Serious incident ATR 72-212 N434AT, Monday 11 January 2010
ASN logo
This information is added by users of ASN. Neither ASN nor the Flight Safety Foundation are responsible for the completeness or correctness of this information. If you feel this information is incomplete or incorrect, you can submit corrected information.

Date:Monday 11 January 2010
Time:20:00 LT
Type:Silhouette image of generic AT72 model; specific model in this crash may look slightly different    
ATR 72-212
Owner/operator:American Airlines
Registration: N434AT
MSN: 434
Year of manufacture:1994
Engine model:Pratt & Whitney PW127
Fatalities:Fatalities: 0 / Occupants: 48
Other fatalities:0
Aircraft damage: Minor
Category:Serious incident
Location:Saint Croix-Henry E. Rohlsen Airport (STX/TISX) -   U.S. Virgin Islands
Phase: Take off
Nature:Passenger - Scheduled
Departure airport:Saint Croix-Henry E. Rohlsen Airport (STX/TISX)
Destination airport:Saint Croix-Henry E. Rohlsen Airport (STX/TISX)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
During takeoff the No. 1 (left) engine fire warning illuminated in the cockpit. The pilot declared an emergency, shut down the No. 1 engine and discharged one fire bottle. The fire warning continued and the pilot discharged the second bottle; but the fire warning did not extinguish. The pilot performed an air turnback and landed the airplane uneventfully approximately 11 minutes later.

Engine testing at the manufacturer's facility revealed a large fuel leak emanating from the No. 2 fuel nozzle manifold adapter-to-transfer tube O-ring connection.

Examination revealed two manufacturing defects in the No. 2 fuel nozzle manifold adapter. The first defect, poor surface finish, caused damage to the transfer tube O-ring during the installation process, initiating an internal fuel leak. The second defect, blockage of the internal safety tell-tale drain due to an improper machining and subsequent cleaning procedure, prevented the leaking fuel from flowing into the tell-tale drain and being detected by maintenance personnel.

Examination of the transfer tubes revealed an undersized O-ring retention zone, which allowed the O-ring to fit loosely such that it was not capable of withstanding continuous maximum fuel pressure load. Eventually the O-ring failed to seal properly, fuel leaked and was ignited by the hot combustor case. The undersized O-ring retention zone was created during the cleaning and overhaul process of the transfer tube.

Probable Cause: The sealing failure between the fuel nozzle adapter assembly and fuel transfer tubes that allowed fuel to leak into the nacelle fire zone where it was subsequently ignited by the hot combustor case. Contributing to the failure was a combination of manufacturing defects of the fuel nozzle adapter assembly by the manufacturer and incorrectly overhauled fuel transfer tubes by the engine manufacturer. Contributing to the incident was a second defect of the fuel nozzle adapter assembly by the manufacturer which prevented maintenance personnel from detecting the internal fuel leak.

Accident investigation:
Investigating agency: NTSB
Report number: ENG10IA010
Status: Investigation completed
Duration: 3 years and 7 months
Download report: Final report



Revision history:

02-Jun-2023 19:19 ASN Update Bot Added
04-Jun-2023 05:53 harro Updated

Corrections or additions? ... Edit this accident description

The Aviation Safety Network is an exclusive service provided by:
Quick Links:

CONNECT WITH US: FSF on social media FSF Facebook FSF Twitter FSF Youtube FSF LinkedIn FSF Instagram

©2024 Flight Safety Foundation

1920 Ballenger Av, 4th Fl.
Alexandria, Virginia 22314