SPC Aircraft Systems and Performance 3 — Questions and Answers
Question 1: What does a gyroscopic instrument's 'precession' error cause in turns?
- The attitude indicator may show a slight bank even when wings are level after a coordinated turn (Correct answer)
- The altimeter over-reads during steep turns
- The VSI lags behind actual vertical speed changes
- The airspeed indicator under-reads in banked flight
Correct answer: The attitude indicator may show a slight bank even when wings are level after a coordinated turn
Gyroscopic precession can cause the attitude indicator to display a slight bank error after prolonged or steep turns, requiring occasional re-centering.
Question 2: In a standard atmosphere, what is the approximate temperature lapse rate per 1,000 feet of altitude gain?
- 2°C (3.5°F) (Correct answer)
- 5°C (9°F)
- 1°C (1.8°F)
- 4°C (7.2°F)
Correct answer: 2°C (3.5°F)
The standard atmosphere lapse rate is approximately 2°C (or 3.5°F) per 1,000 feet up to the tropopause.
Question 3: What is the primary purpose of an aircraft's oil system?
- To lubricate, cool, and clean internal engine components (Correct answer)
- To pressurize the fuel system for high-altitude flight
- To operate the hydraulic flight controls
- To cool only the cylinder heads during cruise
Correct answer: To lubricate, cool, and clean internal engine components
The oil system lubricates moving parts, helps cool the engine, and carries away contaminants and metal particles.
Question 4: What is 'ground effect' and how does it affect takeoff performance?
- Increased lift and reduced induced drag close to the ground, allowing liftoff at lower speeds (Correct answer)
- Increased drag caused by surface turbulence near the runway
- Reduced lift near the ground forcing longer takeoff rolls
- A cushion of air that increases runway friction
Correct answer: Increased lift and reduced induced drag close to the ground, allowing liftoff at lower speeds
Ground effect occurs within about one wingspan of the surface; it reduces induced drag and increases lift, allowing the aircraft to become airborne at lower speeds.
Question 5: What information does a tachometer provide to a pilot?
- Engine rotational speed in revolutions per minute (RPM) (Correct answer)
- Manifold pressure in inches of mercury
- Engine temperature in degrees Fahrenheit
- Fuel flow in gallons per hour
Correct answer: Engine rotational speed in revolutions per minute (RPM)
The tachometer measures and displays crankshaft rotational speed in RPM, helping the pilot set the correct power for each phase of flight.
Question 6: What does a positive load factor greater than 1G mean for an aircraft?
- The wings must produce lift greater than the aircraft's weight (Correct answer)
- The aircraft is in unaccelerated level flight
- The aircraft is experiencing negative G forces
- The engine is producing excess thrust over drag
Correct answer: The wings must produce lift greater than the aircraft's weight
A load factor above 1G means the wings must generate lift exceeding the aircraft's weight, which occurs in turns, pull-ups, and turbulence.
Question 7: What is the result of leaning the mixture too aggressively at low altitude?
- Engine roughness, loss of power, and possible detonation (Correct answer)
- Smoother engine operation and improved fuel economy
- Increased manifold pressure and higher RPM
- Lower cylinder head temperatures and reduced wear
Correct answer: Engine roughness, loss of power, and possible detonation
An excessively lean mixture can cause rough running, power loss, and dangerously high cylinder temperatures that may lead to detonation.
SPC Aircraft Systems and Performance 3
What does a gyroscopic instrument's 'precession' error cause in turns?