SIKORSKY S-55
Chelan, WA — July 24, 2009
Event Information
| Date | July 24, 2009 |
| Event Type | ACC |
| NTSB Number | WPR09LA371 |
| Event ID | 20090727X55233 |
| Location | Chelan, WA |
| Country | USA |
| Coordinates | 47.86611, -119.94278 |
| Highest Injury | NONE |
Aircraft
| Make | SIKORSKY |
| Model | S-55 |
| Category | HELI |
| FAR Part | 091 |
| Aircraft Damage | SUBS |
Conditions
| Light Condition | DAYL |
| Weather | VMC |
Injuries
| Fatal | 0 |
| Serious | 0 |
| Minor | 0 |
| None | 1 |
| Total Injured | 0 |
Event Location
Probable Cause
Failure of a seal in the hydraulic system resulting in a loss of hydraulic pressure while maneuvering at low altitude.
Full Narrative
On July 24, 2009, about 1445 Pacific daylight time, a Sikorsky S-55, N1255T, encountered rough terrain during an off airport emergency landing near Chelan, Washington. The pilot/owner was operating the helicopter under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The certificated commercial pilot was not injured; the helicopter sustained substantial damage to the fuselage from impact forces. The local other work flight departed Chelan about 1245. Visual meteorological conditions prevailed, and no flight plan had been filed.
The pilot was drying cherries at low altitude when the helicopter lost hydraulic pressure. He flew the helicopter up to clear the trees, and made a run-on landing into a vacant field. The helicopter encountered a large hole that he had not seen, and the main rotor severed the tail boom.
The operator reported that post accident examination revealed that an internal seal had leaked resulting in the loss of pressure in the hydraulic system.
To date, the National Transportation Safety Board Pilot/Operator Accident Report Form 6120.1/2 has not been submitted.
About This NTSB Record
This aviation event was investigated by the National Transportation Safety Board (NTSB). NTSB investigates all U.S. civil aviation accidents to determine probable cause and issue safety recommendations to prevent future accidents.