Schweizer 269C accident near Darlington, Maryland, July 29, 2011
On July 29, 2011 at about 8:30 pm local time, a Schweizer 269C (helicopter), registered N39SH, was substantially damaged in an accident during standing (engine(s) operating) near Darlington, Maryland (Private Heliport airport). It was a positioning flight under general aviation rules (Part 91). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
Inadequate maintenance of the helicopter's landing gear dampers, which resulted in a main rotor out-of-balance condition and ground resonance encounter.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 29, 2011 · about 8:30 pm local time
- Place
- Darlington, Maryland · Private Heliport · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Schweizer 269C · all 269Cs on the register
- Registration
- N39SH · registry record · serial S1287
- Damage
- Substantial damage
- Flight
- Positioning flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot of the helicopter stated that he conducted a light touchdown on the helipad and reduced engine power and applied collective friction for cooldown, per the helicopter’s checklist. About 1 minute after the touchdown, the helicopter began to vibrate violently. The pilot further reduced engine power, but the helicopter continued to vibrate until it fell apart. Before the day's flights, the pilot performed a preflight inspection of the helicopter, during which he visually inspected both forward and aft landing gear dampers and also squeezed them to confirm that they contained oil and were not leaking. He did not observe any anomalies during this inspection. The landing gear dampers were examined by the manufacturer after the accident, and during load testing three of the four dampers did not meet required specifications. The minority owner of the helicopter stated that, based on the helicopter's fuel consumption during the time since its last inspection, he believed that the helicopter was more than 50 hours overdue for a 100-hour inspection. He also stated that, on one occasion, he found the helicopter's Hobbs meter disconnected. The helicopter manufacturer’s maintenance instructions state that, "Incorrect fluid levels, improper pressure or inoperable valving will deteriorate the damping capabilities of the landing gear dampers. These conditions may result in ground resonance and destruction of the helicopter.”
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 standing (engine(s) operating) defining event
The NTSB's findings
- cause Aircraft › Aircraft handling/service › Maintenance/inspections › (general) › Not serviced/maintained
- Personnel issues › Task performance › Maintenance › Scheduled/routine maintenance › Owner/builder
- cause Aircraft › Aircraft systems › Landing gear system › Main landing gear › Not serviced/maintained
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: single-engine land; instructor: helicopter; instructor: instrument helicopter; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 968 hours in all; 541 in this make and model; 47 in the last 90 days; 29 in the last 30 days; 817 as pilot in command; 172 on instruments
- Last flight review: February 12, 2011
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: left
- Injury: minor injuries
The aircraft
- Airframe total time: 2,907 hours
- Last inspection: annual inspection, August 4, 2010
- Maximum gross weight: 2,050 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming HIO-360 SER (piston); 0 hours total
The flight
- Departed from: NA Bel Air MD at 8:00 pm
- Destination: NA Darlington MD
- Flight plan: none
Weather at the time
- Light: dawn
- Wind: from 230° at 9 knots
- Visibility: 10 statute miles
- Sky: a few clouds at 8,000 ft
- Temperature: 100°F (38°C), dew point 70°F (21°C)
- Altimeter: 29.82 inHg
- Observation at 9:55 pm from MTN, 20 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
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.