Aviation Accident Summaries

Aviation Accident Summary WPR11FA334

Joshua Tree, CA, USA

Aircraft #1

N7510H

PIPER PA-12

Analysis

The pilot reported that, during the cross-country repositioning flight over mountainous desert terrain, the airplane impacted the terrain, nosed over to the inverted position, and caught fire. He recalled that the engine was generating power at impact, but he could not recall any details of the flight before the impact. Data recovered from a handheld global positioning system (GPS) device indicated that, during the flight, the pilot was flying at altitudes ranging from about 100 to 1,000 feet above ground level (agl). The last position recorded by the GPS device showed the airplane about 1 nautical mile from the accident site at an altitude of about 4,100 feet mean sea level (msl), which was about 100 feet agl. The accident site was at 4,600 feet msl near the top of a ridgeline at the head of a box canyon. Postaccident examination of the airframe and engine revealed no evidence of any preimpact mechanical failure or malfunction that would have prevented normal operation. The calculated density altitude at the accident site at the time of the accident was about 7,300 feet. It is likely that the pilot flew the airplane into the box canyon, and, given the high density altitude, the airplane did not have the climb capability to clear the rising terrain.

Factual Information

On July 18, 2011, at 0846 Pacific daylight time, a Piper PA-12, N7510H, collided with mountainous terrain near Joshua Tree, California. The commercial pilot, the sole occupant onboard, was seriously injured. The airplane sustained substantial damage. Van Wagner Aerial Media LLC of Hollywood, Florida, was operating the airplane under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the cross-country repositioning flight. The flight departed from Lake Havasu City, Arizona, about 1 hour 30 minutes before the accident; its destination was Compton, California. No flight plan had been filed. According to the operator, the airplane had been at Lake Havasu conducting banner towing operations, and the purpose of the flight was to return the airplane to its home base in Compton. The pilot reported that the weather was clear along his planned route of flight. He was unable to recall any of the flight before the airplane impacted terrain. He recalled the airplane striking the ground, nosing over to the inverted position, and catching fire. He also recalled that the engine was generating power at impact. Although his right leg was broken, he was able to release his lap belt and shoulder harness and escape from the airplane by kicking out the left side window. An on scene examination of the wreckage was conducted by a National Transportation Safety Board (NTSB) investigator and a Federal Aviation Administration (FAA) inspector. The accident site was located in the Joshua Tree National Forest at an elevation of about 4,600 feet near the top of a ridgeline at the head of a box canyon. The airplane was lying inverted on a 20-degree slope about 50 feet upslope from an area with a 60-degree slope. The engine cowling, fabric fuselage skin, cabin area, and the inboard portions of both wings were consumed by fire. The steel tubing airframe and the control cables were exposed. Control continuity was confirmed from all control surfaces to the cockpit controls. The left wingtip, the right wingtip, and the right wing had leading edge crush damage. The rudder and vertical stabilizer had vertical crush damage. One propeller blade was twisted, bent after near the tip, and displayed trailing edge buckling. The other propeller blade was twisted and bent aft about midspan. No evidence of preimpact mechanical failure or malfunction was noted during the examination of the airframe and engine. A Garmin handheld Global Positioning System (GPS) device (Garmin GPSMAP 96) was recovered from the accident site, and data recorded during the flight was downloaded from the unit using NTSB laboratory equipment. The data parameters recorded included date, time, latitude, longitude, and GPS altitude. The data indicated that the airplane departed from Lake Havasu City Airport about 0715 and proceeded southwest over sparsely populated mountainous desert terrain with elevations ranging from about 500 to 5,500 feet. The airplane’s height above the ground was calculated at selected points. Time Altitude 0730 83 feet above ground level (agl) 0742 106 feet agl 0754 137 feet agl 0809 650 feet agl 0824 549 feet agl 0833 1,042 feet agl 0839 573 feet agl 0845 103 feet agl The last location recorded by the GPS device showed the airplane about 1 nautical mile northeast of the accident site, at an altitude of 4,016 feet mean sea level (103 feet agl). At 0856, the reported weather conditions at Twentynine Palms, California, located about 16 nautical miles northeast of the accident site, were wind 360 at 4 knots; visibility 7 miles; few clouds at 8,000 feet; temperature 28 degrees C; dew point 1 degree C; and altimeter setting 29.98 inches of mercury. The calculated density altitude at the accident site was about 7,300 feet.

Probable Cause and Findings

The pilot's decision to conduct low altitude flight at a high density altitude and into a box canyon, which resulted in the airplane colliding with rising terrain when its climb capability was exceeded.

 

Source: NTSB Aviation Accident Database

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