The investigation further revealed that faulty maintenance practices within PIA were to blame for such failures and the issue had been allowed to happen by weak oversight by the airline and the nation's aviation regulatory body.

Following the discovery of loopholes within CAA oversight, AAIB ordered authorities to impose stricter monitoring regarding airworthiness and airliner operation in the country.

[6]: 8 While he was making the announcement, he was interrupted by the trainee first officer, who informed him that an alert of a mechanical fault on the Propeller Electrical Control-1 (PEC-1) had suddenly appeared.

Captain Janjua asked the crew to read the procedure checklist for such issue and ordered the trainee first officer to call the flight engineer in the cabin to the cockpit.

[6]: 10–13 At 16:11 local time, Captain Janjua ordered First Officer Akram to request permission for the flight to descend and to make a mayday call.

In his effort to stabilize the flight, Captain Janjua added more thrust to the right engine several times, but his actions somehow aggravated the situation as it worsened the condition.

As Captain Janjua made excessive right turn inputs on the control column, the aircraft immediately banked to the right at a large angle, taking the crew by surprise.

He was successful as the aircraft gradually turned, but the airspeed continued to deplete, causing stall warnings to blare inside the cockpit.

The aircraft crashed at about 16:15, leaving wreckage ablaze on the side of a hill between the villages of Saddha Batolni and Gug, near the Pakistan Ordnance Factory in Havelian in Khyber Pakhtunkhwa province about 90 kilometres (56 mi; 49 nmi) from the airport.

[24] According to an eyewitness, Mohammad Haroon, the aircraft flew at a very low altitude and made a high-pitched noise, flying in an erratic, up-and-down mode before crashing into the hillside.

[25] Announcements were broadcast by local mosques to mobilise villagers, who rushed to the site to look for survivors but were unable to get close due to the heat of the fire.

During his address to the parliament, he ordered an inquiry to be made immediately under the CAA's Safety Investigation Board (SIB), vowing to "bring out the truth".

[27] In the immediate aftermath, workers from PIA and CAA set up helpdesks and a hotline in Islamabad's Benazir Bhutto International Airport for relatives of the victims.

PIA management stated that attempts were being made to reserve 40 hotel rooms to accommodate grieving families who were waiting for the body identification process.

The mother of the ATR 42's first officer reported that he frequently mentioned to her that PIA's aircraft "are not fit to fly, and they should not be allowed to operate on dangerous routes".

PIA responded that "it defies common sense that pilots and engineers would fly an aircraft that does not meet safety standards and risk their own lives.

[48][6] On 12 December, the nine members of the investigation team, three representatives from ATR, three from Pratt & Whitney Canada, and three from Pakistan, visited the crash site for wreckage examination.

[10] An initial report into the accident by the Pakistan Civil Aviation Authority (PCAA) was said to have determined that the aircraft's left engine malfunctioned at an altitude of 13,375 feet (4,077 m).

[53] Despite claims from PIA chairman that the aircraft was airworthy and had been checked properly by their employees, the findings from the investigation revealed that the aircraft in fact had three pre-existing technical problems; a fractured turbine blade of the left engine, a fractured pin inside the flyweights of the overspeed governor (OSG) of the left engine, and debris inside the overspeed line of the propeller valve module (PVM).

Meanwhile, the OSG valve became closed again as the last remaining flyweights began to break due to fatigue, causing the blade pitch to decrease and the propeller speed to accelerate.

The report described the PIA maintenance facility as one of the pioneers in the region to achieve high-level certification, including from the European Union Aviation Safety Agency (EASA).

Operational review from investigators revealed that some improvements were required in several fields, including the assembly and disassembly of engines, bearing inspection and material handling.

Irregularities on physical pilot attendance during licensing exams and recorded number of participants during a specific period of time gave rise to the suspicion.

The names of Captain Janjua and First Officer Akram initially were among the list of pilots who were suspected of having such dubious licenses, but the issue eventually became irrelevant to the cause of the crash as the AAIB concluded that the actions of the crew during the flight had been commensurate with their respective training and experience.

The annual audits of PIA from 2014 to 2018 revealed that there were gaps and loopholes in the monitoring and evaluation of aircraft airworthiness and safety spectrum and CAA was unable to identify the issues.

The report concluded that the oversight mechanism that had been established by PIA and CAA was inadequate or ineffective to identify weak areas within the system's scope.

The cause of the accident was a fracture of a turbine blade in the number one (left side) turboprop engine as a result of improper maintenance.

The first recommendation was issued in January 2019, in which PIA was asked to inspect their entire ATR fleet to change the blades that had met the criteria for replacement.

Among those, PIA was asked to ensure strict compliance with the issued service bulletin, to conduct improvements on weak areas in its MRO facility and to identify critical performance indicators within its airworthiness and flight safety operation.

Following multiple complaints from family members of the victims regarding the delayed release of the result of the probe, the government of Pakistan created a new bill.