Editing De Havilland Comet (section)

===Early hull losses===

On 26 October 1952, the Comet suffered its first hull loss when a BOAC flight departing Rome's [[Rome Ciampino Airport|Ciampino airport]] failed to become airborne and ran into rough ground at the end of the runway. Two passengers sustained minor injuries, but the aircraft, G-ALYZ, was a write-off. On 3 March 1953, a new [[Canadian Pacific Airlines]] Comet 1A, registered CF-CUN and named ''Empress of Hawaii,'' failed to become airborne while attempting a night takeoff from [[Karachi, Pakistan]], on a delivery flight to [[Australia]]. The aircraft plunged into a dry drainage canal and collided with an embankment, killing all five crew and six passengers on board.<ref>{{Cite web |title=Comet Accident Record |url=https://asn.flightsafety.org/asndb/335403 |access-date=22 September 2010 |website=Aviation Safety Network}}</ref><ref>{{Cite web |title=CF-CUN |url=http://www.edcoatescollection.com/ac4/CF-CUN.html |access-date=18 February 2011 |website=Ed Coates' Civil Aircraft Photograph Collection}}</ref> The accident was the first fatal jetliner crash.<ref name=JAPL/> In response, Canadian Pacific cancelled its remaining order for a second Comet 1A and never operated the type in commercial service.<ref name=JAPL/>

[[File:De Havilland Comet 1 BOAC Heathrow G-ALYX 1953.jpg|thumb|BOAC Comet 1 ''G-ALYX'' (Yoke X-Ray) at [[London Heathrow Airport]] in 1953 prior to a scheduled flight]]

Both early accidents were originally attributed to pilot error, as [[rotation (aeronautics)|overrotation]] had led to a loss of lift from the [[leading edge]] of the aircraft's wings. It was later determined that the Comet's wing profile experienced a loss of lift at a high [[angle of attack]], and its engine inlets also suffered a lack of pressure recovery in the same conditions. As a result, de Havilland re-profiled the wings' leading edge with a pronounced "droop",<ref name=Withuhn85>Withuhn 1976, p. 85.</ref> and [[wing fence]]s were added to control spanwise flow.<ref name=Birtles127>Birtles 1970, p. 127.</ref> A fictionalised investigation into the Comet's takeoff accidents was the subject of the novel ''Cone of Silence'' (1959) by [[Arthur David Beaty]], a former BOAC captain. ''Cone of Silence'' was made into a [[Cone of Silence (film)|film]] in 1960, and Beaty also recounted the story of the Comet's takeoff accidents in a chapter of his non-fiction work, ''Strange Encounters: Mysteries of the Air'' (1984).<ref>Beaty 1984, pp. 113–114.</ref>

The Comet's second fatal accident occurred on 2 May 1953, when [[BOAC Flight 783]], a Comet 1, registered G-ALYV, crashed in a severe [[squall|thundersquall]] six minutes after taking off from Calcutta-Dum Dum (now [[Netaji Subhash Chandra Bose International Airport]]), India,<ref>Darling 2005, p. 36.</ref> killing all 43 on board. Witnesses observed the wingless Comet on fire plunging into the village of Jagalgori,<ref name=lokurNS>{{cite web |last1=Lokur |first1=N. S. |title=Report of the court investigation on the accident to COMET G-ALYV |url=http://lessonslearned.faa.gov/Comet1/G-ALYV_Report.pdf |website=Lessons Learned |publisher=Federal Aviation Administration |access-date=23 February 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150415121817/http://lessonslearned.faa.gov/Comet1/G-ALYV_Report.pdf |archive-date=15 April 2015}}</ref> leading investigators to suspect structural failure.<ref name=Walker37/>

====India Court of Inquiry====
After the loss of G-ALYV, the [[Government of India]] convened a court of inquiry<ref name=lokurNS/> to examine the cause of the accident.{{refn|The court acted under the provisions of Rule 75 of the Indian Aircraft Rules 1937.<ref name=Walker37>Walker 2000, p. 37.</ref>|group=N}} Professor [[Natesan Srinivasan]] joined the inquiry as the main technical expert. A large portion of the aircraft was recovered and reassembled at Farnborough,<ref name=Walker37/> during which the break-up was found to have begun with a left elevator spar failure in the [[tailplane|horizontal stabilizer]]. The inquiry concluded that the aircraft had encountered extreme negative [[g-force]]s during takeoff; severe turbulence generated by adverse weather was determined to have induced down-loading, leading to the loss of the wings. Examination of the cockpit controls suggested that the pilot may have inadvertently over-stressed the aircraft when pulling out of a steep dive by over-manipulation of the fully powered flight controls. Investigators did not consider metal fatigue as a contributory cause.<ref name=LoBao7>Lo Bao 1996, p. 7.</ref>

The inquiry's recommendations revolved around the enforcement of stricter speed limits during turbulence, and two significant design changes also resulted: all Comets were equipped with [[weather radar]] and the "Q feel" system was introduced, which ensured that control column forces (invariably called stick forces) would be proportional to control loads. This [[aircraft flight control system#Artificial feel devices|artificial feel]] was the first of its kind to be introduced in any aircraft.<ref name=Walker37/> The Comet 1 and 1A had been criticised for a lack of "[[feedback|feel]]" in their controls,<ref>Job 1996, p. 14.</ref> and investigators suggested that this might have contributed to the pilot's alleged over-stressing of the aircraft;<ref>Darling 2001, p. 26.</ref> Comet chief test pilot John Cunningham contended that the jetliner flew smoothly and was highly responsive in a manner consistent with other de Havilland aircraft.<ref name=Faith>Faith 1996, pp. 63–64.</ref>{{refn|Cunningham: "[the Comet] flew extremely smoothly and responded to the controls in the best way de Havilland aircraft usually did."<ref name=Faith/>|group=N}}