Air Freight NZ Flight 642

On Air Freight NZ Flight 642, on 3 October 2003 an Air Freight NZ Convair CV-580 freighter on the flight from Christchurch Airport to Palmerston North Airport crashed due to in-flight icing. The two pilots on board were killed in the accident.

Accident sequence

During the night of 3 to 4 October 2003 the aircraft was to operate two regular night cargo flights from Christchurch to Palmerston North and back. At 20:32 the aircraft took off as scheduled from runway 20 and climbed to 21,000 feet. The flight proceeded without any particular incidents. At 21:13 air traffic control in Wellington first gave clearance to descend to 13,000 feet and then to 11,000 feet. After making contact with air traffic control in Ohakea, the pilots received clearance to descend to 7000 feet and received vectors for the approach to Palmerston North. During the descent the aircraft flew through an area for which severe icing conditions had been forecast, which apparently overwhelmed the capacity of the in-flight de-icing system that was supposed to prevent ice from forming on the wings and tail. The aircraft subsequently stalled, probably due to rapidly progressing, significant ice formation. The aircraft's nose pitched down, whereupon the pilots apparently lost their orientation. The airspeed rose to 392 knots and the structural load reached a peak of 3.21g. The pitch angle was probably between −50° and −60°. An increasing load on the wing roots finally caused the panels to buckle and separate. At an altitude of 6,800 feet the wings and engines tore off. Nine seconds later the fuselage struck the sea surface vertically and at high speed.