ASN Wikibase Occurrence # 297405
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| Date: | Sunday 14 April 2002 |
| Time: | 08:15 LT |
| Type: |  Schweizer 269C |
| Owner/operator: | Scottsdale Helicopters |
| Registration: | N324PH |
| MSN: | S1665 |
| Year of manufacture: | 1994 |
| Total airframe hrs: | 1950 hours |
| Engine model: | Lycoming HIO-360 Ser |
| Fatalities: | Fatalities: 0 / Occupants: 2 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Scottsdale, Arizona -
 United States of America
|
| Phase: | Unknown |
| Nature: | Training |
| Departure airport: | Phoenix-Scottsdale Municipal Airport, AZ (SCF/KSDL) |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The helicopter sustained substantial damage after experiencing a severe vibratory event during liftoff. The certified flight instructor (CFI) reported that the helicopter was positioned on a slope. The preflight and runup were uneventful. The engine was advanced to 3,100 rpm and the CFI instructed the student to bring the downslope skid level with the upslope skid. As the collective was raised, the helicopter began to vibrate. The CFI decreased engine power and control pressures. He then increased the engine speed to 3,100 rpm. As soon as pressure was placed on the controls, the helicopter began to "self destruct." The uphill skid did not leave the surface during either attempted takeoff. No unresolved mechanical discrepancies were noted with the helicopter prior to the accident. The helicopter was examined by an FAA airworthiness inspector. No preimpact discrepancies were noted with the main rotor dampers or the skid strut oleos. In the FAA Rotorcraft Flying Handbook (FAA-H-8083-21) it states that ground resonance is associated with fully articulated rotor systems. If a helicopter touches down on one corner, the blades may move out of their normal phase. If the rpm is in the normal operating range, the pilot should fly the helicopter off the ground, allowing the blades to automatically realign themselves. If not, the helicopter may self-destruct in a matter of seconds.
Probable Cause: The flight instructor's inadequate remedial action following the onset of ground resonance.
Accident investigation:
 |
|
Sources:
NTSB LAX02LA137
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 14-Oct-2022 18:14 | ASN Update Bot | Added |
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