Bell UH-1B accident near Detroit Lake, Oregon, September 24, 1993
On September 24, 1993 at about 5:50 pm local time, a Bell UH-1B (helicopter), registered N70NW, was substantially damaged in an accident near Detroit Lake, Oregon. It was an other work-use flight under agricultural flying rules (Part 137). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
FAILURE OF A SECOND STAGE TURBINE WHEEL TOO LOW FOR A SUCCESSFUL AUTOROTATION. FACTORS INCLUDE A TREE IN THE APPROACH PATH.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 24, 1993 · about 5:50 pm local time
- Place
- Detroit Lake, Oregon · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell UH-1B · all UH-1Bs on the register
- Registration
- N70NW · no longer on the register · serial 60-3568
- Damage
- Substantial damage
- Flight
- Other work-use flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
THE AIRCRAFT STRUCK TREES WHILE ATTEMPTING AN AUTOROTATION AFTER AN ENGINE FAILURE. THE PILOT HAD PUNCHED OFF HIS EXTERNAL LOAD AFTER THE POWER LOSS, BUT WAS UNABLE TO SUCCESSFULLY ACCOMPLISH THE AUTOROTATION DUE TO INSUFFICIENT ALTITUDE AND UNSUITABLE TERRAIN. THE ENGINE FAILURE WAS THE RESULT OF THE FATIGUE FRACTURE OF BLADE NUMBER 19 OF THE SECOND STAGE TURBINE ROTOR ASSEMBLY.
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; rotorcraft: helicopter
- Flight time: 6,800 hours in all; 1,241 in this make and model; 50 in the last 90 days; 50 in the last 30 days; 6,200 as pilot in command
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 4,465 hours
- Last inspection: annual inspection, September 13, 1993; 47 hours since
- Maximum gross weight: 8,500 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming T53-L-11D (turboshaft); 0 hours total
- Operator: Northwest Helicopters, INC
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Visibility: 25 statute miles
- Sky: clear
- Temperature: 63°F (17°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.
Other NTSB records under N70NW 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.