Robinson R44 accident near Honolulu, Hawaii, August 19, 2024
On August 19, 2024 at about 2:00 am local time, a 2018 Robinson R44 (helicopter), registered N740RH, was substantially damaged in an accident during prior to flight near Honolulu, Hawaii (Honolulu airport). It was a business flight under charter and air-taxi rules (Part 135). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A failure of the flex plate yoke flange assembly due to incorrectly torqued bolts. Contributing was the maintenance personnel’s inadequate inspection of the tail rotor flex plate assembly.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 19, 2024 · about 2:00 am local time
- Place
- Honolulu, Hawaii · Honolulu · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Robinson R44 II, built 2018 · all R44s on the register
- Registration
- N740RH · registry record · serial 2559
- Damage
- Substantial damage
- Flight
- Business flight · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that, before boarding passengers, she started the engine, engaged the clutch and, as the main rotor system began to engage, she felt and saw the left pedal deflect full forward without any control input. The pilot immediately shut down the engine, stopped the rotors, and exited the helicopter to inspect the tail rotor assembly. The tail rotor push-pull tube was found bent and severed aft of the tail rotor gear box, near the bell crank assembly. A postaccident examination revealed a bolt missing from the flex plate assembly, just forward of the tail rotor gearbox. The bolt was found in the tailboom just below the flex plate assembly and exhibited significant circumferential wear marks. A second bolt from the flex plate assembly exhibited similar wear; the two other bolts in the assembly exhibited no wear and were firmly torqued to the flex plate assembly. Black dust was observed on the flex plate and associated hardware, indicative of fretting. The helicopter went through a major overhaul in May of 2024, at which time the tail rotor drive shaft, aft flex plate assembly, and tail rotor push-pull tube were installed. Since May of 2024 the accident helicopter had flown about 338 hours. The most recent 100-hour inspection was completed on August 1, 2024, by the operator. The 100-hour inspection requires the operator to inspect the tail rotor flex plate assembly. A review of the airframe maintenance logbooks showed evidence of compliance with the helicopter manufacturer’s 100-hour inspection to include the flex plate assembly. The circumferential wear and black dust present during the postaccident examination indicate that the bolts were likely loose during the 100-hour inspection; however, no evidence of fretting or looseness was documented. It is likely that, over time, two of the bolts in the flex plate assembly became loose during operation because they were not properly torqued during installation.
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
- Sys/Comp malf/fail (non-power) during prior to flight defining event
The NTSB's findings
- Aircraft › Aircraft propeller/rotor › Tail rotor drive system › (general) › Incorrect service/maintenance
- Personnel issues › Task performance › Maintenance › Scheduled/routine maintenance › Maintenance personnel
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: instructor: helicopter; instructor: instrument helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 1,532 hours in all; 791 in this make and model; 256 in the last 90 days; 84 in the last 30 days; 1,453 as pilot in command; 673 on instruments
- Last flight review: November 10, 2023
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 4,736.6 hours
- Last inspection: 100-hour inspection, August 1, 2024; 67.9 hours since
- Maximum gross weight: 2,400 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming O-540-F1B5 (piston); 2,694 hours total
- Operator: Novictor Aviation LLC
The flight
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 020° at 13 knots, gusting 20
- Visibility: 10 statute miles
- Sky: a few clouds at 3,900 ft
- Temperature: 85°F (29°C), dew point 64°F (18°C)
- Altimeter: 30.00 inHg
- Observation at 4:00 pm from HNL
Weather report (METAR): PHNL 021553Z 05009KT 10SM FEW025 SCT045 23/18 A3014 RMK AO2 SLP205 T02280178 $,M
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Photographs from the investigation 4 pictures from the NTSB's docket, as the NTSB released them
Photograph 1 – Push pull tube fractured at bell crank
Photograph 2 – Bolt missing from flex plate yoke assembly
Photograph 3 – Bolt and washer from flex plate assembly in tail boom
Photograph 4 – Push pull tube with witness signature from boltThe NTSB's photographs with the NTSB's captions, at screen size. Open a picture to see it full size or to report one that should not be shown.
Documents from the investigation the NTSB's docket: the evidence folder behind the report
5 documents, released by the NTSB on July 23, 2025. 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 | Component Exam | PDF, 8 pages | View Download |
| 3 | Maintenance Records | PDF, 33 pages | View Download |
| 4 | Mor Ryan Williams | PDF, 1 page | View Download |
| 5 | Photos | PDF, 5 pages · our copy | 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.