AET Instrument Systems 1 — Questions and Answers
Question 1: What does an Air Data Computer (ADC) primarily compute?
- Fuel quantity and flow
- Airspeed, altitude, vertical speed, and Mach number from pitot-static data (Correct answer)
- Engine RPM and EGT
- Magnetic heading and drift
Correct answer: Airspeed, altitude, vertical speed, and Mach number from pitot-static data
An ADC processes pitot and static pressure inputs to compute calibrated airspeed, altitude, vertical speed, Mach number, and outside air temperature.
Question 2: What type of sensor is used to measure outside air temperature (OAT) in avionics systems?
- Thermocouple
- Platinum resistance thermometer (PRT/TAT probe) (Correct answer)
- Thermistor only
- Bimetallic strip
Correct answer: Platinum resistance thermometer (PRT/TAT probe)
Aviation OAT/TAT probes typically use platinum resistance thermometers (PRTs), which provide accurate temperature measurement based on resistance change.
Question 3: What is the function of an Inertial Reference System (IRS)?
- Provide GPS position only
- Measure and integrate accelerations to determine attitude, heading, and position (Correct answer)
- Decode VOR/ILS signals
- Monitor engine parameters
Correct answer: Measure and integrate accelerations to determine attitude, heading, and position
An IRS uses accelerometers and gyroscopes (or ring laser gyros) to measure motion and compute aircraft attitude, heading, velocity, and position without external references.
Question 4: Which instrument displays a combination of attitude, heading, and navigation information on a single screen?
- ADI only
- EFIS/PFD (Primary Flight Display) (Correct answer)
- EICAS
- TCAS display
Correct answer: EFIS/PFD (Primary Flight Display)
A Primary Flight Display (PFD) on an EFIS-equipped aircraft combines attitude, airspeed, altitude, heading, and navigation data on one integrated screen.
Question 5: What does RVSM stand for and why is accurate altimetry critical for it?
- Reduced Vertical Separation Minima — aircraft must maintain altitude within ±60 ft (Correct answer)
- Radar Vectoring and Speed Management
- Required VOR Separation Minimum
- Remote Vertical Stability Monitor
Correct answer: Reduced Vertical Separation Minima — aircraft must maintain altitude within ±60 ft
RVSM (Reduced Vertical Separation Minima) reduces vertical separation to 1,000 ft between FL290–FL410, requiring altimetry accuracy within ±60 ft to prevent conflicts.
Question 6: What is the purpose of a pitot heater in the aircraft instrument system?
- Warm the cockpit instruments
- Prevent ice formation in the pitot tube that would cause false airspeed readings (Correct answer)
- Heat the static ports
- Defrost the windshield
Correct answer: Prevent ice formation in the pitot tube that would cause false airspeed readings
The pitot heater electrically warms the pitot tube to prevent ice accumulation that could block the pressure sensing port and cause erroneous airspeed indications.
AET Instrument Systems 1
What does an Air Data Computer (ADC) primarily compute?