Aviation Accident Summaries

Aviation Accident Summary ANC01LA097

Anchorage, AK, USA

Aircraft #1

N7775H

Piper PA-12

Analysis

The pilot reported he was attempting to land on a remote, rural airstrip he had landed on several times before. He said the airstrip is approximately 1000 feet long by 30 feet wide. After touchdown, the airplane veered to the right. He said he was unable to maintain directional control by using full left rudder and left brake, and attempted to abort the landing, but collided with brush. During the airplane's recovery, the pilot said he discovered that the left main wheel brake assembly was missing a hydraulic fitting which would have allowed the brake fluid pressure to drop. He said it appeared to him that the fitting vibrated loose in-flight, as his brakes worked fine during the preflight check and taxi.

Factual Information

On August 1, 2001, about 1913 Alaska daylight time, a wheel-equipped Piper PA-12 airplane, N7775H, received substantial damage during a precautionary landing at a remote airstrip near Anchorage, Alaska. The private pilot/owner of the airplane and the two passengers were not injured. The personal flight operated in visual meteorological conditions without a flight plan. The local flight departed the Flying Crown airstrip, Anchorage, about 1900. In a telephone interview with the NTSB investigator-in-charge (IIC) on August 2, the pilot said he was landing at the ridge top airstrip because he noted an increase in cylinder head temperature, and wanted to land and check the engine. He noted that he had landed several times before without incident at the approximately 1000 feet long by 30 feet wide strip. He said he landed to the south, and the airplane may have bounced upon touchdown, and then it went sideways, towards the right edge of the strip. He said he applied full left rudder and brake, but the airplane continued toward the right side of the airstrip. He attempted to abort the landing by adding power, but the right wing and tires struck alders on the right side of the airstrip, and the airplane went off the side and slowly nosed over. The pilot contacted the NTSB IIC again on August 4, and indicated that the left brake hydraulic actuator was missing a fitting that may have come loose prior to the accident, allowing the loss of hydraulic fluid and causing the left brake to be ineffectual. In his written report to the NTSB dated August 20, the pilot checked the block "Yes" under the section, "Mechanical Failure" and wrote, in part: "bleeder valve from bottom of left brake caliper missing and assumed to have vibrated loose during flight." He noted the brakes functioned normally during preflight taxi and run-up.

Probable Cause and Findings

The loss of left brake pressure due to a missing hydraulic brake fitting.

 

Source: NTSB Aviation Accident Database

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