Pilot of small aircraft private aircraft experienced a loss of power and was forced to land.

Attributes
ACN	226294
Time
Date	199211
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : nh14
State Reference	NH
Altitude	msl bound lower : 5500 msl bound upper : 5500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : instrument pilot : atp
Experience	flight time last 90 days : 8 flight time total : 2500 flight time type : 300
ASRS Report	226294
Events
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 other
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

Leveling at 5500 ft -- 40 min into flight with full tanks 100 low lead. Temperature -08 degrees C, smooth air, barometer 30.56, engine cycled from 2300 RPM to 1200 RPM repeatedly to landing on private gravel strip (freedom-mt washington- gateway). Subsequent runup and flts show no problem. 2 attending a&P mechanics stated their belief as valve problems. Valves had been checked, pushrod cleaned 16 hours prior. Fuel system placarded 'switch to single tank operation immediately reaching cruise altitudes above 5000 ft.' had not leveled. Reached 5500 ft and had decided to immediately descend to landing at kbml, with right turn to clear mountains. Density altitude below 4000 ft always. All mechanics believe placarded problem did not occur. 2 previous occurrences (aircraft). Callback conversation with reporter revealed the following information: reporter stated that there has been nothing found to cause the engine failure. However, water in the fuel system was discussed and a faulty ignition system. He said that the latter was a possibility since the mechanic did find a problem with one of the magnetos. He further stated that the flying club in which this aircraft is used, is adding new procedures to write up mechanical discrepancies for not only the maintenance personnel, but the other club members so that the aircraft will not be used with a known problem.

Original NASA ASRS Text

Title: PLT OF SMA PRIVATE ACFT EXPERIENCED A LOSS OF PWR AND WAS FORCED TO LAND.

Narrative: LEVELING AT 5500 FT -- 40 MIN INTO FLT WITH FULL TANKS 100 LOW LEAD. TEMP -08 DEGS C, SMOOTH AIR, BAROMETER 30.56, ENG CYCLED FROM 2300 RPM TO 1200 RPM REPEATEDLY TO LNDG ON PRIVATE GRAVEL STRIP (FREEDOM-MT WASHINGTON- GATEWAY). SUBSEQUENT RUNUP AND FLTS SHOW NO PROBLEM. 2 ATTENDING A&P MECHS STATED THEIR BELIEF AS VALVE PROBLEMS. VALVES HAD BEEN CHKED, PUSHROD CLEANED 16 HRS PRIOR. FUEL SYS PLACARDED 'SWITCH TO SINGLE TANK OP IMMEDIATELY REACHING CRUISE ALTS ABOVE 5000 FT.' HAD NOT LEVELED. REACHED 5500 FT AND HAD DECIDED TO IMMEDIATELY DSND TO LNDG AT KBML, WITH R TURN TO CLR MOUNTAINS. DENSITY ALT BELOW 4000 FT ALWAYS. ALL MECHS BELIEVE PLACARDED PROBLEM DID NOT OCCUR. 2 PREVIOUS OCCURRENCES (ACFT). CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT THERE HAS BEEN NOTHING FOUND TO CAUSE THE ENG FAILURE. HOWEVER, WATER IN THE FUEL SYS WAS DISCUSSED AND A FAULTY IGNITION SYS. HE SAID THAT THE LATTER WAS A POSSIBILITY SINCE THE MECH DID FIND A PROBLEM WITH ONE OF THE MAGNETOS. HE FURTHER STATED THAT THE FLYING CLUB IN WHICH THIS ACFT IS USED, IS ADDING NEW PROCS TO WRITE UP MECHANICAL DISCREPANCIES FOR NOT ONLY THE MAINT PERSONNEL, BUT THE OTHER CLUB MEMBERS SO THAT THE ACFT WILL NOT BE USED WITH A KNOWN PROBLEM.

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.