Accident Details
On August 13, 2013, at about 1240 Alaska daylight time, a float-equipped Piper PA-18-150 airplane, registered as N44RT, sustained substantial damage during a forced landing following a partial loss of engine power. The accident occurred near Paxson, Alaska. The private pilot and one passenger were not injured.
The airplane was registered to and operated by the pilot as a visual flight rules personal cross-country flight under 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated from Tangle Lakes, Alaska, at about 1220, with a destination of Anchorage, Alaska.
Pilot Statement
In a written statement to the National Transportation Safety Board (NTSB), the pilot reported that approximately 20 minutes into the flight, the engine suddenly went to idle RPM. She moved the throttle forward and received a momentary response, but the engine again went to idle power. She switched fuel tanks, and the engine still did not respond. She then initiated a forced landing in an area of brush-covered tundra. During the forced landing, the airplane nosed over, sustaining substantial damage to the wings, fuselage, and empennage.
Weather Information
The closest official weather observation station is at Gulkana Airport, Gulkana, Alaska, about 52 miles south of the accident site. At 1253, an Aviation Routine Weather Report (METAR) reported: wind 160 degrees true at 6 knots; visibility 10 statute miles; clear skies; temperature 72°F; dew point 48°F; altimeter 29.95 inHg.
Examination Findings
On August 20, the NTSB investigator-in-charge, along with an inspector from the Anchorage Flight Standards District Office, examined the airplane at Alaska Claims Services, Inc., in Wasilla, Alaska. The examination revealed no preaccident anomalies with the airframe that would have precluded normal operation.
Examination of the Lycoming O-320-B2B engine revealed that the throttle cable clamp was loose around the throttle cable, allowing the cable housing to move as well as the cable to move inside the housing. The airplane was secured, and the engine was started and run for approximately 10 minutes through various power settings without anomaly.
Maintenance History
The airplane underwent an annual inspection on June 27, 2013, and had flown approximately 10 hours since being returned to service.
The throttle cable clamp used to secure the throttle cable in the airplane is known in the community to loosen and allow the cable to slip. While there is no requirement to do so, many Piper PA-18 operators and mechanics use safety wire on both sides of the clamp to ensure security of the cable. The clamp on the accident airplane was not secured with safety wire.