Incident Overview
On December 13, 2018, after landing at Warsaw Chopin Airport (EPWA), technical personnel discovered an oil leak originating from the area of the left propeller on an ATR 72-202 aircraft. A subsequent inspection revealed several discrepancies in the propeller installation.
Findings
The inspection documented the following issues:
- Oil seepage from the propeller shaft seal.
- Nuts connecting the propeller hub to the engine shaft were not tightened to the required torque.
- Two bolts securing the propeller hub to the shaft had damaged threads.
- Sixteen hexagonal nuts securing the propeller hub to the shaft exhibited cracks and material loss.
- A sliding ring between the actuator and the hub was missing.
The propeller installation had been performed by an external maintenance organization.
Probable Cause
The cause of the incident was that the propeller installation on the engine shaft was not carried out in accordance with the aircraft maintenance manual.
Subsequent Actions
The investigating entity verified the scope and quality of the propeller installation work performed by the external maintenance organization. Technical staff were briefed on the circumstances and causes of the incident. No safety recommendations were issued.