Grumman G-164A and Ayres S2R mid-air collision near Dewitt, Arkansas, May 18, 2006
On May 18, 2006 at about 5:10 pm local time, 2 aircraft, Grumman G-164A (N6629) and Ayres S2R (N4121G), were involved in a mid-air collision near Dewitt, Arkansas. 1 person was killed and 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The failure by both pilots to maintain adequate visual lookout and the Grumman G-164A pilot's impairment caused by the recent use of marijuana.
The failure by both pilots to maintain adequate visual lookout and the Grumman G-164A pilot's impairment caused by the recent use of marijuana.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 18, 2006 · about 5:10 pm local time
- Place
- Dewitt, Arkansas · map
- Type
- Accident · mid-air collision
- Injuries
- 1 person was killed and 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft 1
- Grumman G-164A · all G-164As on the register
- Registration
- N6629 · no longer on the register · serial 759
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
- Aircraft 2
- Ayres S2R
- Registration
- N4121G · no longer on the register · serial T660-105
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative for the Grumman G-164A final · quoted from the NTSB record
The 5,700-hour commercial pilot of a turbine powered agricultural bi-plane had completed an aerial application run, and was returning on a northerly heading to the municipal airport in order to pickup another load of fertilizer. The owner of the bi-plane stated that it's typical for the pilot to fly between 200 and 300 feet above the ground en route to, or from the airport. A 12,300-hour commercial pilot of an agricultural, turbine powered low-wing airplane departed a private airstrip, located west of the municipal airport, and was heading in a southeasterly direction en route to deliver his aerial application load. The airplanes collided in-flight while en route to their destinations and there was no reported witnesses to the event. The weather in the area was reported as VFR (Visual Flight Rules). The GPS logging unit was not installed in bi-plane at the time of the accident. The GPS memory card from the low-wing airplane was removed and sent to the manufacturer for download. However, the GPS manufacturer reported that the unit was not recording information at the time, and no data was available with regards to the accident. The Federal Aviation Administration's Civil Aerospace Medical Institute conducted toxicology tests on the remains of the Grumman G-164A pilot. Tetrahydrocannabinol (THC/marijuana) was detected in the pilot's heart and lung tissue. Tetrahydrocannabinol carboxylic acid (THC-COOH, a marijuana metabolite) was detected in lung, heart and urine samples. The testing indicated that the pilot had recently used marijuana, which resulted in his impairment.
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 NTSB's narrative for the Ayres S2R final · quoted from the NTSB record
The 5,700-hour commercial pilot of a turbine powered agricultural bi-plane had completed an aerial application run, and was returning on a northerly heading to the municipal airport in order to pickup another load of fertilizer. The owner of the bi-plane stated that it's typical for the pilot to fly between 200 and 300 feet above the ground en route to, or from the airport. A 12,300-hour commercial pilot of an agricultural, turbine powered low-wing airplane departed a private airstrip, located west of the municipal airport, and was heading in a southeasterly direction en route to deliver his aerial application load. The airplanes collided in-flight while en route to their destinations and there was no reported witnesses to the event. The weather in the area was reported as VFR (Visual Flight Rules). The GPS logging unit was not installed in bi-plane at the time of the accident. The GPS memory card from the low-wing airplane was removed and sent to the manufacturer for download. However, the GPS manufacturer reported that the unit was not recording information at the time, and no data was available with regards to the accident. The Federal Aviation Administration's Civil Aerospace Medical Institute conducted toxicology tests on the remains of the Grumman G-164A pilot. Tetrahydrocannabinol (THC/marijuana) was detected in the pilot's heart and lung tissue. Tetrahydrocannabinol carboxylic acid (THC-COOH, a marijuana metabolite) was detected in lung, heart and urine samples. The testing indicated that the pilot had recently used marijuana, which resulted in his impairment.
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 for the Grumman G-164A from the NTSB's investigation tables, in plain English
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land
- Flight time: 5,700 hours in all; 1,200 in this make and model; 75 in the last 90 days; 40 in the last 30 days; 5,300 as pilot in command
- Last flight review: March 1, 2005
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: sngl
- Injury: fatal
The aircraft
- Last inspection: annual inspection, January 1, 2006
- Seats: 1
- Landing gear: fixed
- Engine: Garrett TPE-331 (turboprop); 0 hours total
The flight
- Departed from: 5M1 De Witt AR
- Destination: De Witt AR
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 320° at 11 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 79°F (26°C), dew point 55°F (13°C)
- Altimeter: 29.87 inHg
- Observation at 4:55 pm from SGT, 26 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
The factual record for the Ayres S2R from the NTSB's investigation tables, in plain English
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; instrument: airplane
- Flight time: 12,300 hours in all; 3,200 in this make and model; 12,300 as pilot in command
- Last flight review: January 1, 2006
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: sngl
- Injury: serious injuries
The aircraft
- Airframe total time: 3,174 hours
- Last inspection: 100-hour inspection, May 1, 2006
- Seats: 1
- Landing gear: fixed
- Engine: Pratt & Whitney PT6A (turboprop); 0 hours total
The flight
- Departed from: Dewitt AR
- Destination: Dewitt AR
- Flight plan: none
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.
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.