FlightDetent, you called?
Actually, I don't recall commenting on the TR deployment on this thread.
Originally Posted by
sycamore
Would a real 737 pilot care to comment on the likelihood of a thrust reverser opening in flight...?
After Lauda, Boeing added a 'third lock' to the reverser system on all aircraft (I believe the 737 NG uses a 'sync lock' that locks the device that synchronizes the movement of the T/R actuators). It would require three independent failures - of which two are non-dispatchable faults that should result in the reverser being locked out prior to flight. There have been issues in the past with improper lockout procedures on the 737 NG (basically it was possible to insert the lockout pin without it actually engaging) - memory says Boeing issued a fix for that (which was promptly AD'ed by the feds) maybe 15 years ago.
The probability of all three faults allowing a reverser to deploy in flight is something like 10-13/hr (i.e. one in 10 trillion flight hours), and even when dispatched with a latent failure of one the locks is something like 10-8/hr. So possible, but very, very unlikely.
All that being said, the reported flight profile of this accident does have a striking resemblance to what happened to Lauda.
At the risk of being called a racist again, I'd really like to know what was done to that aircraft as it sat on the ground for the two days prior to event flight.