# NTSB DCA89MA034: Boeing 737-300, N12318, Oakland, CA, March 17, 1989

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Major investigation · Final report
- Date: March 17, 1989, 12:00 local (20:00 UTC)
- Place: Oakland, CA
- Location: 37.7213° N, 122.2212° W: Placed by OpenAirDocs at OAKLAND SAN FRANCISCO BAY (OAK), within about a mile (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=37.7213&lon=-122.2212&mi=10
- Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 69 uninjured
- Status: Completed, report June 26, 1992
- Report: Approved by Office Director
- NTSB office: Major Investigations Division
- NTSB case key (mKey): 15917
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DCA89MA034
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/15917/pdf
- Page: https://openairdocs.org/ntsb/DCA89MA034

## 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

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Fire, standing - starting engine(s)
  - auxiliary power unit - blocked(partial) (cause)
  - maintenance,overhaul - inadequate, company maintenance personnel (cause)
  - auxiliary power unit - fire

## 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](https://openairdocs.org/deregistered/N12318-2013-03-21), registration cancelled 2013-03-21, S/N 23369, built 1986 (OpenAirDocs)
- Reported make and model: BOEING 737-300
- Registry model: [Boeing 737-3TO](https://openairdocs.org/model/boeing-737-3to) (registry code 138447G) (OpenAirDocs)
- Registry engine: [CFM International CFM56 series](https://openairdocs.org/engine/cfm-international-cfm56-series) (registry code 13802, turbo-fan) (OpenAirDocs)
- Category: Airplane
- Serial number: 318
- Airframe hours: 10633
- Engines: 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

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 42; 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)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB NYC99IA024](https://openairdocs.org/ntsb/NYC99IA024), Nov 6, 1998: Boeing 737-3TO (N12318), Newark, NJ, incident, minor damage. Probable cause: A loss of torque on the apex nut of the shimmy damper for undetermined reason(s), which resulted in a failure of the shimmy damper, and the subsequent failure of the lower torsion link of the right…

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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