Two Alaska Airlines planes drag tails across Seattle runway while taking off due to software glitch that miscalculated weight
SEA-TAC, WASHINGTON: In an incident that left people concerned, two Alaska Airlines planes ended up dragging their tails on the tarmac at Seattle-Tacoma International Airport as they took off due to a software glitch that gave the pilots the impression that their aircraft were 20,000lbs lighter than they actually were. The two planes took off on January 26 six minutes apart, without coming into contact with one another.
Alaska Airlines determined the problem to be serious enough to order an immediate nationwide grounding of all planes, according to the Seattle Times. A representative for Alaska Airlines claimed the incident did occur and the grounding lasted about 20 minutes, according to the Daily Mail. "The tail touches were caused by a vendor software update that mistakenly installed code resulting in inaccurate take-off performance weight data for a small subset of our flights," the representative said. The representative claimed that none of the passengers were aware of it.
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Why did the two airplanes scrape their tails?
The first flight, an Alaska 737 Max9 headed for Kona, Hawaii, took off from Seattle at 8.48 am. After its scraped on the runway, the captain reportedly decided turn around and head back to Seattle, where it landed safely at 9.26 am. The second aircraft, a 737-900ER operated by Alaska Flight 887, left at 8.54 am for Hawaii. However, its captain decided to turn it around after the same thing happened. It reached the airport by 9.45 am.
DynamicSource, a Swedish software company, is used by Alaska Airlines planes to calculate the amount of power needed for takeoff based on the weight of the aircraft, according to Seattle Times. On the day of the incident, the pilots believed the planes were lighter than they actually were because of a software update by DynamicSource that malfunctioned. Both pilots rotated too soon as a result of using less power than was necessary to take off.
Of the 727 Alaska flights that were scheduled to depart that day, just 30 had inaccurate data, and only two of those scraped their tails. The airlines reported that both flights were fully within safety parameters despite the inaccuracy in calculation.
How were the two airplanes made to land safely?
Alaska's on-duty director of operations Bret Peyton reported that numerous flight crews had contacted dispatch on that particular day to express their belief that the DynamicSource data on the weight was inaccurate. This made it possible for the airline to find and solve the issue promptly.
Aviation expert Kit Derby stated the pilots who frequently flew on the same route would be aware of any significant errors in the calculations, according to DailyMail. An unnamed Alaska Airlines pilot said, "We rely on that data to safely operate the plane... Alaska dealt with it very quickly and appropriately," according to Seattle Times. Derby stated that a mistake of this type would normally only result in an over usage of electricity and was not a serious accident.