De Havilland Comet

DH.106 Comet
British European Airways (BEA) Comet 4B arriving at Berlin Tempelhof Airport in 1969
Role	Narrow-body jet airliner Type of aircraft
National origin	United Kingdom
Manufacturer	de Havilland
First flight	27 July 1949
Introduction	2 May 1952 with BOAC
Retired	14 March 1997 (Comet 4C XS235)[1]
Status	Retired
Primary users	BOAC British European Airways Dan-Air Royal Air Force
Produced	1949–1964
Number built	114 (including prototypes)[2][N 1]
Developed into	Hawker Siddeley Nimrod

The de Havilland DH.106 Comet is the world's first commercial jet airliner. Developed and manufactured by de Havilland in the United Kingdom, the Comet 1 prototype first flew in 1949. It features an aerodynamically clean design with four de Havilland Ghost turbojet engines buried in the wing roots, a pressurised cabin, and large windows. For the era, it offered a relatively quiet, comfortable passenger cabin and was commercially promising at its debut in 1952.

Within a year of the airliner's entry into service, three Comets were lost in highly publicized accidents after suffering catastrophic mishaps mid-flight. Two of these were found to be caused by structural failure resulting from metal fatigue in the airframe, a phenomenon not fully understood at the time; the other was due to overstressing of the airframe during flight through severe weather. The Comet was withdrawn from service and extensively tested. Design and construction flaws, including improper riveting and dangerous stress concentrations around square cut-outs for the ADF (automatic direction finder) antennas were ultimately identified. As a result, the Comet was extensively redesigned, with structural reinforcements and other changes. Rival manufacturers heeded the lessons learned from the Comet when developing their own aircraft.

Although sales never fully recovered, the improved Comet 2 and the prototype Comet 3 culminated in the redesigned Comet 4 series which debuted in 1958 and remained in commercial service until 1981. The Comet was also adapted for a variety of military roles such as VIP, medical and passenger transport, as well as surveillance; the last Comet 4, used as a research platform, made its final flight in 1997. The most extensive modification resulted in a specialised maritime patrol derivative, the Hawker Siddeley Nimrod, which remained in service with the Royal Air Force until 2011, over 60 years after the Comet's first flight.

Cite error: There are <ref group=N> tags on this page, but the references will not show without a {{reflist|group=N}} template (see the help page).