Scheduled Revenue Flight

The accident was the consequence of an asymmetrical loss of wing lift properties at the stage of takeoff, which resulted in the aircraft crashing down immediately after leaving the runway and rolling to the right on the snowy ground, breaching the airport perimeter fence and colliding with a two-story private building located 9-10 m from the fence. As a result of collision, 11 passengers and one crew member died and 47 passengers received different injuries because of overloading, striking, destruction and crushing of the aircraft structure. The cause of the loss of wing lift properties was most likely the effect of ground icing.
Contributing factors:
- The crew, after analyzing the actual meteorological situation at Almaty airport, may not have drawn sufficient conclusions to better inspect the entire aircraft and especially (tactile method) the leading edge of the wing;
- The Flight Safety Management System (FMS) of Beck Air JSC contains mainly only general provisions and specific actions that were not adapted for implementation, which did not allow timely identification and elimination of existing risks affecting flight safety.
- Collision of the aircraft with a two-storey private structure, which affected the severity of the consequences.

The cause of the accident, i.e. runway excursion, which caused significant damage to the structural elements of the aircraft B-737-800 TC-JGZ of Turkish Airlines, which took place on 21.11.2019 during landing at «Odesa» Aerodrome, was failure to maintain the direction of the aircraft movement during the landing run in the conditions of a strong crosswind of variable directions.
Contributing Factors:
- Use by the crew of the landing approach method using the Touchdown in Crab technique, which is not recommended by FCTM B-737NG document for use on dry runways in the conditions of a strong crosswind;
- Untimely and insufficient actions of the crew to maintain the landing run direction;
- Presence of a significant cross component of the wind;
- Effect of an omnidirectional wind – from cross-headwind to cross-tailwind directions – during the landing run.

The National Transportation Safety Board determines that the probable cause of this accident was the landing gear manufacturer’s incorrect wiring of the wheel speed transducer harnesses on the left main landing gear during overhaul. The incorrect wiring caused the antiskid system not to function as intended, resulting in the failure of the left outboard tire and a significant loss of the airplane’s braking ability, which led to the runway overrun.
Contributing to the accident were
1) Saab’s design of the wheel speed transducer wire harnesses, which did not consider and protect against human error during maintenance;
2) the Federal Aviation Administration’s lack of consideration of the runway safety area dimensions at Unalaska Airport during the authorization process that allowed the Saab 2000 to operate at the airport; and
3) the flight crewmembers’ inappropriate decision, due to their plan continuation bias, to land on a runway with a reported tailwind that exceeded the airplane manufacturer’s limit. The safety margin was further reduced because of PenAir’s failure to correctly apply its company-designated pilot-incommand airport qualification policy, which allowed the accident captain to operate at one of the most challenging airports in PenAir’s route system with limited experience at the airport and in the Saab 2000 airplane.

The accident was the consequence of the combination of the following factors:
- Control skills – undetermined.
While facing adverse conditions, the use of controls may have been inappropriate for the situation and may have contributed to the aircraft not being able to maintain a positive climb rate.
- Attitude – undetermined.
Familiarization with the region may have led to an attitude, on the part of the PIC, of minimizing the importance of analyzing adverse weather conditions, to the detriment of compliance with the minimum limits established by the company in its manuals.
- Training – undetermined.
It is possible that, due to possible inadequate training, the SIC did not identify the critical situation that arose shortly after the take-off in time to assist the PIC in maintaining flight control.
- Tasks characteristics – undetermined.
The characteristics present in the type of operation, compliance with schedules without the possibility of delays, due to the runway closing period, may have favored the self imposed pressure on the part of the PIC, leading him to operate with reduced safety margins.
- Adverse meteorological conditions – a contributor.
The conditions at the time of the take-off contributed to the aircraft not being able to maintain the flight with a positive climb rate. The probable occurrence of Windshear determined that the trajectory of the aircraft was modified until its collision with the ground.
- Crew Resource Management – undetermined.
On the part of the SIC, no assertive attitude was perceived in the sense of alerting the PIC that those conditions were not favorable for takeoff. Thus, the crew decided to carry out the take-off despite the company's SOP.
- Organizational culture – undetermined.
The company encouraged compliance with the legs even though, within the planning of flights, there was not an adequate margin of time to absorb any delays. This culture may have influenced the PIC's decision-making, which, despite encountering adverse conditions, chose to take off, since the short time on the ground in the intermediate locations did not allow room for delays.
- Emotional state – undetermined.
The reports indicated that the PIC felt pressured to perform the take-off even in the weather conditions found on the day of this occurrence. Also, according to the interviewees, this pressure would be related to the fulfillment of the flight schedule and the need to keep to the scheduled times. In this way, it is possible that their assessment of the performance of the flight was influenced by the stress resulting from the pressure to complete the flight within the expected time, given the closing time of the runway for works.
- Flight planning – a contributor.
The flight planning was not carried out properly, considering that the planned schedules and routes would end after the closing time of the SBEG runway for works, provided for in the NOTAM. This meant that there was little time to adjust the legs, increasing the workload and stress in the cabin.
- Decision-making process – a contributor.
There was a wrong assessment of the meteorological conditions, which contributed to the decision of performing it in an adverse situation.
- ATS publication– undetermined.
The TWR-EG did not inform, before the take-off, of the changes in the significant weather conditions that were occurring at the terminal, which could have contributed to the PIC's decision-making.

A loss of in-flight control of the aircraft due to possible excess weight. The aircraft probably managed to take off due to "ground effect", but, once in the air and out of ground effect, it was not able to obtain the speed that would allow it to safely accomplish the climb.
Contributing Factors:
- Absence of Dispatch procedures of the operator to perform a correct Weight and Balance of the aircraft, and the effective control of the boarded cargo.
- Incorrect calculation of the weight and balance of the aircraft by the crew, by not considering all the cargo that was loaded, causing the aircraft to take off with a possible excess weight.
- Weak operational safety management processes of the operator by not considering the operating characteristics of airfields such as Popayán (high altitude, high ambient temperature) that significantly limit the operation.