WPR17LA209 · Trudel GP 4
Trudel GP 4 and Farnsworth RV-8 · Accident: midair collision while maneuvering
Event
- NTSB case
- WPR17LA209
- 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
- 0 · 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
Aircraft 1 · Trudel GP 4
- Aircraft type
- Trudel GP-4
- 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
- C-GTPX
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Reno-Stead Airport (RTS), Reno, NVTo Reno-Stead Airport (RTS), Reno, NV
- Aircraft age
- About 1 year (built 2016)
- 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 91: General Aviation
- 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
- Maneuvering
- 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
- Midair collision
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Minor
Aircraft 2 · Farnsworth RV-8
- Aircraft type
- Farnsworth RV-8
- 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
- N248DF
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Reno-Stead Airport (RTS), Reno, NVTo Reno-Stead Airport (RTS), Reno, NV
- Aircraft age
- About 4 years (built 2013)
- 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 91: General Aviation
- 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
- Maneuvering
- 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
- Midair collision
- 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
- Environmental issues › Physical environment
- Personnel issues › Psychological
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
During the initial start of an air race, nine airplanes were positioned in a line-abreast formation. The RV-8 was positioned in the No. 7 slot, and the GP 4 was right of the RV-8 in the No. 8 slot. The RV-8 pilot reported that, during the race start, he felt an air current push down his airplane. He then moved forward of the No. 6 slot airplane and initiated corrections to reestablish his position within the formation. The GP 4 pilot reported that he saw the RV-8 descend below his airplane's left wing and that he reduced power while initiating a slight right bank in an attempt to "back out" of the formation. The pilot who was in the No. 9 slot reported that he observed the GP-4 move forward back into the formation very quickly. At that time, he noticed the pilot of the GP-4 trying to slow or correct his position to the right using ailerons. Shortly after, the propeller of the GP-4 struck the right aileron of the RV-8. Following the collision, the RV-8 entered an uncommanded left roll; however, the pilot was able to level the airplane and land uneventfully. The GP-4 pilot pitched his airplane upward and rolled right to avoid the surrounding airplanes and was also able to land the airplane uneventfully.
It is likely that, if the pilot of the GP-4 had maintained adequate lateral distance from the RV-8 while advancing forward to maintain a line-abreast formation, he would have been able to maintain clearance from the RV-8 as it descended and would not have needed to bank right, which further reduced the GP-4 pilot's visual contact with the RV-8 and led to the midair collision.
Probable cause
The pilot's failure to maintain clearance from another airplane during the line-abreast formation.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR17LA209
- Event ID
- 20170919X21640
- Case number
- WPR17LA209
- 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. 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: 998186ce5678e0b69d973d5d645dd4dbf99dcfdf964a8d09ec9ba4d4abc3572f; retrieved 2026-09-13T18:27:04.565Z.