ASN Wikibase Occurrence # 354578
This information is added by users of ASN. Neither ASN nor the Flight Safety Foundation are responsible for the completeness or correctness of this information.
If you feel this information is incomplete or incorrect, you can submit corrected information.
| Date: | Monday 20 April 1998 |
| Time: | 16:15 LT |
| Type: |  Bell 206B |
| Owner/operator: | Papillon Airways |
| Registration: | N8533F |
| MSN: | 254 |
| Year of manufacture: | 1968 |
| Total airframe hrs: | 21392 hours |
| Engine model: | Allison 250-C20B |
| Fatalities: | Fatalities: 0 / Occupants: 2 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Grand Canyon, AZ -
 United States of America
|
| Phase: | Landing |
| Nature: | Training |
| Departure airport: | , AZ (KGCN) |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The instructor pilot and new company pilot were practicing autorotations, which were terminating in a power-recovery. The flight instructor demonstrated a straight-in autorotation and said that the governor lagged behind but stayed in the green range. The instructor stated that this was typical of this particular helicopter and that he didn't consider the governor lag unusual. The instructor then had the dual student set up for a 180-degree autorotation. During the maneuver he told the student that he was ready to roll on the throttle at 200 feet agl. He stated that at 50 feet and 50 to 55 knots, the pilot flared the helicopter and at 15 feet he had the pilot pull in more collective. At this point, the instructor pulled in some collective himself. He stated that the torque gauge did not move and that it sounded like the engine sound was dragging down and the rpm's in the dual tach decayed. The flight instructor proceeded to take the controls and level the aircraft. The aircraft landed hard and came to a complete stop. After the aircraft was shut down, the tail boom was found still attached but hanging to the ground. A Bell Operations Safety Notice advises that tail boom failure can occur in autorotations where touchdown occurs at 70 percent main rotor speed due to a resonance response of the structure to the main rotor. A postaccident test of the governor function was performed. Power checks were done to duplicate an autorotation and the tests revealed that the engine was slow to accelerate and the governor surged with continual fluctuation of Ng readings.
Probable Cause: The malfunction and erratic speed control of the engine's governor, and the flight instructor's delayed remedial action.
Accident investigation:
 |
|
Sources:
NTSB LAX98LA139
History of this aircraft
Other occurrences involving this aircraft
| 3 November 2010 | N8533F | Aviation Technology Services Llc | 1 | North of Meeker, CO | |
sub |
| Collision with pole or wires | ||||||
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 11-Mar-2024 16:00 | ASN Update Bot | Added |
Corrections or additions? ... Edit this accident description
The Aviation Safety Network is an exclusive service provided by:
Quick Links:
| ASN Home | Send Correction / Feedback |
| FSF Home | Disclaimer | Copyright |
| Contact Us | Privacy Policy |
| Press / Media |
CONNECT WITH US:
©2024 Flight Safety Foundation