Flight Data Recorder question.
 

This may seem like a dumb question, but when is the flight data recorder turned on?

Like for example, would the flight data recorder be turned on if there crew is going to perform a ground run-up only?

Usually automatic as the first engine is started.

As said above it, and the cockpit voice recorder, come on automatically when an engine is started (normally rising oil pressure is the switch) and cannot be turned off by the crew, except by pulling a circuit breaker, until the parking break has been set and the engines shut down. Once this has occurred the cockpit voice recording, which is normally a 1 or 2 hour loop, can be erased by the crew so that you can get rid of the rude comments you just made about the Chief Pilot. The flight data recorder cannot be erased by the crew.

CVR picks up interphone calls as well so be careful what you say to f/d crew!! :E

on the 'bus the cvr can be switched on by the f/d by a switch in the o/head panel or as said when an engine is started and it can pick up the interphone, pa and what you say in the F/D :eek: so watch who you insult on the pa!!!