British Aerospace BAE 125-1000A accident near San Francisco, California, September 11, 2004
On September 11, 2004 at about 4:38 pm local time, a British Aerospace BAE 125-1000A, registered N520QS, was substantially damaged in an accident near San Francisco, California (San Francisco International airport). It was a positioning flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
An electrical arc from an undetermined source initiated a hydraulic line rupture, which resulted in an equipment bay fire.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 11, 2004 · about 4:38 pm local time
- Place
- San Francisco, California · San Francisco International · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- British Aerospace BAE 125-1000A · all BAE 125-1000As on the register
- Registration
- N520QS · registry record · serial 259020
- Damage
- Substantial damage
- Flight
- Positioning flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The business jet experienced a fire in the aft equipment bay while holding short for takeoff. The two-person aircrew were performing a positioning flight. While the airplane was holding short for takeoff, the crew noticed a Master Caution and a Pack & Aux Overheat warning light illuminated on the cockpit annunciator panel, followed by a Rear Baggage Smoke Detector warning light. The crew shut down the APU. The captain declared an emergency and the crew evacuated the airplane. Fire crews arrived shortly thereafter, and determined that the fire had extinguished itself. Examination of the aft pressure bulkhead by the manufacturer revealed metal discoloration and soot residue, and it was determined that there was structural damage to the aft pressure bulkhead due to a heat induced loss of material temper. After the incident the operator inspected the aft equipment bay and identified a hydraulic line with a pinhole leak. The stainless steel hydraulic line had a small crater like deformation with evidence of recast metal and a 0.005-inch hole at the base of the crater, which is consistent with damage caused by an electrical arc. There was no evidence of chafing on the hydraulic line. Copper, cadmium, and nickel material were acid rinsed from the crater; none of which are listed as alloying element in stainless steel. Copper wire is commonly used as an electrical circuit conductor. A pinhole leak could be expected to atomize the hydraulic fluid that was at 3,000 psi. The hydraulic system working fluid used was Aeroshell Fluid 41, which has a reported flash point between 221F and 230F. The electrical looms/cables that were in the aft equipment bay were disposed of prior to the Safety Board initiating the accident investigation; therefore, determination or identification of the electrical arc source was not possible.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot, commercial pilot, flight engineer
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 14,692 hours in all; 1,692 in this make and model; 89 in the last 90 days; 38 in the last 30 days; 5,000 as pilot in command
- Last flight review: June 1, 2004
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: rgt
- Injury: no injuries
Co-pilot
- Certificate: airline transport pilot, flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 10,649 hours in all; 1,049 in this make and model; 135 in the last 90 days; 49 in the last 30 days; 8,349 as pilot in command
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 9,413 hours
- Last inspection: approved inspection programme, August 26, 2004; 49.2 hours since
- Maximum gross weight: 31,100 lb
- Seats: 11
- Landing gear: retractable
- Engine 1: Pratt & Whitney Canada PW305B (turbofan); 0 hours total
- Engine 2: Pratt & Whitney Canada PW305B (turbofan); 0 hours total
- Fire on the ground
The flight
- Departed from: KSFO San Francisco CA at 4:38 pm
- Destination: KVGT North Las Vegas NV
- Flight plan: IFR
- Runway 01R, 8,648 ft by 200 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 330° at 5 knots
- Visibility: 10 statute miles
- Sky: a few clouds at 900 ft
- Temperature: 66°F (19°C), dew point 57°F (14°C)
- Altimeter: 30.00 inHg
- Observation at 4:56 pm from KSFO
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.