Pakistan's national carrier Monday grounded its 10 French-built ATR turboprop planes after a crash last week killed 47 people and a second aircraft reported technical issues shortly before it was supposed to take off overnight.
Pakistan International Airlines flight 661 smashed into a hillside in the country's north while travelling from the city of Chitral to the capital Islamabad last Wednesday.
The airline has said one of the plane's two turboprop engines failed.
Another PIA ATR faced "technical issues" late Sunday just before it was set to take off from the central city of Multan on a flight to southern Karachi and was called back to its parking bay, though the airline denied media reports that one of the engines caught fire.
The fleet would now undergo thorough testing after the two incidents, the airline said.
"In view of Civil Aviation Authority's decision of holding shakedown tests of PIA's entire ATR fleet, it has been decided to keep all 10 ATR aircraft grounded till they are cleared after thorough examination," PIA spokesman Danyal Gilani said in a statement.
The ATR 42-500 is a twin turboprop regional aircraft that carries 48 passengers in standard configuration. ATR aircraft are capable of operations on both paved and unpaved strips. The engines are built by US manufacturer Pratt & Whitney.
The company has so far declined to comment while Pakistani authorities investigate the causes of the crash.