Amateur-built 400 accident near Aguilares, Texas, July 2, 2018
On July 2, 2018 at about 4:30 pm local time, a 2018 amateur-built 400 (helicopter), registered N326RW, was substantially damaged in an accident during enroute (cruise) near Aguilares, Texas. It was a personal flight under general aviation rules (Part 91). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The loss of tail rotor control due to the in-flight failure of the tail rotor pinion.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 2, 2018 · about 4:30 pm local time
- Place
- Aguilares, Texas · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built 400, built 2018
- Registration
- N326RW · no longer on the register · serial 6686
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The private pilot departed in an amateur-built helicopter on a local flight for phase I flight test requirements. The helicopter was between 20 and 30 ft above ground level when it started to shudder. The pilot looked for a place to land and then heard a "pop"; the helicopter then lost tail rotor authority. The helicopter started to rotate counterclockwise, and the pilot attempted to stop the rotation without success. The helicopter impacted the ground and rolled onto its left side, which resulted in substantial damage. Postaccident examination of the transmission revealed that the tail rotor pinion had failed. There was no damage to the tail rotor blades or the tail rotor driveshaft. Laboratory examination of the tail rotor pinion revealed that both halves of the pinion shaft fracture surface exhibited mechanical damage by recontact resulting in rubbing of the fracture surfaces. No evidence of a preexisting crack was observed. Microhardness measurement values were consistent with the specifications for the pinion shaft. There were no other mechanical anomalies with the helicopter or its systems that would have precluded normal operations. The lack of damage to the tail rotor blades and tail rotor driveshaft is consistent with the failure of the tail rotor pinion in flight and not as a result of ground impact. Due to the recontact rubbing of the fracture surface, the investigation was not able to determine the exact reason for the pinion failure.
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
- Powerplant sys/comp malf/fail during enroute (cruise) defining event
- Collision with terrain or object (not controlled flight into terrain) during uncontrolled descent
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Tail rotor drive system › (general) › Failure
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Yaw control › Attain/maintain not possible
Pilot
- Certificate: private
- Ratings: multi-engine land; single-engine land; single-engine sea; rotorcraft: helicopter
- Flight time: 13,425 hours in all; 27 in this make and model; 35 in the last 90 days; 10 in the last 30 days
- Last flight review: December 5, 2017
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: serious injuries
The aircraft
- Airframe total time: 24.3 hours
- Last inspection: condition inspection, May 15, 2018
- Maximum gross weight: 1,650 lb
- Seats: 2
- Landing gear: fixed
- Engine: Aero Sport Power Ltd. O-360-C2A (piston); 24 hours total
The flight
- Departed from: Slator Ranch TX at 10:00 am
- Destination: Slator Ranch TX
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 140° at 11 knots, gusting 16
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 93°F (34°C), dew point 72°F (22°C)
- Altimeter: 29.96 inHg
- Observation at 4:56 pm from KLRD, 23 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
6 documents, released by the NTSB on November 13, 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 | Pilot Statement to FAA | PDF, 1 page | View Download |
| 3 | Record of Conversation - FAA Inspector | PDF, 1 page | View Download |
| 4 | Record of Conversation - Safari Helicopter | PDF, 1 page | View Download |
| 5 | NTSB Materials Laboratory Report | PDF, 5 pages | View Download |
| 6 | Accident Report Photographs | PDF, 6 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
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.