Event Description
On 16 December 2000, at 19:05 UTC, a McDonnell Douglas MD-82, registration I-DAVT, departed from Naples Capodichino Airport on flight AZ1850 to Palermo. During initial climb, while passing flight level 120, the left engine experienced a flameout. The crew declared an emergency at 19:42 and requested an immediate return. The aircraft landed safely at 20:25. No damage or injuries were reported.
The aircraft was operated by Alitalia Team and was configured for public passenger transport. It was equipped with two Pratt & Whitney JT8D-217A engines. The same crew and aircraft had operated the previous flight from Turin to Naples.
Investigation Details
Witnessed by the crew, around 19:36, the left engine parameters (EPR, EGT, N1, N2, oil pressure) began to drop, followed by thrust loss. Despite advancing the throttle, all parameters continued to decrease until the engine stopped completely two minutes after the onset. After landing, ground personnel found a copious external fuel leak from the left engine's pressurization and drain (P&D) valve.
The investigation included analysis of flight data from the DFDR for the event and the previous 20 flights. On 21 February 2001, the P&D valve was examined at Fiat Avio in an "as received" condition. Further tests on 11 April 2001 assessed cover deformations under operating pressures.
Probable Cause
The probable cause of the event was identified as a maintenance error: excessive tightening of two nuts securing the filter cover of the P&D valve, which damaged the threaded seat of the valve body. This led to the fuel leak and subsequent engine flameout.
Safety Actions
The maintenance company responsible had already implemented procedural modifications to prevent recurrence. Therefore, no specific safety recommendations were issued by the investigation agency.