The de Havilland Comet was the world's first commercial jet airliner to reach production in Britain. It first flew in 1949 and was considered a milestone in aeronautical design.
After being introduced into commercial service, the early Comets had major problems with metal fatigue that caused a string of accidents. After an accident in January 1954 caused the loss of all 35
on board, the fleet was grounded until a committee investigated possible causes of the crash. Though no definitive cause was established, modifications were made to cover "every possibility that
imagination has suggested as a likely cause of the disaster." But the Comet's troubles weren't over yet....
On April 8, 1954 a Comet on a Rome to Cairo leg of a longer flight crashed in the waters off Naples - the Royal Navy assisted in retrieving the wreckage so that the cause of this incident could be determined -
SQUARE WINDOWS!
Engineers subjected an identical airframe to repeated pressure testing and determined stress concentration at the windows' corners was responsible for the accident. You'll notice that today's airliners' windows are all curved!
Most recently - the mysterious crash of Air France Flight 447 has been investigated by a variety of experts and engineers and one scenario being strongly considered is that the airplane's pitot tubes
may have malfunctioned, causing the crash. Pitot tubes - developed in the 1700's and named for their inventor, Henri Pitot - were originally used to measure water speed in rivers and canals. Their
current use is to measure airspeed with inherently simple technology described by one engineer "like sticking your hand out a car window"
The pitot tubes have heating elements included in their design and normally these elements are sufficient to keep the tubes free of ice. However, the pitot tube used on the Airbus A330-200 may have
a design flaw that allowed it to become encrusted with ice during encounters with heavy freezing precipitation. Ultimately, frozen pitot tubes could have caused false airspeed readings that would
have triggered the airliner's computers to increase speed resulting in shearing off of the plane's vertical stabilizer. Newly designed tubes have been installed on the Airbus A330-200.
