Ask yourself the following two questions: Which of the two possibilities would likely prevent another DXB / SFO autothrottle type accident:
1) System enhancement by Boeing of the autothrottle to account for known design issues.
2) Successful defence in court by Boeing of the current autothrottle system design.
3) Train pilots correctly!!
So follow the A/T with the hand if they move, and verify engine acceleration by instrument indications/human senses whether they move or not. Just because one thinks they remember having ordered another scotch doesn't necessarily mean it's been served and consumed. That feeling in the throat will be a better indicator!
LoL: mine's a double just to make sure.
Pushing a button is meaningless until you see proof that the commanded action is actually occurring. Each commanded action must then be monitored to the extent necessary to verify execution.
Spot ON. Remember the Air Kenya B737 crash at night where they spiralled to the ground after takeoff. The captain thought he had engaged the autopilot and then directed his attention to Wx avoidance while the a/c slowly rolled into a spiral. They did not get the A/P disconnect warning wailer; I can't remember if they got CWS. Either way the button push did not have the desired effect and they did not check/confirm and died. I don't remember a great out-pouring of wrath that Boeing should have designed it such that the A/P disconnect wailer should have sounded with the failure to connect. That indeed could have been a good idea.
In the DXB case if there had been an A/T disconnect siren when it failed to connect?????? but there isn't such an alert even during a normal disconnect. Should there be? Disconnects are normally a manual action, but any electronic system can go AWOL. Should they all have audible warnings? Not only for disconnect, but also for failure to connect? The list would never end. The design philosophy must have been that visual alerting is enough as that is what pilots are supposed to do, monitor and confirm, and should be trained to do so. A symphony of differing audios is not the best way. If it was a voice saying "auto-throttle disconnect" perhaps that might work. Remember the B737 confusion between the audio take-off config warning & cabin altitude warning. The fix was a visual addition to solve the confusion. OK, B737 doesn't have voice alerts, (except EGPWS) but it is known that they are more affective (except to certain Spanish speaking DC-10 pilots)
But we are back again to training and individual standards. That conclusion keeps cropping up in many occurrences. People keep saying that technology has made flying safety with less crashes per.........etc. However, I'd guess that in decades before there were more crashes due to malfunctions in the aviation system, and then human mis-actions, than direct simple screw ups. There have also been many instances where technology screwed up and the human went back to basics to compensate and avert disaster. The human, and there are many links in the chain, has always been identified as the weakest link. Technology has been used to try and solve this problem, and to some degree succeeded, and still does.
It is deeply worrying that in the past decade there have been quite a few perfectly serviceable a/c that have speared in due to the crew not understanding this supposedly life saving technology, mismanaging it, or not being able to compensate for its malfunction. The back to basics approach was not available or not applied.
Last edited by RAT 5; 26th Aug 2017 at 08:34.