Bell 222 accident near Midlothian, Texas, June 2, 2010
On June 2, 2010 at about 7:00 pm local time, a Bell 222 (helicopter), registered N515MK, was substantially damaged in an accident during enroute (cruise) near Midlothian, Texas. It was an other work-use flight under general aviation rules (Part 91). 2 people were killed. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
The fracture of a swashplate drive pin as a result of hydrogen embrittlement due to an unknown source, which resulted in an in-flight breakup of the main rotor system during cruise flight.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 2, 2010 · about 7:00 pm local time
- Place
- Midlothian, Texas · map
- Type
- Accident
- Injuries
- 2 people were killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 222 U · all 222s on the register
- Registration
- N515MK · registry record · serial 47515
- Damage
- Substantial damage
- Flight
- Other work-use flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The helicopter was on a postmaintenance flight when it experienced an in-flight breakup about 8 minutes after departure, collided with the ground, and exploded into flames. Several witnesses reported seeing the tail boom, main rotor hub, main rotor blades, and other debris separate from the helicopter. One witness heard a "loud crack" sound. A postaccident examination revealed that the helicopter's swashplate A-side drive pin had failed in flight, which resulted in the helicopter's in-flight breakup and uncontrolled descent. The separated head of the drive pin remained in the interior of the swashplate. The fractured drive pin hole exhibited mechanical damage, with the markings of increased amplitude and spacing progressing outward, which suggests that the fractured drive pin oscillated and then ejected from its hole. The fracture surface of the swashplate A-side drive pin displayed brittle cleavage-like fractures interspersed with intergranular separations and small regions of ductile dimples, consistent with hydrogen embrittlement. The B-side drive pin, on the opposite side, was found intact. Both drive pins met engineering drawing requirements for material, hardness, heat treatment and plating. However, there were no engineering standards for hydrogen content. During tests of two pins intentionally charged with hydrogen, one pin fractured under static load, and the fracture topography was consistent with the fracture topography on the failed A-side pin from the accident helicopter. Based on the fracture topography, it is likely that the swashplate A-side drive pin fractured as a result of hydrogen embrittlement. Investigators were unable to conclusively determine the source of the hydrogen. No other material discrepancies of the drive pin were found. Metallurgical examination revealed that fractures through the mast, B-side pitch link bolt and actuator attachments were consistent with overstress separations.
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
- Part(s) separation from AC during enroute (cruise) defining event
- Aircraft structural failure during enroute (cruise)
- Collision with terrain or object (not controlled flight into terrain) during uncontrolled descent
- Fire/smoke (post-impact) during post (impact)
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Main rotor system › Main rotor mast/swashplate › Failure
- cause Aircraft › Aircraft propeller/rotor › Main rotor system › Main rotor mast/swashplate › Not specified
- cause Not determined › Not determined › (general) › (general) › Unknown/Not determined
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; instructor: helicopter; instructor: instrument helicopter; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 6,500 hours in all; 346 in this make and model; 19 in the last 90 days; 3 in the last 30 days; 4,800 as pilot in command
- Last flight review: April 22, 2010
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: rgt
- Injury: fatal
The aircraft
- Airframe total time: 9,925 hours
- Last inspection: approved inspection programme, May 27, 2010; 1 hours since
- Maximum gross weight: 8,250 lb
- Seats: 5
- Landing gear: fixed
- Engine 1: Lycoming LTS101 (turboshaft); 0 hours total
- Engine 2: Lycoming LTS101 (turboshaft); 0 hours total
- Fire in flight and on the ground
The flight
- Departed from: GPM Grand Prairie TX at 6:52 pm
- Destination: GPM Grand Prairie TX
Weather at the time
- Light: daylight
- Wind: from 200° at 8 knots, gusting 14
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 91°F (33°C), dew point 66°F (19°C)
- Altimeter: 29.77 inHg
- Observation at 6:53 pm from KGKY, 11 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flig | 2 |
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 CEN10FA291.