Robinson R44 accident near Knox City, Texas, November 18, 2018
On November 18, 2018 at about 2:30 pm local time, a 2008 Robinson R44 (helicopter), registered N4167Y, was substantially damaged in an accident during maneuvering (low-alt flying) near Knox City, Texas. It was an aerial observation flight under general aviation rules (Part 91). No one was hurt; 4 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot's failure to maintain adequate airspeed with a tailwind, which resulted in the helicopter settling with power, and his subsequent incorrect collective application while attempting to recover, which resulted in a loss of helicopter control due to a loss of tail rotor effectiveness.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 18, 2018 · about 2:30 pm local time
- Place
- Knox City, Texas · map
- Type
- Accident
- Injuries
- No one was hurt; 4 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Robinson R44 Undesignat, built 2008 · all R44s on the register
- Registration
- N4167Y · no longer on the register · serial 1889
- Damage
- Substantial damage
- Flight
- Aerial observation flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The helicopter pilot reported that, while conducting a photography flight about 70 ft above ground level, the helicopter's heading was 190°, and the airspeed was less than 9 knots. With a 10-knot tailwind, the helicopter began to settle with power. The pilot increased the collective and applied forward cyclic to increase the airspeed, but the helicopter continued to settle and impacted the ground hard. The helicopter sustained substantial damage to the main rotor system and fuselage. The pilot reported that there were no mechanical malfunctions or failures with the helicopter that would have precluded normal operation. The pilot reported that the wind about the time of the accident was from the north at 10 knots. According to the Helicopter Flying Handbook, Chapter 11, page 11-10 When recovering from a settling with power condition, the pilot tends first to try to stop the descent by increasing collective pitch. However, this only results in increasing the stalled area of the rotor, thereby increasing the rate of descent. Since inboard portions of the blades are stalled, cyclic control may be limited. Recovery is accomplished by increasing airspeed, and/or partially lowering collective pitch. In many helicopters, lateral cyclic combined with lateral tailrotor thrust will produce the quickest exit from the hazard assuming that there are no barriers in that direction. In a fully developed vortex ring state, the only recovery may be to enter autorotation to break the vortex ring state.
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
- Settling with power/vortex ring state during maneuvering (low-alt flying)
- Loss of control in flight during maneuvering (low-alt flying) defining event
- Collision with terrain or object (not controlled flight into terrain) during maneuvering (low-alt flying)
The NTSB's findings
- cause Personnel issues › Action/decision › Action › Incorrect action performance › Pilot
- cause Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Airspeed › Not attained/maintained
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Prop/rotor parameters › Not attained/maintained
- Environmental issues › Conditions/weather/phenomena › Wind › Tailwind › Effect on operation
Pilot
- Certificate: commercial pilot
- Ratings: instrument: helicopter; rotorcraft: helicopter
- Flight time: 302.8 hours in all; 302.8 in this make and model; 35.2 in the last 90 days; 30.8 in the last 30 days; 224.8 as pilot in command
- Last flight review: September 28, 2018
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 2,087.5 hours
- Last inspection: 100-hour inspection, July 10, 2018
- Maximum gross weight: 2,400 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming O-540-F1B5 (piston); 2,088 hours total
The flight
- Departed from: F75 Knox City TX at 1:30 pm
- Destination: F75 Knox City TX
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 350° at 10 knots
- Visibility: 10 statute miles
- Sky: overcast at 3,300 ft; a few clouds at 1,900 ft
- Temperature: 30°F (-1°C), dew point 23°F (-5°C)
- Altimeter: 30.37 inHg
- Observation at 2:53 pm from KCDS, 57 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 3 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
2 documents, released by the NTSB on June 27, 2019. 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 | Photo | 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.
Other NTSB records under N4167Y 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.