The Martin 4-0-4 is a pressurized airliner powered by two Pratt and
Whitney R-2800-CB16 Double Wasp eighteen-cylinder radial-air cooled
engines, that accommedated forty passengers and
three or four crew. The Martin 4-0-4 was developed and built by the Glenn L. Martin Company in
Middle River, Maryland, USA. The Martin 4-04 was derived from the Model 2-0-2 from which it differed primarily in having a 39-inch increase of
fuselage length, pressurization and more powerful engines. The Martin 2-0-2, also known as "Martin Executive", was designed by the
Glenn L. Martin Company as a replacement of the Douglas DC-3 and flew first on 22 November 1946. The Martin 2-0-2 provided accomodation
for a maximum of forty passengers end was powered by two 2.100 hp Pratt
and Whitney R-2800-CA18 Double Wasp engines, and thirty-one were built. The fatal crash
on 29 August 1948 of Martin 2-0-2 NC93044 on Northwest Airlines Flight 421 revealed a serious structural problem in the wings.
Structural metal fatigue was the problem in a major wing spar. Aluminium Alloy 7075-T6 was used,
which is susceptible to stress-corrosion cracking and low toughness. The Martin 2-0-2s
were grounded and modifications were made. The wing components were redesigned and the engines replaced
by similar engines to the later model 4-0-4. Twelve Model 2-0-2As were built before it was replaced in production by the Martin 4-0-4.
The prototype Model 4-0-4, a modified Model 2-0-2, flew on 21 October 1951, and 103 Model 4-0-4 were built, deliveries commencing in the Autumn of 1951.
The first Martin 4-0-4 was delivered to Eastern Air Lines (EAL) which had ordered sixty. The other customers were Trans World Airlines (TWA)
which had ordered fourty and United States Coast Guard which had ordered two as executive
transports with the designation RM-1G later changed to RM-1 and then in 1962 to VC-3A.
In 1969, both Coast Guard aircraft were transferred to the United States Navy and they
had both been withdrawn from use by 1970. The Martin 2-0-2 and 4-0-4 were operated in airliner service in the
U.S.A. and Latin America with the last flight of an airworthy Martin 4-0-4 in February 2008. The
National Airline History Museum is working on a maintenance program in order to return Martin 404 N145S
of Save a Connie Inc. to flying condition.
Martin 4-0-4 N40432 was one of a batch of 41 aircraft for Trans World
Airlines. She first flew on 11 July 1952, and entered service with TWA as "Skyliner
Detroit" under fleetnumber 433 on 25 L.uly 1952. In November 1959, the N40432 was sold
to Pacific Air Lines that operated a total of fourteen secondhand Martin 4-0-4s over the years.
Pacific Air Lines operated Martin 4-0-4 N40432 until August 1968. After
several private Traveller Club's like Fiesta Air, Stardusters, Lake Los
Angeles the airliner found her way to Bolivia via Sky Commerce Inc.,Miami.
Registration N40432 was cancelled as exported to Bolivia on 4 August 1980.
In Bolivia the Martin 4-0-4 was registered CP-1570 with CAMBA (Comercializadora Aérea Mixta Boliviana Ltda), Aeroporte El Alto, La Paz, and
operated as cargo/meat hauler to the Beni, the Bolivia lowlands. CAMBA operated the CP-1570 until 16 June 1987, when a forced belly landing
was carried out at Paraparau, after one of the Pratt & Whitney R-2800 engines backfired. The aircraft was destroyed by fire after the
landing. On 31 March 1980, Martin 4-0-4 N40432 was seen at Opa Locka airport near Miami prior delivery to Bolivia.