EXPEDITED APCH AND LNDG ACCOUNT FUEL FUMES IN THE COCKPIT AREA.

Date: 1988-07 · Aircraft: Small Transport; Low Wing; 2 Recip Eng

Anomalies: aircraft-equipment-problem-critical|other-unspecified

Synopsis

EXPEDITED APCH AND LNDG ACCOUNT FUEL FUMES IN THE COCKPIT AREA.

Narrative

THIS EVENT FITS NEITHER THE USUAL ASRS CRITERIA NOR THE NTSB RPTING REQUIREMENTS; BUT I FEEL THAT SOMEONE OUGHT TO BE INFORMED ABOUT IT; AND YOU FOLKS SEEMED TO BE THE BEST BET. I WAS ON A SHORT HOP FROM MY BASE AT GNOSS FIELD; NOVATO; CA; TO MONTEREY PENINSULA ARPT TO POS THE ACFT FOR A CHARTER PICKUP. SHORTLY AFTER I TOPPED OUT MY CLB AT 9500; MY RIGHT ENG BEGAN TO SURGE; SO I TURNED ON THE BOOST PUMPS. THE RIGHT ENG IMMEDIATELY STABILIZED; AND I THOUGHT NO MORE ABOUT IT. SHORTLY AFTER XING WOODSIDE VOR; I BEGAN TO SMELL FUEL FUMES. I RAN THE CONTAMINATED AIR CHKLIST; WHICH SEEMED TO ALLEVIATE THE SMELL SOMEWHAT; NOTIFIED OAKLAND CENTER OF MY SITUATION; AND BEGAN TRYING TO FIGURE OUT WHERE THE SMELL WAS COMING FROM. THE CENTER HANDED ME OFF TO MONTEREY APCH; AND I INFORMED THE NEW CTLR THAT THE SMELL WAS GETTING WORSE DESPITE MY HAVING RUN THE CONTAMINATED AIR PROC. THE FUEL VAPOR IN THE CABIN WAS SO STRONG THAT I BECAME CERTAIN THAT IF FURTHER CORRECTIVE ACTION WAS NOT TAKEN; I WOULD PROBABLY EXPERIENCE AN EXPLOSION AND CATASTROPHIC DESTRUCTION OF THE ACFT; MISSING OUT ON THE OPPORTUNITY TO FIND OUT WHAT ON EARTH HAD HAPPENED; NOT TO MENTION LIVING OUT THE REST OF MY LIFE. I DEPRESSURIZED THE AIRPLANE; OPENED THE VENT WINDOWS; AND TOOK ADVANTAGE OF THE OFFER OF THE APCH AND TWR CTLRS TO GET EVERYONE OUT OF MY WAY AND CALL OUT THE FIRE TRUCKS. I LANDED THE ACFT W/O FURTHER INCIDENT; BUT; HAD I KNOWN THEN WHAT I KNOW NOW; I SURE WOULDN'T HAVE USED THE ELECTRIC FLAP AND GEAR SYS. SINCE THE SMELL WAS THE STRONGEST COMING OUT OF THE OVERHEAD AIR GASPERS; I WAS CONVINCED THAT THE FUEL VAPOR WAS ENTERING THE PRESSURIZED AIR SYS SOMEWHERE IN THE ENG NACELLES; AND THAT I HAD ALLEVIATED THE PROB BY DUMPING THE RAM AIR AND DEPRESSURIZING; VENTILATING THE CABIN. I COULD NOT HAVE BEEN MORE WRONG. LATER INSPECTION OF THE ACFT REVEALED THAT AN ELECTRICAL WIRE HAD BEEN RUN FROM A CIRCUIT BREAKER AND LEFT FORGOTTEN; WITH ITS BARE END UNDER THE DECK BENEATH THE PLT'S SEAT AND LYING ON ONE OF THE FUEL XFEED LINES (WHICH SOME LUNATIC IN THE FAA CERTIFICATION BRANCH ALLOWED TO RUN INSIDE THE PRESSURE VESSEL). OVER TIME; THE WIRE HAD GNDED TO THE FUEL LINE; AND THE RESULTING ARC HAD WEAKENED THE FUEL LINE WHICH ULTIMATELY BURST (REMEMBER WHEN MY RIGHT ENG BEGAN SURGING?); ULTIMATELY TRANSFERRING MOST OF THE 300 # OF FUEL IN MY TIP TANK TO THE 'BILGE' UNDER THE CABIN. MY THEORY OF WHY THE WHOLE THING DID NOT BECOME A FIREBALL; ESPECIALLY WHEN I USED THE ELECTRIC (DC MOTORS WITH BRUSHES THAT ARC) FLAP AND GEAR MOTORS IS THAT; BY THAT TIME; THEY WERE BOTH IMMERSED IN FUEL; AND NO AIR COULD GET TO THEM TO SUPPORT COMBUSTION. I HOPE YOU FIND THIS INFO OF SOME USE. KEEP UP THE GOOD WORK; AND LET ME SAY IN CLOSING THAT IT SURE IS NICE TO BE HERE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: FAA DID NOT INVESTIGATE THE INCIDENT; PROBABLY BECAUSE AN EMER WAS NOT DECLARED. THIS IS NOT A DESIGN PROB. THE ACFT HAD EXTENSIVE AVIONICS MODIFICATION DONE AT A MUCH EARLIER DATE; INSTALLING FANCY COM EQUIP; AND HE FEELS THE SHOP MECH FORGOT THIS ONE WIRE AND IT EVENTUALLY GNDED TO THE FUEL LINE. LNDG WAS MADE AT MRY W/O ANY PROB.

Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.