By David Kaminski-Morrow in London

Canadian investigators say misunderstanding of laptop performance tool caused 2004 MK 747 freighter accident

Canadian investigators are recommending the installation of systems to warn crews of inadequate take-off performance following the fatal loss of an MK Airlines Boeing 747-200 freighter during departure from Halifax nearly two years ago.

In its final report on the 14 October 2004 crash of MK flight 1602, the Transportation Safety Board of Canada (TSB) says that the crew’s misunderstanding of a laptop computer tool for calculating take-off performance led to the accident. It concludes that the crew unwittingly transferred and used weight data from the aircraft’s previous flight while calculating performance criteria for the next take-off. The obsolete data misled the crew to derive incorrect thrust settings and critical speeds for take-off.

About two-thirds of the way along Halifax’s runway 24, the aircraft rotated, but failed to become airborne. Its tail struck the ground twice, the second time with just 130m (420ft) of the 2,682m runway remaining. The jet overran the runway by 250m and briefly lifted off for a distance of 100m before it struck an earth berm, the impact severing the tail section and causing the 747 to crash 370m beyond. All seven crew members on board were killed.

MK1602 flight data recorder W445
© TSB 

Comparison of the flight-data recorder (pictured above recovered from the crash scene) information from the Halifax take-off with that from the aircraft’s previous departure, from Connecticut’s Bradley International airport, revealed that the data was “nearly identical”. Both rotations were conducted at 130kt (240km/h) with 20° of flap and the engine data in both cases was similar.

This indicates, says the report, that the Bradley take-off weight of just under 240,000kg (530,000lb) was unintentionally used to calculate the aircraft’s take-off performance from Halifax – despite the additional cargo and fuel making its weight nearly 50% more.

The TSB says: “The Bradley weight in the weight and balance page [of the laptop tool] was likely unknowingly transferred to the performance page due to a reversion feature of the software.” It states that inadequate training on the Boeing laptop tool used by the crew, as well as personal stresses and non-adherence to procedures, contributed to the accident. MK Airlines stopped using the laptop tool two weeks after the crash.

The crew was probably suffering from fatigue, says the report, and the departure in darkness would have made the performance error difficult to detect.

Canadian investigators have acknowledged efforts by Ghana-registered MK Airlines to improve safety. To read more, click here.

Source: Flight International