|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||atc facility : lrp|
|Altitude||msl bound lower : 7000|
msl bound upper : 7000
|Operator||general aviation : instructional|
|Make Model Name||PA-28 Cherokee Arrow IV|
|Operating Under FAR Part||Part 91|
|Flight Phase||cruise other|
|Function||flight crew : single pilot|
|Qualification||pilot : instrument|
|Experience||flight time last 90 days : 19|
flight time total : 600
flight time type : 100
|Affiliation||government : faa|
|Function||controller : approach|
|Anomaly||aircraft equipment problem : critical|
other anomaly other
|Independent Detector||aircraft equipment other aircraft equipment : unspecified|
other flight crewa
|Resolutory Action||flight crew : declared emergency|
flight crew : overcame equipment problem
During cruise at 7000 ft in thick IMC and rain at handover harrisburg from 124.1 to 126.45 frequency, the radio system started to emit a steadily increasing screeching/screaming high pitch sound overriding all radios, disabling all communications. Simultaneously, the transponder stopped blinking. All other electricals worked. This developed over a period of 20 seconds. I transmitted blind that I had system failure and squawked 7600. I continued on magnetic heading off gyro at altitude but slowed down. I was southeast of harrisburg, northwest of lancaster, west of philadelphia airspace. All radios lost displays and went blank/dark, indicators red-flagged. While continuously transmitting blind, flying the airplane manually, I was going over my checklist and systematically checking all switches and the bus bar. Recycling switches did not help. Ammeter and other electrics looked good and worked. Panel lights worked. I shut off all electricity again and pulled all fuses. Nothing wrong. I set all radios to off. Switched the avionics master to off. Switched all electrics on, then the avionics master to on. Then all radios and navs back on. Transmitted blind. While doing this for the 4TH time, I realized I could not navigation at all and started a controled descent in thick IMC away from the airways, transmitting intentions blind. I broke out at 3000 ft MSL over flat farmland. Continuously transmitting blind. Having contact with ground, I reset the system 3 more times. The 7TH time all radios came back on. I contacted ATC and explained the situation and I was 'nursed' to ptw at 3000 ft. I suspect overvoltage or a short. No overvoltage light came on. The audio panel lit up like a christmas tree before total system failure. It could be the cause. There was nothing available in terms of navigation equipment with which to continue my flight plan. I had no means of navigation left. Unless the system could be restored, I had idented an emergency landing field on a farm. Pilotage was out of the question. P.south. I have ordered a hand-held GPS communication today.
Original NASA ASRS Text
Title: PA28-200R PLT ON IFR FLT PLAN IN IMC HAS TOTAL ELECTRICAL FAILURE. UNABLE TO NAV HE DSNDS TO VFR AND MAKES DIVERSION.
Narrative: DURING CRUISE AT 7000 FT IN THICK IMC AND RAIN AT HANDOVER HARRISBURG FROM 124.1 TO 126.45 FREQ, THE RADIO SYS STARTED TO EMIT A STEADILY INCREASING SCREECHING/SCREAMING HIGH PITCH SOUND OVERRIDING ALL RADIOS, DISABLING ALL COMS. SIMULTANEOUSLY, THE XPONDER STOPPED BLINKING. ALL OTHER ELECTRICALS WORKED. THIS DEVELOPED OVER A PERIOD OF 20 SECONDS. I XMITTED BLIND THAT I HAD SYS FAILURE AND SQUAWKED 7600. I CONTINUED ON MAGNETIC HDG OFF GYRO AT ALT BUT SLOWED DOWN. I WAS SE OF HARRISBURG, NW OF LANCASTER, W OF PHILADELPHIA AIRSPACE. ALL RADIOS LOST DISPLAYS AND WENT BLANK/DARK, INDICATORS RED-FLAGGED. WHILE CONTINUOUSLY XMITTING BLIND, FLYING THE AIRPLANE MANUALLY, I WAS GOING OVER MY CHKLIST AND SYSTEMATICALLY CHKING ALL SWITCHES AND THE BUS BAR. RECYCLING SWITCHES DID NOT HELP. AMMETER AND OTHER ELECTRICS LOOKED GOOD AND WORKED. PANEL LIGHTS WORKED. I SHUT OFF ALL ELECTRICITY AGAIN AND PULLED ALL FUSES. NOTHING WRONG. I SET ALL RADIOS TO OFF. SWITCHED THE AVIONICS MASTER TO OFF. SWITCHED ALL ELECTRICS ON, THEN THE AVIONICS MASTER TO ON. THEN ALL RADIOS AND NAVS BACK ON. XMITTED BLIND. WHILE DOING THIS FOR THE 4TH TIME, I REALIZED I COULD NOT NAV AT ALL AND STARTED A CTLED DSCNT IN THICK IMC AWAY FROM THE AIRWAYS, XMITTING INTENTIONS BLIND. I BROKE OUT AT 3000 FT MSL OVER FLAT FARMLAND. CONTINUOUSLY XMITTING BLIND. HAVING CONTACT WITH GND, I RESET THE SYS 3 MORE TIMES. THE 7TH TIME ALL RADIOS CAME BACK ON. I CONTACTED ATC AND EXPLAINED THE SIT AND I WAS 'NURSED' TO PTW AT 3000 FT. I SUSPECT OVERVOLTAGE OR A SHORT. NO OVERVOLTAGE LIGHT CAME ON. THE AUDIO PANEL LIT UP LIKE A CHRISTMAS TREE BEFORE TOTAL SYS FAILURE. IT COULD BE THE CAUSE. THERE WAS NOTHING AVAILABLE IN TERMS OF NAV EQUIP WITH WHICH TO CONTINUE MY FLT PLAN. I HAD NO MEANS OF NAV LEFT. UNLESS THE SYS COULD BE RESTORED, I HAD IDENTED AN EMER LNDG FIELD ON A FARM. PILOTAGE WAS OUT OF THE QUESTION. P.S. I HAVE ORDERED A HAND-HELD GPS COM TODAY.
Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.