C152 pilot loses power and is forced to land off airport.

Attributes
ACN	510876
Time
Date	200105
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : hwo.airport
State Reference	FL
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : lax.tower
Operator	general aviation : personal
Make Model Name	Cessna 152
Operating Under FAR Part	Part 91
Flight Phase	landing : roll
Flight Plan	None
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : instrument pilot : multi engine
Experience	flight time last 90 days : 90 flight time total : 500
ASRS Report	510876
Person 2
Affiliation	government : faa
Function	controller : local
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : landed in emergency condition
Consequence	other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

Off airport landing due to loss of power. No injuries, no damage to aircraft. Landed aircraft on roadway outside of populated area. No traffic conflicts. Callback conversation with reporter revealed the following information: reporter advised situation caused by engine failure. A major 'top end' engine job had been completed, and the reporter was conducting the required lycoming engine test and break-in procedure. As the reporter stated, lycoming requires a new washer to be installed with recommended torque. The problem is that the bolt can't be torqued and the gauge gap maintained -- there's not sufficient room to do both at the same time, and there is no safety wire. The break-in procedure requires a 1 hour test. During the test flight, the nut worked loose, causing the exhaust valve to collapse close, causing sufficient back pressure to blow the intake vale, which bent the connecting rod, causing the loss of the cylinder. A C152 will not fly on 3 cylinders. The reporter advised that all parts failed as they should without further engine damage. Lycoming is allegedly aware of the overall problem. The FAA was notified.

Original NASA ASRS Text

Title: C152 PLT LOSES PWR AND IS FORCED TO LAND OFF ARPT.

Narrative: OFF ARPT LNDG DUE TO LOSS OF PWR. NO INJURIES, NO DAMAGE TO ACFT. LANDED ACFT ON ROADWAY OUTSIDE OF POPULATED AREA. NO TFC CONFLICTS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR ADVISED SIT CAUSED BY ENG FAILURE. A MAJOR 'TOP END' ENG JOB HAD BEEN COMPLETED, AND THE RPTR WAS CONDUCTING THE REQUIRED LYCOMING ENG TEST AND BREAK-IN PROC. AS THE RPTR STATED, LYCOMING REQUIRES A NEW WASHER TO BE INSTALLED WITH RECOMMENDED TORQUE. THE PROB IS THAT THE BOLT CAN'T BE TORQUED AND THE GAUGE GAP MAINTAINED -- THERE'S NOT SUFFICIENT ROOM TO DO BOTH AT THE SAME TIME, AND THERE IS NO SAFETY WIRE. THE BREAK-IN PROC REQUIRES A 1 HR TEST. DURING THE TEST FLT, THE NUT WORKED LOOSE, CAUSING THE EXHAUST VALVE TO COLLAPSE CLOSE, CAUSING SUFFICIENT BACK PRESSURE TO BLOW THE INTAKE VALE, WHICH BENT THE CONNECTING ROD, CAUSING THE LOSS OF THE CYLINDER. A C152 WILL NOT FLY ON 3 CYLINDERS. THE RPTR ADVISED THAT ALL PARTS FAILED AS THEY SHOULD WITHOUT FURTHER ENG DAMAGE. LYCOMING IS ALLEGEDLY AWARE OF THE OVERALL PROB. THE FAA WAS NOTIFIED.

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.