VSI's & DFDR questions
Recent Instruments question. If a VSI has a partially blocked orifice then:
a. The instrument will under read
b. The instrument will over read
c. There will be no effect on the reading.
I put (a) down, going on the theory that there will be a time lag induced, until the pressures inside the VSI equalise. Anyone think it's different.
Also, when does a helicopter's DFDR become active? Is it:
a. On engine start
b. When the battery is turned on.
c. When the machine lifts.
Any help much appreciated. Season's greetings to everyone.