Pakistan International Airlines Flight 661

Pakistan International Airlines Flight 661 was a Pakistani domestic passenger flight from Chitral to Islamabad, operated by Pakistan's flag carrier Pakistan International Airlines. On 7 December 2016, the aircraft serving the route, an ATR 42-500 twin-turboprop, crashed near Havelian following an engine failure. All 47 people on board died, including singer-turned-preacher and entrepreneur Junaid Jamshed, and the Deputy Commissioner of the District of Chitral.

Four years after the crash, Pakistan Aircraft Accident Investigation Board (AAIB) published the result of their investigation. In the final report, the crash was described as a unique case and the first ever of its kind in the entire operational life of ATR aircraft. The aircraft's left engine had failed mid-flight and the aircraft's safety system prevented the pilots from resolving the issues, which led to the sudden appearance of huge amount of drag on the left side. The bizarre nature of the emergency that the crew faced eventually caused them to lose control. 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.^{: XI–XXXVI}

The complex nature of the crash led to the issuance of several recommendations, two of which were urgent enough that mentioned parties were asked to comply immediately. Following the discovery of loopholes within CAA oversight, AAIB ordered authorities to impose stricter monitoring regarding airworthiness and airliner operation in the country. Pakistan's CRM training system was asked to be revamped. While extremely remote, there were also fears from the investigators about the possibility of another similar crash in the future. The manufacturer of the aircraft, ATR, was asked to include a specific procedure to safely recover from the situation.^{: 156–158}