CEN17FA170 · Air Tractor Inc AT 602
Gray Ag Air Air Tractor Inc AT 602 · Accident on approach
From Hollis Municipal Airport (O35) to Hollis Municipal Airport (O35)
Event
- NTSB case
- CEN17FA170
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 1 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Air Tractor Inc AT 602
- Aircraft type
- Air Tractor AT-602
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N604RH
- Operator
- Gray Ag Air
- Onboard fatalities
- Unknown
- Route
- From Hollis Municipal Airport (O35), Hollis, OKTo Hollis Municipal Airport (O35), Hollis, OK
- Aircraft age
- About 6 years (built 2011)
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 137: Agricultural
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Approach · VFR pattern final
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Unknown or undetermined
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Not determined › Not determined
Approximate · Coordinates from the NTSB case API, not marked as estimated; no uncertainty radius is established.
NTSB narrative
The pilot was returning from an application flight at the time of the accident. A witness observed the airplane approaching the airport. He noted that an unusual noise came from the airplane but was unsure of the exact nature. Shortly afterward, he heard a loud explosion. Ground-based video footage depicted the airplane entering a rapid descent while on final approach until it went behind an intervening tree line. A plume of smoke rose from that location few seconds later.
A postaccident examination of the airframe, engine and propeller did not reveal any anomalies consistent with a preimpact failure or malfunction. However, an examination of some components was limited due to the extent of the impact damage.
Toxicology testing revealed that the pilot had used three sedating drugs: cetirizine, oxycodone, and oxazepam. However, only oxycodone was still present at a level that could have been impairing. Because patients using opioids may develop significant tolerance to the sedating side effects, there is no accepted relationship between blood levels and impairment from these medications. Therefore, the extent of impairment, if any, could not be determined.
The reason for the abrupt descent and impact with terrain while on final approach could not be determined because the postaccident examination did not reveal any preimpact anomalies.
Probable cause
An impact with terrain during final approach for reasons that could not be determined because no evidence of an in-flight failure or malfunction was observed.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN17FA170
- Event ID
- 20170501X81827
- Case number
- CEN17FA170
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 6397146672f0f19143947204a4e3b012cfb7c5f2504ed0a9c8919b6d51be6eb6; retrieved 2026-09-15T06:01:56.546Z.