Last week, birds managed to ground one of freight carrier TNT's 737s at Istanbul’s Ataturk airport. The 737’s pilots started up the auxiliary power unit (APU) before departing for Liege in Belgium, then noticed a sudden increase in temperature of the APU. The tower informed them that smoke was coming from the 737’s tail.
When technicians arrived to inspect the APU they found lancets, shears and other parts of burned metal. The pilots initially suspected that the 737 had been sabotaged and asked the airport authority to investigate.

TNT Istanbul 1

TNT Istanbul 3

TNT left staff on the apron to check subsequent flights. The next day a 737 freighter landed at Ataturk Airport and parked in the same area near the cargo terminal. During the day, staff saw birds, mainly crows, carrying metal objects in their beaks. The birds flew round the back of the APU and tried to put the objects in its exhaust. This continued all day.

TNT Istanbul 4 

TNT Istanbul 01

The airport authority started an investigation about the metal objects. Last year, the special cargo bonded warehouse was destroyed in a fire. There is still some damaged cargo in the area, including pieces of metal, which zoologists believe could attract birds, particularly crows.
The Ataturk airport authority said it doesn’t normally use the parking area where the TNT 737 was kept. But TNT’s freighter was sent there on this particular day because of a parking problem.
Since the incident, TNT has been covering the APU when the plane is parked.

Istanbul Ataturk airport cargo fire under control, says airport chief

TNT's first 747-400ERF