Convair CV-240/340/440 Metropolitan

Updated: October 2026 – Two fat radial engines rumble deep and uneven, the fuselage stands dead level on a tricycle landing gear, and behind the propellers a long engine nacelle stretches back: that is what modern short-haul service looked like in the 1950s. The Convair liners CV-240, CV-340 and CV-440 Metropolitan were the aircraft with which airlines such as Lufthansa, Swissair or KLM replaced the DC-3. On this page you will learn how the three piston generations differ, how to tell them from the DC-3, Viscount or the later turboprop conversions, and where you can still encounter a Convair liner today.

What is the Convair liner?

Behind the collective term Convair liner is a family of twin-engine airliners that the US manufacturer Consolidated Vultee – Convair for short – developed in San Diego from the mid-1940s. The brief was clear: a successor to the ubiquitous Douglas DC-3, faster, more comfortable and above all with a pressurized cabin. That let the aircraft fly above the weather without passengers suffering from thin air.

The path there led through a prototype: the Model 110 flew on July 8, 1946, had 30 seats and no pressurized cabin yet. Convair discarded it and developed from it the longer, pressurized CV-240, which took off on March 16, 1947. Reference works call it the first twin-engine airliner with a pressurized cabin. The launch customer was American Airlines, which put the type into service on February 29, 1948.

Two further piston generations grew out of the CV-240: the CV-340 with a longer fuselage and larger wingspan (first flight October 5, 1951) and the CV-440 Metropolitan (first flight October 6, 1955), which above all was quieter and more modernly equipped. Together with the military versions, Convair built 1,076 aircraft according to standard reference works, plus ten examples built in Canada. All piston versions were powered by two Pratt & Whitney R-2800 Double Wasp, an 18-cylinder twin-row radial engine you also know from the Douglas DC-6. More about the engine manufacturer is on the page about Pratt & Whitney.

Three generations: CV-240, CV-340 and CV-440

From the outside the three versions look very similar, but in detail Convair worked on the fuselage, wings and comfort with each generation. The following table summarizes the most important differences; the values come from standard reference works and may deviate slightly depending on the sub-version.

Feature	CV-240	CV-340	CV-440 Metropolitan
First flight	March 16, 1947	October 5, 1951	October 6, 1955
Length	22.76 m	24.13 m	24.84 m
Wingspan	27.97 m	32.12 m	32.12 m
Seats	40	44 (up to 52)	44 (up to 52)
Weather radar	no	no	optional, in extended nose
Special feature	first Convair liner	longer fuselage, larger wings	quieter, new exhaust system

The CV-240 was the pioneer. Besides American Airlines, Western, Continental, Pan Am, KLM, Swissair, Sabena and Trans Australia Airlines, among others, ordered it. For the civilian market, 176 examples were built; many more went to the US military as T-29 navigation trainers or as transports.

The CV-340 came about at the request of United Airlines, which ordered 55 aircraft. The fuselage was stretched, the wings grew considerably, and more powerful engines improved performance at higher altitudes. Four additional seats made operation more economical.

The CV-440 Metropolitan was the last piston version. Convair changed the exhaust routing on the engines, refined the nacelles and insulated the cabin against noise and vibration. Customers could order a weather radar, for which the nose was extended by about 70 centimeters. Because Convair offered a conversion kit, several airlines – including Lufthansa – upgraded their CV-340s to the CV-440 standard. For spotters and historians that means: the designation on the data plate and the appearance of the aircraft do not always match one to one.

The three features that are enough to identify it

You can recognize a Convair liner from a distance if you watch for three things. Especially at vintage aircraft meets, where several piston aircraft stand side by side, this sequence helps.

As always: the registration provides the final certainty. Especially with Convair liners that have long careers, conversions and several owners, a look in a registration database is worthwhile. How registrations are structured and what they tell you is explained in the article Understanding aircraft registrations.

Convair liner, DC-3, Viscount or CV-580?

Piston-engine classics quickly look the same to untrained eyes. The finder helps you narrow it down with three questions.

Other possible mix-ups: the Vickers Viscount from the same era has four turboprop engines and large oval windows. The Fokker F27 Friendship is a shoulder-wing aircraft – the wings sit on top of the fuselage. The four-engine Douglas DC-4 and DC-6 are much larger and have exactly twice as many engines. A good overview of such distinctions is given by the guide Identifying vintage aircraft in the sky.

The Convair liners in Germany and Switzerland

For German aviation history, the Convair liner has a special significance. When Lufthansa resumed scheduled service in 1955, Convair CV-340s were part of its initial equipment. The aircraft were later upgraded to CV-440 standard, and further CV-440s were added. Until 1968, Convair liners remained in Lufthansa service and served mainly domestic German and European routes, while the four-engine Super Constellation took over long-haul.

Part of Lufthansa’s history with the type is also a dark day: on January 28, 1966, the CV-440 D-ACAT crashed during a go-around in Bremen, and all 46 people on board were killed. The investigation found a chain of technical and human factors; a clear cause could not be established, partly for lack of a flight data recorder. The aircraft had previously flown with Deutscher Flugdienst, the predecessor of Condor, which also operated Convair liners.

Besides the airlines, the Luftwaffe also used six CV-440s as transports. How the Lufthansa of those days became today’s Lufthansa Group is covered on the group page.

In Switzerland, Swissair was an important Convair customer: first it flew the CV-240, later twelve CV-440 Metropolitans. Other European operators were KLM with CV-240s and CV-340s, Sabena, SAS, Iberia and Alitalia.

Operator	Versions	Period / note
Lufthansa	CV-340, CV-440	1955 to 1968
Deutscher Flugdienst / Condor	CV-240, CV-440	from the late 1950s
Luftwaffe	CV-440	six aircraft
Swissair	CV-240, CV-440	twelve CV-440s
KLM	CV-240, CV-340	CV-340 from 1953 to 1963

A second life with turboprop engines

The airframe of the Convair liner was so robust that many aircraft outlived their piston engines. From the late 1950s, several conversion programs emerged:

• CV-540: CV-340 with Napier Eland turbines, used among others by Allegheny Airlines.
• CV-580: CV-340 or CV-440 with Allison 501 turbines, four-blade propellers and an enlarged tail – the best-known conversion. More on this on the page about the Convair CV-580.
• CV-600 and CV-640: CV-240 and CV-340/440 respectively with Rolls-Royce Dart turbines.
• CV-5800: stretched conversion from former Navy aircraft, first flight 1992.

These turboprops ran for a long time in North America in freight and special-mission service, and individual examples still serve today as flying research laboratories, for instance. If you see a Convair fuselage in the sky today, it is therefore very likely a turboprop conversion – not the original piston version.

Convair itself then turned to the jet age: with the CV-880 and the CV-990 Coronado, the company built fast four-engine jets that, however, did not match the commercial success of the Convair liners.

Where you can see a Convair liner today

Airworthy piston Convairs have become a real rarity. As early as 2004, reference works counted only a few dozen surviving CV-440s, some of them airworthy; since then the number has shrunk further. Realistically you have three options:

Place	Chance of a hit	Why
Aviation museums	medium	Some airframes are preserved as exhibits
Vintage aircraft meets and airshows	low	Piston Convairs fly only very rarely now
North America (turboprop conversions)	medium	CV-580s and relatives are still in special-mission service there

A famous museum piece is the CV-240 “Caroline,” in which John F. Kennedy flew his 1960 campaign. It is now part of the collection of the National Air and Space Museum. If you are in Washington, the Udvar-Hazy Center at Dulles Airport is also worthwhile – whether a particular aircraft is currently on display is best checked on the museum’s website before your visit.

In Germany, take a look at the overview of Aviation museums in Germany and at events such as the Hahnweide vintage aircraft meet. Whether a piston aircraft of this size is announced there changes from year to year.

How to judge how special such a sighting is, you can read in the article How rare is my sighting?. Tips for hunting rarities are bundled in the guide Spotting rare aircraft.

Photo tips especially for piston Convairs

A running radial engine is one of the most rewarding subjects there is – if you keep a few things in mind.

Further background on the predecessor that the Convair liner was meant to replace is provided by the article on the History of the Douglas DC-3.

Common mix-ups and how to rule them out

Conclusion

The Convair liner stands for the moment when short-haul service grew up: pressurized cabin, tricycle landing gear and a level of comfort the DC-3 could not offer. For German spotters it is also a piece of Lufthansa history, because the airline restarted in 1955 with the CV-340. Today you meet the piston versions mainly in museums; their turboprop descendants still fly occasionally in North America.