Accident Boeing 737-3T0 N12318, Friday 17 March 1989
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Date:Friday 17 March 1989
Time:14:00 LT
Type:Silhouette image of generic B733 model; specific model in this crash may look slightly different    
Boeing 737-3T0
Owner/operator:Continental Airlines
Registration: N12318
MSN: 23369/1188
Year of manufacture:1986
Total airframe hrs:10633 hours
Engine model:CFMI CFM56-3
Fatalities:Fatalities: 0 / Occupants: 69
Other fatalities:0
Aircraft damage: Substantial
Category:Accident
Location:Oakland International Airport, CA (OAK/KOAK) -   United States of America
Phase: Standing
Nature:Passenger - Scheduled
Departure airport:Oakland International Airport, CA (OAK/KOAK)
Destination airport:Denver-Stapleton International Airport, CO (KDEN)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
The crew was not aware an APU fire had occurred at the gate prior to starting the main engines. After departure the airplane experienced severe vibrations; an emergency was declared, and the flight landed without incident. About 1/2 of the underside of the elevator & trim tab were severely fire damaged. The tail cone was charred & blistered over a 3 ft by 3 ft area. Four ground service personnel handled the aircraft during pushback. The APU combustor cap drain line was found clogged with several pieces of room temperature vulcanizing (RTV) material (potting compound) used in the APU buildup process. The APU manufacturer's overhaul manual cautions operators to use RTV sparingly, and to remove any excess prior to installing exhaust pipe shims to prevent plugged fuel drain fittings and torching starts. In addition, the atomizer assembly showed streaking in the primary orifices, and examination of the oil pump revealed slow sequencing (ignition and fuel initiation).

Probable Cause:
Ignition of puddled fuel from a blocked combustor drain line, and a slow start during which fuel was misted and blown out the tail pipe. An existing tailwind at the gate allowed the fuel to wet the tail surfaces and be ignited during the APU start. The operator confirmed using RTV material in the APU buildup process at their facility.

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: DCA89MA034
Status: Investigation completed
Duration: 3 years and 3 months
Download report: Final report

Sources:

NTSB DCA89MA034

https://www.jetphotos.com/photo/10861455 (Photo)

History of this aircraft

Other occurrences involving this aircraft

6 November 1998 N12318 Continental Airlines 0 Newark, NJ min

Revision history:

Date/timeContributorUpdates
24-Mar-2024 10:32 ASN Update Bot Added
04-May-2025 12:44 Justanormalperson Updated [Location, Departure airport, Destination airport, Source, Narrative, ]

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