Scenario: high engine vibrations on takeoff
Hello people,
I'd love to have Your thoughts on that one:
Takeoff from a runway for which an engine out departure is prescribed. During gear retraction one engine starts vibrating (Twin narrow body, let's say A320). Procedure calls for thrust reduction till vibrations are below a certain limit. Before actioning the checklist we obviously must ensure the Fly-Navigate-Communicate and a safe height AGL is reached.
Would You: stay on assigned SID or join the engine out procedure?
Question arises from the fact that we do not yet how much thrust we need to reduce on the engine and therefore we could become unable to comply with SID gradient requirements.
Other options are to continue on the SID and assess according to the thrust reduction level or ask vectors towards areas of flatter terrain.
That brings me to the final question: from a performance point of view, is an engine considered "failed" the moment it produces zero thrust or the moment it is unable to produce the required thrust according to the phase of flight?
Thanks for your inputs.