JS Air Flight 201

Investigation

An inquiry was ordered into the crash. No evidence was found of a bird strike, pilot incapacitation, sabotage, in-flight structural failure or fire.

The investigation started with the examination on the plane's propellers, as evidence from the cockpit voice recorder (CVR) suggested that an engine failure occurred in mid-flight. Investigators retrieved the propeller from the wreckage and stated that the beta valve in the aircraft may have malfunctioned in mid flight. There are two possibilities of beta valve malfunction: mis-rigging after some maintenance work or fair wear and tear during routine service. Unfortunately, the beta system's integrity and rigging status could not be verified because the propeller governor had been completely consumed in the post ground impact fire. However, it was confirmed from the documented history and the engineering staff that there was neither any reported defect related to the beta system nor was there any scheduled or unscheduled maintenance performed in the recent past. Therefore, the only probable cause of occurrence could be fair wear and tear of the beta valve.

However, investigators stated that even if a mid-air engine failure occurred, the pilots still could have returned to the airport safely. If an aircraft had a mid air engine failure in one engine, the plane still could fly. All twin engine aircraft are designed to sustain a safe flight even if one of the engines has failed or is switched off due to any abnormality, provided the emergency handling procedures are correctly followed. Similarly, the Beechcraft 1900C also had the capability to sustain safe flight with single engine operation. This suggests that pilot error may be the main cause of the accident.

Investigators reviewed the CVR data and stated that the pilot may have lacked situational awareness. After experiencing the abnormal engine No 2 operation, at one stage the cockpit crew indicated confusion about the engine No 1 or 2 and subsequently transmitted incorrect information to the ATC Tower that they were experiencing abnormal operation of engine No 1. The first officer was exposed to a serious level of stress and anxiety when he observed the propeller feathering of No 2 (right) engine. The situation was aggravated due to the fact that the auto feathering was selected to "Off" which entailed the cockpit crew to manually manage feathering of the propeller in case of any anomaly. He did communicate to the captain correct information; however, the captain did not register engine No 2 and told him to inform ATC Tower that they were experiencing problem with engine No 1 and FO communicated the same without questioning the captain or correcting himself. He was mentally preoccupied to a level where he could not perform the recommended remedial action. Thus, he did not effectively contribute towards handling of abnormal set of conditions.

Investigators checking the captain's flight history discovered that his performance during simulator training check flights remained consistently below acceptable levels. He was not able to safely handle training scenarios during critical phases of takeoff and post-takeoff, and was only able to achieve satisfactory performance levels with coaching during these mandatory exercises. The final report stated that the captain suffered from "lack of confidence" and also revealed that the captain lacked the required proficiency and skills to independently handle aircraft operations with a single functioning engine during critical phases of flight.

Investigators concluded that the cockpit crew neither discussed nor raised the landing gear after takeoff. The wreckage also confirmed the landing gear were in the extended position at the time of ground impact. The Beechcraft 1900C aircraft has a very low rate of climb with landing gear in extended position due to increased drag while operating with a single engine. Any banking of the aircraft would aggravate the situation and the marginal rate of climb would degrade into a rate of descent, which happened in this particular case.

In December 2015, Pakistan's Safety Investigation Board released their final report stating that the accident was caused by the inability of the captain to handle the abnormal operation of engine No 2 just after takeoff, failure of the cockpit crew to raise the landing gear after experiencing the engine anomaly, and execution of remedial actions by the first officer before the attainment of minimum safe altitude. The crew did not follow standard procedures, lacked situational awareness, displayed poor crew resource management, and handled the anomaly unprofessionally.