Task: Question Generation
Input (English): Theodore Honey (James Stewart), an eccentric "boffin" with the Royal Aircraft Establishment, is working on solving a difficult aviation crash problem. A widower with a 12 year old daughter, Elspeth (Janette Scott), Honey is sent from Farnborough to investigate the crash of a Rutland Reindeer airliner in Labrador, Canada. He theorizes the accident happened because of the tailplane's structural failure, caused by sudden metal fatigue after 1440 flight hours. To test the theory in his laboratory, a rear airframe is being vibrated at a very high rate in daily eight-hour cycles.It is not until Honey finds himself on board a Reindeer airliner that he realizes he is flying on an early production aircraft that is close to the number of hours his theory projects for the metal fatigue failure. Despite the fact that his theory is not yet proven, he decides to warn the aircrew and Hollywood actress Monica Teasdale (Marlene Dietrich), a fellow passenger. After the Reindeer safely lands at Gander Airport in Newfoundland, an inspection clears the aircraft to continue on its route. Honey then takes drastic action to stop the flight by activating the Reindeer's port undercarriage lever, dropping the airliner on its belly, damaging it. Shocked by the act, some of his colleagues demand that he be declared insane to discredit his unproved theory and save the reputation of British passenger aviation now awash in a sea of bad press.Teasdale and Reindeer flight attendant Marjorie Corder (Glynis Johns) both take a liking to Honey and Elspeth, who they discover is lonely and isolated from her schoolmates. Teasdale speaks to Honey's superiors on his behalf, claiming she believes in him. Corder, meanwhile, has stayed on with Honey and his daughter as a nurse. Having now observed Honey's many qualities beyond his minor eccentricities, and after becoming very close to Elspeth, she decides to make the arrangement permanent by marrying the scientist.During a hearing in which his sanity is questioned, Honey angrily protests, refusing to be railroaded. He resigns and walks out, threatening to collapse other Rutland Reindeers until all the aircraft are grounded. He then goes back to his laboratory to prove his metal fatigue theory is sound, but the time he predicted for the structural failure soon passes without anything happening. The Reindeer airliner he disabled at Gander, however, is repaired, and shortly after it completes a test flight, the tail falls off while taxiing. Shortly thereafter, the same thing happens to the tail frame in the laboratory, and Honey discovers that he failed to include temperature as a variable factor in his fatigue calculations.
Output (English): What variable factor did Honey fail to include in his fatigue calculations?