- Date
- March 17, 1989, 12:00 local (20:00 UTC)
- Place
- Oakland, CA
- Injuries
- 69 uninjured
- Damage
- Substantial damage
- Phase of flight
- Standing
- Aircraft
- N12318Boeing 737-300
- Weather
- Visual (VMC) · Day
- Status
- Completed · report June 26, 1992
- Report
- Approved by Office Director
- NTSB office
- Major Investigations Division
- Case key
- 15917
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
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.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
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).
Aircraft
- Registration
- N12318
- Reported as
- Boeing 737-300
- Category
- Airplane
- Serial number
- 318
- Airframe hours
- 10,633
- Engine
- GE CFM-56-3, turbo fan
- Damage
- Substantial damage
- Fire
- On-Ground
- Flight
- Part 121
- Registered owner
- Continental Airlines Inc.
- Airworthiness certificate
- Standard, Transport
- Destination
- DEN · Denver, CO
- Flight plan
- IFR
- Airport
- OAK · Oakland Intl
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 42
- Certificate
- Airline transport
- Airplane ratings
- Single-engine land, Multi-engine land
- Instrument ratings
- Airplane
- Medical
- Class 1, Valid Medical--no waivers/lim.
- Seat
- Left
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 160° at 7 knots
- Visibility
- 20 statute miles
- Lowest ceiling
- 20,000 ft broken
- Temperature
- 57 °F, dew point 43 °F
- Observed at
- OAK, 5 nm away
Other investigations on N12318 · 1
Matched to the same aircraft by N-number and date.