Hughes 269A accident near Anderson, South Carolina, June 27, 2023
On June 27, 2023 at about 9:30 pm local time, a 1966 Hughes 269A (helicopter), registered N90270, was substantially damaged in an accident during landing near Anderson, South Carolina (Anderson Regional Airport). It was a flight test under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
The mechanics’ improper torquing of the main rotor blade dampers, which resulted in a ground resonance event during landing.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 27, 2023 · about 9:30 pm local time
- Place
- Anderson, South Carolina · Anderson Regional Airport · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Hughes 269A, built 1966 · all 269As on the register
- Registration
- N90270 · registry record · serial 66-18283
- Damage
- Substantial damage
- Flight
- Flight test · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
Prior to the accident flight, the pilot reported experiencing vibrations in the helicopter. The pilot (who was also a mechanic) and another mechanic adjusted the main rotor dampers to address the issue. Following this adjustment, a 10-minute ground run was performed without any observed problems. The pilot then conducted a test flight during, which no issues were detected. Upon landing and while reducing the rotor rpm, the helicopter began to shake violently. The pilot attempted to perform the ground resonance recovery procedure and climbed the helicopter, but the vibration worsened, and he subsequently landed. After contacting the ground, the helicopter shook and spun uncontrollably before coming to a stop. The airframe and main rotor were substantially damaged during the accident sequence. Federal Aviation Administration inspectors examined the helicopter after the accident and found that the yellow main rotor blade’s damper had significantly higher torque than the red and blue blades, and that none of the dampers were torqued to the specification in the helicopter’s maintenance manual. The manual also described that incorrect torque adjustments of the dampers could result in “…conditions that may result in ground resonance and destruction of the helicopter. During a subsequent discussion with the assisting mechanic, he stated that he, “may have unintentionally over-torqued the blade [damper].” Based on this information, it is likely that the mechanics’ improper maintenance of the helicopter’s main rotor dampers resulted in the ground resonance event experienced at the conclusion of the post maintenance test flight test flight.
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
- Ground resonance during landing defining event
- Aircraft maintenance event during prior to flight
The NTSB's findings
- Personnel issues › Task performance › Maintenance › (general) › Maintenance personnel
- Aircraft › Aircraft propeller/rotor › Main rotor system › Main rotor blade system › Incorrect service/maintenance
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; instructor: helicopter; instrument: airplane; rotorcraft: helicopter
- Flight time: 8,460 hours in all; 1,120 in this make and model; 49 in the last 90 days; 18 in the last 30 days; 8,212 as pilot in command
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 6,354 hours
- Last inspection: annual inspection, September 28, 2022; 3 hours since
- Maximum gross weight: 1,669 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming HIO-360-81A (piston); 18,840 hours total
The flight
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 250° at 11 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 86°F (30°C), dew point 63°F (17°C)
- Altimeter: 29.84 inHg
- Observation at 5:56 pm from AND
Weather report (METAR): METAR KAND 272156Z AUTO 25011KT 10SM CLR 30/17 A2984 RMK AO2 SLP093 T03000167=
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flig | 1 |
Other NTSB records under N90270 the same tail number, which may have belonged to a different aircraft at the time
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The docket at the NTSB holds the report as a PDF and the investigation's photographs and documents. This site never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number ERA23LA289.