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de Havilland DH.106 Comet

de Havilland · Long-Range Jet Passenger Transport · UK · Early Jet (1946–1969)

de Havilland DH.106 Comet — Long-Range Jet Passenger Transport
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The de Havilland DH.106 Comet was the world's first jet-powered passenger airliner. Built by de Havilland in Hatfield, England, the Comet first flew on 27 July 1949 and entered BOAC service on 2 May 1952 — almost six years before any other commercial jet airliner. About 114 airframes were produced between 1951 and 1964 across four distinct generations. The Comet's commercial dominance was destroyed by three catastrophic in-flight breakups (1953-1954) caused by a previously-unknown phenomenon — metal fatigue at pressurisation cycle stress concentrations — that grounded the entire fleet and gave Boeing's 707 (1958) the global jet-airliner market.

The Comet 1 was a 36-seat all-metal four-engine airliner powered by four de Havilland Ghost 50 turbojets (5,000 lbf each) buried in the wing roots. Cruise speed 460 mph; range 2,800 miles (London to New York with one fuel stop); cabin pressurised to 8.25 psi. The aircraft set a new standard for passenger comfort: smooth high-altitude cruise, no propeller vibration, panoramic square cabin windows. BOAC's London-Johannesburg service launched 2 May 1952 cut the trip from 36 hours to 18 hours and made the Comet the most-prestigious airliner of its era.

The Comet's catastrophic 1953-1954 breakups — BOAC Flight 783 in May 1953, BOAC Flight 781 on 10 January 1954, South African Airways Flight 201 on 8 April 1954 — killed 99 people total. Investigation by the Royal Aircraft Establishment, Farnborough (the largest aviation accident investigation in history at the time, including raising wreckage from 500 ft of Mediterranean water) traced the cause to metal-fatigue cracks initiated at the corners of the Comet's square cabin windows. Each pressurisation cycle stress-concentrated at the window corners; after about 1,000 flights the cracks grew explosive. The entire Comet fleet was grounded; BOAC lost market leadership permanently.

The Comet was redesigned with rounded windows, oval emergency-exit doors, and reinforced fuselage skin. The Comet 2 (1954-1956) was used by the Royal Air Force as a transport. The Comet 4 (1958) re-entered commercial service with BOAC and other carriers; about 75 Comet 4s were built. By the early 1960s the Comet 4 was outclassed by the larger, faster Boeing 707 and Douglas DC-8. Production ended in 1964. The Comet 4 also fathered the Hawker Siddeley Nimrod maritime patrol aircraft, which served the RAF until 2010. Several Comet airframes survive in U.K. museums; the 1954 Comet G-ALYP wreckage from Elba is on permanent display at the de Havilland Aircraft Museum.

For Kids — a shorter, friendlier version

The de Havilland Comet was the world's first commercial jet airliner. The British-built Comet first flew in 1949 and started carrying passengers in 1952. For two years it was the only jet airliner in the world. Then a series of crashes shocked the aviation industry — and changed how airplanes are designed forever.

The Comet is about 112 feet long — longer than three school buses end to end. Four de Havilland Ghost engines were buried inside the wings (so they didn't hang underneath like modern jets). The Comet could fly faster (490 mph) and higher (40,000 feet) than any other airliner. Passengers loved the smooth, quiet ride.

In 1954, two Comets exploded in mid-air over the Mediterranean Sea. Engineers couldn't figure out why at first. Then they reconstructed one wreckage piece by piece and discovered the cause: metal fatigue at the corners of the windows. The Comet's square windows had sharp corners that concentrated stress every time the cabin pressurized and depressurized. Over many flights, microscopic cracks grew at the corners — until one day the cabin tore open.

The Comet was redesigned with round-cornered windows (which every airliner since has used). But by then, Boeing's 707 had taken over. Only 114 Comets were built between 1952 and 1964.

The Comet was retired from passenger service in 1981. About 5 Comets survive today in UK museums. The Comet's lessons about metal fatigue + window shape are still taught in aviation engineering schools.

Fun Facts

  • The de Havilland Comet was the world's first commercial jet airliner — first passenger flights in 1952.
  • Comet windows were originally square — and the sharp corners caused metal fatigue that led to crashes.
  • Every passenger airliner since the Comet has round-cornered windows because of this lesson.
  • Only 114 Comets were built — the crashes ruined the program's reputation.
  • Boeing's 707 (1958) replaced the Comet as the world's leading jet airliner.
  • The Comet's engines were buried inside the wings, instead of hanging underneath like modern airliners.
  • About 5 Comets survive today in UK museums.

Kids’ Questions

What is metal fatigue?

Metal fatigue is when a piece of metal weakens from being bent or stressed many times in the same way. Imagine bending a paper clip back and forth — eventually it breaks, even though one bend wouldn't break it. Airplanes experience this every time they fly: cabin pressure goes up and down, wings flex from turbulence, engines vibrate. Most modern airplanes are designed to last for thousands of flights without fatigue cracks. But the early Comet's square windows had sharp corners that concentrated all the stress — like bending the paper clip exactly at the same spot every time. Cracks grew at the corners until one day the metal failed. Engineers now use round corners and special tests to make sure no part of an airplane will fail from fatigue.

Did Britain ever recover from the Comet failure?

Sort of. After the Comet's crashes in 1954, Britain lost its lead in commercial jet aviation. Boeing's 707 (1958) and Douglas's DC-8 (1959) took over the global market. Britain tried to compete with the redesigned Comet 4, then the BAC VC-10 (1962), but never won back its dominant position. Today no big commercial jets are designed in Britain anymore — the Concorde (1969-2003) was the last, and it was a joint British-French project. The Comet's lessons live on, though: every modern airliner uses round-cornered windows, and fatigue testing is a standard part of every airplane's certification.

Variants

Comet 1 (1952-1954)
Original commercial airliner. 36 seats, 4 Ghost 50 turbojets. About 21 built. Grounded April 1954 after three fatal in-flight breakups; re-engineered.
Comet 2 / Comet T2 (1954-1956)
Re-engined upgrade with Rolls-Royce Avon 504 turbojets + structural reinforcement. Commercial use brief; about 12 conversions plus new-build to the Royal Air Force as transport / signals-intelligence.
Comet 4 / 4B / 4C (1958-1964)
Stretched-fuselage final commercial variant. About 75 built. 81 seats, longer range, Avon 524 turbojets. Re-entered BOAC service 1958; used by airlines into the late 1970s.
Hawker Siddeley Nimrod (military descendant)
Maritime patrol derivative. 49 built 1969-1992. Retained Comet 4 fuselage with bomb bay, search radar, sonobuoy launchers. RAF service to 2010.

Notable Operators

BOAC (British Overseas Airways Corporation)
Launch operator. Comet 1 entered service 2 May 1952 on London-Johannesburg route. Lost three aircraft in 1953-1954 fatal breakups; re-equipped with Comet 4 in 1958. Operated Comets through merger into British Airways in 1974.
Royal Air Force
Operated Comet 2 as transport (later signals-intelligence) from 1956. Hawker Siddeley Nimrod (military Comet 4 derivative) served as maritime patrol aircraft from 1969 to 2010.
International airlines
United Airlines, East African Airways, Aerolíneas Argentinas, Olympic Airways, Mexicana, Sudan Airways, Middle East Airlines, others operated Comet 4s 1958-late 1970s. Combined fleet about 30 airframes.

Frequently Asked Questions

Why did the de Havilland Comet crash?

Metal-fatigue cracks initiated at the corners of the Comet's square cabin windows. Each pressurisation cycle stress-concentrated at the window corners; after about 1,000 cycles the cracks grew until they propagated catastrophically. Three Comets broke up in flight in 1953-1954 (BOAC 783, BOAC 781, South African 201) killing 99 people total. The Royal Aircraft Establishment investigation pioneered the modern field of aircraft fatigue analysis.

Was the Comet really the first jet airliner?

Yes — first to enter commercial service. The Comet 1 carried fare-paying passengers on BOAC's London-Johannesburg route starting 2 May 1952 — almost six years before any other commercial jet airliner (the Boeing 707 entered service in October 1958, the Tu-104 in September 1956 for Soviet Aeroflot, but the Tu-104 was a converted bomber not a clean-sheet airliner).

How many Comets were built?

About 114 total: 21 Comet 1 (1952-1954) + 22 Comet 2 (1954-1956) + 75 Comet 4 (1958-1964) + a handful of prototypes and conversion-trainers. Plus 49 Hawker Siddeley Nimrod maritime-patrol derivatives 1969-1992.

What replaced the Comet?

The Boeing 707 (1958) and Douglas DC-8 (1959) — both larger, faster, longer-range than the Comet 4. The Comet's three-year head-start was wasted on the 1954 grounding; by 1958 when Comet 4 re-entered service, the U.S. competitors were ready to launch and quickly captured the global jet-airliner market.

Are any Comets preserved?

Yes — several airframes are preserved in U.K. museums: the de Havilland Aircraft Museum (Salisbury Hall), Bruntingthorpe (a complete Comet 4C), Imperial War Museum Duxford, RAF Museum Cosford. The wreckage of Comet 1 G-ALYP recovered from the Mediterranean off Elba in 1954 is also on permanent display.

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