Unraveling the Tragedy of a Mitsubishi MU-2B-40 Solitaire

On April 12, 2025, a Mitsubishi MU-2B-40 Solitaire, registered as N635TA, crashed in a muddy agricultural field near Copake, New York, killing all six occupants. For pilots, this accident underscores the unforgiving nature of higher-performance turboprop aircraft like the MU-2; for aviation lawyers, it raises critical questions about liability, pilot training, and aircraft maintenance. After looking at some of the preliminary reports, studying the aircraft’s characteristics (I’ve never flown the aircraft), I thought I’d take a stab at what might have happened.

The Mitsubishi MU-2B-40 Solitaire is a twin-engine turboprop aircraft, known for its speed, efficiency, and demanding handling characteristics. Powered by two Honeywell (Garrett) TPE331-10-501M engines, each producing 665 shaft horsepower, the Solitaire achieves cruise speeds up to 310 knots and a range of 1,000–1,200 nautical miles with its 403-gallon fuel capacity. Its high-wing design, full-span double-slotted Fowler flaps, and over-wing spoilers (replacing conventional ailerons) enable short-field performance and low stall speeds (around 80 knots with flaps extended). With a 6.0 psi differential, the aircraft's pressurized cabin supports operations up to its certified ceiling of 29,750 feet.

N635TA, a 1985 model (serial number 458 S.A.), was a well-equipped example. Registered to Dynamic Spine Solutions LLC in Weston, Massachusetts, since October 2024, it featured a modernized cockpit with dual Garmin G-600 flight displays, GTN-750/650 navigators, dual GTX-33ES ADS-B Out transponders, and a GDL-88 ADS-B In transceiver. These upgrades, part of Air 1st’s Platinum Series refurbishment at 3,520 airframe hours, offered enhanced situational awareness. This avionics suite theoretically reduced workload, but the MU-2’s inherent complexity—sensitive controls, high wing loading (59 pounds per square foot in cruise), and demanding single-engine performance—still required some good stick and rudder skills. Lawyers often scrutinize such aircraft for maintenance lapses or pilot error in accident investigations, given their history of incidents tied to human factors.

On April 12, 2025, at approximately 12:06 p.m. EDT, N635TA crashed in an open field near Two Town Road, Copake, New York, about 10 miles south of Columbia County Airport (1B1). The aircraft was on a Part 91 personal flight, having departed Westchester County Airport (HPN) in White Plains, New York, after an earlier leg from Norwood Memorial Airport (OWD) in Massachusetts. The pilot, Michael Groff, a neurosurgeon and experienced flyer, was accompanied by five passengers, all family members.

Preliminary reports from the National Transportation Safety Board (NTSB) indicate the aircraft was diverting to Columbia County Airport due to deteriorating weather, operating under instrument flight rules (IFR). Around 12:15 p.m., the pilot reported a missed approach on the RNAV Runway 3 approach to 1B1, informing air traffic control (Albany Approach) of the need for a new plan. ADS-B data shows the aircraft veered east after completing a right turn, climbing briefly to 3,200 feet before entering a rapid, uncontrolled descent. Air traffic controllers issued three low-altitude warnings, but the pilot did not respond, and no distress call was recorded. The aircraft impacted the ground at a high rate of descent, resulting in virtual disintegration. All six occupants were fatally injured, and the wreckage was heavily fragmented, though intact upon impact, per NTSB observations.

The weather at the time was marginal. Four minutes before the crash, the 1B1 AWOS reported a 400-foot AGL cloud ceiling, winds from 010 at 8 knots, and a temperature/dewpoint spread of 37°F/36°F, suggesting near-saturation conditions. An AIRMET for icing noted a freezing level between 2,000 and 4,000 feet, with IFR conditions possible. While the NTSB has not confirmed weather as a factor, these conditions likely complicated the approach, particularly for a high-performance aircraft like the MU-2.

The NTSB, led by investigator Albert Nixon, dispatched a go-team to the crash site on April 12, supported by the FAA, Honeywell (engine manufacturer), and the Japanese Safety Board (due to the aircraft’s origin). The team recovered avionics components, including a “large number of memory cards,” sent to NTSB headquarters in Washington, D.C., for analysis. The TPE331 engines were shipped to Phoenix for teardown, and the wreckage was transported to Massachusetts for further inspection by April 15—a drone captured over 1,000 photos, mapping the compact debris field for post-impact evaluation.

NTSB briefings on April 13 and 14, delivered by member Todd Inman, confirmed the pilot completed MU-2-specific training in October 2024, suggesting compliance with Part 91 Subpart N requirements, which mandate rigorous training for MU-2 operators despite requiring no type rating. Maintenance records are under review, with N635TA’s modern avionics and recent ownership change (from Toth Financial Advisory Corporation to Dynamic Spine Solutions) noted. The absence of a distress call and the pilot’s unresponsiveness to low-altitude alerts raise questions about possible incapacitation, spatial disorientation, or mechanical failure, though no conclusions have been drawn. The NTSB expects a preliminary report within 30 days, with a final report in 12–24 months.

The MU-2B-40 Solitaire’s design contributes to its reputation as a “hot” aircraft. Its spoilers provide crisp roll control, eliminating adverse yaw, but require precise inputs, mainly during low-speed operations like approaches. The TPE331 engines deliver robust performance (100% torque up to 16,000 feet on a standard day). Still, single-engine scenarios demand immediate action—rudder to counter yaw, pitch to maintain airspeed (around 120 knots), and power adjustments to avoid asymmetric thrust. The aircraft’s descent capabilities (up to 5,000 feet per minute in idle) are an asset, but rapid configuration changes can destabilize an approach in turbulent or low-visibility conditions.

For pilots, the N635TA crash highlights the MU-2’s unforgiving nature in IFR environments. The missed approach at 1B1, followed by a non-standard flight path, suggests potential disorientation or mishandling during a high-workload phase. The aircraft’s low stall speed (80 knots with flaps) and short-field capabilities (landing distance under 2,000 feet) should have aided a safe recovery, but the rapid descent points to a loss of control. Recurrent training, often 10–15 hours annually for MU-2 pilots, emphasizes these scenarios, yet accidents persist, as seen in historical MU-2 data (over 180 fatal crashes since 1963, many tied to pilot error). My history with the MU-2 involved utilizing them as a training aid when I was attached to the 95th Tac Fighter Training Squadron at Tyndal AFB many years ago. A civilian contractor flew the MU-2s to act as targets. I don’t recall any accidents involving the MU-2 while I was there. However, the MU-2 has a broader history of accidents, with 188 accidents worldwide between 1968 and 2014, resulting in 347 fatalities, often attributed to pilot error due to the aircraft’s high-performance characteristics and inadequate training.

For aviation lawyers, the N635TA crash presents a multifaceted case. Key areas of focus include:

**Pilot Qualifications**: The pilot’s recent MU-2 training suggests compliance, but investigators will verify the depth of his experience (total hours unknown) and recency in IFR operations. Discrepancies could shift liability toward inadequate preparation or training provider oversight.

**Maintenance and Modifications**: N635TA’s Platinum Series upgrades and any airworthiness directives (ADs) compliance records will be scrutinized. The TPE331 engines’ maintenance history (5,400-hour overhaul interval) will also be scrutinized, as will the installation of Garmin avionics, to rule out system failures.

**Weather and ATC**: The marginal weather and ATC’s low-altitude warnings raise questions about decision-making. If icing or turbulence overwhelmed the pilot, liability may hinge on whether he should have diverted earlier (e.g., to Albany, with better weather). ATC’s role in vectoring the aircraft for a second approach will also be examined.

**Wrongful Death Claims**: The victims’ prominence—a neurosurgeon, a pelvic surgeon, a medical student, and others—may amplify claims for economic and non-economic damages. Families may target the pilot’s estate, the aircraft owner (Dynamic Spine Solutions), or third parties like maintenance providers or training schools.

**Product Liability**: While the MU-2’s design is robust, its safety record (e.g., 1993 propeller ADs) could prompt claims against Mitsubishi or Honeywell, though the aircraft’s age (1985) and upgrades may limit manufacturer exposure.

The compact debris field and “jet fuel contamination” noted by the NTSB suggest a high-energy impact, potentially complicating evidence recovery. Lawyers will monitor the NTSB’s analysis of flight data, memory cards, and engine components to build or defend claims. Comparative negligence—balancing pilot error against external factors like weather or avionics—will be central to litigation.

The MU-2’s safety history, scrutinized by the FAA in 2005–2008, concluded it’s safe with proper training and maintenance. Yet, incidents like N635TA’s fuel debates about mandating type ratings or retrofitting enhanced avionics (e.g., envelope protection systems). For lawyers, the crash may spur regulatory proposals, particularly if icing or avionics issues emerge as factors. The NTSB’s findings could influence Part 91 training rules or ADs for older MU-2s, impacting operators nationwide.

The crash of N635TA reminds us of the Mitsubishi MU-2B-40 Solitaire’s dual nature: a high-performance marvel that demands respect. For pilots, it underscores the need for relentless preparation to master its controls and navigate challenging conditions. It presents a complex puzzle for aviation lawyers—balancing pilot actions, aircraft condition, and external factors to assign responsibility and seek justice for six lives lost. As the NTSB investigation unfolds, its insights will guide safer operations and sharper legal strategies, ensuring the tragedy informs aviation safety and accountability progress.