Engine failure. Emergency landing on highway.

Attributes
ACN	302760
Time
Date	199504
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : azq
State Reference	KY
Altitude	msl bound lower : 5500 msl bound upper : 5500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 35 flight time total : 420 flight time type : 79
ASRS Report	302760
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : critical
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:

While en route to W13 from M52 at 5500 ft MSL a loud explosion occurred without warning. Vibration of the engine was severe. I reduced power to idle and the vibration quit. Any increase in power increased vibration. I kept the throttle to idle and declared mayday to ZID with whom I was in contact through flight following. I determined the nearest airport to be 10 mi into the wind and immediately knew that it was not an option. I had just passed over a 4-LANE highway so I told center that I was going to land there. I then flew along the highway until I found a suitable area. I was able to navigation through the electrical lines and miss traffic. There were no injuries and no damage to the aircraft or any other structures. I then radioed to another aircraft that I was safe and he relayed the information to ZID. The aircraft was taken to a salvage yard adjacent to the highway where it was repaired by an a&east mechanic. The following day the police blocked the road and a cfii flew the plane off the road and to hazard, ky, airport. The engine was found to have physically blown a spark plug out of the engine. The copper washer had previously deformed from over-torquing.

Original NASA ASRS Text

Title: ENG FAILURE. EMER LNDG ON HWY.

Narrative: WHILE ENRTE TO W13 FROM M52 AT 5500 FT MSL A LOUD EXPLOSION OCCURRED WITHOUT WARNING. VIBRATION OF THE ENG WAS SEVERE. I REDUCED PWR TO IDLE AND THE VIBRATION QUIT. ANY INCREASE IN PWR INCREASED VIBRATION. I KEPT THE THROTTLE TO IDLE AND DECLARED MAYDAY TO ZID WITH WHOM I WAS IN CONTACT THROUGH FLT FOLLOWING. I DETERMINED THE NEAREST ARPT TO BE 10 MI INTO THE WIND AND IMMEDIATELY KNEW THAT IT WAS NOT AN OPTION. I HAD JUST PASSED OVER A 4-LANE HWY SO I TOLD CTR THAT I WAS GOING TO LAND THERE. I THEN FLEW ALONG THE HWY UNTIL I FOUND A SUITABLE AREA. I WAS ABLE TO NAV THROUGH THE ELECTRICAL LINES AND MISS TFC. THERE WERE NO INJURIES AND NO DAMAGE TO THE ACFT OR ANY OTHER STRUCTURES. I THEN RADIOED TO ANOTHER ACFT THAT I WAS SAFE AND HE RELAYED THE INFO TO ZID. THE ACFT WAS TAKEN TO A SALVAGE YARD ADJACENT TO THE HWY WHERE IT WAS REPAIRED BY AN A&E MECH. THE FOLLOWING DAY THE POLICE BLOCKED THE ROAD AND A CFII FLEW THE PLANE OFF THE ROAD AND TO HAZARD, KY, ARPT. THE ENG WAS FOUND TO HAVE PHYSICALLY BLOWN A SPARK PLUG OUT OF THE ENG. THE COPPER WASHER HAD PREVIOUSLY DEFORMED FROM OVER-TORQUING.

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.