Aviation Accident Summaries

Aviation Accident Summary FTW95LA313

AKRON, CO, USA

Aircraft #1

N593JN

STEINKE EARLY BIRD

Analysis

THE PILOT SAID THAT DURING TAKEOFF FROM AN EN ROUTE STOP ON A CROSS-COUNTRY FLIGHT, THE AIRCRAFT FELT SLUGGISH AFTER BECOMING AIRBORNE AND THAT THE ENGINE FAILED TO PRODUCE SUFFICIENT POWER TO REMAIN IN THE AIR. A FORCED LANDING WAS MADE WHICH WAS HARD. REPORTEDLY, THE AIRCRAFT BOUNCED AND DRIFTED OFF THE RUNWAY, WHERE IT TOUCHED DOWN, SHEARING OFF THE MAIN LANDING GEAR AND NOSED OVER. THE AIRCRAFT WAS EQUIPPED WITH A ROTORY ENGINE. EXAMINATION OF THE ROTORY ENGINE PROVIDED EVIDENCE THAT THE PTO SIDE RAVE VALVE MAY HAVE STUCK SHUT, LIMITING MAXIMUM RPM. ALSO, THE MIXTURE (WHICH WAS ADJUSTABLE ON THE GROUND) WAS SET SO THAT THE CARBURETOR JETTING WAS TOO RICH FOR THE DENSITY ALTITUDE. THE DENSITY ALTITUDE AT THE AIRPORT WAS APPROXIMATELY 7,200 FEET AT THE TIME OF TAKEOFF.

Factual Information

On July 23, 1995, at 1200 mountain daylight time, a homebuilt Steinke Early Bird homebuilt (2/3 scale Jenny), N593JN, landed hard following a partial power loss on takeoff from Akron, Colorado. The pilot was not injured and the aircraft sustained substantial damage. Visual meteorological conditions prevailed and no flight plan was filed for this personal flight to Oshkosh, Wisconsin. According to the pilot, the aircraft was sluggish after takeoff and in an interview said the "engine was not developing sufficient power to remain airborne." The pilot stated that he made a hard landing, bounced, and allowed the aircraft to drift off the runway where it touched down breaking off the main landing gear and nosed over. The engine was removed and sent to Northland Recreational Products, Phillips, Wisconsin, for examination. According to the attached examination report provided by that facility, there were several problems noted with the engine which would account for the partial power loss. Item number 2 reported a PTO side rave valve possibly being stuck shut. This may have caused maximum rpm to be limited. Item number 3 reported a problem with an overly rich mixture. This problem would be exacerbated by density altitude which was approximately 7,200 feet above mean sea level at the Akron Airport.

Probable Cause and Findings

FAILURE OF THE PILOT TO PROPERLY FLARE THE AIRPLANE FOR LANDING DURING AN EMERGENCY LANDING AFTER TAKEOFF. FACTORS RELATING TO THE ACCIDENTS WERE: A MALFUNCTION OF THE SIDE RAVE VALVE, AN EXCESSIVELY RICH FUEL MIXTURE, AND THE HIGH DENSITY ALTITUDE, WHICH RESULTED IN A PARTIAL LOSS OF ENGINE POWER.

 

Source: NTSB Aviation Accident Database

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