The pilot of a flight that crashed in Pakistan had made a mayday call just before losing contact, the airline said.
He also told flight controllers of an engine problem at 16:09 local time (11:09 GMT) on Wednesday, Pakistan International Airlines (PIA) Chairman Muhammad Azam Saigol told reporters.
All 48 people on the twin-propeller plane flying to Islamabad were killed.
An investigation is ongoing, but the carrier has insisted strict checks left “no room for any technical error”.
“I want to make it clear that it was a perfectly sound aircraft,” Mr Saigol said. “I think there was no technical error or human error.”
A flight data recorder has been found, the airline said.
Pakistani authorities have said the apparent engine issue will be a focus of inquiries.
Irfan Elahi, from Pakistan’s Civil Aviation Authority, told Dawn newspaper: “At the moment, there is no other reason for the plane crash other than the failure of the left engine.”
The plane crashed in the Havelian area of Khyber-Pakhtunkhwa province, about 70km (43 miles) from Islamabad.
Police said the passengers’ charred remains have been taken to a hospital for DNA identification.
Famous pop singer turned Islamic preacher Junaid Jamshed was on board, along with three foreigners – two Austrians and one Chinese citizen.
There was anger amongst relatives of the victims, gathering at the hospital to collect their loved ones’ remains.
Ghulam Rasool Khan told the AP news agency: “It is a murder and I want to know who killed my brother.”
Plane crashes are not uncommon in Pakistan, but the last major crash involving a PIA aircraft was in 2006, in which 44 people died.