Is addressed to:
- Operators of large (CS-25) turboprop aeroplanes
Briefing:
Recipients must ensure that this notice is communicated to all members of their staff who need to take appropriate action or who may be interested in the contents of the notice.
INTRODUCTION
This SIAN is issued following EASA SIB 2024-08 dated 23 July 2024 which was initiated after the issuing of the final report on the accident of ATR72/212A version 500 on 15th of January 2023, near Pokhara International Airport. Both documents are attached.
DESCRIPTION
Flight decks of large turboprop aeroplanes are designed in accordance with the applicable Certification Specifications for Large Aeroplanes (i.e. CS-25) to prevent inadvertent movement of propeller feathering controls. However, the AAIC Final Report concluded that the most probable cause of the accident was the “movement of both propeller condition levers to the feathered position in flight, which resulted in the feathering of both propellers” causing a “subsequent total loss of thrust leading to an aerodynamic stall and collision with terrain”. The AAIC further listed contributing factors to the accident, identifying “Human factor issues such as high flight crew workload and stress” which could have contributed to the “misidentification and selection of both propellers to the feathered position”.
RECOMMENDATIONS
Operators of large turboprop aeroplanes are recommended to:
- Make their flight crew members aware of the importance of reporting flight crew errors, including erroneous selection of propeller feathering controls. A propeller feathering control movement error that may endanger the safe operation of the aircraft should be identified by flight crew alerts and cockpit indications. Without prejudice to Regulation (EU) No 376/2014, such flight crew errors, even when rapidly recognised and recovered, should be reported under ORO.GEN.160 (b) to HCAA, to the organisation responsible for the design of the aircraft and, if applicable, to the applicable STCHs as part of the mandatory occurrence reporting scheme due to the human factor implication in the incorrect operation of the controls.
Thank you all for working on improving flight safety
