Cessna T210N accident near Armonk, New York, June 18, 2011
On June 18, 2011 at about 5:06 pm local time, a Cessna T210N, registered N210KW, was substantially damaged in an accident during initial climb near Armonk, New York (Westchester County airport). It was a personal flight under general aviation rules (Part 91). 4 people were killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot's decision to depart on the flight with a suspected mechanical deficiency and his subsequent decision to fly the final approach at a reduced power setting. Contributing to the accident was the improper timing of the magneto(s) that resulted in a severe detonation event.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 18, 2011 · about 5:06 pm local time
- Place
- Armonk, New York · Westchester County · map
- Type
- Accident
- Injuries
- 4 people were killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna T210N · all T210Ns on the register
- Registration
- N210KW · no longer on the register · serial 21064181
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
Witnesses observed the pilot perform multiple engine run-ups both on the parking ramp and at the end of the runway prior to departure. Both witnesses reported that the engine initially idled rough. Shortly after takeoff from runway 34, the pilot informed the air traffic controller that he needed to return to the airport and requested runway 16. The pilot declared an emergency but did not state the reason why. The airplane impacted trees and terrain about 1 mile from the approach end of runway 16. The cockpit and cabin sections were found inverted and mostly consumed by a post-crash fire. The wreckage path through the trees indicated that the airplane was established on a shallow glide angle when the impact occurred, with the landing gear and flaps retracted. A disassembly and examination of the engine revealed that the No. 2 cylinder piston head exhibited severe thermal deterioration consistent with a pre-ignition or detonation event. The electrodes of the No. 2 cylinder spark plugs were fully imbedded with aluminum and appeared incapable of producing a spark. The other five cylinders appeared to be functional and were undamaged. The left magneto was set to 30 degrees before top dead center (BTDC); the manufacturer's specification was 22 degrees BTDC. The right magneto was broken at its mount and its timing could not be verified. Examination of the engine maintenance records revealed that the magnetos were last retimed during an annual inspection about 27 months before the accident. The airplane was flown infrequently since the engine was installed in 2007. The airport was equipped with noise abatement monitoring microphones that captured the airplane on the outbound and inbound (return) legs during the accident sequence. Although the engine appeared to be running just prior to impact, the engine sound pressure recorded on the outbound leg was significantly greater than on the inbound leg, suggesting that the pilot was approaching the airport at a reduced power setting. Although the amount of engine power available could not be determined, it is likely that additional power was available had the throttle been advanced.
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
- Loss of engine power (partial) during initial climb defining event
- Controlled flight into terrain or object (CFIT) during approach (VFR pattern final)
The NTSB's findings
- factor Aircraft › Aircraft power plant › Ignition system › Magneto/distributor › Incorrect service/maintenance
- factor Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng cyl section › Damaged/degraded
- cause Personnel issues › Action/decision › Info processing/decision › Decision making/judgment › Pilot
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instrument: airplane
- Flight time: 4,150 hours in all
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: fatal
The aircraft
- Airframe total time: 2,791 hours
- Last inspection: annual inspection, June 4, 2010
- Maximum gross weight: 4,000 lb
- Seats: 6
- Landing gear: retractable
- Engine: Cont Motor TSIO-520 SER (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: HPN White Plains NY at 5:03 pm
- Destination: MTP Montauk NY
- Flight plan: IFR
- Runway 16, 6,548 ft by 150 ft
Weather at the time
- Light: daylight
- Wind: from 300° at 10 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 6,000 ft; scat at 4,600 ft
- Temperature: 81°F (27°C), dew point 63°F (17°C)
- Altimeter: 29.84 inHg
- Observation at 4:56 pm from HPN, 1 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 3 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
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.