Posts about: "Engine Failure (All)" [Posts: 410 Pages: 21]

That’s what got me headed down the low altitude capture route. While the mind does really strange things post traumatic event — and memory and recollection are greatly affected by it — if true it means that thrust was lost but the engines stayed lit.

There may have been other electrical and systems malfunctioning. But if whatever happened, let’s say the auto throttle simply pulled power to idle —or a low power setting—at a critical time. Perhaps on its own perhaps with other systems failures.

We like to think it basic that we’d slam the throttles forward. Right away.

But Asiana didn’t.

And neither did Air Florida years ago.

Sorry if this has been covered in the previous 1 million posts, but do we know if the training captain or trainee was handling the takeoff? The one thing that does change at V1 is PF\x92s hand comes off the thrust levers and joins the other hand on the control column. How long until people then put their hand back on the thrust levers varies a lot. Especially if turbulent or there is a perception of difficult handling ie) engine failure which often delays it. If your hand is on the thrust lever then should be able to feel them moving - unless gripping them so firmly it over rides the clutches.

Oh, and the FDRs haven\x92t been read yet as they were damaged in the fire.

Sailvi767 wrote It happened to a BAC 111 taking off from Linate Milan in 1969 when the wrong engine was shut down after a surge on takeoff. The plane never got above 250 feet and landed in a snow covered field gear up. The wrong engine identification was initiated by a Captain on the jumpseat!

https://aerossurance.com/safety-mana...human-factors/

Disclaimer: the numbers I mention are from publicly available sources, namely Wiki (for the ZFW weight calculation) and a Boeing FCOM dated 2010, and my own estimations.

IMO, if those engines failed just after rotation, there is no way that jet would have got anywhere near 200ft, especially if the fuel was "cut off", as opposed to back to Idle.

At 420k lbs (310k lb ZFW+110k lb Fuel), the (takeoff) V2 Flap 5 is 157kts. The (landing) Vref for Flap 5 I estimate to be at least 160kts (the FCOM I have has no figures for Flap 5 landings; F20 Vref is 154; the manoeuvre speed for Flap 5 is 189). Typically, you'd probably be at V2+15 when you get established in the climb after rotation.

No. With a pitch attitude of around 15\xb0, that's quite a bit of weight being supported not only by the wings but by the engine thrust vector. Cut that and you stop going up very quickly. Note Sailvi's comment above.

ANY reduction in pitch attitude would cause the climb to cease immediately. These aircraft are going so slowly, relatively, and the drag is so high that any small change in pitch attitude will cause an increase in descent rate with very little increase in speed (or no lessening of deceleration).

Not IMO. Basically, the only reason this jet is flying is because of the whopping long thrust vector out the back. It's already almost back at minimum speed anyway for flap 5 so there is very speed to trade. In this case, I wouldn't be trading anything, because the speed reduction rate would be too fast.

My estimate is around 200ft (one wingspan) and I hypothesise the engines were producing plenty of thrust until about 7 seconds, before it stops climbing at around 12 seconds after liftoff.

@Brace , I think you're exaggerating the residual thrust effect at lower RPMs. Of course 70% would get you round the pattern but you're at a much lower drag config and you're going much faster, again less drag. And are improved-climb takeoffs in the 787-8 even a thing? I can't see a two-stage rotation.

I've made up a YT combo video:

Sailvi767
" The fan never stops rotating in a normal engine loss. Having been through a catastrophic engine failure in a 767 I can tell you that trust stops almost instantly."

I can well believe that "trust" stops instantly

I posted my first-cut analysis in the earlier thread.
I've had a bit more time to analyse now.
Those ADS-B data points (and particularly the rate of deceleration) are EXACTLY what you would expect to see from a total engine failure at or very shortly after TAKE-OFF
(it implies a 13:1 L/D which must be pretty close for gear down and flaps 5).
It places takeoff at 700m before the runway end @ ~185kt
Based on those, max altitude was c250ft @ 140kt (or the equivalent total energy equivalent), 500m after the end of the runway.
13:1 L/D would also get you groundspeed on impact of 120kt
Do those numbers make sense?

Exact location of house, Approx distance of 1.5 km from end of runway to crash site .

Coordinates of the camera : 23\xb003'42.3"N 72\xb037'03.5"E

The Approx Camera location of the Balcony is the Red Mark . Can the speed be calculated . Does the speed line up with the ADS B data , Does it Gain Any speed after this Balcony point ?

Co-incidently Another Witness is the Grand Mother of the Balcony Teen, she was closer to the airport as per her . she is saying that the engine was silent after it passed over (but making sound , when it was Over , RAT already deployed?? ) and made offhand comment it was gonna crash . Found that out later .

Are you certain of that? Because tdracer (and perhaps others) have asserted that the valves are latching, and must be powered on OR off, precisely so that an electrical power loss does not close the valve (and shut down the engine).

You are using explanations that are correct but with wrong appreciation for the values and how much thrust is available and what it is used for. Yes, the relation is not linear, far from, but the thrust required at low altitudes is for the initial climbout and acceleration, aka against gravity.

70% is not "very little", it is almost the required thrust in level flight with intermediate flaps out and gear down at those altitudes (depending on the weight). Without the gear, 60% is enough to keep level flight. If you want to descend, 55% is enough to keep speed with flaps full landing configuration and gear down on a 3\xb0 glide. So even at 55% N1, the aircraft wouldn't stall, it would gradually descend if the pitch would be correct.

It is what is between 70 and max rated that is needed for the initial climbout and that thrust is "excess" as it is there needed for the second segment in case of engine out. Considering the fact that the climb only lasted 10 seconds, 2 seconds is 20% of that time where the engines were still pushing. It is not because it is "significantly less" that it is nothing (that's why when you apply full reverse and don't let the engines slow down with idle selected, you will feel the kick forward.)

If you look at the takeoff video, you will see that the aircraft does a very rotation that some pilots prefer to avoid tailstrike: first initial rotation, constant pitch to allow the aircraft to become airborne avoiding tailstrike, second increase in pitch at which point the rate of climb quickly disappears. At that point, the "parabolic" maneuver with constant nose up is created, very typical for a loss of thrust (loss of airspeed with constant pitch).

Which begs the question why they never lowered the nose...

GA guy who's been reading the thread from the beginning..

I'm assuming my question is moot because I don't believe it's been mentioned in the entire thread, however is there any possible maintenance issue that could affect two engines over time?

This is certainly happened before, I'm thinking of N334EA where all three engines were lost due to maintenance replacing all three chip detectors with defective detectors before the flight.

Of course it took 40 something minutes before the first engine oil was drained and the other two engines failed at different times after that.

So that pattern doesn't fit, but my question is are there other things that could be replaced on both engines that could theoretically take a relatively long time to fail but might do so under TOGA?

In other words are there any devices that could have been changed on both engines before the previous flight that were defective and didn't fail until full power on both engines on take off on the accident flight?

Obviously this is pure speculation, I don't claim to know anything and I'm just curious.

Both the B777 and B787 have a minimum autopilot engage height of 200'. I would suggest it is often the best course of action after an engine failure to engage the autopilot at 200' to dramatically reduce the workload!

When talking about low altitude capture below the 400' VNAV engagement height, although it has been talked about, would mean (mis) setting the MCP altitude to less than 400'. I really find that implausible. You are correct though that the modes would be SPD | LNAV | ALT should this occur.

All correct.

The lack of autothrottle automatic activation when the autothrottles are in HOLD mode and the speed has decayed below minimum manouevring speed has been addressed. The autothrottle will now automatically activate if, when in HOLD mode, the speed decays below minimum manouevring speed with FMC software after BP4 on the B787 and after AIMS V17B on the B777.

Since the Asiana accident many airlines prohibit use of FLCH below 1,000' and the lowest altitude setting when using FLCH is then, of course, 1.000'

Almost fully correct, the speed when autothrottles transition to HOLD on takeoff is 80kts. on both the B777 and B787.

Great first post (IMMHO!) If this is correct, then I think you are onto something very significant. No expert, just an outside the box thinker who has been trying to see what ordinary (non-pilot-blaming) explanations there could be for a near simultaneous dual engine failure. I imagine a complete electrical failure leading to fuel starvation from lack of pump feed pressure from the centre tank would not result in apparently near simultaneous engine failure, but who knows? (Aren't there (suction) bypass valves here, but maybe they get stuck after long non-opening - instead long subject to closing pressures?) This could have been the case here as my experience suggests the probabilities aren't small.

FWIW, according to earlier posts, the fuel load was about 50T, leaving about 18T in the centre tank, so (I think) about 25-30% full. A full centre tank might allow engine pump suction to work fine, but this might not? (Contrary to what some have said.)

Anyway, FWIW, not everyone agrees with RAT Deployment - see recent post by shep69. Would love to know why he doesn't go with RAT deployment...

Thanks much; been a few years with other A/C in between.

For those postulating the RAT was not deployed, what counter explanations do you have for the following clues?

• Distinctive RAT sound in the rooftop video, audio analysis here .
• RAT visible in rooftop video, example in this image .
• APU door open suggesting auto APU start, suggestive of a full electrics failure (one of the criteria for auto RAT deployment)
• Loss of ADSB data suggestive of a full electrics failure (one of the criteria for auto RAT deployment)
• Unusual gear forward tilt position, suggestive of hydraulic failure and/or full electrics failure (one of the criteria for auto RAT deployment).
• Loss of all thrust, ie dual engine failure (one of the criteria for auto RAT deployment)

Great summary. I've already mentioned the first below, but I'd add another:

• The existence (and timing) of the flyby video by a young lad who apparently lived where the footage was shot from. With planes flying past every few minutes, why would he choose to film this one, before he could even see it? The video starts with the plane still approaching, out of view, and his position suggests it was unplanned, before he could move to a better vantage point. I say he already knew it was extraordinary - from the sound.
• Eye witness account from the mother of the lad who filmed the flyby, apparently said that the plane was "shaking". I'll assume she didn't know how to describe it properly, and that maybe it sounded like it was shaking, from hearing the noise from the RAT. Or it's a translation issue of a word/s with multiple meanings or used colloquially.

One question - are there two exterior doors to the APU compartment, one on top, one below, presumably inlet and outlet of cooling airflow? I've seen photos showing two open doors, but the lower one could be something else, and busted open during the crash.

Hoover from the generally respected Pilot Debrief channel put up his analysis.

He analyses the point of rotation looking at the airport layout and using the video with the shack showing the aircraft rotate behind it, in that case the aircraft rotates at a reasonably normal place. That being the case what is the "cloud of particles" that appear to the left of the aircraft ?

He discounts electrical failure affecting both engines due 787 design, and fuel contamination due both engines fed from separate tanks unlikely to affect both engines at the same time.

The possibility that one engine failure occurred at a critical point in the take off and that possibly the wrong engine fuel cutoff switch was pulled.


camera angle with shack and suggested point of rotation



whats this..

All of which has been discussed and for the wing vortices and the fuel feed has been explained quite comprehensively, along with the fuel cut offs: have you not read these posts only made recently?

I repeat, do NOT post repeats of discussions already had unless there is something of value which may change or enhance previous posts. This is a prime example of a post which should be vetted and dismissed before pressing Submit Reply 🙈

It\x92s a possibility (as is virtually anything that doesn\x92t break the laws of physics) but all the training, practicing and checking would have been to emphasise SOPs, which are to leave all the engine controls where they are until you have done a proper interactive diagnosis at a safe height with the flightpath assured.

Where the meme has come from that jet pilots have to shut down engines as quickly as possible I don\x92t know but it is incorrect. If you left a failed engine without securing it for 5 minutes, little to no harm would come of it. Even if it was on fire (which is not necessarily flames, just higher than normal temperatures inside the nacelle) they are certified to be in this condition for some considerable time before it becomes a problem. Yes, I think the phrase \x93without undue delay\x94 could be used for a fire indication but that\x92s a minimum of 400\x92AGL in Boeings and does not absolve you of all the cross-checking and CRM that should happen with an engine shutdown. This is practiced/checked at the least every 6 months in EASA land and any attempt to rush a shutdown at low level would lead to a debrief and more training/checking.

To put it this way, control of the aeroplane and lateral/vertical navigation is far more important than doing stuff with a failed power plant. Something like an ET should be absolutely prioritised over engine drills.

This is not true. The AAI could be at 50 feet and a pilot can set a suitable climb attitude and push the thrust levers forward to enter a “normal” climb. The flight director would be useless at this point as it is commanding the descent.
So no, the AAI does not need to be changed to commence a climb.

I completely agree. I imagine it relates to the ten minute max power limit on the live engine. Less and less relevant as the aircraft can give MCP easily. My current jet type does not have an engine failure memory item. I looked for a B787 EFATO memory item in the QRH but could not find one. Perhaps a current B787 pilot could confirm?

I don\x92t really know what you are talking about. I\x92m current 787 and have flown many types including airbus prior to this. EFATO is normally an SOP handling exercise, not a memory item in itself. Memory items on nearly all types cover the specific drill for the engine only in all regimes of flight\x85ie severe damage/separation, engine limit exceedance/surge, engine fire. ie you\x92d never say \x93I\x92ll take the memory items for an engine failure after takeoff\x94.

EFATO handling is similar on most types too\x85in essence, contain any yaw, rotate, get the gear up and either trim it out or (787) let the aircraft trim it out\x85.AP in and once safely climbing away at a defined altitude diagnose followed by memory items if applicable. 787 you don\x92t action any drills until above 400ft so it would be extremely unlikely this crew actually got the stage of touching a fuel control switch.