Narrative:

We departed gallup at AM40 MST with the owner in the left seat. We were level at 8500 ft for 40 mins as we observed oil temperature climb. Propeller governor control, which had evidently become temperature sensitive, was lost as the oil temperature climbed through 180 degree F. To prevent a runaway propeller, we reduced mp, loaded the propeller, and cruise climbed to a colder 10500 ft. After about an hour, we tried 12500 ft, climbing at about 100 FPM. After about 20 mins at 12500 ft we started descent into kingman, az. On downwind for runway 21 at kingman, aircraft was slowed, hydro circuit breaker was reset, gear handle was positioned to 'down' and hydro pressure was up to an expected 900-1000 pounds. On base leg, we consulted with each other to ensure we had 3 green jewel led lights. Uncomfortable with a gear selector handle that moves horizontal instead of vertical, I reconfirmed that the gear selector was positioned to the 'down' slot, and pressure up, during final. Pilot continued a well flown final to touchdown, propeller stopped with 2 aft curled tips and the aircraft settled smoothly onto runway 21, gear up, just short of the intersection with runway 17-35, sliding to a gentle stop. No injuries, minor bottom damage. Both of us had just been fooled by early am sunlight striking the downlight lenses so as to make them appear lit. Proper shading or brighter lamps might have helped correct that problem. Could mild hypoxia have been a factor in our perception of 3 green gear lights? About 45 mins later, aircraft was lifted. No electrical power was needed for the pilot/owner to open the landing gear emergency dump valve. All 3 gear extended and locked, dumping approximately 2 cups of 5606 on the runway, a normal occurrence for 'emergency dump'. Puzzling over why the gear had not extended during initial approach, we've theorized that we had been at freezing altitude long enough to have solidified trapped water somewhere in the gear 'up' lines, preventing fluid return to reservoir and hydro- locking the gear up, or in some transitory position. Moving the gear handle to 'down' mechanically pulls all 3 uplock hooks. Aircraft had been stored outside, inactive for about a yr at santa monica. Water was drained from both fuel tanks during condition inspection. While the gear was drop checked on perhaps a dozen occasions and extended via the emergency dump system at least 4 times, it's conceivable that hydro reservoir condensation could have accumulated at a low point and not manifested itself until altitude cold soak. A quick letdown into the pattern had not allowed warming that would have disguised the condition. 5 previous lndgs from warmer altitudes had been uneventful. Correct through inspection of line low points or install low point drains.

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Original NASA ASRS Text

Title: GEAR UP LNDG.

Narrative: WE DEPARTED GALLUP AT AM40 MST WITH THE OWNER IN THE L SEAT. WE WERE LEVEL AT 8500 FT FOR 40 MINS AS WE OBSERVED OIL TEMP CLB. PROP GOVERNOR CTL, WHICH HAD EVIDENTLY BECOME TEMP SENSITIVE, WAS LOST AS THE OIL TEMP CLBED THROUGH 180 DEG F. TO PREVENT A RUNAWAY PROP, WE REDUCED MP, LOADED THE PROP, AND CRUISE CLBED TO A COLDER 10500 FT. AFTER ABOUT AN HR, WE TRIED 12500 FT, CLBING AT ABOUT 100 FPM. AFTER ABOUT 20 MINS AT 12500 FT WE STARTED DSCNT INTO KINGMAN, AZ. ON DOWNWIND FOR RWY 21 AT KINGMAN, ACFT WAS SLOWED, HYDRO CIRCUIT BREAKER WAS RESET, GEAR HANDLE WAS POSITIONED TO 'DOWN' AND HYDRO PRESSURE WAS UP TO AN EXPECTED 900-1000 POUNDS. ON BASE LEG, WE CONSULTED WITH EACH OTHER TO ENSURE WE HAD 3 GREEN JEWEL LED LIGHTS. UNCOMFORTABLE WITH A GEAR SELECTOR HANDLE THAT MOVES HORIZ INSTEAD OF VERT, I RECONFIRMED THAT THE GEAR SELECTOR WAS POSITIONED TO THE 'DOWN' SLOT, AND PRESSURE UP, DURING FINAL. PLT CONTINUED A WELL FLOWN FINAL TO TOUCHDOWN, PROP STOPPED WITH 2 AFT CURLED TIPS AND THE ACFT SETTLED SMOOTHLY ONTO RWY 21, GEAR UP, JUST SHORT OF THE INTXN WITH RWY 17-35, SLIDING TO A GENTLE STOP. NO INJURIES, MINOR BOTTOM DAMAGE. BOTH OF US HAD JUST BEEN FOOLED BY EARLY AM SUNLIGHT STRIKING THE DOWNLIGHT LENSES SO AS TO MAKE THEM APPEAR LIT. PROPER SHADING OR BRIGHTER LAMPS MIGHT HAVE HELPED CORRECT THAT PROBLEM. COULD MILD HYPOXIA HAVE BEEN A FACTOR IN OUR PERCEPTION OF 3 GREEN GEAR LIGHTS? ABOUT 45 MINS LATER, ACFT WAS LIFTED. NO ELECTRICAL PWR WAS NEEDED FOR THE PLT/OWNER TO OPEN THE LNDG GEAR EMER DUMP VALVE. ALL 3 GEAR EXTENDED AND LOCKED, DUMPING APPROX 2 CUPS OF 5606 ON THE RWY, A NORMAL OCCURRENCE FOR 'EMER DUMP'. PUZZLING OVER WHY THE GEAR HAD NOT EXTENDED DURING INITIAL APCH, WE'VE THEORIZED THAT WE HAD BEEN AT FREEZING ALT LONG ENOUGH TO HAVE SOLIDIFIED TRAPPED WATER SOMEWHERE IN THE GEAR 'UP' LINES, PREVENTING FLUID RETURN TO RESERVOIR AND HYDRO- LOCKING THE GEAR UP, OR IN SOME TRANSITORY POS. MOVING THE GEAR HANDLE TO 'DOWN' MECHANICALLY PULLS ALL 3 UPLOCK HOOKS. ACFT HAD BEEN STORED OUTSIDE, INACTIVE FOR ABOUT A YR AT SANTA MONICA. WATER WAS DRAINED FROM BOTH FUEL TANKS DURING CONDITION INSPECTION. WHILE THE GEAR WAS DROP CHKED ON PERHAPS A DOZEN OCCASIONS AND EXTENDED VIA THE EMER DUMP SYS AT LEAST 4 TIMES, IT'S CONCEIVABLE THAT HYDRO RESERVOIR CONDENSATION COULD HAVE ACCUMULATED AT A LOW POINT AND NOT MANIFESTED ITSELF UNTIL ALT COLD SOAK. A QUICK LETDOWN INTO THE PATTERN HAD NOT ALLOWED WARMING THAT WOULD HAVE DISGUISED THE CONDITION. 5 PREVIOUS LNDGS FROM WARMER ALTS HAD BEEN UNEVENTFUL. CORRECT THROUGH INSPECTION OF LINE LOW POINTS OR INSTALL LOW POINT DRAINS.

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.