Question

What is θi in pitch rate command law?

(a) Tailplane demand angle

(b) Pilot input angle

(c) Gain in loop

(d) Pitch rate gearing

The question was posed to me during an interview.

My question is based upon Control Laws in FBW topic in chapter Fly by Wire Flight Control of Avionics

Answer 1

Correct answer is (b) Pilot input angle

To elaborate: Pitch rate command law is given by

 ηD = K(θi − Gqq)

 where ηD is the tailplane demand angle; θi is the pilot’s input command; q is the pitch rate; K is the forward loop gain, and Gq is the pitch rate gearing.