Amateur-built ROTORWAY EXECUTIVE accident near Sand Springs, Oklahoma, April 13, 1998
On April 13, 1998 at about 11:45 pm local time, a amateur-built ROTORWAY EXECUTIVE (helicopter), registered N71RF, was destroyed in an accident near Sand Springs, Oklahoma. It was a personal flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
The failure of the owner/pilot to complete maintenance on the helicopter.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 13, 1998 · about 11:45 pm local time
- Place
- Sand Springs, Oklahoma · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built ROTORWAY EXECUTIVE ROTORWAY E
- Registration
- N71RF · registry record · serial 1092
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that he was flying the Froberg Rotorway Executive experimental helicopter to the William R. Pogue Municipal Airport, Sand Springs, Oklahoma, for fuel. Approximately 6 minutes after takeoff, the pilot observed smoke entering the cockpit from the right side and noted a loss of oil pressure. He executed an autorotation to a field of tall dry grass and exited the helicopter. After exiting the aircraft, the pilot observed a fire underneath the helicopter. The aircraft was then consumed by the fire within a few minutes. The pilot reported to the FAA inspector that 'there was an oil leak and oil was dripping on the exhaust pipe.' The pilot had purchased the helicopter about a year prior to the accident. He had flown the aircraft about 30 hours since purchasing it and had not registered it. No maintenance had been performed on the helicopter in the last 20 hours.
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: private
- Ratings: single-engine land; rotorcraft: helicopter
- Flight time: 580 hours in all; 30 in this make and model; 30 in the last 90 days; 14 in the last 30 days
- Medical certificate: Class 3 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Last inspection: inspection type not recorded; 20 hours since
- Maximum gross weight: 1,425 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotorway ROTORWAY 145 (piston); 0 hours total
The flight
- Departed from: 4F1 West Port OK at 11:35 pm
- Destination: 0F8 Sand Springs OK
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 81°F (27°C), dew point 0°F (-18°C)
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.
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number FTW98LA182.