What are the four electromechanical devices retained while making an avionics update for old aircraft?
(a) Vertical speed indicator, airspeed indicator, artificial horizon and heading indicator
(b) Altimeter, airspeed indicator, artificial horizon and angle of attack indicator
(c) Altimeter, airspeed indicator, turns coordinator and heading indicator
(d) Altimeter, airspeed indicator, artificial horizon and heading indicator
The question was asked in semester exam.
Origin of the question is Head Down Display Technology topic in chapter Displays and Man-Machine Interaction of Avionics