Narrative:

After IFR takeoff from fnl in PA31R and climbing in VMC on heading assigned by ATC at about 7000 ft MSL, the rate of climb diminished considerably. The right gear had fallen down into the down and locked position. Cycling the gear first had no effect on the condition. At this time ATC was informed of the abnormal, gear condition and vectors to longmont airport requested. During this vector phase the clearance was amended to maintain 7000 ft MSL. ATC reported direction and distance to longmont airport and while looking for the airport, the left gear descended to the down and locked position and the aircraft began a slow descent. ATC reminded me of the 7000 ft clearance. The aircraft had descended to approximately 6000 ft MSL before correction. The airport was then sighted and IFR canceled with a safe landing made at longmont. Inspection of the aircraft revealed a shorted and almost burned up electrical motor in the hydraulic power pack. Continued flight with the gear selected up may have caused an in-flight fire. Callback conversation with reporter revealed the following information: reporter was actually in a PA32R-301T aircraft. He stated that the post-flight inspection by the owner and the mechanic disclosed a burned out hydraulic pump motor. The fault was a 'high resistance' short that did not exceed the trip level of the circuit breaker. He thought that this circuit breaker is not available to in-flight access and the only other way of turning off power to the motor is to turn off the aircraft's master power switch. The fault in the motor occurs around the 800 hour level in older pipers, with a $3000 dollar replacement cost. Reporter said that this is a known problem to piper aircraft and to the mechanics that service these aircraft. He referred to this as being 'an urban legend within the aviation community.' the danger that exists within this scenario of an uncommanded gear extension is that if it occurs at a high speed it can break a gear door loose thereby threatening the integrity of the horizontal stabilizer by a chance in-flight impact with a broken and released gear door. The owner has an extensive library of aircraft information related to this type aircraft and didn't know anything about the discrepancy regarding the pump motor. The reporter does not know of any outstanding 'airworthy directives' regarding this aircraft and the motor problem. The motor in this event was smoking quite badly after the aircraft landed. The gear selector is an up-down type with no 'off' in between. The gear is held in the up position by hydraulic pressure with a hydraulic assist going to the down position. No hydraulic pressure equals an uncommanded gear free fall.

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Original NASA ASRS Text

Title: PA31 PLT EXECUTES A DIVERSION TO ALTERNATE WHEN MAIN LNDG GEARS FREE FALL AND AFFECT ACFT PERFORMANCE. ALTDEV ALT EXCURSION FROM ASSIGNED. FLT ASSIST FROM ATC TO V2V, CO.

Narrative: AFTER IFR TKOF FROM FNL IN PA31R AND CLBING IN VMC ON HEADING ASSIGNED BY ATC AT ABOUT 7000 FT MSL, THE RATE OF CLB DIMINISHED CONSIDERABLY. THE R GEAR HAD FALLEN DOWN INTO THE DOWN AND LOCKED POS. CYCLING THE GEAR FIRST HAD NO EFFECT ON THE CONDITION. AT THIS TIME ATC WAS INFORMED OF THE ABNORMAL, GEAR CONDITION AND VECTORS TO LONGMONT ARPT REQUESTED. DURING THIS VECTOR PHASE THE CLRNC WAS AMENDED TO MAINTAIN 7000 FT MSL. ATC RPTED DIRECTION AND DISTANCE TO LONGMONT ARPT AND WHILE LOOKING FOR THE ARPT, THE L GEAR DSNDED TO THE DOWN AND LOCKED POS AND THE ACFT BEGAN A SLOW DSCNT. ATC REMINDED ME OF THE 7000 FT CLRNC. THE ACFT HAD DSNDED TO APPROX 6000 FT MSL BEFORE CORRECTION. THE ARPT WAS THEN SIGHTED AND IFR CANCELED WITH A SAFE LNDG MADE AT LONGMONT. INSPECTION OF THE ACFT REVEALED A SHORTED AND ALMOST BURNED UP ELECTRICAL MOTOR IN THE HYD PWR PACK. CONTINUED FLT WITH THE GEAR SELECTED UP MAY HAVE CAUSED AN INFLT FIRE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR WAS ACTUALLY IN A PA32R-301T ACFT. HE STATED THAT THE POST-FLT INSPECTION BY THE OWNER AND THE MECH DISCLOSED A BURNED OUT HYD PUMP MOTOR. THE FAULT WAS A 'HIGH RESISTANCE' SHORT THAT DID NOT EXCEED THE TRIP LEVEL OF THE CIRCUIT BREAKER. HE THOUGHT THAT THIS CIRCUIT BREAKER IS NOT AVAILABLE TO INFLT ACCESS AND THE ONLY OTHER WAY OF TURNING OFF PWR TO THE MOTOR IS TO TURN OFF THE ACFT'S MASTER PWR SWITCH. THE FAULT IN THE MOTOR OCCURS AROUND THE 800 HR LEVEL IN OLDER PIPERS, WITH A $3000 DOLLAR REPLACEMENT COST. RPTR SAID THAT THIS IS A KNOWN PROB TO PIPER ACFT AND TO THE MECHS THAT SVC THESE ACFT. HE REFERRED TO THIS AS BEING 'AN URBAN LEGEND WITHIN THE AVIATION COMMUNITY.' THE DANGER THAT EXISTS WITHIN THIS SCENARIO OF AN UNCOMMANDED GEAR EXTENSION IS THAT IF IT OCCURS AT A HIGH SPD IT CAN BREAK A GEAR DOOR LOOSE THEREBY THREATENING THE INTEGRITY OF THE HORIZ STABILIZER BY A CHANCE INFLT IMPACT WITH A BROKEN AND RELEASED GEAR DOOR. THE OWNER HAS AN EXTENSIVE LIBRARY OF ACFT INFO RELATED TO THIS TYPE ACFT AND DIDN'T KNOW ANYTHING ABOUT THE DISCREPANCY REGARDING THE PUMP MOTOR. THE RPTR DOES NOT KNOW OF ANY OUTSTANDING 'AIRWORTHY DIRECTIVES' REGARDING THIS ACFT AND THE MOTOR PROB. THE MOTOR IN THIS EVENT WAS SMOKING QUITE BADLY AFTER THE ACFT LANDED. THE GEAR SELECTOR IS AN UP-DOWN TYPE WITH NO 'OFF' IN BTWN. THE GEAR IS HELD IN THE UP POS BY HYD PRESSURE WITH A HYD ASSIST GOING TO THE DOWN POS. NO HYD PRESSURE EQUALS AN UNCOMMANDED GEAR FREE FALL.

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.