Such was the concern of the Civil
Aeronautics Board, that for the rst time,
aircraft wreckage was loaded onto trucks
and taken to the Douglas manufacturing
centre in Long Beach for reassembly in
order to try to determine the cause of the
accidents. Following the results of the
investigation it soon became standard
practice worldwide. As a result of the
disasters, the entire eet of DC-6s, including
the one used by US President Harry S
Truman, were grounded for four months.
United suffered signi cant operational
and nancial problems because by then
the DC-6 was the mainstay of its eet.
Replacement aircraft were leased to keep
services going.
The cause of the crash was traced to a
design fault, which had allowed fuel vapour
to be drawn into the heater air intake, and in
turn started a re in the cargo compartment.
All DC-6s underwent mandatory retro tted
modi cations before they were reissued with
an Airworthiness Certi cate four months
later.
United lost another DC-6 in June 1948,
when a re in the cargo compartment was
put out using CO 2 extinguishers, but the gas
fumes entered the ight deck, incapacitating
the pilots. All 43 occupants died in the
crash at Mount Carmel, Pennsylvania. This
was a particularly high-pro le accident
because a number of well-known celebrities
were on board, including Broadway theatre
impresario, Earl Carroll and his girlfriend,
actress Beryl Wallace, along with Henry L
Jackson, the Editor of fashion magazine
Collier’s Weekly and co-founder of Esquire
Magazine. The resulting loss of revenue
plunged United into the red.
In total, United lost six DC-6s during their
service with the airline. In November 1955,
a DC-6B was brought down over Longmont,
Colorado by a bomb, placed in the luggage
by Jack Graham, the son of one of the
passengers. Forty-four people were killed.An unhappy childhood had apparently left
him with a grudge against his mother, and
FBI enquiries revealed he was the potential
bene ciary of her life insurance policies and
will.FREIGHTERS
United began the rst all-cargo service in
American aviation history in 1940 by ying
freight, together with air mail, between
New York and Chicago. Between 1956
and 1958, the carrier placed seven new
DC-6As as freighters on the same coast-
to-coast services as those operated by the
passenger airliners.
They were tted with doors forward and aft
of the wing on the left side, and a specialised
cargo oor. Being pressurised, they wereable to carry live animals in the cabin, among
them lions, tigers, gorillas and all manner
of smaller animals and birds, all of which
brought in useful additional revenue.
In 1950, the Civil Aeronautics Board
(CAB) introduced a form of deregulation
that effectively allowed both scheduled
and non-scheduled carriers to y on each
other’s routes, with no restriction on fare
levels. Coach (economy) ights with the
scheduled carriers, which included United,were not allowed to increase the frequency
of services or change ight times. Non-
scheduled carriers could open new routes.
By the mid-1960s, as the jet age
approached, United ew the DC-6s from its
main base in Chicago west towards Omaha,
Nebraska, and east into Michigan and Ohio.
They were also used for the Central Valley
routes of California.
United believed that utilising the jets
on long-haul services and putting the
propliners, including the DC-6, on the
shorter routes was the answer. However,
they hadn’t bargained on the reaction of their
passengers, who now complained when
they had to y on a propeller-driven aircraft.
Indeed, on the Los Angeles–San
Francisco route, travellers would delay their
journeys just to y on a jet, while the DC-6s
departed with spare seats – a situation that
convinced management that the propeller-
driven aircraft would soon have to be retired.
The last service own by this propliner
was between San Francisco and Salt Lake
City, with intermediate stops in Oakland,
Ely and Reno, that continued as a DC-6
operation until February 1970.
The DC-6 era was nally over for United.
The aircraft had been its backbone for a
generation, especially so during the carrier’s
steady growth following World War Two.
None were kept for posterity.
There was a plan to restore a DC-6 in
United’s colours, although it was not an
ex-United machine, having come straight
from the US Air Force. It was registered as
N578AS to Nighthawk Radial Reminiscence
Preservation Group and seen in the carrier’s
colours at Oakland, California, in 1995. It
was still in the same livery in early 1998 in
preparation for a lm. But a shortage of
funds meant that the full restoration did not
take place and the aircraft was stripped back
to bare metal, own to a small air eld near
San Antonio, Texas, and parked in the early
2000s. It is understood to still be there.http://www.aviation-news.co.uk 51A battery cart supplies electrical power to DC-6 N37513. This aircraft was originally called Mainliner Missouri and later was changed to Mainliner
Mt Hood. Jon Proctor‘United limited
the number of
passengers to 50
for daytime services
while some aircraft
had 24 sleeper-type
seats for night-time
operations.’
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