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Boeing 787 Suffers Rare Dual Engine Failure on Landing

thepointsguy.com

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Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#41
post #20
post #14

Earlier quoted context omitted.

Going off your quote it just looks like they're describing the symptom?

It’s a completely neutral statement, and air travel has a strong culture of not accepting “just don’t screw up” as a solution.

NTSB is probably the best example of a safety investigation agency. Air travel in the US is extremely safe for many good reasons.

Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#42

I hope people are beginning to understand that the presence of software in any system is a liability.

Correction: "I hope people are beginning to understand that the presence of poorly-tested software in any system is a liability."

Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#43

Earlier quoted context omitted.

There should be manual override. What if this happened in-AIR?

You really, really do not want the reverse thrust to turn on in-AIR. That would be way worse then then engine shutting down.

I don't mean specifically reverse thrust. I am saying features such as this. The Pilot expects something and computer does something else.

Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#44

I'm not sure this is a bug. It sounds like pilot-error to me (I am not a pilot): "In the bulletin, Boeing said that selecting full reverse too quickly upon landing before the aircraft has fully transitioned to ground mode could cause the system to activate."

Dual engine shutdown is incredibly dangerous, there's no situation (other than a commanded shutdown) where that should occur.

Regardless of cause, regardless of if the pilot activated the thrust reverser too early, this is an incredibly dangerous defect that Boeing (or Rolls Royce) needs to fix before more people are put in danger.

Let me phase it this way: Even when the engines are literally on fire, they don't automatically shutdown, because doing so is considered too dangerous (since the systems don't know the circumstances, and even an engine on fire can generate thrust, and it might be your only engine).

Even if the defect was DISCOVERED due to a pilot error, it is still a defect and a safety critical one at that.

Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#45

Boeing’s answer seems to say if you accidentally pull the thrust reverser lever before the aircraft is on the ground it just force shuts down the engines. That sounds like an odd safety override. Surely a better solution would be to just not activate reverse thrust. Unlike car engines a jet engine can’t just be quickly restarted if it accidentally shuts down. It typically takes 30-60 seconds to get going. This and ea…

A tough call. Your solution would disappoint a pilot who actually wanted to slow down ASAP more than Boeing's solution, and might contribute to a runway overrun.

Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#47

Boeing’s answer seems to say if you accidentally pull the thrust reverser lever before the aircraft is on the ground it just force shuts down the engines. That sounds like an odd safety override. Surely a better solution would be to just not activate reverse thrust. Unlike car engines a jet engine can’t just be quickly restarted if it accidentally shuts down. It typically takes 30-60 seconds to get going. This and ea…

So the bulletin says that activating the thrust reversers too soon can cause un-commanded high trust. Activating it too soon by itself does not cause a shutdown. But one monitor that could stop the engine would be the overspeed monitor. The un-commanded high thrust might have tripped the overspeed monitor on the turbines and shut both of them down. There are numerous other monitors on the engines that might also play a role. So determining root cause might still take a while still.

Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#48

I hope people are beginning to understand that the presence of software in any system is a liability.

I think software has existed in computer systems for 7 or 8 decades now - and the pitfalls are well understood.

I think the problem is one of simplicity vs complexity. New systems today rely on dozens - hundreds even - of packages and libraries - many of which are not written by the implementer. How can you ensure reliability in all these components?

This is why engineering from first principles - even in today's software development environment - is important. Unfortunately, the trends are in the other direction.

Re: Boeing 787 Suffers Rare Dual Engine Failure on Landing

#50

Boeing’s answer seems to say if you accidentally pull the thrust reverser lever before the aircraft is on the ground it just force shuts down the engines. That sounds like an odd safety override. Surely a better solution would be to just not activate reverse thrust. Unlike car engines a jet engine can’t just be quickly restarted if it accidentally shuts down. It typically takes 30-60 seconds to get going. This and ea…

I thought that most modern aircrafts were not allowing the reverse to be deployed if the wheels didn't touch the runway.

Talking about an odd safety override. It's kind of a self-destruct button.

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