Hughes OH-6A accident near Tucson, Arizona, June 15, 1999
On June 15, 1999 at about 8:35 pm local time, a Hughes OH-6A (helicopter), registered N6187C, was destroyed in an accident near Tucson, Arizona (Tucson International airport). It was a public-use flight under general aviation rules (Part 91). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
Fuel exhaustion resulting from pilot's failure to perform adequate fuel consumption calculations. The unreliable and inoperative fuel level indicating system components and the operator's operation of the aircraft with known deficiencies were factors in the accident.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 15, 1999 · about 8:35 pm local time
- Place
- Tucson, Arizona · Tucson International · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Hughes OH-6A · all OH-6As on the register
- Registration
- N6187C · no longer on the register · serial 68-17154
- Damage
- Destroyed
- Flight
- Public-use flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot was on short final approach to land when he reported an engine failure. He attempted to stretch his glide to avoid buildings and cars on the ground; however, the helicopter struck railroad tracks next to the field boundary. Damage to the main rotor blades was consistent with a low rotor rpm at impact. The pilot did not recall how much time had elapsed since his last refueling. Examination of the navigation and fuel endurance log from the helicopter cockpit (required by the operator) showed the pilot had not completed the fuel endurance calculations at the time of last fueling. The helicopter was equipped with a main fuel system and an auxiliary fuel system. A deferred maintenance item, 'main fuel gauge unreliable in forward flight,' was still open. The same discrepancy had also been entered previously and it, too, had not been cleared. The auxiliary fuel gauge was entered as inoperative on the deferred maintenance log with 'parts on order' but had not been cleared at the time of the accident. The pilot last recalled reading approximately 78 pounds on the main fuel gauge. He did not recall seeing the 20-minute light illuminate before the accident. A check of the low fuel warning system found that float arm contact in the fuel cell occurred at 34 pounds, which approximates 20 minutes of usable fuel; no discrepancies were found in the operation of the system. No evidence of a fuel spill was found around or under the wreckage. The crashworthy main fuel cell was uncompromised and about 12 ounces of trapped fuel was found. No fuel was found in the auxiliary fuel tank. The light bulbs for the 'Engine Out, Fuel Low, and Master Caution' were removed for examination. One 'Master Caution' bulb showed a small amount of filament stretching, consistent with hot stretching from a light to moderate impact force. The filaments of both 'Fuel Low' bulbs were intact and unstretched, consistent with bulbs not being illuminated during a light to moderate impact. The filaments from both 'Engine Out' bulbs showed a small amount of stretching, again consistent with hot stretching from light to moderate impact. There were no other discrepancies found with the engine or engine-related systems.
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: single-engine land; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 5,500 hours in all; 1,500 in this make and model; 4,724 as pilot in command
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 7,176 hours
- Last inspection: continuous airworthiness programme, June 7, 1999; 26 hours since
- Maximum gross weight: 2,550 lb
- Seats: 4
- Landing gear: fixed
- Engine: Allison 250-C20B (turboshaft); 0 hours total
The flight
- Departed from: E78 Sells AZ
- Destination: TUC
- Flight plan: none
- Runway 3, 7,000 ft by 150 ft
Weather at the time
- Light: daylight
- Wind: from 150° at 3 knots
- Visibility: 10 statute miles
- Sky: scat at 10,000 ft
- Temperature: 97°F (36°C), dew point 46°F (8°C)
- Altimeter: 29.00 inHg
- Observation at 8:35 pm from TUC
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.