Aircraft crash involving Yeti Airline in Nepal's Pokhara on January 15, 2023, has been attributed to human error.

• The Investigation Commission formed after the air crash submitted the report today with this conclusion.
• The Commission formed under coordination of former Secretary Nagendra Prasad Ghimire submitted the report to the Minister for Culture, Tourism and Civil Aviation, Sudan Kirati.
• It took eight months and three days for the Commission to carry out the investigation and prepare the report. 
• The Yeti Airlines aircraft crash that occurred in Pokhara on January 15, 2023 was due to human error. 

Following an eight month investigation, the inquiry commission team concluded that the Yeti Airlines plane crash in Pokhara on 15 Jan 2023 happened due to human error.

The Nepal government had formed a five-member probe commission on the day of the plane crash. Retired captain of the Nepali Army, Deepak Prakash Bastola, retired Captain Sunil Thapa, aeronautical engineer Ekraj Jung Thapa and Joint-Secretary of the Ministry of Culture, Tourism and Civil Aviation, Buddhi Sagar Lamichhane were the members of the probe commission. 

The preliminary report on the accident , prepared by the aircraft accident investigation commission (AAIC) stated the aircraft did not have enough power due to the propellers being feathered.

The preliminary report also stated how the Yeti Airlines pilot wanted to land on Runway 12 despite being asked to land on Runway 30.

Receiving the report, Nepal's Civil Aviation Minister Kirati directed the subordinate bodies to strictly implement the Probe Commission's suggestions.

The Civil Aviation Regulator came under highlights after the fatal Accident involving this reported Yeti Airlines Flight 691, where an ATR 72 aircraft crashed en route from Kathmandu to Pokhara in Nepal on 15th Jan 2023, killing all 72 onboard.

The Commission tasked with investigating the Yeti Airlines aircraft accident in Pokhara last year submitted its report to the government on Thursday, attributing the cause of the accident to human error.

Background of the Accident :

On 15 January 2023, an ATR72-212A version 500 (Registration: 9N-ANC) operated by Yeti Airlines was operating a scheduled flight from Tribhuvan International Airport to Pokhara International Airport.

This was the flight crew‟s third sector of the day and they had been operating shuttle flights between Kathmandu and Pokhara.

There were 68 passengers and 4 crew on-board the aircraft. On the final approach to Pokhara International Airport's runway 12, the aircraft sustained a loss of control in flight and impacted with the ground between the old Pokhara Domestic and the new Pokhara International Airport. All persons on board were fatally injured.

The Thursday final report provides insights into how the accident unfolded on that day :

Technical Condition and Weather: 

The aircraft, which departed from Kathmandu at 10:51 am bound for Pokhara, did not encounter any technical issues. Weather conditions, visibility, and other factors at Pokhara International Airport were reported to be normal.

Normal Operations: 

The takeoff, cruise, and initial landings proceeded without any abnormalities. The Air Traffic Controller had assigned Runway 30 for the aircraft’s landing during their communication.

Unusual Runway Change: 

Despite the initial designation of Runway 30, the crew opted to change the runway and requested permission to land on Runway 12, which was also suitable for landing.

Rapid Descent: 

The critical moment occurred when the aircraft directly descended from 6,500 feet to 721 feet. During the attempt to regain altitude, the speed remained constant, leading to an inability to recover, causing the plane to crash.

The Tragic Outcome: 

The aircraft plunged into Seti gorge upon impact with the ground and immediately caught fire. Unfortunately, all 72 passengers, including four crew members, lost their lives.

The investigation points to a deviation from standard procedures, emphasizing the crew’s decision to change the runway and the subsequent failure to manage the descent effectively.

Investigation Findings 

• The aircraft possessed a valid certificate of airworthiness and registration at the time of the occurrence. The aircraft departed TIA with no known defects.
• The cockpit crew were qualified and certified in accordance with the rules and the regulations of the CAAN.
• Both the flight crew members had adequate rest and the duty time was within the prescribed limit prior to the flight.
• The aircraft was operating within the performance limitations as per its Flight Manual. The weight and CG were within the prescribed limits.
• The aircraft was maintained as per the requirements. No maintenance work was found to be overdue. And all maintenance records had been maintained properly.
• There was no evidence of aircraft control systems, structural, or power-plant failures before the ground contact. All damages to the aircraft occurred after the impact.
• VMC prevailed at Kathmandu and within the Pokhara valley at the time of the aircraft‟s approach at PHR. The whole flight was conducted under VFR.
• The visual approach circuit pattern followed by the flight for RWY12 did not meet the criteria for a stabilized visual approach. No visual trajectory was published for RWY 12.
• Aerodrome obstacle data and information on facilities available at PHR Airport were published in AIP Nepal and became effective on December 29, 2022, while the ATS IFR procedures and holdings becoming effective on February 23, 2023.
• Air Traffic Services Regulation was not coordinated with that of Aerodromes and not considered within the certification process.
• The MOC carried out by the operator and approved by the regulator was inadequate.
• The MOC carried out by one of the domestic airline planning to operate at PHR identified “Lack of published data of Pokhara International airport in AIP” as a Hazard of High risk category, creating the unsafe event “Crew confusion and disorientation” and ultimately the possible outcome as CFIT.
• The approach on RWY12 was first attempt for the PF and third for the PM since the start of operations at PHR.
• Company trainings prior to clearance to PHR were found insufficient for the crew. Skill based training for new airport was not given to the crew.
• The checklists were not performed by the crew in compliance with the SOP.
• Following the un-intentional feathering of both engine propellers, the flight crew failed to identify the problem and take corrective actions despite the CAP cautions. The PF owned a noise-cancelling headset whereas PM did not.
• It is likely that the PM had misidentified and moved both condition levers to FEATHER when the PF called for flaps 30 without appropriate crosscheck loop as per CRM training.
• The PF did not visually crosscheck the position of Flaps 30 and confirmed it.

Probable cause

The most probable cause of the accident is determined to be the inadvertent movement of both condition levers to the feathered position in flight, which resulted in feathering of both propellers and subsequent loss of thrust, leading to an aerodynamic stall and collision with terrain.

Contributing Factors to the accident are :

1 High workload due to operating into a new airport with surrounding terrain and the crew missing the associated flight deck and engine indications that both propellers had been feathered.

2 Human factor issues such as high workload and stress that appears to have resulted in the misidentification and selection of the propellers to the feathered position.

3 The proximity of terrain requiring a tight circuit to land on runway 12. This tight circuit was not the usual visual circuit pattern and contributed to the high workload. This tight pattern also meant that the approach did not meet the stabilised visual approach criteria.

4 Use of visual approach circuit for RWY 12 without any evaluation, validation and resolution of its threats which were highlighted by the SRM team of CAAN and advices proposed in flight procedures design report conducted by the consultant and without the development and approval of the chart by the operator and regulator respectively.

5 Lack of appropriate technical and skill based training (including simulator) to the crew and proper classroom briefings (for that flight) for the safe operation of flight at new airport for visual approach to runway 12.

6 Non-compliance with SOPs, ineffective CRM and lack of sterile cockpit discipline.

7 High workload due to operating into a new airport with surrounding terrain and the crew missing the associated flight deck and engine indications that both propellers had been feathered.

8 Human factor issues such as high workload and stress that appears to have resulted in the misidentification and selection of the propellers to the feathered position.

9 The proximity of terrain requiring a tight circuit to land on runway 12. This tight circuit was not the usual visual circuit pattern and contributed to the high workload. This tight pattern also meant that the approach did not meet the stabilised visual approach criteria.

10 Use of visual approach circuit for RWY 12 without any evaluation, validation and resolution of its threats which were highlighted by the SRM team of CAAN and advices proposed in flight procedures design report conducted by the consultant and without the development and approval of the chart by the operator and regulator respectively.

11 Lack of appropriate technical and skill based training (including simulator) to the crew and proper classroom briefings (for that flight) for the safe operation of flight at new airport for visual approach to runway 12.

12 Non-compliance with SOPs, ineffective CRM and lack of sterile cockpit discipline.

Recommendation to the Operator

1. The operator should take into consideration the stabilization criteria when designing or proposing approaches for approval by CAAN.

2. The operator should ensure the sufficient skill-based training for the crew before operation at new airport.

3. Safety department should act effectively to monitor and take prompt corrective actions against the violations related to CRM discipline and not following the checklist during flight.

4. The operator should conduct an in-depth MOC study with considerations to human factors and other probable safety issues before establishing criteria for aircraft clearance and approval of crew in a new operating environment.

5. The operator should ensure the sufficient technical ground class to the crew.

Recommendation to CAA Nepal (Safety Regulator)

• While conducting the aerodrome certification process the Aerodrome Safety Standard Department should consider all the safety critical parameters including the ATS procedures, visual circuits and stabilization criteria for the particular aircraft in conformance with the aircraft design criteria and local operational environment to ensure the safety of flight operation.
• CAAN should ensure that the appropriate visual flight path is approved which allows the criteria for a stabilized visual approach to be met by the operator or ANS service provider prior to the start of commercial operation in any new airport or before introducing any new fleet in the existing airport.
• CAAN should evaluate and manage the impact of change in the aviation system so that no operation takes place in a changed system or operational context until all the safety risks are evaluated and controlled prior to implementing the significant changes.

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