Reporter experienced a partial power loss and made a successful lng at a large airport.

Attributes
ACN	278023
Time
Date	199407
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : nhz
State Reference	ME
Altitude	agl bound lower : 8500 agl bound upper : 8500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : nhz
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise other descent : approach landing other
Flight Plan	VFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : private
Experience	flight time last 90 days : 30 flight time total : 90 flight time type : 700
ASRS Report	278023
Person 2
Affiliation	government : faa
Function	controller : local
Qualification	controller : non radar
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency none taken : unable
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

1) successful emergency landing at nhz. 2) followed engine breakage (apparent exhaust valve break in 6 cylinder lycoming o- 54) in cruise flight. 3) continued use of engine at low power to landing. 4) pre-event contact with local ATC speeded emergency communication and ground crew response. 5) pre-event pilotage had idented nearby large airport (nhz), speeding and shortening emergency descent. 6) low power use of engine to landing (on 5 good cylinders and 1 knocking cylinder) aided control of descent, while minimizing internal engine stresses.

Original NASA ASRS Text

Title: RPTR EXPERIENCED A PARTIAL PWR LOSS AND MADE A SUCCESSFUL LNG AT A LARGE ARPT.

Narrative: 1) SUCCESSFUL EMER LNDG AT NHZ. 2) FOLLOWED ENG BREAKAGE (APPARENT EXHAUST VALVE BREAK IN 6 CYLINDER LYCOMING O- 54) IN CRUISE FLT. 3) CONTINUED USE OF ENG AT LOW PWR TO LNDG. 4) PRE-EVENT CONTACT WITH LCL ATC SPEEDED EMER COM AND GND CREW RESPONSE. 5) PRE-EVENT PILOTAGE HAD IDENTED NEARBY LARGE ARPT (NHZ), SPDING AND SHORTENING EMER DSCNT. 6) LOW PWR USE OF ENG TO LNDG (ON 5 GOOD CYLINDERS AND 1 KNOCKING CYLINDER) AIDED CTL OF DSCNT, WHILE MINIMIZING INTERNAL ENG STRESSES.

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.