A Boeing 737 jet struck a light almost 30 meters beyond the end of a runway and just 14 inches high after taking off with insufficient power when its pilots entered the incorrect air-temperature into a computer, according to an air accident bulletin.
On July 21 2017, the jet operated by Canada’s Sunwing Airlines, avoided crashing only because of the “benign nature” of the area beyond the runway at Belfast International airport in Northern Ireland and the low elevation of surrounding terrain, the U.K. Air Accident Investigation Branch said in the report on Wednesday.
The 737 limped into the air with just 60 percent of the usual thrust after the Sunwing crew entered a temperature of minus 52 Celsius into the plane’s flight management system, when the correct reading on July 21 this year was 16 degrees, the AAIB said. The computer reined back the engines because colder air requires less acceleration to achieve the same lift.
The pilots didn’t notice the low takeoff speed until the 737 was approaching the end of the runway, and after takeoff continued the flight to Corfu, Greece, as planned, the AAIB said. The light struck by one of the aircraft’s tires was later found crushed on the ground having been knocked from its mounting.
The AAIB recommended that the U.S. Federal Aviation Administration order upgrades to software that would crosscheck the outside air temperature, where required, as well as the necessary hardware. It also said that the FAA should guide 737 operators on how to verify the required thrust calculated by the flight management computer against an independently derived value.