# [ALT] Supersonic Commercial Aviation (Concorde / Boeing 2707)
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**Supersonic transport (SST)** — commercial aircraft flying at Mach 2–3, halving transatlantic flight times — was a technological triumph that became a commercial failure, killed by fuel economics, sonic boom restrictions, and the 1973 oil crisis. It represents one of the clearest cases of a technology that worked but failed to fit the economic and environmental context of its time.
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## The Fork
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**What won**: Subsonic wide-body jets — the Boeing 747 (first flight 1969), McDonnell Douglas DC-10, and Lockheed L-1011 offered far lower cost per passenger-km and could fly any route without sonic boom restrictions. Long-haul subsonic travel democratised air travel; SST remained a luxury.
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**What was abandoned / retired**:
- **Concorde** (BAC/Aérospatiale, first flight 1969, commercial service 1976–2003): 20 aircraft built, 14 in commercial service, Paris-New York in 3.5 hours. Retired in 2003 after the 2000 crash, 9/11 demand shock, and mounting maintenance costs.
- **Boeing 2707** (US SST programme): 2,700 kph, swing-wing design; cancelled by the US Senate in 1971 before prototype completion. The vote (51-46) was heavily influenced by environmental and sonic boom concerns.
- **Tupolev Tu-144** (Soviet SST, "Concordski"): plagued by reliability problems, one fatal crash at Paris Air Show (1973), retired from passenger service 1978.
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## The Economics That Killed It
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Concorde carried 100 passengers at 10× the fuel burn per seat-km of the 747. At USD 0.10/gallon (1960s planning assumption) this was marginal; at USD 1.00+/gallon post-1973 oil crisis, it was fatal. A Concorde ticket cost 5–10× a 747 Business Class fare, limiting the market to a very small corporate clientele. The 1973 US ban on overland supersonic flight (sonic boom) confined routes to transoceanic paths, eliminating 80% of potential market.
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## What SST Got Right
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Concorde's 27-year operational record demonstrated extraordinary engineering reliability and pilot admiration — "the greatest engineering achievement of the 20th century" in the words of some aviation engineers. Materials engineering for sustained Mach 2 cruise (skin temperature 127°C, airframe stretches 30 cm in flight) was genuinely revolutionary. Concorde's delta wing aerodynamics became standard on fighter aircraft.
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## The Revival: Overture, AS2, X-59
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Private capital is betting that the economics have changed:
- **Boom Supersonic Overture**: Mach 1.7, 65–88 passengers, targeting 2029 service entry. United Airlines ordered 15, American Airlines 20. Key difference from Concorde: modern turbofan engines (2× Concorde's fuel efficiency), composite airframe, restricted to overwater routes.
- **Aerion AS2** (supersonic business jet, Mach 1.4): cancelled 2021 before first flight; insufficient pre-orders.
- **NASA X-59 QueSST**: demonstrating "quiet supersonic" boom-mitigation technology (a gentle thump rather than a double bang); FAA and ICAO sonic boom rules may be relaxed if X-59 proves the concept.
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## Discovery Character
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**Surprise level**: Moderate — engineers knew Concorde worked; the economic failure was predictable in hindsight but not to 1960s planners who assumed continued cheap oil and rapid traffic growth.
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**Mode of failure**: Systematic technical success, contextual economic failure. The oil crisis of 1973 changed the economics of an already-marginal business case. A warning about designing technology for a specific cost environment.
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# Parents
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* [TECH] Jet Engine⏎