the data was recorded somewhere in the middle of the signal path before aditional trigger conditions (speed brake not stowed) were OR'ed to it.
They do not say if the Takeoff config warning would have been captured differently for the FDR :*.

This perpetuates my views I expressed in the most recent MAX thread. E/E wise this plane was mess well before the MAX.

He aborted because of a take off config warning, not a engine failure. Both engines running, so performance was not an issue. Poor excuse.
Not a good warning to get near V1, and he decided to abort. Fair enough, that was the commanders decision.
He failed in the execution of the aborted TO when he started to trouble shoot the warning. Poor decision.
A properly executed abort would have saved the day and we would not have this discussion.

Report states decision to stop was made at 154 Kts. Well after V1 then. Between V1 & 154 kts, looks like the pilots were attempting to correct an indication of a fault. Not good but AIB reckons it was a good decision.

Been in & out of this demanding airfield many times in 767's. Doesn't matter what type or where though, ingrained is the notion that up to V1 you can stop, after V1 you go. No messing.

This case shows it was a false warning and if the crew had of continued, fly the aircraft, get safe and then mess about with analysis later, a better outcome would have resulted.

The report is slightly misleading. My interpretation is that the captain thought that the decision to reject was a good one. Well in the words of Mandy Rice Davies he would say that wouldn’t he? Regardless of his IP status the decision to reject post V1 was not optimum and not a role model performance for Jet transport pilots. I have flown in / out KTM many times and the weather reports were not particularly threatening. The nasty thunderstorms normally occur in the afternoon. As a pilot it is better to take ownership of mistakes. An RTO above V1 is never likely to end well. The Boeing FCTM gives excellent guidance on this. The points ref startle and circadian low are well made. The loop closes on knowing sops and procedures to countenance the threats. Fortunately the outcome was not worse.

Re the thread title.....
 

.....there but the grace of God etc......

Yes, and on the other hand, had there been an actual config problem and PIC had continued the take-off towards mountains in poor weather and then crashed because the speed brakes were deployed, would we be condemning those actions?

This was clearly not PIC's finest hour, and it would seem that recurrent SIM training in this airline had not focused on practising the basics, such as RTOs. In addition, it would appear that B737 speed-brake lever position switches can be less than precise, so crews are probably used to having to jiggle the damn thing on occasion, (this is certainly my experience of old B737 classics, but this was not an old classic).

When the alleged config warning occurred at V1, PIC would have been go minded, and probably thought a quick jiggle of the speed-brake would stop the alarm. Where it all unraveled though was that the alarm was not stopped and PIC then wasted several seconds thinking about the config alarm rather than continuing or stopping. By V1, the first actions of an RTO must have been started, otherwise the take-off must be continued.

According to the report the crews' knowledge of RTO was not solid, and during briefings I have sometimes started to review RTO reasons and actions, only to be interrupted by PIC, saying "yes, yes, that's all SOPs".
Finally, I do not accept the so-called "startle effect", especially on take-off, when one should be prepared for anything. We are supposed to be trained and prepared for things to go wrong. Good PICs I have observed, go through a silent touch drill of the stopping actions before starting the take-off roll.

Extract from QRH;

“Rejected Takeoff
The Captain has the sole responsibility for the decision to reject the takeoff. The decision must be made in time to start the rejected takeoff manoeuvre by V1. If the decision is to reject the takeoff, the Captain must clearly announce “STOP,” immediately start the rejected takeoff manoeuvre and assume control of the airplane. If the First Officer is making the takeoff, the First Officer must maintain control of the airplane until the Captain makes a positive input to the controls.
Prior to 80kt, the takeoff should be rejected for any of the following: • activation of the master caution system
• system failure(s)
• unusual noise or vibration
• tyre failure
• abnormally slow acceleration
• takeoff configuration warning
• fire or fire warning
• engine failure
• predictive windshear warning
• if a side window opens
• if the airplane is unsafe or unable to fly.
Above 80 knots and prior to V1, the takeoff should be rejected for any of the following:
• fire or fire warning
• engine failure
• predictive windshear warning
• if the airplane is unsafe or unable to fly.
During the takeoff, the crew member observing the non-normal situation will immediately call it out as clearly as possible.”

The assumption is that a genuine configuration problem will be obvious on hitting TOGA at the start of takeoff and below 80 kts.

I'm not a 737 jock, so maybe a silly question but no mention of reverse thrust; would that usually be deployed?

Yes, but they are not included in the take off calculation (on a dry runway) so you will normally stop on a shorter distance than what the data says.
IF you do the reject in the correct way.

Malindo. Big brother or kissing cousin to Lion Air.
Take a look at some of the other threads if you want a few clues.

Actually, it is mentioned in appendix 5 containing the Boeing Investigation Report, starting at the 4th page of that appendix. They used reverse detent 2 instead of maximum reverse thrust. There are also mentions on the following pages, for example from page 6 of that appendix:

https://cimg5.ibsrv.net/gimg/pprune....b9cf912eb8.png

"It's not things that upset us, but our judgments about things"
 

George, #12, agree, except we cannot know that the aircraft is unsafe or unable to fly.
Previous QRH items are fact; 'unsafe', 'unable' are … unknowable.
Yes, it's the Captains call, judgement, but what is judgement … .
Hindsight is the gap between an event and subsequent analysis.
Surprise is when fear overcomes fact.
Fear is also when we are unable define every situation before the event. Its these which we should 'fear' before the event, think about how we react to uncertainty in situations.

After the event 'fact' is only opinion; a forum post, a realisation that we had not thought about these situations beforehand. Alternatively with prior thought, not having considered every aspect, so there is still opportunity to learn.
Reduced safety margin when rejecting on a wet, downhill, rubber contaminated runway.

Uplinker,#11.
Our finest hour always precedes the outcome, but no-one knows that.
Config Warning is a difficult case, but the settings and alerting were correct at the start of the roll.
Certification requirements are (statistically) sufficient to eliminate false activation thereafter. We trust requirements in other instances, so why think otherwise in these situations; 'otherwise' involves surprise, lack of knowledge, biased training.

For those who change control for an RTO, consider the time taken; a further reduction in the available stopping distance.

This is a good safety investigation; but where is the strong recommendation that the manufacturer should improve the detent (> recc 4.5, 4.6). How many events are required, how many accidents …

I have worked in KTM a few years ago and there is enough aluminum scattered in the hills around the airport to make you you have an humble view of things.
Startle effect plus knowing the geography around KTM made them take that decision . We were not in their shoes on that flight , . What I see is embarrassment , but nobody hurt and an aircraft undamaged .Could have been worse , yes. But certainly much worse if they had anything less than 500ft/min after taking off for whatever reason. Their call.

Et tu Brute?

Prime example of what often irritates me about Pprune, pedantic attitudes and that overall sense of superiority.
We all know that even after 14,000 hrs a career can be over in seconds.
There is a certain amount of luck required in this profession, we’ve all had our moments where skill had no part in the outcome.

And 200 human beings can be killed within the same number of seconds. In my book this pilot did the right thing. He decided to abort at V1 (for a good reason given where they were) and if he had applied full brakes and full reverser right form the beginning nobody would ever have heard about this incident. That an aircraft briefly continues to accelerate between the decision to abort and the beginning of the actual actions is figured into the calculations.
All this "I will abort for this and that below 80kt and for that and something else between 80 and V1" briefing bla-bla is nice in a classroom and maybe in a simulator (where already less than one half of pilots - me included - will get it right every time) but in real life it will be done wrong in the majority of cases. Because we are not machines. This is why the give us machines to facilitate our decisions, like this configuation warning system, but when those machines get it wrong we are even more alone than before.

Oh, well we'll never know when will we since modesty prohibits me expounding my thoughts on the CVR "issues".

It’s an interesting one. Although a config warning >80kts is not specifically included in the list of RTO triggers, there is the catch-all of “...if the airplane is unsafe or unable to fly”. As there are quite a few things that can cause a config warning, some of them pretty serious, it’s not completely cut-and-dried. If flaps and/or LEDs decided to retract themselves (has happened), flying becomes much more difficult and may not even be possible in the remaining distance - you might have the choice of going off the end at low speed or high speed. A suspicion that the speed brakes may have been deployed likely didn’t help, either.

These kind of scenarios are worth thinking a little bit about ahead of time as what condition(s) would you regard as “unsafe or unable to fly”? It’s not something much trained/practiced as the result could well be an overrun/crash, which could lead to negative training outcome, even though the exercise was successful. For the avoidance of doubt, I firmly support the take-it-into-the-air-and-deal-with-it logic when close to or above V1, just that there is always an exception to a rule somewhere.

What appears at first reading to have contributed to the overrun once the RTO was initiated was manual braking. Autobrake, according to the graphs, would have stopped the aircraft on the paved surface...

Very true. However, this disclaimer is usually made to state that the report may not be used in tort litigation. That's my understanding. Ultimately someone or something or some combination of the two always receive some 'blame'. It's not necessarily a bad thing, unless it's the common practice certain airline manufacturers have of blaming pilots where there's a faulty design, mechanical defect, etc etc. (*cough* Airbus). But, yeah, there's a reason the full quote there is:

Maybe the mob I work for is an exception but startle events like a master caution approaching V1 is routinely trained in the simulator.
As is removing your hand from the thrust levers at V1.
Not being judgemental to point out that on a balanced field length T/O you ARE going off the runway if you reject after V1.
”Unsafe or unable to fly” is the get out of jail card , but it is the very last resort.

Mmmm... and you would take an airplane up in some of the worlds highest terrain, at night, with rain showers and thunderstorms....and possibly a serious aerodynamic issue such as a flap asymmetry?
Yeah right...

White Knight

AIRBUS FCTM
Below 100 kt:
The decision to reject the takeoff may be taken at the Captain's discretion, depending on
the circumstances.
The Captain should seriously consider discontinuing the takeoff, if any ECAM
warning/caution is activated.
Above 100 kt, and below V1:
Rejecting the takeoff at these speeds is a more serious matter, particularly on slippery
runways. It could lead to a hazardous situation, if the speed is approaching V1. At these
speeds, the Captain should be "go-minded" and very few situations should lead to the
decision to reject the takeoff:
1. Fire warning, or severe damage
2. Sudden loss of engine thrust
3. Malfunctions or conditions that give unambiguous indications that the aircraft will not fly
safely
4. Any red ECAM warning
5. Any amber ECAM caution listed bellow:
‐ F/CTL SIDESTICK FAULT
‐ ENG FAIL
‐ ENG REVERSER FAULT
‐ ENG REVERSE UNLOCKED
‐ ENG 1(2) THR LEVER FAULT
Exceeding the EGT red line or nose gear vibration should not result in the decision to reject
takeoff above 100 kt.
In case of tire failure between V1 minus 20 kt and V1, unless debris from the tires has
caused serious engine anomalies, it is far better to get airborne, reduce the fuel load, and
land with a full runway length available.
The V1 call has precedence over any other call.
Above V1:
Takeoff must be continued, because it may not be possible to stop the aircraft on the
remaining runway.
Airbus FCTM

So the AAIB concluded that the decision to conduct a RTO above V1 was the correct course of action. Against the words of the manufacturer and SOP at almost every other carrier in the world.

:rolleyes:

B2N2,

Well said, stones and cast springs to mind.

50m overrun or potential for unscheduled arrival, not too much thinking required

Original thread on the incident from 2018:

PPRuNe: Why is Kathmandu Closed?

Vilas,

Why you've quoted the Airbus FCTM I've no idea, regardless of protocol as Captain the ultimate decision is with him.

There have been a number of incidents where take off has been rejected at or after V1 where carrying on would have led to a certain crash. It wasn't perfect but no injuries and damage limited to tyres being swapped out, I could live with that because like most of the folk on here I'm not striving for perfection, just trying to get it right.

George Glass

Same here but do you practice an “unsafe or unable to fly” level defect being introduced at that point, such that you would crash if an attempt to fly was made? I suspect MCs, etc. are used more to reinforce the idea of continuing than to introduce doubt about whether you should? This is normal practice as on 99.99% of occasions it is the correct course of action but Boeing wouldn’t have included the above phrase in the QRH/FCTM if they didn’t think it might be needed at some point.

In the incident under discussion, it’s not clear precisely when the warning occurred but the RTO was initiated 3sec/10kts after V1. Given the startle effect, that would indicate that the warning was somewhere close to V1 but could have been either side of it. There is no information as to whether the PF had removed their hand or not at V1 - they might have done but put them back to initiate the stop.

It’s not textbook handling by any means but it’s not a textbook airfield or terrain, weather, density altitude, problem, etc. Compared to crossing the threshold at 200kts and trying to land half way down a wet runway with a tailwind, it seems they might have been a little unfortunate in the timing of the warning as the realisation, decision and initial actions were clustered around V1?

Sometimes doing your best is not good enough. Sometimes you must do what is required.
 

- “Churchill"

'… a number of incidents where take off has been rejected at or after V1 where carrying on would have led to a certain crash.''
Certainty' is word which requires careful use in aviation, and begs examples, open to different viewpoints, moderated by context, and supported with facts.
With one possible exception I cannot recall an aircraft which would have been unable to fly - even if investigations suggest otherwise.

'… and possibly a serious aerodynamic issue such as a flap asymmetry.'
All things are 'possible', but few actually happen. The safety requirements for flap asymmetry would involve a similar level of integrity as a wing falling off.
Instructors, simulator scenarios must temper what is chosen for example; it is easier impart dramatic mind numbing situations, than focus on the simple 'mistakes'.
Mis-set flap, incorrect speed, weight, thrust, or no flap with MEL alert. Real events, not RTO scenarios, but more likely 'off-the-end', 'unable-to-fly' situations where training, knowledge, discipline might help.

Lots of this stuff is for back in the classroom & CRM etc. What should come out of it is that V1 is the line. Stop before, go after. End of. Sim should then re-enforce so that, really we get into an action for all cases. No discussion. Longest runway in the world, no obstacles in front or behind, V1 occurring with miles of concrete in front (?)- STOP for heavens sake because that is what we do all the time. Next day, you could be on a very limiting & challenging set of conditions. Up to 80k, stop for anything, even uncontrollable flatulence , 80-V1, only for well specified and briefed circumstance, after V1....................go...................pleeeze !

You pass V1, start to rotate and nothing happens. What do you then? Happened twice in my company.
There will always be a situation outside the box.
On the other hand, a very long runway doesn't mean you have the brake energy to stop at very high weight/speeds.

Does it mean that the purpose of inquiry is to tell a bed time story? If an inquiry reveals that there was a deficiency of skill or procedural knowledge or maintenance so all that they can say is this wasn't done and that wasn't executed but no blame. The involved pilot will be given corrective training not because he did or didn't do something but just for fun? This fits the definition being politically correct which is defined as " trying to pick up piece of **** by its cleaner end".

You don't have a clue what you are talking about, Vilas.
First you mix Airbus procedures into an Boeing incident, and now this?

You pass V1, start to rotate and nothing happens. What do you then?
Good question, but as a professional there should be an answer.

Jammed control drill, failure to rotate drill. Some aircraft - pull harder, announce the condition, both pilots pull, split the controls if the automatic systems has not done so (improbable second failure).
When was this last practiced in the sim; were the forces involved surprisingly high - something which you would not normally consider.
Alternatively, before such situations are encountered, consider:- cg verified, trim setting, when and how the before-takeoff-control check is done; a snowy day, what deicing procedures were used, hold over time.
Its easy to quote the negative, more difficult to think about the positive.

Anyway what happened on those two occasions; accidents avoided because of a long runway. What was the issue which contributed to the situation.
What was learnt, what might we learn.

https://fs.blog/2021/01/practice-failure/
If we don’t practice failing, we can only safely fly on sunny days.

Landflap

Rare occurance but still,
https://skybrary.aero/index.php/MD83...i_MI_USA,_2017
The following crew obviously should have rejected the take off even after V1, alas no config warning due to either a malfunction or a pulled (?) breaker.
https://en.wikipedia.org/wiki/Spanair_Flight_5022
The original incident? Good decision on the reject then buggered up the process.
Nobody got hurt, tires got replaced, plane got washed, back in business.

safetypee

This was some 20+ years ago, and happened to two MD-80s. The MD-80 elevator is not powered, but controlled by tabs. Residue of deice fluid (type IV, new at the time if I remember correctly) build up inside the elevator system and jammed it. The flight control check only moves the tabs, so nothing unusual during the flight control check. Both aborted above VR and managed to stop. Luckily, and the correct decision by both captains.
A GO decision would most likely have killed a lot of people. Yes, a long runway did help.

After V1 you only abort if running of the end at low speed during abort is better than failing to fly at high speed. As we can never put every conceivable failure in the checklist there will alway be the discussion afterwards if it was the right decision. If Sully had hit the geese between V1 and Vr, and overrun into the water aborting it would be the right decision, because you can’t fly with both engines failed. If you think the speed brakes are stuck in the up position it might be the right decision, I wasn’t there.....