SEA02FA063

The non-certificated pilot departed Laurel, Montana, with his passenger at 0746 in the Piper PA-18-150. The wreckage was found shortly after noon the same day and there were no witnesses to the accident. Although the aircraft was extensively damaged by fire, 10-11 foot ground scars indicated a westerly track along the +5 degree up sloped terrain immediately followed by propeller slash marks 14 inches apart placing the aircraft's nose (longitudinal axis) along a west-southwest heading. The distance between the propeller slash marks and the final resting place of the aircraft's engine was 27.5 feet with the aircraft coming to rest with its longitudinal axis along an approximate north/south line (tail north). The leading edge of the left wing displayed aftward compressive damage characteristic of ground impact and the propeller spinner likewise showed aftward compressive damage. The right wing displayed no such damage. Propeller tip fragments were found embedded near the propeller ground slash marks and adjacent to the aircraft's tail. No control discontinuity nor mechanical malfunction was evident during the wreckage examination. A Garmin GPS III on board the aircraft provided 158 data points showing latitude/longitude and time beginning with the departure from Laurel and continuing up to a point coincident with the ground impact site. The track showed a marked left turn during the last moment of flight which terminated at 0807:22.

History of flight

On April 6, 2002, at 0807 mountain standard time, a Piper PA-18-150 "Super Cub," N4389A, registered to a private individual, and being flown by a non-certificated pilot, collided with terrain while maneuvering three miles west-southwest of Silesia, Montana. The pilot and his non-rated passenger both sustained fatal injuries and the aircraft was destroyed during impact and a post-crash fire. Visual meteorological conditions prevailed throughout the area of the accident, and no flight plan had been filed. The flight, which was personal, was operated under 14CFR91, and had originated from the Laurel airport, Laurel, Montana.

An acquaintance of the pilot reported that he and the accident pilot were among a group of individuals who often met Saturday mornings for breakfast. On the morning of the accident (approximately 0720-0725) the passenger called the acquaintance on his cell phone and inquired as to whether he was going to breakfast. Later (approximately 0750) the acquaintance called the passenger back but received no response.

The acquaintance then called the pilot (approximately 0752) on his cell phone. The pilot indicated he was in flight and the acquaintance indicated he and another pilot were going to fly down to Bridger (Montana) for breakfast. The (accident) pilot acknowledged this but it was not clear to the acquaintance whether the pilot would meet them at Bridger or not. There was no other known communication with the accident aircraft after this time (refer to attachment RTC-I). There were no witnesses to the accident and the wreckage was found shortly after noon on the day of the accident.

The initial destination of the flight was reported to be Columbus, Montana, approximately 22 nautical miles southwest of Laurel (refer to CHART I).

Personnel information

Records maintained by the Federal Aviation Administration (FAA) indicated that the pilot possessed an airframe/powerplant mechanic's certificate issued March 5, 1998. The records also showed that the pilot had acquired a Class III medical certificate with a restriction that he "must wear corrective lenses" and the medical was issued April 30, 1986. There was no record of the pilot having any pilot certificates and no record of flight time within the FAA records. An acquaintance of the pilot estimated he had 400 hours in the PA-18 aircraft.

Aircraft information

A Garmin GPS III (Global Positioning System) was carried in the aircraft and, according to an acquaintance of the pilot, could be affixed to the aircraft's glare shield forward of the pilot via a glued Velcro strap. The acquaintance reported that the pilot used the GPS unit to keep track of his flight time.

No logs or aircraft records were located and the aircraft/engine's total time and time since last inspection could not be determined.

Meteorological information

The aviation surface weather observation taken at Billings, Montana, at 0756 on the morning of the accident read in part: visibility 10 statute miles, a few clouds at 8,500 feet, scattered clouds at 11,000 feet, temperature 9 degrees C., dew point -1 degree C., winds 210 degrees magnetic at 13 knots. Billings is located 20 nautical miles north-northeast of the accident site.

Wreckage and impact information

The aircraft crashed in an open field of low grass about three nautical miles west of Silesia, Montana. The accident site coordinates were determined using a hand held GPS unit and were found to be 45 degrees 35.054 minutes north latitude and 108 degrees 54.030 minutes west longitude. The elevation of the accident site was approximately 3,760 feet MSL and the terrain at the accident had a +5 degree gentle up-slope (refer to CHART II).

The first evidence of ground impact was two shallow cuts or abrasions in the soil running approximately parallel with the left (11 and 1/3 feet in length) oriented along a 278 degree magnetic bearing and the right (10 feet in length) oriented along a 287 degree magnetic bearing line (refer to photograph 1). Two distinct slash marks in the soil were noted at the west end of the left shallow cut previously discussed (refer to photograph 2) and a small chordwise segment of one of the propeller blades was observed nearby (refer to photograph 3). A piece of propeller tip was observed embedded in the soil about three feet southeast of the slash marks (refer to photograph 4).

All major portions of the aircraft, which had sustained extensive fire damage, were located in one area (refer to photographs 5 through 8) and the aircraft was observed with the longitudinal axis oriented along a 005/185-degree magnetic bearing line (tail oriented north). The engine was skewed approximately 45 degrees counterclockwise from the fuselage and the engine bore approximately 240 degrees magnetic and 27.5 feet from the slash marks/propeller fragments (refer to DIAGRAM I).

A second propeller tip piece was noted embedded in the soil approximately 10 feet due west of the north end of the empennage (refer to photograph 9). Both vertical and horizontal stabilizers and control surfaces were observed attached (refer to photograph 10 and 11). The left wing displayed a moderate amount of aftward crushing along the non fire-damaged outboard leading edge ribs (refer to photograph 12) while the right wing displayed minimal rib damage (refer to photograph 13). The engine cowl was absent and the engine was observed lying upright with the separated propeller underneath and slight north of the engine (refer to photograph 14). The propeller displayed bending and twisting deformation and both propeller tips were observed to be separated. The spinner displayed aftward compressive deformation (refer to photograph 15).

Control continuity between all three sets of control surfaces and the cockpit was established as well as continuity to the elevator trim. The stabilator trim jackscrew displayed nine threads extending between the actuator sliding fitting and the stabilizer tube (approximately neutral to slightly nose down trim). On site examination of the engine revealed no evidence of pre-impact malfunction and continuity between the engine and cockpit controls was verified.

Medical and pathological information

Post-mortem examination of the pilot was conducted by Thomas L. Bennett, M.D., Yellowstone Pathology Institute, Inc. (SHV autopsy suite), Billings, Montana, on April 7, 2002, (case number M02-48). The pathologist reported that a non-functioning Seiko watch was found on the pilot reading 08:13:18.

The FAA's Toxicology Accident and Research Laboratory, Oklahoma City, Oklahoma, conducted toxicological evaluation of samples from the pilot. The findings were reported as negative (refer to attached TOX report).

Tests and research

The recovered GPS III unit was shipped to Garmin International, Olathe, Kansas, where the manufacturer was able to extract data from the unit's non-volatile memory. The data consisted of position (lat/long), date/time*, leg length, leg time, leg speed, and leg course. The unit did not acquire altitude thus the information was, excluding time, two-dimensional (refer to attachment G-I).

A total of 158 data points were recorded beginning at 06:46:44* at a latitude/longitude coincident with the Laurel airport and with the last target at 07:07:22* at a latitude/longitude coincident with the accident site (refer to attachment D-I).

Garmin International provided a plot of all 158 data points beginning with the first target and concluding with the last (refer to attachment DP-I).

*(The GPS time is shifted earlier one hour from the true (accident) time).

Additional information

On-site examination of the wreckage was conducted on April 7, 2002, after which the wreckage was verbally released to the Carbon County Sheriff's Department who were instructed to verbally release the wreckage to a representative of the pilot's family