LAX97FA217

The aircraft concluded an aerial survey and landed at Brown Field to clear U.S. Customs. On restart, as the left engine began running, a witness noticed two short, yellow flame bursts exit the exhaust. During taxi, the witness heard a popping sound coming from the aircraft. As power was applied to cross runway 26L, the sound went away. The aircraft stopped for a few seconds prior to pulling onto the runway; the witness did not observe or hear a run-up. Witnesses reported hearing a series of popping sounds similar to automatic gunfire and observed the aircraft between 600 and 1,000 feet above the ground with wings level and the landing gear up. The aircraft was observed to make an abrupt, 45-degree banked, left turn as the nose dipped down. Witnesses reported the nose of the aircraft then raised up toward the horizon. This was followed by the aircraft turning to the left and becoming inverted in an estimated 30-degree nose low attitude. With the nose still low, the aircraft continued around to an upright position and appeared to be in a shallow right bank. Witnesses then lost sight of the aircraft due to buildings and terrain. A May 20, 1997, work order indicated the left manifold pressure fluctuated in flight. Both wastegates were lubricated and a test flight revealed the left engine manifold pressure lagged behind the right engine manifold pressure. On June 18, 1997, the left engine differential pressure controller was noted to have been removed and replaced. This was the corrective action for a discrepancy write up that the left engine manifold pressure fluctuated up and down 2 inHg and the rpm varied by 100 in cruise. A test flight that afternoon by the accident pilot indicated the discrepancy still occurred at cruise power settings, but the engine operated normally at high and low power settings. Postaccident functional checks were performed on various components. No discrepancies were noted for the left governor. The left engine differential pressure controller was damaged and results varied on each test. The left density controller was too damaged to test. The right engine density and differential pressure controllers tested satisfactory. The left and right fuel pumps operated within specifications. Both fuel servos were damaged. One injection nozzle on the left engine was partially plugged; all others flow tested within specifications.

History of flight

On June 20, 1997, at 1231 hours Pacific daylight time, a Piper PA 31-310 (Navajo), N266MM, was destroyed when it collided with terrain approximately 1 minute after takeoff from Brown Field, San Diego, California. The airplane was being operated as an other work use flight under the provisions of 14 CFR Part 91 by San-Lo Aerial Surveys, Inc. The airline transport pilot, a second pilot, and the camera operator were fatally injured. The flight was destined for Montgomery Field, also in San Diego. Visual meteorological conditions prevailed and no flight plan was filed.

Company documents found in the aircraft indicated one aerial survey job had been completed. Notations on the document were 1130, 1220, Brown Field, and 1230. End time for the camera run was listed as 1212. A witness stated he observed the aircraft's three-man crew in the U. S. Customs office as he passed by. He stopped at a nearby fence to rest and noticed the three men exit the customs office and board a Piper Navajo that was white with red/ burgundy trim. Several minutes later he heard an engine starting. He turned and observed that the Navajo's right engine was running and the left engine was turning over. He stated that immediately after the left engine was running on its own he observed two short flame bursts exit the exhaust. It seemed odd to him since he had never observed that during daylight before. He described the flame as a very light yellow, almost white. At this time, the engine made no unusual sounds.

Transcripts of Federal Aviation Administration (FAA) communications with the aircraft indicate N266MM was cleared by the ground controller to taxi to runway 26R at 1229:47. After the aircraft started to taxi and made several 90-degree turns, the witness noted he heard a "popping" sound coming from the plane. When power was added as it crossed the left runway, the popping sound went away and it sounded "normal." He observed the aircraft stop just short of runway 26R. After what seemed like a few seconds to him, the aircraft pulled onto the runway and takeoff power was applied. He did not observe or hear a run-up prior to the aircraft's departure. The air traffic control tower cleared N266MM for a downwind departure to the east on runway 26R at intersection bravo at 1230:52.

Witnesses reported hearing a series of popping sounds similar to automatic gunfire and observed the Navajo at what they estimated to be between 600 and 1,000 feet above ground level. One witness noted the wings were level and the landing gear were up. The aircraft was observed to make an abrupt left turn. The right wing was up about 45 degrees, and the nose dipped down. Witnesses reported the nose of the aircraft raised up toward the horizon. Then the aircraft was observed to turn to the left and become inverted in an estimated 30-degree nose low attitude. With the nose still low, the aircraft continued around to an upright position and appeared to be in a shallow right bank. Witnesses then lost sight of the aircraft behind buildings and terrain.

A handheld global positioning system (GPS) unit indicated the aircraft wreckage was at 32 degrees 34.25 minutes north latitude and 117 degrees 00.24 minutes west longitude. The GPS altitude indicated 524 feet.

Personnel information

Review of FAA Airman Records indicate the first pilot held an airline transport pilot certificate with a airplane multiengine land rating and commercial privileges for single engine land airplanes. The pilot also held a type rating for the CE-500. Information supplied by the pilot to the insurance carrier indicated that he had accumulated over 10,000 flight hours. Four thousand were in U.S. Marine Corps fighter attack aircraft. He had over 4,600 hours in multiengine aircraft; over 1,500 hours were in the PA-31 model. The form indicated he had flown more than 340 hours in the previous 12 months; 70 of those hours were in the last 90 days. These records also indicate a biennial flight review occurred March 5, 1997, during 14 CFR Part 135 recurrent training. A second class medical was issued on May 29, 1997, with the limitation that the pilot must have glasses available for near vision.

The second pilot was occupying the left seat. FAA airman records files disclosed that he held a commercial pilot certificate with ratings for single and multiengine land airplanes, and instrument privileges in single engine airplanes. The pilot's multiengine class rating was endorsed with the limitation "multiengine limited to VFR only". The most recent issuance of the certificate was dated June 9, 1997. The pilot's second class medical certificate was dated February 21, 1997, and contained the limitation that corrective lenses must be worn. Information supplied to the insurance carrier indicated he had over 7,400 flight hours. Forty-four hours were in multiengine aircraft, with 15 hours accrued in the PA-31 model.

Aircraft information

FAA records indicate N266MM was a 1968 Piper PA-31-310 Navajo, serial number 31-140. A registration was issued to San-Lo Aerial Surveys, San Diego, on May 20, 1997. The standard airworthiness certificate was issued on September 15, 1995.

Examination of the aircraft's logbooks indicated the left engine was a Textron Lycoming, model TIO-540-A2A (converted from an A1A), serial number L-4468-61. Total time on the engine was 3,829.8 hours and time since overhaul was 827.6 hours. The right engine was a Textron Lycoming, model TIO-540-A2B, serial number L-8244-61A. It was overhauled by Textron Lycoming in October 1993. Total engine time was 5,612.7, and time since major overhaul was 270.7 hours.

Aircraft total time was 8,473 hours. Eighty hours had been flown since the last annual inspection performed on September 27, 1996. An aerial camera kit hole was installed in N266MM on April 22, 1997.

An entry in the aircraft logbooks on December 6, 1996 indicates the left differential pressure controller was removed and replaced at a Hobbs time of 6,028.2. A maintenance work order dated May 30, 1997 noted a Hobbs meter reading of 6,045.5 was replaced by a unit reading 0.0. This work order also indicated the left manifold pressure fluctuated in flight. Both wastegates were lubricated and the accident pilot flew a test flight on May 30, 1997. Maintenance write-ups after the flight indicated the throttles would stick in the closed position, the right tachometer was erratic, and the left manifold pressure lagged behind the right manifold pressure above 4,000 feet. The pilot requested an inspection of the throttle control system. The maintenance manager stated the right engine throttle arm was repositioned and the throttle cable rod end was adjusted for full travel. Additionally, the left propeller dome pressure was measured at 30 psi and serviced to the prescribed 41, plus and minus 1 psi. Maintenance records dated June 18, 1997 indicate the left engine differential pressure controller was removed and replaced with an overhauled unit at Hobbs time 16.9. This was the corrective action for a discrepancy, which indicated the left engine manifold pressure fluctuated up and down 2 inHg, and the rpm varied by 100 rpm in cruise. It was noted that the rpm and manifold pressure operated normally at high and low power settings. The maintenance manager stated the aircraft was flown in the afternoon on the 18th by the accident pilot; the erratic readings persisted. He stated that on June 20, 1997, the propeller dome pressures were checked and were 40 psi on both sides.

A fuel truck operator stated that he serviced N266MM with 92.1 gallons of fuel at 1100 on June 20, 1997. He stated the fuel was distributed evenly between the left and right wings and all four tanks were fueled. He stated the daily checklist had been followed when the truck was put in service. All checklist items were normal and the fuel was observed to be clear and bri