PPRuNe Forums - View Single Post - Boeing incidents/accidents due to Thrust/Pitch mode mishandling
Old 11th Oct 2018, 08:09
  #25 (permalink)  
Dan Winterland
 
Join Date: Jun 2001
Location: Fragrant Harbour
Posts: 4,787
Received 7 Likes on 3 Posts
I'm always amazed by the extent that pilots are willing to blame our colleagues for assumed screw ups while secretly hoping we don't make the same mistake. And when it comes to accident investigation, blaming the operator is the easy way to get to a conclusion. In the Asiana accident at SFO, I've heard many times that it was pilot error - even mainstream media in the US made a joke about it.

But modern accident investigation has moved on from simply blaming the operator as it doesn't stop the same or a similar incident from recurring - which is the primary aim of holding the investigation in the first place. In this incident, you have to look at why the crew didn't manually apply thrust on the approach. By saying "they were stupid" stops the investigation right there and then. You think you have found the issue and when the airline trains their pilots better, the problem goes away. That's until it happens again - which it probably will.

But a thorough multi level investigation will look at the Airline's SOPs, their training system, their culture etc. And as the system correctly maintained and working as it should? Were the crew fatigued? Did they get their mandated rest period? Does the airline have fatigue mitigations in place? It will look at the airline's regulator to see how effective it is in ensuring training and safety standards are met. Then it will look at the design of the AT system. Is it fully understood by other operators using substitution tests, have there been similar incidents reported? Are similar incident actually being reported perhaps distorting the true picture? What was the certification process that led to the system being included - was it effective and did it consider all the threats at pitfalls? So much to consider!

I've flown a similar type with the Thrust Hold AT mode which caught the Asiana crew out. I was warned about it during training and that it can seriously bite you on the bum. Despite the warning in training, I've witnessed the speed reducing while a pilot says "What's it doing now?" to be told "Thrust Hold mate!" on many an occasion. I've done it myself! And at the end of a 14 hours sector after some dodgy crew rest, making an approach in tricky conditions at an unfamiliar airport in a new aircraft in your window of circadian low, I can see how all the factors stack up to make an accident like this more likely. Sure, the crew made an error. But just by pointing the finger at the user will not address all the factors.

And if you ask me my opinion about this accident, I would have to ask why the manufacturer thought it was sensible to have an AT mode which tells you the AT is working, but doesn't let you know the thrust levers won't move.

Last edited by Dan Winterland; 11th Oct 2018 at 08:53.
Dan Winterland is offline