ANC08FA072

Two airplanes were flying northbound over an ocean beach at about 100 feet above the ground. The pilot of the second airplane reported that while the accident airplane was flying at his 10 o'clock position, the accident pilot radioed that he saw what he thought was a whale vertebra on the beach and that he was going take a look. The second pilot said that the accident airplane began circling over the site, and during the second 360-degree turn, the right wing stalled and the airplane descended to the ground in a nose-down attitude, colliding with the gravel-covered beach in a near-vertical attitude. A postcrash fire started immediately after impact. At the time of the accident there were strong westerly winds, ranging between 25 and 30 knots. Examination of the airplane did not disclose any preimpact mechanical malfunction.

History of flight

On June 6, 2008, about 1910 Alaska daylight time, a tundra tire-equipped Piper PA-18 airplane, N897SP, was destroyed by impact and a postimpact fire when it collided with a gravel and mud-covered tidal beach, about 17 miles south of Quinhagak, Alaska. The airplane was being operated as a visual flight rules (VFR) personal flight under the provisions of 14 Code of Federal Regulations Part 91, when the accident occurred. The solo commercial pilot died at the scene. Visual meteorological conditions prevailed, and no flight plan was filed. At the time of the accident, the airplane was one of two airplanes flying from Iliamna, Alaska to Nome, Alaska, with an en route fuel stop in Dillingham, Alaska. According to personnel at the Dillingham Flight Service Station, both airplanes departed Dillingham about 1618.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on June 10, an Alaska State Trooper reported that while conducting an aerial search for a missing person near Quinhagak, he noticed a large plume of black smoke rising from an area south of Quinhagak. The trooper said that as he flew towards the source of the smoke plume he realized that it was coming from the burning wreckage of an airplane on the beach. He added that there was a second Piper Super Cub parked on the beach, adjacent to the burning wreckage, and he could see one person walking from the burning wreckage to the parked Super Cub. The State Trooper said that he was unable to land at the accident site due to high winds, but he was eventually able to talk with the pilot of the second airplane via radio.

The trooper said that the pilot of the second airplane reported the accident airplane had crashed while flying northbound along the beach, and that the pilot was deceased. The pilot of the second airplane did not give the trooper any details of the circumstances about the accident, but he reported that he did not feel comfortable staying there, and said he wanted to leave. The trooper instructed the pilot not to leave the scene, and that help was on the way. The trooper then told the second pilot that he needed to climb up to altitude to make a radio call back to the Alaska State Trooper's post in Bethel, Alaska, 80 miles to the north. The trooper said that after climbing to altitude and making the radio call, he returned to the accident site and the second airplane was gone. The trooper said that he was unable to contact the second pilot via radio.

On June 7, about 2300, the pilot of the second airplane contacted the NTSB IIC using a satellite telephone. During the brief telephone conversation, the pilot reported that just before the accident, the two airplanes were northbound along the beach, flying at an altitude of approximately 100 feet agl. He said that the accident airplane was flying at his 10 o'clock position, when the accident pilot radioed that he saw what he thought was a whale vertebra on the beach, and that he was going to take a look. The pilot of the second airplane said that the accident airplane began circling over the site, and during the second 360-degree turn, the right wing stalled, and the airplane descended to the ground in a nose-down attitude. The airplane collided with the tidal beach in a near-vertical attitude, and a postcrash fire started immediately after impact. The pilot added that at the time of the accident there were strong westerly winds, between 25 and 30 knots.

Personnel information

The pilot held a commercial pilot certificate with airplane single-engine land, and single-engine sea ratings. The most recent second-class medical certificate was issued to the pilot on March 7, 2007, and contained no limitations.

No personal flight records were located for the pilot, and the aeronautical experience listed on page 3 of this report was obtained from a review of the airmen Federal Aviation Administration (FAA) records on file in the Airman and Medical Records Center located in Oklahoma City. On the pilot's application for medical certificate, dated March 7, 2007, he indicated that his total aeronautical experience was about 500 hours, of which 40 were in the previous 6 months.

Aircraft information

No aircraft maintenance records were located for the accident airplane. According to family members of the pilot, the airframe and engine logbooks were presumed to have been on board the airplane at the time of the accident. Copies of the airplane's most recent annual inspection were obtained from the pilot's aircraft maintenance facility in Redlands, California.

The airplane and engine had an annual inspection on March 14, 2008. At that time, the airplane had a total time in service of 1,777.8 hours. The engine had a total time in service of 694.9 hours since installed.

Meteorological information

The closest official weather observation station is Cape Newenham, Alaska, which is about 50 miles south of the accident site. On June 6, 2008, at 1919, an automated weather observation system was reporting, in part: Wind, 300 degrees at 13 knots; visibility, 10 statute miles; clouds and ceiling, 400 few; temperature, 39 degrees F; dew point, 34 degrees F; altimeter, 30.04 inHg.

At the time of the accident strong westerly winds were reported, ranging between 25 to 30 knots.

Communications

After the airplane departed Dillingham, there were no reports of communications with the pilot other than air-to-air communications between the two airplanes.

Wreckage and impact information

The NTSB IIC, along with a Federal Aviation Administration (FAA) airworthiness inspector from the Anchorage Flight Standards District Office (FSDO) traveled to the accident site on June 7. The airplane's incinerated wreckage had been subjected to numerous tide cycles, and the wreckage was partially submerged, which limited the NTSB IIC and FAA inspectors' ability to examine the wreckage.

All of the airplane's major components were found at the main wreckage site.

The airplane wreckage was found in a nose down attitude, in an area of mud and gravel-covered tidal beach. The airplane's longitudinal axis was oriented on a 230-degree magnetic heading.

Except for the tubular fuselage frame, and about 5 feet of the outboard portions of the right wing, the airplane was consumed by fire.

A review of Alaska State Trooper photos taken before the airplane was subjected to the first tide cycle revealed that both wings had significant spanwise leading edge aft crushing.

The outboard half of the left wing had significant leading edge aft crushing, with more crushing evident along the lower portion of the outboard edge. The right wing had leading edge aft crushing. A 1 inch deep depression was visible in the gravel, extending from the tip of the right wing, to a point about 2 feet inboard. The depression matched that of the right wing's leading edge.

Although burned, both wing lift struts assemblies remained attached to their respective wing and fuselage attach points.

Small portions of paint chips and windshield fragments were on the ground, around the wreckage point of rest.

Both wing fuel tanks were ruptured and partially consumed by fire. The inboard portion of both wings and the cockpit and cabin area, were incinerated by the postaccident fire.

The remaining aft portion of the tail assembly and empennage remained attached to the fuselage. The tubular structure was melted and twisted downward from its original vertical position. The vertical stabilizer, elevator, and the rudder sustained fire damage, but remained attached.

The flight control surfaces remained connected to their respective attach points. Due to the impact and postimpact fire damage, as well as tidal activity, continuity of the flight control cables could not be established.

The instrument panel was destroyed by fire.

The engine assembly wa