[Peetwo]

B200C rollback incident YMEN?? -   

Via Popinjay central:

King Air uncommanded power reduction highlights importance of friction lock tightening



Key points

• A King Air departing Essendon for Albury yawed to the left during take-off roll;
  
• ATSB found that the left engine power lever had migrated rearwards as the friction lock had not been sufficiently adjusted during the pre-flight checks;
  
• King Air power lever friction locks require careful adjustment to prevent power lever migration, particularly during take-off.
  

The insufficient tightening of a friction lock during pre-flight checks resulted in a Beechcraft King Air’s left power lever migrating to idle during the take-off roll, an ATSB investigation report details.

The King Air B200C aircraft, operated by Pel-Air, was departing Essendon for Albury on the night of 19 August 2021 to conduct a medical retrieval flight with a pilot, paramedic and doctor on-board. During the take-off, the aircraft experienced a reduction in power on the left engine and an uncommanded yaw to the left.

The pilot, who had about 16,000 hours of aeronautical experience, of which 42 hours were on the King Air B200C, initially managed the situation as an engine power loss and focused on maintaining directional control. However, when troubleshooting, they identified that the left engine power lever had migrated rearwards to the idle position. In response, the pilot moved the power lever back to take‑off power and adjusted the friction lock to prevent further movement.

The flight continued to Albury without further incident.

“The King Air’s power lever friction locks require careful adjustment to prevent the power levers moving inadvertently, particularly during take-off,” said ATSB Director Transport Safety Dr Stuart Godley.
“This is a characteristic generally known among King Air operators and pilots.”

When interviewed by the ATSB, the incident pilot reported that they were new to the B200C and unaware that power lever migration could occur during take‑off.

Another pilot from the operator noted that, until a pilot experienced a power lever migration, it could be difficult to know how much to tighten the friction locks.

“The power lever friction locks fitted to the King Air require careful adjustment to prevent power lever migration during take-off,” said Dr Godley.

“Operators should ensure pre-flight checks provide opportunities to confirm friction lock settings before the take-off run, and ensure pilots have adequate knowledge of friction lock sensitivity to help prevent and recover from inadvertent power lever migration.”

Dr Godley said the ATSB has released a safety advisory notice to all operators and pilots of King Air aircraft advising of power lever migration and the need to be aware of the careful adjustment required for the power lever friction lock.

“This incident highlights the importance of having a detailed understanding of the characteristics that may be specific to an aircraft type,” he said.

“In the case of the King Air, the design of the power lever system means that the friction locks requires careful adjustment to prevent power lever migration.”

Read the report AO-2021-034: Uncommanded power reduction involving Beechcraft King Air B200C, VH-VAH Essendon Fields Airport, Victoria, on 19 August 2021

Hmm..why does this sound so familiar??..

UK Air Accidents Investigation Branch investigation (7/2003)

On 23 December 2000, a Beechcraft B200 aircraft departed Blackbushe, United Kingdom to Palma, Spain on a private flight. Shortly after take‑off, the aircraft was observed to bank left before colliding into a factory complex 13 seconds later, resulting in a fire. All on board were fatally injured.

An examination of the aircraft did not identify any technical issues that would have contributed to the accident. However, analysis of the cockpit voice recorder showed a reduction in one of the propeller’s rpm as the aircraft rotated, which would have led to thrust asymmetry. The investigation concluded that, it was probable a migration of a power lever due to insufficient friction being set had occurred. It was also noted that the friction control had been slackened during recent maintenance and it was possible that it was not adjusted adequately by the pilot when doing their checks prior to take-off. As a result of the investigation, a safety recommendation was made to Raytheon Aircraft Company:

The Raytheon Aircraft Company should ensure that reference to the correct adjustment of power lever friction is suitably emphasised in the Beech 200 Aircraft Operating Manual (AOM) and the consequences of insufficient adjustment are not only highlighted in the AOM but also included in the recommended Beech 200 type training syllabus.

The ATSB was unable to find any follow-up action on this recommendation recorded in the investigation site.

MTF...P2