A major glitch that occurred last Friday in Japan Airlines Co.'s weight management system was caused by a faulty computer program, which was designed by Deutsche Lufthansa AG, the Japanese carrier said Wednesday. JAL also said that Lufthansa for its part has admitted to programming errors, adding, however, that it was "difficult to prevent the system trouble proactively." Friday's glitch led to the cancellation of 50 domestic flights to and from Tokyo's Haneda airport on the day, affecting about 24,000 passengers, according to JAL. JAL commissioned the program to a computer system firm under the Lufthansa group. JAL started using the program in 2014 and updated it March 23.