Robinson Helicopter Company R44 II accident near Lyons, Nebraska, August 3, 2019
On August 3, 2019 at about 8:05 pm local time, a 2013 Robinson Helicopter Company R44 II, registered N440EM, was substantially damaged in an accident during maneuvering near Lyons, Nebraska. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The engine's low cylinder compression, which resulted in low rotor rpm and a subsequent dynamic rollover following landing on soft terrain.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 3, 2019 · about 8:05 pm local time
- Place
- Lyons, Nebraska · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Robinson Helicopter Company R44 II, built 2013
- Registration
- N440EM · no longer on the register · serial 13503
- 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 airline transport pilot of the agricultural aerial application flight stated that as the helicopter entered the field to be sprayed, the low rotor rpm annunciation sounded. He attempted to recover rotor rpm, but the rpm continued to decay rapidly. He then used the remaining rotor rpm to cushion a landing onto the field. As the helicopter touched down, it slid about 150-200 ft before the skid dug into soft dirt and the helicopter rolled over. Post-accident examination of the engine by the operator revealed that the no. 6 cylinder had more leakage/lower compression than the previous 100-hour recorded compression checks. Reduced compression on one or more cylinders would have reduced excess power available to maintain a rotor RPM and altitude.
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 (partial) during maneuvering defining event
- Attempted remediation/recovery during emergency descent
- Dynamic rollover during post (impact)
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng cyl section › Failure
- Environmental issues › Physical environment › Runway/land/takeoff/taxi surface › Soft surface › Contributed to outcome
Pilot
- Certificate: airline transport pilot, flight instructor
- Ratings: instructor: helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 2,750 hours in all; 669 in this make and model; 107 in the last 90 days; 63 in the last 30 days; 1,675 as pilot in command
- Last flight review: October 27, 2018
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: minor injuries
The aircraft
- Airframe total time: 588.3 hours
- Last inspection: 100-hour inspection, April 23, 2017
- Maximum gross weight: 2,500 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming IO-540-AE1AB (piston); 1,149 hours total
- Operator: Wallin Agricultural Aviation
The flight
- Departed from: Lyons NE
- Destination: Lyons NE
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 140° at 8 knots
- Visibility: 10 statute miles
- Sky: scat at 11,000 ft
- Temperature: 84°F (29°C), dew point 61°F (16°C)
- Altimeter: 30.04 inHg
- Observation at 8:54 pm from TQE, 17 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
4 documents, released by the NTSB on October 17, 2020. 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 | Record of Correspondence - Pilot | PDF, 1 page | View Download |
| 3 | Aircraft Logs | PDF, 20 pages | View Download |
| 4 | Aircraft Weight and Balance | PDF, 2 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.