“The Alaska 737 captain said the data was on the order of 20,000 to 30,000 pounds light.”
A software update from DynamicSource, a Swedish vendor, told two Hawaii-bound 737s they weighed up to 30,000 pounds less than they did. Both scraped their tails six minutes apart. The tool trims takeoff thrust to save fuel and engine wear, so a weight bug turns straight into a power shortfall. The bug got caught because some crews thought the numbers looked wrong. The safety system was a pilot squinting at a printout.