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Movie Monday - November 30 - Comet to Jo'Burg

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In the ever growing list of "Things Aviation Geeks Love", combining airline nostalgia, classic route structures, new aircraft, trip reports and complex accident investigations might put this week's Movie Monday close to the top of my favorites.

The first half of this classic news reel from the earliest days of commercial jet travel chronicles the May 1952 London to Johannesburg flight (via Rome, Beirut, Khartoum, Entebbe, Livingstone) of the De Havilland Comet 1 (G-ALYP) on the British Overseas Airways Corporation. Pathe Cameraman Ced. Baynes films the world's first jet passenger service aboard the square-windowed Comet.

Flight's 22 December 1949 Issue discussed the performance of the Comet 1 this way:
It is officially stated that the Comet has a cruising speed of 490 m.p.h. at an all-up weight of 105,000 lb and, as a 36-seater, a capacity payload of 12,000 lb. With this maximum payload its Still-Air Range (standard atmosphere, no wind, no allowances) is 3,540 statute miles. The corresponding Practical Range is 2,645 miles, i.e., with due allowance for ground running, taxying-out, take-off, climb and descent, navigational errors, airframe and engine variation and deterioration, the Comet with 12,000 1b payload can fly to a point 2,645 miles distant and, on arrival, have sufficient fuel left for 30 minutes of circuits and stand-off prior to approach, landing and taxying in. By reducing the payload to 6,000 lb, the practical range becomes 3,000 miles; with no payload, it becomes 3,220 miles.

Additional allowances for head wind and diversion to an alternative airport are necessary in order to arrive at the stage lengths that can be operated. For example, the practical range of 2,645 miles with 12,000 lb payload represents a stage length of 2,140 miles, plus 200 miles diversion allowance, all against a head wind of 50 m.p.h. These loadings to 105,000 lb call for a runway length of 2,175 yards, and at this weight the Comet is stated to have a satisfactory three-engine climb gradient.
The news reel then turns to the loss of that same aircraft (G-ALYP) in 1954 over the Mediterranean Sea as BOAC Flight 781, the first explosive decompression of a Dh.106 Comet aircraft. The investigation that followed saw sister-ship G-ALYU encased in a water tank at Farnborough and repeatedly cycled for the equivalent of 15,000 hours until cracks formed near the corner of an escape hatch due to metal fatigue.

The investigation update was filmed during the grounding of the Comet fleet and ends on a hopeful note as it looks ahead to the entry into to service of the Comet 2 and Comet 3, aircraft that applied the lessons learned from the loss of the early Comets.

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