On a spring morning at Bordeaux-Mérignac in 1971, a sleek twin-jet lifted off carrying the hopes of the French aircraft industry. Marcel Dassault had built fighters that governments queued up for. Now he was going after Boeing, on Boeing's own ground, with a short-haul airliner named after the winged messenger of the gods.

Twelve of them were built. Eleven found a buyer, and every one went to the same airline. The Mercure is remembered today not as a bad aeroplane but as one of the most complete commercial failures in the history of the jet airliner — and the reason has almost nothing to do with how it flew.

A gap in the market that turned out to be a trap

The idea came from a real observation. In the mid-1960s Dassault and France's civil aviation directorate looked at the market and concluded nobody was building an aircraft designed specifically for very short routes. The DGAC wanted a French answer to the 737 and suggested a 140-seat machine. In April 1969 the programme was formally launched, with the French government covering 56 per cent of development costs.

Dassault's engineers made a deliberate trade: fuel volume for seats. The result carried up to 17 per cent more passengers than the 737 it was aimed at, and on paper it was the faster of the two. The wing was worked over with wind tunnels and, unusually for the era, computer simulation.

Marcel Dassault himself chose the name, reaching into mythology for a god who came with wings already fitted.

The number that killed it

At maximum payload the Mercure could manage roughly 1,700 kilometres. The Boeing 737-200 of the same period could fly more than twice as far. For an airline flying Paris to Marseille that hardly mattered. For an airline anywhere else, it was disqualifying, because the aircraft could not be redeployed onto a longer route when the market shifted.

Dassault marketed hard. There were approaches to Douglas, Lockheed and General Dynamics about building the type in the United States. A stretched Mercure 200 was studied with Air France, then a version with the new CFM56 and a supercritical wing. The government would only fund the 200C if Dassault paid half, which after the Mercure 100 was impossible. As late as 1981 Marcel Dassault was still trying to license the design to an American manufacturer.

Not one foreign order was ever signed. Ten aircraft were sold, and a refurbished prototype became the eleventh, all of them to Air Inter, the French domestic carrier. The dollar devaluation and the 1970s oil shock did not help, but the range figure was the wound that would not close.

The aircraft the crews actually liked

Here is the part that gets lost. Air Inter's Mercures were genuinely good at the job they were built for. The type was certified in February 1974 and cleared for Category IIIA automatic landings that September — serious all-weather capability for the time. Over 22 years the fleet flew some 44 million passengers across roughly 440,000 flights with a dispatch reliability around 98 per cent.

The Mercure also holds a small footnote in aviation history: it was the first commercial airliner flown by an all-female crew. The last one flew in 1995, and the type disappeared almost without comment outside France.

The lesson has outlived the aeroplane. Dassault built exactly the aircraft one customer wanted, and in doing so built an aircraft nobody else could use. Airbus, watching closely from the same country, drew precisely the opposite conclusion when it designed the A320.

And for anyone who wants to see one working for a living, this 1994 footage follows a Mercure from Paris-Orly to Nantes near the very end of its career.

Sources: Wikipedia, Dassault Aviation, Flight International, Simple Flying, and GlobalSecurity.org.