US Agency Recommends Modifications To 747 Flight Management Software

It happened more than two years ago as a Singapore Airlines 747-400 was taking off from Auckland, New Zealand, headed for Singapore. The flight crew rotated to V1 -- but far too early, according to New Zealand investigators. As a result, the plane's empennage dragged along the runway for more than 1,500 feet before V2.

Instead of rotating to V1 at 163 knots, the jumbo jet rotated at 130 knots. The reason? An error in the weight and balance computer entry made by the copilot showed the aircraft weighing 100 tons less than its true weight. That resulted in the cockpit crew's decision to use less-than-needed thrust on take-off.

The aircraft got off the ground, but not before using up a lot more runway than planned. New Zealand's Transport Accident Investigation Commission also found pilots didn't respond properly when they heard a stall warning.

Now, the NTSB has recommended the FAA mandate an Airworthiness Directive aimed at forcing modifications to the 747's flight management software.

"The NTSB added its weight by recommending to the United States Federal Aviation Administration that it require the equipment manufacturer to modify its aircraft flight management system software, which would result in a global fix to a technology shortcoming that was found during the investigation," said TAIC chairman Bill Jeffries -- who's also head of the International Transport Safety Association. He was quoted by the New Zealand Press Association.

The ITSA is meeting in Auckland, New Zealand, this week.

As for the Singapore Airlines 747, which had 389 passengers and crew on board, the aircraft circled Auckland and dumped fuel before safely returning to the airport.

FMI: www.ntsb.gov