Incident: PIA B772 near Riyadh on Nov 11th 2016, loss of cabin pressure
A PIA Pakistan International Airlines Boeing 777-200, registration AP-BHX performing flight PK-760 from Jeddah (Saudi Arabia) to Lahore (Pakistan), was enroute at FL390 about 230nm west of Riyadh (Saudi Arabia) when the crew initiated an emergency descent to 10,000 feet due to the loss of cabin pressure. The aircraft diverted to Riyadh for a safe landing about 50 minutes after leaving FL390.
The occurrence aircraft remained on the ground in Riyadh for 4 hours, then departed to continue the flight to Karachi (Pakistan) at maximum cruise level 110. The aircraft safely landed in Karachi about 3:10 hours after departure from Riyadh.
A replacement Boeing 777-200 registration AP-BMG continued the flight to Lahore and reached Lahore with a delay of 8.5 hours.
The airline reported the flight suffered some technical problems, landed in Riyadh for repairs and was then re-routed to Karachi. The passengers were then accomodated on continuing flights.
The Aviation Herald