AET Aircraft Instrument Systems

Question 1

Which set of flight instruments receives input directly from the pitot-static system?

Accepted Answer

Altimeter, airspeed indicator, and vertical speed indicator (VSI)

Answer

The pitot-static system supplies air pressure data to three instruments: the altimeter (static pressure), the airspeed indicator (pitot minus static pressure), and the vertical speed indicator (rate of static pressure change). Gyroscopic instruments use vacuum or electrical power, not pitot-static pressure.

Question 2

What type of pressure does the pitot tube sense?

Accepted Answer

Total ram air pressure (static + dynamic)

Answer

The pitot tube is forward-facing and captures total (ram) air pressure — the sum of static atmospheric pressure and dynamic pressure created by the aircraft's forward motion. The airspeed indicator then subtracts static pressure (from the static port) to derive dynamic pressure, from which airspeed is calculated.

Question 3

If the static port becomes completely blocked during a climb, what indication will the altimeter display?

Accepted Answer

It will freeze at the altitude where the blockage occurred

Answer

A blocked static port traps the air pressure inside the static system at the value present when the blockage occurred. Since no new pressure reference can enter the system, the altimeter, VSI, and airspeed indicator are all frozen at their last readings. The altimeter will not change as the aircraft climbs or descends.

Question 4

What fundamental gyroscopic property allows an attitude indicator (artificial horizon) to maintain a reference to the earth's horizon?

Accepted Answer

Rigidity in space — a spinning gyro resists any change to its orientation

Answer

Gyroscopic rigidity in space (also called gyroscopic inertia) means that a rapidly spinning mass tends to maintain its plane of rotation in a fixed orientation relative to inertial space. The attitude indicator exploits this to keep the gyro aligned with the true horizon as the aircraft maneuvers around it.

Question 5

What is the primary function of an Air Data Computer (ADC) in a modern glass-cockpit avionics suite?

Accepted Answer

To convert raw pitot-static pressure inputs into digital altitude, airspeed, and air temperature outputs for other avionics systems

Answer

The ADC receives analog pressure inputs from the pitot and static systems, applies temperature compensation and calibration, and outputs calibrated digital data (pressure altitude, indicated and true airspeed, Mach number, outside air temperature) via ARINC 429 buses to the flight displays, autopilot, and other avionics.

(AET) Aircraft Electronics Technician Practice Test

(AET) Aircraft Electronics Technician Practice Test

AET Aircraft Instrument Systems