Bell BHT-206L-1 accident near Highland, California, July 7, 1997
On July 7, 1997, a Bell BHT-206L-1 (helicopter), registered N27591, was destroyed in an accident near Highland, California. It was a flight of an unrecorded kind under public-use (government) rules. 1 person was killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
Loss of engine power due to fuel contamination. Also causal was the ingestion of entrapped air that occurred during an abrupt maneuver and fuel-borne contamination that caused the fuel system check valves to leak, resulted in a lower than expected fuel level in the main fuel cell. A related factor was mountainous terrain.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 7, 1997
- Place
- Highland, California · map
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell BHT-206L-1
- Registration
- N27591 · no longer on the register · serial 45273
- Damage
- Destroyed
- Flight
- Flight of an unrecorded kind · public-use (government) rules
The NTSB's narrative final · quoted from the NTSB record
The pilot was conducting water dropping operations as part of an ongoing forest fire fighting effort. A firefighter reported that the helicopter made two water drops before the accident. A battalion fire chief, who was directing the effort, reported that he saw the helicopter making water drops on a slope. After a water drop which involved an abrupt pull up and turn after the water was released from the bucket, he reported hearing the words 'May Day,' 'I have a flame out' and finally 'I'm going down'. Several other people who were monitoring the common frequency also reported hearing a transmission with the phrase 'flame out.' The helicopter impacted the bottom of the canyon. An inspection revealed that the lines from the engine fuel nozzle to the fuel control and the airframe fuel filter contained fuel. The lines and in-line filters contained both fuel and particulate matter in the bottom of both filter housings. Testing revealed that the manifold check valve leaked from both inlet ports. When the valves were disassembled additional foreign material was found. The material was found to be a combination of organic and inorganic materials. A 5-gallon fuel sample was taken from the refueling truck on the day of the accident. The analytical report stated that the sample submitted was that of aviation turbine fuel. No contamination was noted. According to historical records, there have been a series of engine flameout related accidents and incidents related to this engine make and model. Controlled tests have demonstrated that should entrapped air migrate through the fuel system to the engine, an engine flame out can occur.
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: commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane single-engine; instructor: helicopter; instrument: airplane; rotorcraft: helicopter
- Flight time: 11,000 hours in all; 2,900 in this make and model; 61 in the last 90 days; 13 in the last 30 days
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 7,705 hours
- Last inspection: 100-hour inspection, May 26, 1997; 39 hours since
- Maximum gross weight: 4,250 lb
- Seats: 7
- Landing gear: fixed
- Engine: Allison 250-C30P (turboshaft); 0 hours total
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 240° at 16 knots
- Visibility: 15 statute miles
- Sky: clear
- Temperature: 90°F (32°C), dew point 59°F (15°C)
- Altimeter: 29.00 inHg
- Observation at 11:50 pm from ONT, 23 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
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.