Sequence of Events
During a return flight to San Jose and subsequent descent and approach to Long Beach Airport, the two pilots experienced a series of malfunctions: failure of the turbocharger system, loss of an alternator, loss of engine oil pressure, an unsafe landing gear indication, and an in-flight fire. This was followed by a loss of engine power during a nighttime circling approach to an unfamiliar airport in visual meteorological conditions. The aircraft made a flyby of the tower to confirm landing gear position before crashing onto the southbound lanes of the San Diego freeway at Long Beach.
Findings
The investigation revealed an improperly installed turbocharger, a cracked manifold exhaust, a burned main power lead, a separated cylinder, and a low fluid level in the hydraulic reservoir. Two years prior to this accident, the instructor pilot made an unintentional gear-up landing in another aircraft. One year prior, the FAA revoked the mechanic's inspection authorization.
The National Transportation Safety Board listed multiple findings: failure of the exhaust system turbocharger, disengagement of the turbocharger, separation of an engine mounting bolt, improper maintenance installation, poor maintenance inspection, burned electric wiring, disabled alternator, low hydraulic accumulator level, false landing gear indication, intentional low pass by the pilot, pilot anxiety, fatigue of an engine cylinder, cylinder separation, go-around performed, poor pilot judgment, oil starvation, night light conditions, and a stall encountered by the pilot.
Probable Cause
The NTSB determined the probable cause to be the pilot's failure to land the aircraft after experiencing system failures, and his faulty decision based on a previous gear-up landing.