Robinson R-22M accident near Portland, Oregon, July 7, 1994
On July 7, 1994 at about 6:25 pm local time, a Robinson R-22M (helicopter), registered N42WC, was substantially damaged in an accident near Portland, Oregon. It was an instructional flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
TAIL ROTOR GEARBOX FAILURE DUE TO INADEQUATE ASSEMBLY AND INSPECTION PROCEDURES BY THE MANUFACTURER.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 7, 1994 · about 6:25 pm local time
- Place
- Portland, Oregon · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Robinson R-22M · all R-22Ms on the register
- Registration
- N42WC · registry record · serial 1531M
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE PILOT ATTEMPTED AN AUTOROTATION AFTER LOSS OF TAIL ROTOR EFFECTIVENESS. THE TAIL BOOM AND ROTOR STRUCK THE SURFACE WHEN THE FLOAT EQUIPPED HELICOPTER LANDED IN THE RIVER. INVESTIGATION REVEALED THAT THE TAIL ROTOR GEARBOX OUTPUT SHAFT PINION RETAINING KEY HAD NOT BEEN INSTALLED DURING ASSEMBLY. THE TAIL ROTOR HUB AND BLADE ASSEMBLY WERE FREE TO TURN ON THE SHAFT AT THE TIME OF INVESTIGATION.
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: flight instructor, commercial pilot, private
- Ratings: single-engine land; instructor: helicopter; rotorcraft: helicopter
- Flight time: 1,822 hours in all; 1,475 in this make and model; 257 in the last 90 days; 101 in the last 30 days; 1,263 on instruments
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 460 hours
- Last inspection: annual inspection, January 28, 1994; 22 hours since
- Maximum gross weight: 1,370 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming O-320-B2C (piston); 0 hours total
- Operator: Hillsboro Helicopters, INC.
The flight
- Departed from: HIO Hillsboro OR at 6:05 pm
- Flight plan: none
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 330° at 8 knots
- Visibility: 30 statute miles
- Sky: clear
- Temperature: 81°F (27°C), dew point 57°F (14°C)
- Altimeter: 30.00 inHg
- Observation at 5:46 pm from HIO
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 2 |
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 N42WC the same tail number, which may have belonged to a different aircraft at the time
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.