Air Tractor INC AT 502B and Air Tractor INC AT 502B mid-air collision near Zamora, California, July 23, 2016
On July 23, 2016 at about 2:45 pm local time, 2 aircraft, Air Tractor INC AT 502B (N502WC) and Air Tractor INC AT 502B (N5044N), were involved in a mid-air collision near Zamora, California (Riego Flight Strip Airport). 1 person was killed and 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The failure of both pilots to maintain an adequate visual lookout, which resulted in a midair collision. Also causal was the pilot's use of two sedating antihistamines and two impairing medication and the effect of sun glare on his visual lookout, which likely led to his inability to successfully see and avoid the other airplane.
The failure of both pilots to maintain an adequate visual lookout, which resulted in a midair collision. Also causal was the other pilot's use of two sedating antihistamines and two impairing medication and the effect of sun glare on his visual lookout, which likely led to his inability to successfully see and avoid the other airplane.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 23, 2016 · about 2:45 pm local time
- Place
- Zamora, California · Riego Flight Strip Airport · map
- Type
- Accident · mid-air collision
- Injuries
- 1 person was killed and 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft 1
- Air Tractor INC AT 502B B, built 2012 · all AT 502Bs on the register
- Registration
- N502WC · no longer on the register · serial 502B-2830
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
- Aircraft 2
- Air Tractor INC AT 502B B, built 1997 · all AT 502Bs on the register
- Registration
- N5044N · registry record · serial 502B-0452
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative for the Air Tractor INC AT 502B final · quoted from the NTSB record
Both agricultural application airplanes were returning to their respective home bases after completing application operations when they collided in-flight at an altitude less than 500 ft agl. Following the collision, one of the airplanes (N502WC) descended to ground contact, fatally injuring the pilot. The pilot of the second airplane (N5044N) performed a forced landing to a field. That pilot reported that he did not see the other airplane until immediately before the collision. Examination of the engine and flight control systems of both airplanes revealed no mechanical anomalies that would have precluded normal operation including the ability to maneuver the airplanes away from each other. The deceased pilot had at least therapeutic levels of two impairing medications, cyclobenzaprine and hydrocodone, at the time of the accident. In addition, he had low levels of two sedating antihistamines, chlorpheniramine and diphenhydramine. These four drugs, in combination, would likely have slowed his psychomotor functioning and decreased his attentiveness to the flight environment. Therefore, it is likely that the fatally injured pilot's use of a combination cyclobenzaprine, hydrocodone, and two sedating antihistamines, contributed to his inability to successfully see and avoid the other airplane. Based upon the sun's position and the statement from the second pilot, the sun was likely in the eyes of the deceased pilot. There was no evidence of the deceased pilot performing any evasive maneuver prior to the collision, which suggests that he never visually acquired the other airplane prior to the collision.
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 Air Tractor INC AT 502B final · quoted from the NTSB record
Both agricultural application airplanes were returning to their respective home bases after completing application operations when they collided in-flight at an altitude less than 500 ft agl. Following the collision, one of the airplanes (N502WC) descended to ground contact, fatally injuring the pilot. The pilot of the second airplane (N5044N) performed a forced landing to a field. That pilot reported that he did not see the other airplane until immediately before the collision. Examination of the engine and flight control systems of both airplanes revealed no mechanical anomalies that would have precluded normal operation including the ability to maneuver the airplanes away from each other. The deceased pilot had at least therapeutic levels of two impairing medications, cyclobenzaprine and hydrocodone, at the time of the accident. In addition, he had low-levels of two sedating antihistamines, chlorpheniramine and diphenhydramine. These four drugs, in combination, would likely have slowed his psychomotor functioning and decreased his attentiveness to the flight environment. Therefore, it is likely that the fatally injured pilot's use of a combination cyclobenzaprine, hydrocodone, and two sedating antihistamines, contributed to his inability to successfully see and avoid the other airplane. Based upon the sun's position and the statement from the second pilot, the sun was likely in the eyes of the deceased pilot. There was no evidence of the deceased pilot performing any evasive maneuver prior to the collision, which suggests that he never visually acquired the other airplane prior to the collision.
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 Air Tractor INC AT 502B from the NTSB's investigation tables, in plain English
What happened, in order
- Midair collision during enroute (cruise) defining event
The NTSB's findings
- cause Personnel issues › Action/decision › Action › Lack of action › Pilot
- cause Personnel issues › Psychological › Attention/monitoring › Monitoring other aircraft › Pilot
- cause Personnel issues › Physical › Impairment/incapacitation › Prescription medication › Pilot
- cause Environmental issues › Conditions/weather/phenomena › Light condition › Bright light › Ability to respond/compensate
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land
- Flight time: 2,250 hours in all; 0 in this make and model; 450 in the last 90 days
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: ctr
- Injury: fatal
The aircraft
- Airframe total time: 967.5 hours
- Last inspection: annual inspection, May 1, 2016; 968 hours since
- Landing gear: fixed
- Engine: Pratt And Whitney Canada 502B-2830 (turboprop); 968 hours total
- Operator: Farm Air Flying Services
The flight
- Departed from: 38CL Verona CA
- Destination: 38CL Verona CA
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 72°F (22°C), dew point 57°F (14°C)
- Altimeter: 29.94 inHg
- Observation at 2:53 pm from KSMF, 11 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
The factual record for the Air Tractor INC AT 502B from the NTSB's investigation tables, in plain English
What happened, in order
- Midair collision during enroute (cruise) defining event
The NTSB's findings
- cause Personnel issues › Action/decision › Action › Delayed action › Pilot
- cause Personnel issues › Psychological › Attention/monitoring › Monitoring other aircraft › Pilot
- cause Personnel issues › Physical › Impairment/incapacitation › Prescription medication › Pilot of other aircraft
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; instrument: airplane
- Flight time: 0 hours in all; 0 in this make and model
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: minor injuries
The aircraft
- Last inspection: inspection type not recorded
- Landing gear: fixed
- Engine: Pratt And Whitney Canada 502B-0452 (turboprop); 0 hours total
- Operator: Growers Air Service INC
The flight
- Departed from: 69CL Davis CA
- Destination: 69CL Davis CA
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The NTSB has not released the docket for this case yet. The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), is usually released when the investigation is nearly complete, and the list here is refreshed when it appears. Check 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.