Just One Airline Ever Flew The Dassault Mercure, France’s Answer To The Boeing 737

Just over 51 years ago, France’s answer to the Boeing 737 first took flight. The Dassault Mercure was supposed to be the ultimate short-haul airliner with performance that the Americans couldn’t match. But by the end of its production just 12 ever took to the skies. Here’s the story about an airliner that came and went so fast that you may not know about it.

The 2020s are marking the half-century anniversaries of some awesome pieces of aviation history. Among those aircraft are the deadly, but sexy Bede BD-5, the advanced Lockheed L-1011, and even the introduction of the Boeing 747. In 1971, Dassault Aviation launched its first-ever commercial airliner with the promise of beating Douglas and Boeing.

During the 1960s, air travel was expanding and in response, airlines were asking manufacturers to build aircraft to fit different roles. Marcel Dassault, the founder of French manufacturer Dassault Aviation, noticed that there was a hole in the market. A number of routes were under 540 nautical miles (1,000 km), but they were being served by the likes of the Boeing 737, Douglas DC-9, and BAC One-Eleven. These aircraft worked for the role of short-haul flights, but they weren’t really optimized for it. For example, a Douglas DC-9 flying a short route still had to haul tanks large enough for range more than double than what was needed.

Dassault felt that short-haul routes were ripe for a plane designed just for them, and in 1967 the company set to build a highly specialized aircraft.

But the aircraft manufacturer immediately faced one problem. Dassault was a well-known aircraft manufacturer, but the planes that it built were the likes of the famous Mirage fighter and the Falcon family of business jets. It had never built a commercial airliner in its history, making the Mercure a completely new venture. As luck would have it, the French government was also watching the market and it, too, saw an opportunity for a specialized short-haul airliner. The French Directorate General for Civil Aviation wanted in, and suggested for the Dassault aircraft to seat 140 passengers, more than a Boeing 737-200 in a max seating configuration of 130.

The DGAC wanted to see the aircraft reach production so much that it loaned Dassault 56 percent of the development cost. According to a 1971 issue of Flight International, the cost of building two prototypes, two static test airframes, and obtaining certification ran 75 million Pound Sterling. Dassault threw in 10 million Francs of its own cash and the French government was to get its money back by levying sales of the aircraft. Development started in earnest in 1969.

The Mercure would be advanced for its day, employing computer design for its wings. And under those wings sat two Pratt & Whitney JT8D-15 low bypass turbofans producing 15,500 lbf thrust each. These were the same engines that could be found slung under a 737 of the day. On the flight deck, pilots got to enjoy a heads-up display and the plane could even land itself in foul weather. And its name called to mythology. Mercure translates to Mercury, or the only figure that Marcel could think of that had wings on a helmet and ailerons.

[Editor’s Note: I’m not sure I’ve ever seen a depiction of Mercury with “ailerons” but maybe he meant the foot-wings? – JT]

Another way that the aircraft would be different is with its size and fuel capacities. The Mercure was bigger than its proposed direct target. A Boeing 737-100 is 93 feet long with the 737-200 being around 100 feet. The Mercure, with its larger seating capacity, stretched just a little over 114 feet from nose to tail. In addition, while the heavier 737-200 of the day came in at 65,300 pounds empty, the Mercure weighed in at 70,100 pounds.

And of course, it carried less fuel. The 737-200 could carry 5,970 gallons of fuel to get it around 2,600 nautical miles. The Mercure flew with up to 4,900 gallons of fuel onboard, getting the larger plane just 1,125 nautical miles on a single fill.

But for what the Mercure lacked in range it made up for in performance. Its design enabled it to climb twice as fast as the competition while also achieving a similar cruising speed.

The Mercure had its first flight on May 28 1971.

The government and Dassault expected the aircraft to be such a success that four factories were built to manufacture the aircraft. And it was expected that by 1980, perhaps 300 units would be flying. The Mercure was a multinational effort, too. ADAP (Belgium), Canadair (Canada), CASA (Spain), Fiat (Italy), and FW of Emmen (Switzerland) were all contracted to help with production.

Government-backed French airline Air Inter placed an order for 10 Mercures in 1972. A year later, the production version of the Mercure would take to the skies. And in 1974, the plane would get its civil certification with Air Inter as the launch customer. The production aircraft would bear the designation Mercure 100.

Unfortunately, Air Inter would end up being the only customer for the Mercure.

Dassault had proven that the Mercure was an exceptional aircraft for short-haul flights. It was fast, it carried a bunch of people, and promised to be a cheap airliner to run. In theory, airlines should have been begging for something like this. According to Flight International, airlines could purchase them for 6 million Euro each. But while there was some interest from other airlines, none of them followed through.

In a rather surprisingly honest review of the demise of its own aircraft, Dassault Aviation has laid out why this plane failed:

Four external events came as hammer-blow to the Mercure program:

• the first oil crisis which diminished the margins of airlines, restricting their ability to purchase new aeroplanes;

• devaluation of the US dollar;

• a higher rate of inflation in Europe than in the United States which was to the advantage of Boeing and Douglas;

• a preference on the part of the airlines for a versatile aircraft capable of providing short- and medium-haul service.

As you’ve seen written time and time again on your favorite sites, that pesky oil crisis tightened the belts of airlines. They had less money to buy new aircraft. And on top of that, a poor economy, inflation, and devaluation of the U.S. Dollar made the aircraft more expensive. But perhaps the biggest hurdle that the Mercure had to overcome was its own design.

While the 737 and the DC-9 weren’t optimized for short routes, they still did the job. And when the airline needed to use the same aircraft on longer routes, they could do that, too. On the other hand, the Mercure 100 could do only short flights. It simply didn’t have the range to be able to be used on longer routes without refueling. As Dassault itself admits, airlines preferred aircraft that could serve multiple roles fine enough over a plane that could do just one thing really well.

Still, it’s a bit amazing that Dassault found nobody outside of Air Inter bothered. According to transportation YouTuber Mustard, Dassault needed to sell 125 to 150 Mercures to break even. In an effort to give airlines what they wanted, Dassault began development of the longer-range Mercure 200. According to France’s Le Conservatoire de l’Air et de l’Espace d’Aquitaine (an air and space conservatory), the French government was willing to loan Dassault 200-million French Francs to build the Mercure 200. The government would make its money back after the sale of the 201st sale. However, costs began to balloon due to Air France’s requests for new engines and supercritical wing. Eventually, the government decided that Dassault had to pay for half of the new plane.

Of course, since the Mercure 100 had sold just 10 units, that money wasn’t there.

Further efforts to market and sell the Mercure failed, and just 12 were ever built, including prototypes. One prototype was entered into service, making Air Inter’s total 11 aircraft. They went on to have successful careers. The aircraft flew some 44 million passengers, racking up 360,000 flight hours and a 98 percent in-service reliability. The last Mercure made its last flight in spring 1995.

The Mercure may have been a failure, but it was really only the start of French aviation. Dassault went back to doing what it did best, and today offers some seriously attractive business jets. And France-based European multinational manufacturer Airbus builds planes that compete with America’s best, and even hold their own in the airline sales dogfight.