AN IFR C172 EXPERIENCED UNUSUAL INTERMITTENT ELECTRICAL AND FUEL QTY INDICATION PROBLEMS. THE PLT MADE A SAFE OFF ARPT LNDG.
Synopsis
AN IFR C172 EXPERIENCED UNUSUAL INTERMITTENT ELECTRICAL AND FUEL QTY INDICATION PROBLEMS. THE PLT MADE A SAFE OFF ARPT LNDG.
Narrative
I WAS PLANNING TO DEPART FROM ZZZ AT ABOUT XD00 LCL TIME. HOWEVER; CONVECTIVE ACTIVITY WHICH WAS FORMING IN THE LCL AREA THREATENED TO KEEP MY FRIEND AND I OVERNIGHT; AN OPTION THAT WE PREFERRED TO AVOID. SO; WE DECIDED TO LEAVE EARLIER; AT ABOUT XA00 LCL TIME; INSTEAD. I ATTAINED A WX BRIEFING FROM A BRIEFER OVER THE TELEPHONE AND FROM A COMPUTER; AND DECIDED TO CONTINUE FOR A DEP BACK EVEN THOUGH 2 TSTM CELLS EXISTED IMMEDIATELY FOLLOWING OUR TKOF. THE DEP WAS TYPICAL AND UNEVENTFUL WITH NO FAULTS OBSERVED. SHORTLY FOLLOWING TKOF; THE ZZZ APCH CTLR GAVE ME VECTORS AROUND CONVECTIVE ACTIVITY AND CLRED US DIRECT TO ABC1 VOR SHORTLY AFTER REACHING OUR CRUISE ALT OF 5000 FT. NEARING ABC1 VOR; WHILE TALKING TO CTR; I WAS GIVEN PERMISSION TO TEMPORARILY SWITCH TO FLT WATCH TO GET MORE UPDATED INFO ON ANY CONVECTIVE ACTIVITY THAT MAY HAVE FORMED SINCE OUR DEP. THE CTLR INFORMED ME THAT MORE CONVECTIVE ACTIVITY EXISTED IN THE VICINITY S OF ABC4 VOR. I WAS ONCE AGAIN GIVEN PERMISSION BY CTR TO SWITCH FREQS IN ORDER TO SPEAK WITH ZZZ1 FSS. THIS CTLR INFORMED ME THAT THE CONVECTIVE ACTIVITY STILL EXISTED S OF ZZZ1 AND THAT IT WAS MOVING AT ABOUT 10 KTS E. WHILE ON AIRWAY TO ABC4 VOR; I VISUALLY IDENTED THE CONVECTIVE ACTIVITY IN DISCUSSION; AND THE CTR CTLR CLRED ME TO DEVIATE FROM WX TO THE L OF RTE AS NECESSARY. I ACKNOWLEDGED; AND I TURNED L OFF OF AIRWAY TO A HDG OF ABOUT 120 DEGS; TO THE BEST OF MY MEMORY. AFTER REACHING A SAFE DISTANCE FROM THE ACTIVITY; THE ZZZ2 CTR CTLR CLRED ME DIRECT TO ZZZ2 AND I AGAIN ACKNOWLEDGED. SHORTLY AFTER RECEIVING THIS CLRNC; A SERIES OF EVENTS BEGAN WHICH LED TO THE EMER LNDG. FIRST; I NOTICED THAT THE FUEL GAUGES INDICATE AT OR NEAR EMPTY. BEFORE LEAVING ZZZ1; I VISUALLY CONFIRMED THROUGH THE USE OF A DIPSTICK THAT I HAD 28 GALS OF FUEL TOTAL. WITH THAT; I EXPECTED AN ENDURANCE OF 3 HRS. THAT IS PLENTY TO COVER THE ESTIMATED TIME ENRTE OF 2 HRS PLUS THE IFR FUEL REQUIREMENTS OF 45 MINS OF FLYING TIME PLUS THE TIME IT TAKES TO FLY TO THE PLANNED ALTERNATE. THROUGHOUT THE FLT; I NOTICED THAT THE FUEL GAUGES WERE FLUCTUATING RATHER SIGNIFICANTLY. THEY WOULD INDICATE LESS OF FUEL REMAINING IN 1 TANK IN ONE MOMENT; AND THEN UP TO EQUAL OR MORE OF FUEL REMAINING THE NEXT MOMENT. THIS WAS OCCURRING TO THE FUEL GAUGES FOR BOTH FUEL TANKS. SHORTLY THEREAFTER; I EXPERIENCED AN ELECTRICAL FAILURE TO A DEGREE. I NOTICED MY GPS (GARMIN 430) HAD TURNED OFF; AND THE ENTIRE RADIO STACK SEEMED TO BE UNDERGOING LARGE FLUCTUATIONS IN ELECTRICAL FLOW. IN DETAIL; ALL OF THE LIGHTS FOR THE RADIO CTLS WERE DIMMING AND THEN LIGHTING UP AGAIN EVERY SECOND OR SO; AND THE RADIOS THEMSELVES SEEMED TO KEEP RESETTING. THIS INCLUDED THE XPONDER AS WELL. I ATTEMPTED TO ENTER 7600 INTO THE XPONDER; BUT THE DIGITS WOULD NOT CHANGE AND IT REMAINED ON MY ASSIGNED XPONDER CODE. I THEN ATTEMPTED TO CONTACT THE GUARD FREQ; BUT AS I SAID; THE RADIOS CONTINUED TO RESET; DISABLING MY ABILITY TO SPEAK TO A CTLR OR STAY ON A CERTAIN FREQ. AT THIS POINT; I HAD ALREADY BEGUN MY DSCNT FOR A LNDG. ALSO AT THIS POINT; I WAS AWARE THAT THE FAR'S STATE THAT WHILE ON AN IFR FLT PLAN IN VMC; I COULD HAVE CONTINUED TO THE NEAREST SUITABLE ARPT IN THE EVENT OF A COMS FAILURE TO INVESTIGATE THE PROB. HOWEVER; VARIOUS FACTORS LED ME TO DECIDE TO CONDUCT AN EMER LNDG INTO A REMOTE FIELD. 1) MY FUEL GAUGES WERE INDICATING AT OR NEAR EMPTY; AS I EXPLAINED ABOVE. I DID NOT KNOW IF A FUEL LEAK EXISTED THAT I WAS UNAWARE OF OR IF I HAD SOMEHOW ALREADY BURNT 3 HRS WORTH OF FUEL. WHEN I WAS INITIATING THE DSCNT; I THOUGHT IT WAS MORE PROBABLE THAT I WAS RUNNING LOW OR POSSIBLY EMPTY ON FUEL AND THE ENG WAS BEGINNING TO FAIL; WHICH I THOUGHT WOULD EXPLAIN THE ELECTRICAL ISSUES. 2) I KNEW MY APPROX POS AT THE TIME; WHICH WAS ABOUT 20-30 MI E OF ABC4 VOR; OR ROUGHLY HALF-WAY BTWN ABC4 VOR AND THE ZZZ3 AREA. WITHOUT LOOKING AT A SECTIONAL; I ALREADY KNEW THAT THE AREA WAS SPARSE OF EVEN AN UNCTLED ARPT. I LATER LEARNED THAT THE NEAREST ARPT WAS ABOUT 16-20 MI FURTHER S. SINCE I WORRIED THAT WE MAY HAVE BEEN DANGEROUSLY LOW ON FUEL; I DID NOT WANT TO RISK FLYING ANOTHER DISTANCE TO LAND AT AN ARPT (WHICH POSSIBLY COULD HAVE BEEN IN A POPULATED AREA) AND POSSIBLY LOSING THE ENG ENTIRELY. 3) I COULD NOT MANIPULATE THE NAV OF ADF FREQS. THEREFORE; I HAD NO ACCURATE WAY OF NAVING TO A VOR OR NDB WHICH MAY OR MAY NOT HAVE LED ME TO A SUITABLE ARPT. I CONTINUED A PWR-OFF DSCNT (KEEP IN MIND; THE ENG WAS STILL RUNNING). THE LNDG WAS SAFE AND NORMAL AND WAS CONDUCTED INTO AN UNCUT FIELD IN ZZZ4. AFTER SHUTTING DOWN AND SECURING THE ACFT; I EXITED AND I CONFIRMED THAT THERE WAS NO VISUAL DAMAGE TO THE ACFT. NO INJURIES WERE ENCOUNTERED. I VISUALLY INSPECTED THE FUEL TANKS; AND DETERMINED THAT THERE WAS SUFFICIENT FUEL TO COMPLETE OUR FLT TO ZZZ2 CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE REPORTER STATED THAT AFTER LANDING HE EXAMINED THE FUEL TANKS AND DISCOVERED THAT THERE WAS SUFFICIENT FUEL TO CONTINUE TO THE DESTINATION. HOWEVER; BECAUSE HE LANDED IN A FIELD WITH AN UNKNOWN ELECTRICAL PROBLEM HE DID NOT TAKE OFF. THE NEXT DAY HIS INSTRUCTOR CAME TO THE ACFT WITH A FERRY PERMIT AND THEY FLEW THE ACFT TO THE HOME ARPT WITH NO ELECTRICAL OR FUEL PROBLEMS. THE REPORTER SUSPECTS THE ELECTRICAL PROBLEM THAT HE EXPERIENCED WAS DUE TO THE STATIC ELECTRICITY IN THE AREA WHERE THERE WERE NUMEROUS THUNDERSTORMS THE PREVIOUS DAY. HE DOES NOT BELIEVE THERE WAS ANYTHING WRONG WITH THE ACFT. IT IS THIRTY YEARS OLD AND HAS SOME IDIOSYNCRASIES.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.