What happened
On July 30, 2010, at approximately 18:00 UTC, a Hawker 400A, registration CS-DMV, operated by NetJets, was taxiing at Lisbon Airport for departure from runway 03. While awaiting position, the crew of a following aircraft alerted the tower that white smoke was visible emerging from beneath the left engine nacelle of the CS-DMV.
In response to the report, airport fire services were dispatched to the scene. Upon inspection, firefighters confirmed the presence of white smoke emitting not only from beneath the fuselage but also from both engines. The flight crew immediately shut down the engines, and although the smoke was visible, firefighters found no evidence of active fire.
The investigation
The aircraft was subsequently handed over to maintenance personnel for inspection. To investigate the source of the smoke, technicians performed a full-power engine run-up to monitor oil consumption and simultaneously tested the cabin air conditioning system to ensure the air supply was not being contaminated by oil combustion.
During this high-power test, technicians observed a small amount of white smoke exiting specifically from the left engine oil breather. Further inspection revealed a minor oil leak, quantified at a rate of approximately one drop every 10 minutes.
Findings
- The investigation established that the white smoke was caused by the sporadic combustion of trace amounts of lubricating oil within the left engine.
- The oil leak rate was found to be within the operational limits specified in the manufacturer's maintenance manual.
- All necessary documentation and maintenance programs for the aircraft were found to be valid and up to date.
- No injuries were reported, and there was no damage to the aircraft.