Bell 206B accident near Cresco, Iowa, August 18, 2015
On August 18, 2015 at about 6:30 pm local time, a 1980 Bell 206B (helicopter), registered N5743W, was substantially damaged in an accident during maneuvering near Cresco, Iowa. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The loss of engine power due to the high-cycle fatigue failure of the third-stage turbine wheel.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 18, 2015 · about 6:30 pm local time
- Place
- Cresco, Iowa · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 206B, built 1980 · all 206Bs on the register
- Registration
- N5743W · registry record · serial 3050
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
The commercial pilot reported that the helicopter departed with 30 gallons of fuel and about 90 gallons of chemical to spray a soybean field. About 5 minutes into the application flight and while 3 to 5 ft above the soybeans, the pilot heard a loud screech for about 2 seconds and pulled up to gain altitude. The pilot then heard the low rotor rpm horn and noticed that the main rotor rpm was at 85 percent. The pilot initiated an autorotation to a waterway between two cornfields. Upon touchdown on uneven terrain, the main rotor blades contacted and severed the tailboom, and the helicopter then came to rest upright. Disassembly of the engine revealed that the third-stage turbine wheel was missing five airfoils (blades), that several other airfoils were damaged, and that portions of the shroud were liberated. Materials examination of the third-stage turbine wheel revealed that the five airfoils had cracked in fatigue, initiating from the trailing edge root area and progressing forward until final fracture occurred in overload. All five cracks had initiated and progressed in high-cycle fatigue. Extensive testing by the engine manufacturer could not identify a single root cause for the liberation of the airfoils. As a result of the investigation, the engine manufacturer planned to release a new wheel design and process improvements to improve the robustness and capability of the turbine wheel.
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
What happened, in order
- Loss of engine power (total) during maneuvering defining event
- Autorotation Collision with terrain or object (not controlled flight into terrain)
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Turbine section › Failure
- cause Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Turbine section › Fatigue/wear/corrosion
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; instrument: airplane; rotorcraft: helicopter
- Flight time: 5,200 hours in all; 1,500 in this make and model; 250 in the last 90 days; 200 in the last 30 days; 5,200 as pilot in command
- Last flight review: March 19, 2015
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 12,008 hours
- Last inspection: 100-hour inspection, August 12, 2015
- Maximum gross weight: 3,350 lb
- Seats: 5
- Landing gear: fixed
- Engine: Rolls-Royce M250-C20J (turboshaft); 11,797 hours total
- Operator: Fly Hangar 13 LLC
The flight
- Departed from: Cresco IA at 6:20 pm
- Destination: Cresco IA
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 150° at 3 knots
- Visibility: 4 statute miles
- Sky: a few clouds at 3,100 ft
- Temperature: 66°F (19°C), dew point 66°F (19°C)
- Altimeter: 29.77 inHg
- Observation at 6:35 pm from DEH, 19 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
8 documents, released by the NTSB on March 1, 2017. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 9 pages | View Download |
| 2 | Rolls-royce Metallurgical Investigation Report | PDF, 83 pages | View Download |
| 3 | NTSB Materials Lab Email | PDF, 1 page | View Download |
| 4 | Excerpt of Rolls Royce Engine Examination Report | PDF, 30 pages | View Download |
| 5 | Excerpts of Turbine Records | PDF, 2 pages | View Download |
| 6 | FAA Ad 2015-02-22 | PDF, 7 pages | View Download |
| 7 | Statement of Party Representatives to NTSB Investigation - Rolls-royce | PDF, 1 page | View Download |
| 8 | Statement of Party Representatives to NTSB Investigation - Hangar 13 | PDF, 1 page | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
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.