BOSTON, MA, USA
N154US
MCDONNELL DOUGLAS DC-10-40
DRG TAXI TO GATE AFTER LDG, CREW STARTED APU NORMALLY. WHILE TAXIING NR 3 PNEUMATIC DUCT FAIL LT ILLUMINATED. LATER, THE CENTER ACCESSORY COMPT (CAC) DOOR WARNING LT ILLUMINATED AND GND PERS SAW SMOKE EMANATING FM THE FUSELAGE OUTFLOW VALVES. AFTER ENG SHUTDOWN, SMOKE ENTERED THE CABIN AND THE APU TRIPPED OFF. FIRE DEPT PERS FND CAC OUTSIDE DOOR HOT, THEN, USING CABIN FLOOR HATCH, OBSRVED 1-2 FT HIGH FLAMES IN CAC. FIRE WAS EXTINGUISHED WITH DMG LIMITED TO CAC. INVEST REVEALED IMPROPER/LOOSE BATTERY GND CONNECTION. NORMAL CABLE MOVEMENT WOULD LOOSEN CONNECTION DRG BATT DISCONNECT. BURNED INSULATION BLANKETS MET SPEC BUT WERE COATED WITH SYNTHETIC HYD FLUID (SLAT ACTUATOR LKG) AND JET FUEL. FIRE PATTERN SUGGESTED FUEL SEEPAGE ALONG BULKHEAD FASTENER LINE. BATT GND LAST INSTALLED NOV,87. BATT LAST CHDG 2 WKS BEFORE INCIDENT. SERVICE BULLETIN PERTAINING TO BATT GND NOT COMPLIED. INOPERATIVE CAC DRAIN VALVES ALLOWED FUEL TO POOL IN CAC BILGE. NO CAC FIRE WARNING OR EXTINGUISHER SYSTEM WAS INSTALLED.
THE IMPROPER INSTALLATION OF THE BATTERY GROUND CONNECTION THAT RESULTED IN PREMATURE LOOSENING OF THE CONNECTION AND ELECTRICAL ARC IGNITION OF POOLED FUEL IN THE CAC BILGE. THE FUEL WAS NOT DRAINED OVERBOARD DUE TO INOPERATIVE CAC BILGE AREA DRAIN VALVES. CONTRIBUTING TO THE INCIDENT WAS NORTHWEST'S NON-COMPLIANCE WITH A SERVICE BULLETIN TO MODIFY THE GROUND CABLE ATTACHMENT BRACKET TO PREVENT LOOSENING OF THE CONNECTION.
Source: NTSB Aviation Accident Database
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