FAA Aviation Mechanic Airframe (AMA)Landing Gear SystemsEasy
During a 100-hour inspection, a technician cleans and inspects a main landing gear wheel bearing. Which condition would require rejection of the bearing?
- ASpalling or pitting visible on the bearing races or rollers
- BA thin, even film of fresh grease remaining after cleaning
- CLight, uniform gray discoloration from normal grease exposure
- DSlight surface polish on the roller contact path
Show answer & explanationAnswer & explanation
Correct answer: A. Spalling or pitting visible on the bearing races or rollers
Spalling or pitting indicates fatigue damage to the bearing races or rollers and is cause for immediate rejection, since it can lead to bearing failure under load. Light discoloration, residual grease film, and normal polish from rolling contact are expected conditions on serviceable bearings.
Why the other options are wrong
- B. A light protective grease film is expected after proper cleaning and lubrication.
- C. Mild discoloration from grease exposure is a normal, acceptable condition.
- D. A slight polished path from normal rolling contact is normal wear, not damage.
Wheel Bearing Inspection
Examination of landing gear wheel bearings for damage such as spalling, pitting, corrosion, or overheating discoloration during scheduled inspections.
- Bearings must be cleaned and repacked with approved grease
- Spalling/pitting requires rejection
- Bluish discoloration may indicate overheating damage
- Bearings are matched sets and not interchanged with new rollers
Memory trick: Pits and spalls mean the bearing falls (out of service).