C152 instructor and student had the engine quit.

Attributes
ACN	435996
Time
Date	199904
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : arb.airport
State Reference	MI
Altitude	agl single value : 3000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : arb.tower
Operator	general aviation : instructional
Make Model Name	Cessna 152
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	other
Function	instruction : instructor
Qualification	pilot : cfi pilot : commercial pilot : instrument pilot : multi engine
Experience	flight time last 90 days : 40 flight time total : 5600 flight time type : 200
ASRS Report	435996
Person 2
Affiliation	other
Function	instruction : trainee
Qualification	pilot : student
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : overcame equipment problem
Consequence	other
Supplementary
Problem Areas	Chart Or Publication Aircraft
Primary Problem	Aircraft
Situations
Publication	POH

Narrative:

On apr/xx/99 I was flying with a primary student in a C152 approximately 12 mi west of ann arbor, mi, airport at 3000 ft MSL reviewing air maneuvers including MCA, steep turns and the stall series. I was in the process of demonstrating a power-on stall. As I raised the nose of the C152 the engine began to detonate then ceased operating with the propeller in the vertical position. I chose an appropriate field in which to land, then went through the restart procedure several times without success. Finally, I told the student to prime the engine while I engaged the started. The engine started and we returned to base. In a discussion with the school's mechanic we agreed: 1) when gliding at the best glide speed of 60 KTS the propeller does not rotate and fuel is not metered from the carburetor so the restart procedure will fail. 2) the cessna poh for the C152, C172 and C182 calls for the primer to be in and locked in engine out circumstances. 3) upon disassembly, the carburetor was found to be in good order. The fuel was dry and clean with no pollutants in the carburetor. 4) the probable cause of engine failure was a stuck float valve interrupting the fuel supply to the engine from the carburetor.

Original NASA ASRS Text

Title: C152 INSTRUCTOR AND STUDENT HAD THE ENG QUIT.

Narrative: ON APR/XX/99 I WAS FLYING WITH A PRIMARY STUDENT IN A C152 APPROX 12 MI W OF ANN ARBOR, MI, ARPT AT 3000 FT MSL REVIEWING AIR MANEUVERS INCLUDING MCA, STEEP TURNS AND THE STALL SERIES. I WAS IN THE PROCESS OF DEMONSTRATING A PWR-ON STALL. AS I RAISED THE NOSE OF THE C152 THE ENG BEGAN TO DETONATE THEN CEASED OPERATING WITH THE PROP IN THE VERT POS. I CHOSE AN APPROPRIATE FIELD IN WHICH TO LAND, THEN WENT THROUGH THE RESTART PROC SEVERAL TIMES WITHOUT SUCCESS. FINALLY, I TOLD THE STUDENT TO PRIME THE ENG WHILE I ENGAGED THE STARTED. THE ENG STARTED AND WE RETURNED TO BASE. IN A DISCUSSION WITH THE SCHOOL'S MECH WE AGREED: 1) WHEN GLIDING AT THE BEST GLIDE SPD OF 60 KTS THE PROP DOES NOT ROTATE AND FUEL IS NOT METERED FROM THE CARB SO THE RESTART PROC WILL FAIL. 2) THE CESSNA POH FOR THE C152, C172 AND C182 CALLS FOR THE PRIMER TO BE IN AND LOCKED IN ENG OUT CIRCUMSTANCES. 3) UPON DISASSEMBLY, THE CARB WAS FOUND TO BE IN GOOD ORDER. THE FUEL WAS DRY AND CLEAN WITH NO POLLUTANTS IN THE CARB. 4) THE PROBABLE CAUSE OF ENG FAILURE WAS A STUCK FLOAT VALVE INTERRUPTING THE FUEL SUPPLY TO THE ENG FROM THE CARB.

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.