Robinson Helicopter Company R44 II accident near Gunnison, Utah, August 12, 2016
On August 12, 2016 at about 6:25 pm local time, a 2003 Robinson Helicopter Company R44 II, registered N247DB, was substantially damaged in an accident during maneuvering (low-alt flying) near Gunnison, Utah. 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
A total loss of engine power for reasons that could not be determined based on the available evidence.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 12, 2016 · about 6:25 pm local time
- Place
- Gunnison, Utah · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Robinson Helicopter Company R44 II, built 2003
- Registration
- N247DB · registry record · serial 10086
- 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 was nearing the end of his second agricultural application pass; about the time that he turned off the spray system, he heard a "pop" and felt a "thump" that shook the helicopter. After he observed chemical spray in the air and along the side of the helicopter, he pushed the "kill" button for the spray pump. As he was doing so, the engine rpm dropped, and the pilot heard the engine "sputtering." The pilot lowered the collective to re-establish main rotor rpm; the engine subsequently experienced a total loss of power. He entered an autorotation between 50 and 75 ft above the ground, and the helicopter landed hard. The spray system was recently installed, and the helicopter had flown about 16 hours since the installation. The spray system pump was mounted on the right side skid. The engine air filter compartment was located above and behind the spray pump. A postaccident examination of the spray system revealed that the plastic pipe nipple on the spray system fractured. The initial crack progressed through the wall of the nipple during flight and caused a pesticide leak. Examination of the internal and external surfaces of the engine intake air filter revealed no cake deposits. Because there was no evidence of chemical residue on the airframe between the engine and the air intake filter and the condition of the air filter was relatively clean, it is unlikely that the engine ingested enough chemical to cause the total loss of power. Additionally, the operator later had the engine successfully run in a test cell with no anomalies noted; therefore, the reason for the loss of engine power could not be determined.
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
- Miscellaneous/other during maneuvering (low-alt flying)
- Loss of engine power (total) during maneuvering (low-alt flying) defining event
- Autorotation Hard landing
The NTSB's findings
- cause Not determined › Not determined › (general) › (general) › Unknown/Not determined
- Aircraft › Fluids/misc hardware › Misc hardware › (general) › Not specified
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: instructor: helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 1,534 hours in all; 973 in this make and model; 345 in the last 90 days; 125 in the last 30 days; 1,325 as pilot in command
- Last flight review: July 28, 2016
- Medical certificate: Class 1 (with waivers/limitations)
- Seat: frt
- Injury: no injuries
The aircraft
- Airframe total time: 46.3 hours
- Last inspection: annual inspection, May 2, 2016; 25 hours since
- Maximum gross weight: 2,500 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming IO-540-AE1A5 (piston); 46 hours total
The flight
- Departed from: Gunnison UT at 6:15 pm
- Destination: Gunnison UT
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 050° at 7 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 84°F (29°C), dew point 30°F (-1°C)
- Altimeter: 30.22 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
5 documents, released by the NTSB on May 2, 2018. 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 | Materials Laboratory Factual Report | PDF, 37 pages | View Download |
| 2 | Pilot/operator Aircraft Accident Report, NTSB Form 6120 | PDF, 9 pages | View Download |
| 3 | Engine Test Run Results | PDF, 1 page | View Download |
| 4 | Airframe and Engine Examination Report | PDF, 5 pages | View Download |
| 5 | Accident Photos | PDF, 4 pages | 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.