Amateur-built 200 accident near Kent, Washington, August 31, 1999
On August 31, 1999 at about 2:02 am local time, a amateur-built 200 (gyroplane), registered N85Z, was destroyed in an accident near Kent, Washington (Crest Airpark airport). It was a flight of an unrecorded kind 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 owner/builder's failure to properly torque the rotor blade retaining bolts.
Source: NTSB aviation accident database, copy made October 12, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 31, 1999 · about 2:02 am local time · cases in 1999
- Place
- Kent, Washington · Crest Airpark · cases near this airport · map
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built 200
- Registration
- N85Z · no longer on the register · serial 1
- Damage
- Destroyed
- Flight
- Flight of an unrecorded kind · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The co-owner/builder had been engaged in resetting the angle of attack (pitch angle) of the main rotor blades previous to the accident. Witnesses reported observing the gyrocopter depart to the south, proceed west, and then execute several oscillatory, rocking or pitching like maneuvers after which the aircraft entered a steep descent to the ground. Post-crash examination revealed that all eight of the main rotor blade pitch adjustment bolts were loose. Examination of the upper outboard shim plate of each blade attach bar revealed markings which clearly established a pitch bolt torque of 190 inch-pounds. Release of the main rotor blade pitch adjustment bolts would allow a rotor blade pitch change and subsequent loss of control.
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; single-engine sea; instrument: airplane
- Flight time: 2,000 hours in all
- Medical certificate: Class 3 (valid medical--no waivers/lim.)
- Seat: frt
The aircraft
- Airframe total time: 56 hours
- Last inspection: continuous airworthiness programme, May 15, 1999
- Landing gear: fixed
- Engine: Lycoming O-290-D2 (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: S36 at 2:00 am
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 180° at 7 knots
- Visibility: 10 statute miles
- Sky: scat at 6,500 ft
- Temperature: 68°F (20°C), dew point 43°F (6°C)
- Altimeter: 29.00 inHg
- Observation at 1:53 am from RNT, 8 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.
Other NTSB records under N85Z the same tail number, which may have belonged to a different aircraft at the time
Connections how this case links to the rest of the register
- N85Z: not on the register today · the record of its deregistration
- Engine: Lycoming O-290-D2 58 aircraft carry this series today · as the NTSB recorded it
- Crest Airfield · nearest airport
- Accidents and incidents in Washington 2,709 since 1982 · 358 in the last ten years
- Washington 10,568 aircraft registered
- Other NTSB records under N85Z 1 records · the number may have belonged to another aircraft at the time
The whole map of how records connect · these connections as data: /graph/accident/SEA99LA151.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
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 does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.