td, this is not entirely correct, as the loss of Lauda Air Flight 004 (the first 767 loss) sadly proved. That was the seminal event that resulted in a truly fail-safe thrust reverser design.
KenV, on Lauda the Direction Control Valve changed state (for reasons that were never positively identified) and the reverser was commanded to deploy - it didn't drift open like on Cranbrook. That lead to the installation of the 'third lock' system that is designed to be able to prevent even a powered deployment. I was directly involved in the Lauda investigation - probably the most difficult and painful thing I've ever done as part of my job (I honestly don't know how the people who spend their career investigating air disasters do it - I was a mental train wreck for weeks - and it didn't help that I was under a gag order and literally couldn't talk to anyone about it).
How come airbus doesn't agree with that? After all airbus doesn't manufacture engines. reverse is full stop for airbus.
Vilas, don't confuse "capable" with being an "approved" maneuver. Boeing also says, once the reversers are deployed, you're committed to landing - but we design for the other alternative because we don't want another Cranbrook if a snowplow or aircraft suddenly appears after the reversers are deployed. I'd be a bit surprised if Airbus doesn't design for the scenario as well.