Primary finding
Probable cause
the pilot's inadequate in-flight decision to attempt low altitude flight operations into a box canyon in mountainous terrain, and his failure to maintain an adequate airspeed while maneuvering to reverse direction, which led to an accelerated stall and spin.
Investigator assessment
Analysis narrative
Radar data disclosed that the pilot flew the airplane from the departure airport toward the accident site, with the last recorded target at 610 feet above ground level (agl) over rising mountainous terrain. The floor of the radar coverage in the area was about 200 feet agl. The accident site was located at an elevation of about 2,293 feet mean sea level (msl) on the slope of a bowl-shaped box canyon about 25 nautical miles (nm) from the departure airport. In character, the canyon and surrounding hills were steeply sloped, averaging between 60 to 80 degrees, with the tops of the canyon terrain about 700 feet higher than the accident site elevation and 1,000 feet laterally in front of the wreckage. An analysis of the airplane's climb performance capability found that a lateral distance of 2 miles would be required to climb 700 feet. Ground scar analysis, impact signatures, and wreckage fragmentation patterns disclosed that the airplane impacted in a descending steep vertical nose down attitude traveling downslope. The impact geometry was consistent with the airplane encountering an accelerated stall while attempting a course reversal in the canyon. The width of the canyon immediately surrounding the wreckage measured about 1,250 feet. With a turn radius of 637.5 feet, and airspeed of 99 knots (maneuvering speed), the bank angle required for the airplane to complete a 180-degree turn was a minimum of 55 degrees. According to stall speed versus angle of bank data, the stall speed would be 55 knots at 55 degrees of bank. No evidence of mechanical malfunction or failure was found during a post accident examination of the airplane and engine. The pilot had accumulated 75 hours total flight experience, of which about 2 hours was in the same make and model as the accident airplane and acquired in the location of the departure airport.
Source record
Factual narrative
HISTORY OF FLIGHT On July 13, 2007, about 1745 Pacific daylight time, a Piper PA-28-181, N38137, departed controlled flight and collided into the slope of a canyon near El Cajon, California. National Air College, Inc., was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The private pilot and one passenger were killed. The airplane was substantially damaged. The personal local area flight departed Montgomery Field, San Diego, California, at 1701. Visual meteorological conditions prevailed, and no flight plan had been filed. According to the operator, the pilot scheduled the airplane about 2 days prior to the accident flight. A lineman, employed by the operator, reported fueling the airplane with full fuel just prior to the accident flight. While fueling the airplane, he observed the pilot and passenger performing a preflight inspection. Records established that the airplane was fueled with the addition of 28.9 gallons of aviation fuel. Recorded radar data was obtained and reviewed by a National Transportation Safety Board investigator. The data covering the area of the accident was supplied by the Federal Aviation Administration (FAA) in the form of a National Track Analysis Program (NTAP) printout from Southern California Terminal Radar Approach Control (Southern California TRACON). As the airplane did not have a discrete transponder code, investigators reviewed the primary targets for the accident time frame and proximity to the anticipated flight track of the airplane. Southern California TRACON radar data disclosed a series of approximately equidistant radar returns from 1701:41 to 1714:07. The data was consistent with the accident airplane flying in a northeasterly direction. The radar plot stretched over a distance of approximately 20 nautical miles (nm) in 13 minutes 38 seconds, equating to a radar-derived ground speed of about 88.1 knots. The last radar return was recorded southwest of the accident location, approximately 7.6 nm from the accident location on a true course of 045 degrees. The target was identified at 1701:14 on Mode C (squawk 1200), located adjacent to Montgomery Field at a reported altitude of 500 feet mean sea level (msl). The track, starting on a northeast direction, increased in altitude and made a right turn towards the southeast. At 1704:30, the target was 4 miles east of Montgomery Field, climbing though 2,000 feet msl. The target momentarily turned to a northern direction, and then established a northeastern heading. According to the FAA, this momentary direction change coincided with an air traffic controller advising the accident pilot to turn north to avoid arriving traffic. During the proceeding 7 minutes, radar returns disclosed a gradual climb to a maximum altitude of 3,800 feet msl. Beginning at 1711:17, radar returns revealed a trend of decreasing altitude while terrain elevation was increasing, which continued for the last 3 minutes until the track ended. The last return occurred at 1724:07, with a reported altitude of 2,400 feet msl and the corresponding terrain elevation of about 1,790 feet, equating to an approximate altitude of 610 feet above ground level (agl). At that location, the Southern California TRACON radar floor was about 200 feet agl. PILOT INFORMATION A review of FAA airman records revealed the pilot held a private pilot certificate with a rating for airplane single engine land, issued on February 19, 2007. The pilot additionally held a second-class medical certificate that was issued on January 3, 2007, with no limitations. Copies of the pilot's personal flight logbooks were obtained by the Safety Board investigator-in-charge (IIC). A review of the logbooks disclosed that the pilot had accumulated 75 hours total flight experience, of which about 73 hours was amassed in Cessna airplanes, and the remaining 2 hours in the accident airplane. Following the obtainment of his license, the pilot recorded making three flights. The first entry was recorded as a 3.3-hour solo cross-country flight in a Cessna 172 conducted in Florida. The other two flights were documented as being instructional flights conducted in the accident airplane over a duration of 1.2 and 1.1 hours, respectively; both flights departed from Montgomery Field. Safety Board investigators interviewed the certificated flight instructor (CFI) that had given the accident pilot a checkout that enabled him to rent the accident airplane. The CFI reported that as part of the checkout, he had flown with the accident pilot two times prior to the accident, occurring on July 3 and July 10, 2007. He noted that during their initial conversations, the pilot stated that he intended to obtain his instrument rating after the checkout phase; the accident pilot had commented that he aspired to be a bush pilot. The CFI further stated that prior to the initial flight, the pilot had conveyed that he wanted to receive familiarization training in the San Diego area, as he had just moved from Florida. He added that he was additionally not accustomed to mountainous terrain and had never flown in vicinity of mountains. The initial flight departed from Montgomery Field and encompassed basic air work and area familiarization. The second flight, and last with the CFI, comprised basic instrument flight training maneuvers (e.g. compass turns, etc.). He noted that he had never taken the accident pilot near the area of the accident, nor had the pilot inquired about the terrain in that area. The CFI added that he believed the accident pilot to be a competent pilot, diligent with utilizing checklists. He was not aware that the accident pilot was planning to fly the airplane on the day of the accident and noted that they had never discussed the flight. A search of the FAA airman records database disclosed no record that the passenger had ever held any grade of pilot certificate. AIRCRAFT INFORMATION The single engine, low wing Piper PA-28-181 (serial number 28-7790522), was manufactured in 1977. It had accrued a total time in service of 10,288 hours. Review of the aircraft maintenance records disclosed that a 100-hour inspection was completed on June 28, 2007, 13 hours prior to the accident. The most recent annual inspection was completed on April 28, 2007, 123 hours prior to the accident. The Lycoming O-360-A4M engine, serial number L-23208-36A, had accumulated a total time in service of 10,150 hours. The engine had accrued 1,169 hours since the most recent major overhaul. Both the engine's annual and 100-hour inspections were accomplished on the dates noted for the airframe. No unresolved maintenance discrepancies were noted during the records review. The Safety Board IIC obtained fueling records documented by the operator. The records disclosed that the accident aircraft was last fueled on the accident date with the addition of 28.9 gallons of 100LL aviation fuel. Performance The performance data was calculated using information from the Piper Archer II PA-28-181 Pilot Operating Handbook for airplane serial numbers 28-7790001 and after, which was applicable to the accident airplane. For the purpose of the calculations, investigators utilized an estimated gross weight at the time of the accident to be 2,060 pounds, which was derived by the assumption of 180 pounds of fuel on board and a combined total weight of pilot and passenger of 340 pounds; the airplane's empty weight was about 1,540 pounds. Using the Ramona, California, airport temperature of 31 degrees Celsius (see Meteorological Section of this report), and the aforementioned estimated weight of 2,060 pounds, performance charts indicated a possible climb rate of about 500 feet per minute at the accident site elevation. From the accident site's elevation of 2,293 feet, the peak of the canyon's rim rose about 700 feet over a distance of 1,000 feet. Based on the