Amateur-built Hughes 1-B accident near Yellowstone Nat, Wyoming, August 5, 2003
On August 5, 2003, a amateur-built Hughes 1-B, registered N258Y, was destroyed in an accident near Yellowstone Nat, Wyoming. It was a personal flight under general aviation rules (Part 91). 1 person was killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The in-flight loss of a propeller counterweight, followed by the pilot's loss of aircraft control during a forced landing attempt and subsequent inadvertent stall/spin to the ground.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 5, 2003
- Place
- Yellowstone Nat, Wyoming · map
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built Hughes 1-B
- Registration
- N258Y · registry record · serial 2
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
Several witnesses at Yellowstone National Park's Midway Geyser basin area reported seeing the airplane approaching them at a "low altitude" from the southeast. The airplane was quiet, and was observed gliding with its wings tipping back and forth. Next, it was observed to corkscrew, or spiral to the ground. The airplane's propeller was a highly modified constant speed Hamilton Standard 12D40 hub. Neither of the two 7 pound counterweights were found at the accident site. Examination of the #2 counterweight bracket revealed a fatigue crack at the proximal end of the counterweight slot. The propeller's shim plates exhibited impact signatures of the two blades indicating an angular difference of 10 degrees. The propeller's cylinder was crushed on one side, locking the piston inside the cylinder; the location of the piston inside the cylinder correlated to a blade angle of 34.9 degrees. If a propeller counterweight had separated in flight, aerodynamic forces would have driven the blade towards fine pitch or low blade angle. The blade's rotation would be limited to the low blade angle, of 24 degrees, by the remaining portion of its counterweight bracket arm which would contact and be stopped by the propeller’s barrel. If one blade was at the low blade angle of 24 degrees, the measured angular difference of 10 degrees, would indicate that the other blade was at an angle of 34 degrees. The agreement between this derived blade angle of 34 degrees and the piston position of 34.9 degrees suggests that one blade was still slaved to its counterweight at the time of impact and one blade was not.
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
- Flight time: 2,500 hours in all
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: frt
- Injury: fatal
The aircraft
- Airframe total time: 74 hours
- Last inspection: condition inspection, June 12, 2003; 61 hours since
- Maximum gross weight: 4,806 lb
- Seats: 1
- Landing gear: retractable
- Engine: Pratt & Whitney R-1535-11 (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: GCC Gillette WY at 11:30 pm
- Destination: EUG Eugene OR
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 160° at 8 knots
- Visibility: 20 statute miles
- Sky: broken clouds at 4,000 ft
- Temperature: 72°F (22°C), dew point 48°F (9°C)
- Altimeter: 30.26 inHg
- Observation at 11:46 pm from WYS, 18 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.