History of Flight
On April 11, 2009, about 1054 Pacific daylight time, a Piper PA-24-250, N7690P, experienced an in-flight breakup during an uncontrolled descent in instrument meteorological conditions (IMC) in San Diego, California. The airplane was destroyed during the breakup sequence and subsequent ground fire. The private pilot, who owned and operated the airplane, and his passenger were killed. The personal flight was conducted under an instrument flight rules (IFR) flight plan and 14 Code of Federal Regulations Part 91. The flight originated from Whiteman Airport in Los Angeles, California, about 1004, with a destination of Brown Field Municipal Airport (SDM) in San Diego.
The flight began in visual meteorological conditions (VMC). According to the Federal Aviation Administration (FAA), the pilot did not report any difficulties during the flight. While en route, the pilot cruised at 7,000 feet mean sea level (msl). The pilot transitioned from VMC to IMC approaching San Diego.
At 1050:34, approximately 29 miles north of SDM, the pilot informed FAA Southern California Terminal Radar Approach Control (SOCAL) that he was descending from 6,200 to 4,000 feet msl. The controller acknowledged at 1050:45. About 1053:04, the controller instructed the pilot to "descend and maintain two thousand six hundred keep your speed up." The pilot responded "two thous" at 1053:09, but the remainder of the transmission was interrupted or not recorded. No further communications were received.
Radar data from the airplane's Mode C transponder showed that at 1053:07, the altitude was 4,200 feet; at 1053:11, 3,800 feet; and at 1053:16, 3,300 feet. The average descent rate during this 9-second interval was about 6,000 feet per minute, and the course was turning clockwise. By 1053:16, the airplane was on a westerly course, and no further radar hits were recorded.
Two ground witnesses heard the accident. The first reported hearing the sound of an airplane diving at high engine rpm, lasting 5 to 6 seconds, with a broken ceiling at about 3,000 feet and unrestricted visibility below clouds. The second witness, about half a mile from the impact site, heard a high-pitched sound like an incoming missile, increasing in intensity until a boom, then observed a fireball on a nearby hill and pieces of wreckage floating down. Weather was overcast with mist.
Personnel Information
The pilot, age 51, held a private pilot certificate with single-engine and instrument ratings. His last aviation medical certificate (third class) was issued in July 2008, with a restriction for corrective lenses for near vision. On his insurance application dated July 29, 2008, the pilot reported total flight time of 820 hours, 20 hours in the preceding 90 days, and 370 hours in the accident airplane model.
A certified flight instructor (CFI) reported giving the pilot a flight review on August 2, 2008, which was successfully completed. On December 27, 2008, the CFI flew with the pilot for instrument practice, including three instrument approaches (two VOR and one ILS).
Aircraft Information
The airplane, manufactured in 1961, had been modified with upgrades including a 3-blade propeller, engine exhausts, one-piece windshield, Lopresti speed enhancement devices, wingtips, and avionics such as a multifunction display, engine analyzer, and autopilot. Maintenance was performed on an annual inspection basis. Acquaintances reported that the pilot occasionally performed maintenance, and a mechanic believed some was not supervised by a licensed mechanic as required. Family members noted an "owner-assisted" annual inspection a few weeks before the accident.
Meteorological Information
At 0827, the pilot received a weather briefing from Prescott AFSS, planning a VFR flight to Brown Field at 5,500 feet msl, duration 1 hour. The briefer asked if the pilot could fly IFR; the pilot said yes. The briefer noted a marine layer and expected the pilot might need IFR. Conditions included scattered to overcast clouds with bases from 2,000 to 5,000 feet msl, and at Brown Field a ceiling of 4,100 feet overcast with 10 miles visibility. No convective weather or icing forecasts existed.
Near the accident site, the Miramar Marine Corps Air Station (5.7 miles west-southwest) reported at 1055: broken clouds at 2,500 and 3,100 feet, overcast at 4,800 feet, wind 210° at 5 knots, visibility 10 miles, temperature 13°C, dew point 9°C. At 1108, a special observation showed ceiling 200 feet broken, 3,000 and 5,000 feet overcast, visibility 7 miles.
Wreckage and Impact Information
The wreckage was located on a hillside about 5.5 miles east-northeast of Miramar, approximately 900 feet north-northwest of the last radar position. The site spanned a 30-degree downslope between 1,000 and 850 feet msl. The initial impact point (IPI) crater and main wreckage (cockpit) were 50 feet apart on a magnetic bearing of 167 degrees. Fragments were scattered over a 150-foot-wide by 530-foot-long southeasterly path. All flight control surfaces were found.
Separated outer wing sections were not fire-damaged and were found north of the crater, between 100 and 300 feet away. The engine and main wreckage were to the south near lower elevations. Inboard wing spans, vertical stabilizer with rudder, and left stabilator were attached to the fire-damaged fuselage. The instrument panel, cockpit, and cabin were consumed by fire.
Components far from the main wreckage were not burned. Wing spars were bent and fractured upward. The right stabilator was separated, with its attachment structure bent aft and leading edge crushed aft, consistent with deformation from a separated right wing skin. The engine was separated from its firewall and case broken open; no preimpact anomalies were found internally. Two of three propeller blades were in the IPI crater, the third nearby; two blades had tip curl, gouges, and chordwise scratches.
Medical and Pathological Information
An autopsy on April 13, 2009, determined the pilot died from multiple blunt force injuries. Forensic toxicology detected no ethanol, carbon monoxide, cyanide, or screened drugs.
Additional Information
Family and acquaintances reported the pilot's wife was ill, and the flight was to take her to southern California for treatment. The pilot was familiar with the route.