FAA Aviation Mechanic Airframe (AMA)Airframe InspectionHard
A technician is performing a scheduled inspection on a transport category aircraft and checks the resistance of the static discharge wicks (static wicks) on the trailing edges of the flight control surfaces. Excessive resistance in a static wick would most likely result in which condition?
- AIncreased radio and navigation equipment interference from precipitation static buildup
- BReduced control surface flutter resistance
- CLoss of anti-icing capability on the wing leading edge
- DIncreased fuel consumption due to added aerodynamic drag
Show answer & explanationAnswer & explanation
Correct answer: A. Increased radio and navigation equipment interference from precipitation static buildup
Static wicks are designed to dissipate static electricity buildup from precipitation or airframe friction into the atmosphere. If wick resistance exceeds manufacturer limits, static charge cannot dissipate efficiently, causing precipitation static (P-static) that interferes with radio and navigation receivers.
Why the other options are wrong
- B. Static wicks have no relation to flutter resistance, which is a structural/aerodynamic issue.
- C. Static wicks are unrelated to anti-icing systems.
- D. Static wicks are small and their resistance does not meaningfully affect aerodynamic drag or fuel burn.
Static Discharge Wicks
Small conductive devices attached to trailing edges of flight control surfaces that dissipate static electricity buildup to prevent radio interference.
- Checked periodically for resistance with an ohmmeter
- Excessive resistance causes precipitation static (P-static) interference
- Typically replaced when resistance exceeds manufacturer limit, e.g., around 1 megohm
Memory trick: Static wick = the airplane's lightning rod for radio static