FAA 107 Aircraft Maintenance & Pre-flight Inspection 4 — Questions and Answers
Question 1: What is the primary reason to inspect the sUAS airframe for loose screws and fasteners before each flight?
- Loose screws add unnecessary weight
- Vibration from motors can loosen fasteners over time, risking structural failure mid-flight (Correct answer)
- FAA regulations require torque verification of all screws
- Loose fasteners can trigger compass errors
Correct answer: Vibration from motors can loosen fasteners over time, risking structural failure mid-flight
Motor vibration gradually loosens screws, and if critical fasteners fail in flight, components can separate causing a crash or endangering people below.
Question 2: A remote pilot is conducting a pre-flight check and finds the GPS module reports fewer than the minimum recommended satellites. What is the correct action?
- Switch to manual mode and fly using visual references
- Wait for adequate satellite acquisition before beginning flight operations (Correct answer)
- Calibrate the compass to improve GPS reception
- Increase the flight controller's GPS sensitivity setting
Correct answer: Wait for adequate satellite acquisition before beginning flight operations
Insufficient GPS satellite lock compromises position hold accuracy and may disable GPS-dependent safety features like RTH and geofencing.
Question 3: During a pre-flight check, how should a remote pilot verify that the failsafe behavior is correctly configured?
- Simulate a signal loss in a safe area and confirm the drone behaves as expected (Correct answer)
- Trust the manufacturer's default factory settings without verification
- Check the failsafe only after the first commercial flight
- Review the manual and assume correct configuration
Correct answer: Simulate a signal loss in a safe area and confirm the drone behaves as expected
Actively simulating signal loss in a controlled environment is the only reliable way to confirm that the failsafe triggers the intended behavior such as RTH or land.
Question 4: Which of the following is an acceptable storage condition for LiPo batteries between flights?
- Fully charged at 4.2V per cell in a sealed plastic bag
- At storage voltage (approximately 3.8V per cell) in a fire-resistant LiPo bag (Correct answer)
- Discharged below 3V per cell to minimize chemical activity
- Stored in a hot vehicle to prevent moisture absorption
Correct answer: At storage voltage (approximately 3.8V per cell) in a fire-resistant LiPo bag
LiPo batteries stored at approximately 3.8V per cell (storage voltage) in a LiPo-safe bag experience minimal degradation and present the lowest fire risk.
Question 5: A sUAS remote pilot observes that one motor sounds rougher than the others during a ground spin test. What does this most likely indicate?
- Normal variation between motors of the same model
- Possible bearing wear or debris inside the motor that requires inspection (Correct answer)
- The ESC needs recalibration for that motor
- The propeller is generating normal aerodynamic noise
Correct answer: Possible bearing wear or debris inside the motor that requires inspection
A rough or grinding sound from a motor during a spin test suggests worn bearings, contamination, or internal damage that could lead to motor failure in flight.
Question 6: What is the purpose of the pre-flight 'control surface' check on a fixed-wing sUAS?
- To test the range of the radio controller signal
- To verify that control surfaces move in the correct direction in response to controller inputs (Correct answer)
- To calibrate the airspeed sensor
- To ensure the autopilot can override manual inputs
Correct answer: To verify that control surfaces move in the correct direction in response to controller inputs
Verifying correct control surface deflection direction ensures that the aircraft will respond as expected to pilot inputs, preventing a crash due to reversed controls.
Question 7: Before a flight over a populated area, a remote pilot discovers the collision avoidance sensors are covered with dust. What is the appropriate action?
- Fly cautiously since the sensors only assist, not control the aircraft
- Clean the sensors and verify proper function before proceeding with the flight (Correct answer)
- Disable the sensors to prevent false obstacle detections
- Proceed only if the flight will be below 50 feet AGL
Correct answer: Clean the sensors and verify proper function before proceeding with the flight
Obstructed sensors provide inaccurate obstacle detection data, which could cause false avoidance maneuvers or fail to detect real obstacles, especially critical over populated areas.
FAA 107 Aircraft Maintenance & Pre-flight Inspection 4
What is the primary reason to inspect the sUAS airframe for loose screws and fasteners before each flight?