What happened
Following the transport of an entertainment group to Lindbergh Field, the Hawker Siddeley HS.125 was moved to nearby Brown Field to avoid noise curfew restrictions. The flight was significantly delayed, eventually departing at 01:41 PST, much later than the original midnight scheduled departure. During the pre-flight process, the pilot communicated with a Flight Service Station (FSS) specialist three times. During these communications, the pilot noted a lack of specific departure instructions, prompting the specialist to read the procedures via telephone.
On the final communication before takeoff, the pilot indicated an intention to depart under Visual Flight Rules (VFR) toward the northeast, intending to acquire Instrument Flight Rules (IFR) clearance once airborne. This planned route directed the aircraft toward mountainous terrain. During the exchange, the pilot expressed concern regarding maintaining separation from the Terminal Control Area (TCA) and requested to remain below 3,000 feet.
While the aircraft was in flight, the FSS specialist was in the process of re-entering the flight plan into the system, as the original plan had expired due to the delay. During the climb, the aircraft struck rising terrain approximately 8 miles northeast of the airport at an elevation of roughly 3,300 feet. The accident resulted in 10 fatalities and no survivors.
Findings
Investigations into the accident revealed that there were no mechanical or engine deficiencies present in the aircraft. However, several operational factors were identified. The pilot's request to stay below 3,000 feet led to a misunderstanding; the specialist believed the pilot meant 3,000 feet above ground level (AGL), whereas the pilot was referring to 3,000 feet mean sea level (MSL). Additionally, while the co-pilot had performed limited takeoffs and landings in the Hawker Siddeley HS.125, he did not hold a formal type rating for the aircraft.