Lost bearings

An auditor is checking the books of an airline. He is puzzled by the excess use of fuel on a Melbourne to Canberra flight. He rings up the pilot and asks for an explanation. "It was late at night'" says the pilot, "Canberra was covered in fog and I lost my bearings." "I'm sorry," says the auditor, "but you'll have to bear the cost yourself." "The cost of what?" asks the pilot. "Of the bearings you lost."