ASN Wikibase Occurrence # 244798
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: | Friday 22 January 2016 |
| Time: | 09:45 |
| Type: |  Enstrom 280C |
| Owner/operator: | Flugschule Eichenberger |
| Registration: | HB-XLS |
| MSN: | 1211 |
| Year of manufacture: | 1980 |
| Fatalities: | Fatalities: 0 / Occupants: 2 |
| Aircraft damage: | Minor |
| Category: | Accident |
| Location: | Buttwil Airport (LSZU) -
 Switzerland
|
| Phase: | Standing |
| Nature: | Training |
| Departure airport: | LSZU |
| LSZU | |
| Investigating agency: | STSB |
| Confidence Rating: |  Information verified through data from accident investigation authorities |
After the flight briefing, the trainee pilot and the flight instructor boarded the helicopter HB-XLS. The trainee pilot started the engine and began to work through the preparation checklist. When the drive belt between the engine and the drive shaft was tensioned by the clutch and the engine had warmed up, the trainee pilot noticed that the emergency location transmitter (ELT) had not been fitted to the helicopter. In HB-XLS, this was normally mounted on the trainee pilot’s side of the aircraft below the collective pitch control lever. The flight instructor told the trainee pilot he would enquire about the ELT with the maintenance company and that the trainee pilot could complete the remaining checks on his own. Before the flight instructor disembarked from the helicopter, he once again pointed out to the trainee pilot the dangers associated with carrying out the magneto check on snow-covered ground.
Subsequently, the trainee pilot opened the throttle to carry out the magneto check at an engine speed of approximately 2,900 rpm1. Shortly before this speed was reached, the helicopter began to turn slowly around its vertical axis to the left. The trainee pilot then applied the right anti-torque pedal to stop the helicopter’s rotation.
However, he was not able to remember, whether the helicopter turned back to the initial position in the process. At this moment, the helicopter suddenly started to turn to the left again. From then on, the trainee pilot initially did not take any measures to counter the rotation as everything happened very quickly. After approximately four rotations, the trainee pilot reduced the engine speed using the twist-grip throttle. This resulted in the helicopter coming to a standstill. During the rotations, the helicopter slid towards the snow-covered meadow.
The flight instructor ran back to the helicopter, opened the door, shut down all of the systems and closed the fuel valve. The trainee pilot was able to disembark from the helicopter unharmed.
Causes
The accident emerged from a loss of control of the tail rotor control system, which can be attributed to the fact that the tail rotor severed a control cable.
Improper maintenance of the helicopter was found to be the cause of the accident. This led to the following deficiencies that made the accident possible, either individually or in combination:
- poor condition of the rubber teeter bumpers on the static stop;
- prior damage to the left control cable;
- in all likelihood, insufficient tension in the control cables.
The fact that the helicopter was being operated on ground that offered reduced traction contributed to the accident.
Accident investigation:
 |
|
Sources:
STSB
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 11-Nov-2020 11:02 | harro | 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