Chapter 4
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hours on the ground. Originally scheduled for Thursday, 28 April,
GRAND SLAM was canceled because of bad weather over the north-
ern Soviet Union. This had been the case for the past several weeks.
When this flight was canceled, the U-2 returned to Adana before sun-
rise. That evening the U-2 flew for another attempt
to stage the mission early on thee z9m, out bac eather again forced
cancellation of the mission, and the U-2 returned to Adana. Because
of continued bad weather over the target areas, no mission was
planned for Saturday, 30 April.6
Meanwhile, the plane ferried tol n 27 and 28 April
had accumulated so many hours of tlighttime that it had to be
removed from service for periodic maintenance. A different aircraft
was, therefore, ferried n Saturday night, 30 April. This
aircraft, article 360, had made a crash landing uring the pre-
vious September (see chapter 5). Although it haL refurbished by
Lockheed and now had the more powerful 175 engine that would give
it greater altitude, pilots did not completely trust this aircraft and con-
sidered it a -hangar queen." As Powers noted in his memoirs, "Its
current idiosyncrasy was one of the fuel tanks, which wouldn't feed
all its fuel." 27 The aircraft was equipped with a B-model camera. a
System-VI electronic intelligence unit,'
Operation GRAND SLAM, mission 4154 and the 24th deep-pen-
etration overflight of the Soviet Union, began almost 30 minutes late
on Sunday, 1 May 1960, a delay due to difficulty in getting takeoff
approval from Washington. This delay was caused by
communications problems that are typical at sunrise and sunset
during spring and autumn, when the ionosphere will not support reli-
able communications. In attempting to relay the authorization mes-
sage, the radio operator in Adana was unable to reach
Realizin g that neither
the prearranged nighttime nor daytime frequencies were working, the
operator began sending a messa ge in the clear, using one of the guard
frequencies in the transition area between the daytime and nighttime
frequencies. The radio operators at :ept hearing the Morse
Mission folder 4154 ( I May 1960), OSA records (TS Codeword).
Powers, Operation Overflight, p. 76.
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