oblivia

They may care, but only as they see it affecting their bottom line and their judgment about the cost of safety vs the probability and cost of accident is flawed.

it happened over time, the accumulation of bad management decisions with less than obvious consequences compared to the immediate and obvious costs.

Winemaker

The suggestion was made that it’s possible for the auto thrust clutch to fail, and that could lead to the power of one engine to reduce, possibly all the way back to idle. I’m not on plan B, so not sure if they are suggesting the throttle itself would move too, but I would guess it would. Having one engine at idle, and the other at climb thrust would obviously induce a yaw. If this would happen with the autopilot on, the autopilot would try to maintain the path with ailerons deflection, but it has no automatic rudder trim, so the aircraft would have a sideslip. I would think that as long as they were climbing in an airspeed mode the speed would not have gotten low enough to get near to any Vmc condition. It is possible that, perhaps because of the loss of performance the pilots selected a higher climb rate using vertical speed, and the speed loss that followed lead to an autopilot disconnect and loss of control because of the out of trim situation, but that is pure speculation.

hans brinker

The thrust lever won't close by itself ordinarily, although there is one particular case where that certainly will occur. A clutch problem will leave the thrust lever at a position, anywhere along the available TLA's.

The problem with an asymmetry while on APLT and without rudder input is not a VMCA issue, it is simply that there is an APLT roll input to maintain attitude due to uncorrected yaw, and the APLT will happily apply the roll input until it doesn't. If the APLT roll authority is limited, then eventually a roll-off that exceeds the APLT limits can occur and the APLT disconnects. at that time, the Roll input is removed, the yaw remains and a rapid roll occurs. The authority to stop the roll is lower than normal due to the roll induced by the yaw, so recovery is less than expected in normal handling, and on occasions that has resulted in confusion in the cockpit. (I observed that in a B744 on one occasion, and the roll in the screw up was sufficient o leave a well-deserved scar on the loopy captain's RH forehead from the storm light switch poetically shaped as a blade).

Within the normal envelope of the APLT, if the APLT is disconnected the crew may not be ready for the removal of the force of the APLT on the ailerons, which will rapidly return to neutral unless counted by the driver. That may seem obvious, especially when the driver is going to be trying to pickle off the APLT from a control position that is decidedly not neutral, but often crew will not be ready for the loads that are being assumed by them to maintain the current control position. An insidious problem can be encountered as well if the driver happens to mistakenly use aileron trim instead of rudder trim while the APLT is engaged. On too many aircraft, doing that will not disconnect the APLT immediately where using the stab trim will, but the extent of trim input is not observable on say, Boeings... and so a wild ride can occur at disconnect if it is not recognized.

All of these issues should be nonissues, but then that is the case with most accidents and most human endeavours; when the humans understanding of their state differs from actual, wild rides happen. If you are not used to wild rides (and even when you are) they can escalate rapidly as the human scurries to get back into the loop, which means doing all of the OODA stuff in quick time. The normal envelope of +/- 35, +25/-10 (or whatever the limits of your ride are set at) leaves a lot of attitudes and accelerations that the driver doesn't get to spend time experiencing.

Tim27

Not only that a hand should be on thrust levers at ALL times when the AT is active. Ie when making significant movements. Caught out the guys in Emirates, big time, crashing a perfectly serviceable jet.

....and during a coupled approach hard to believe that guys are not following through on both yoke and thrust levers.

Only if company sop's don't prohibit such action.

Which is exactly why we practise them in the sim every six months. Jet Upset, UAs, limited panel etc, for a good reason.

Surely every airline SOP mandates on a coupled approach, following through, hands on controls and thrust levers during final approaches. (My Company B 747,below 1000ft.) And most importantly on a Go Around. EK would not have lost the 777 at DXB, due this omission.
Basic Airmanship?

Trasport airplanes (Icao)
 

(Maneuver diagram Icao)
Transport category aircraft

upset
pitch of + 25 ° / -10 °
Roll +/- 45

RetiredBA/BY

I don't follow through. I put the yoke and levers where I want them and usually find the autopilot and auto throttle agreeing with me.

Some aircraft may require 'follow through' from certification.
e.g. autopilot runaway above 1000 ft may use a 4 sec reaction time. Below 1000 ft, 2 sec could apply providing the pilots is 'hands on' to reduce height loss, quicker reaction.

jimtx, if you imply that you are over-riding the autopilot - applying force other than that from the AP, then be prepared for a surprise: - back driven trim, sudden force disconnect.

Icarus2001

As do the crews that end up out of sorts. UAL, USAir, etc had upset training before 587, 585, 427... and had bad days. So did a bunch of 604 drivers, AF447 etc. Now, before the cries of but the b737 rudder PCU....!, note that the roll rates were well above flight control available rates, so autorotative effects were in pkay on 427 and 585, and lo, 427 elevators are NU throughout the sad event. 585 rates... Etc.. NTSB was silent on rates achieved.

Anyway, if you aren't in the head, have conpetency and are aware of what and preferably why, and are not inconvenienced by the accelerations and vibrations at your seat, then it is all good. For the rest, the training hopefully gives a capability to sort out what they got and undo it.

The B717 stall video shows a competent crew having a wild old ride.. As did perpignan. A while back i did a BFR in a SE jet with a sharp examiner. While he was doing a barrel roll it turned into a half cuban, but with an entry of around 350kts... And not so much height for what then occurred, an indecision on which way to roll, he had to look behind the wing or in the mirror for the horizon, and then he went for a pull through rather than a roll out to a recovery, which was at about 450kts indicated and 7g. We were well clear of the ground, but not by design. It had enough margin for the recovery to be talked through, but the split S was not a manoeuver i was expecting to see a good driver get into outbof a barrel roll. Post flight, the examiner noted he was disoriented with trying to acquire the horizon and needed to follow the recovery that was being called. It was a non event, but was still curious in the recovery attempted and the reason why. There but for Grace etc...

PEI_3721

It's just a semantic mindset. I don't apply force to the yoke.

fdr

Yes, I agree with all that. Was just trying to explain in non pilot terms to self proclaimed SLF what could have happened.

cessnapete

Don't disagree, always have my hand on controls per SOP below 2500' AAL, but FWIW tactile feedback doesn't happen on brand A. (and that is easily the worst thing)

is the search still on for the missing part of the CVR?

As of 3 days ago the KNKT were still talking about "if we find the flight recorder ...", which would imply that the search continues.

No official report, but


Victims families are suing BOEING

I’d be interested to know from any 737 drivers here, how obvious a sideslip is when engine thrust is asymmetrical. I assume it much depends on how out of balance the thrust is, but....something you can feel easily in seat of pants?....

When you are disorientated, seat of the pants does not help. AF 447 descended at 10000ft/min yet the crew held the stick full back. Although I did 'upset training' in the commercial world it was of little use and I relied upon training received in the military.

Joejosh999

Depends on the situation at the time of engine failure.
If the autopilot is engaged in level flight for example, then the control wheel will be displaced (turn) towards the "live" engine. If there is no rudder input to counteract yaw, then the autopilot will disconnect when the AFDS cannot cope.
Without an autopilot engaged, then the turn and slip indicator will show the pilot the sideslip. Boeing do not recommend trimming the rudder to completely get rid of the sideslip, as a "neutral" control column is desired which avoids inadvertent spoiler extension which causes increased drag and a reduction in lift.