CIA/CSI/ History Staff Monograph, The Central Intelligence Agency and Overhead Reconnaissance: The U-2 and Oxcart Programs, 16 July 2002.

199
Aftermath of the Bay of Pigs
invasion, 20 April 1961
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Refueling a U-2 in flight was a very delicate task. When fully
loaded with fuel, KC-135 tankers found it difficult to reduce airspeed
to-200 knots, the safest speed for refueling a U-2. As for the U-2s,
they were in a very vulnerable position when approaching a tanker at
200 knots because their frail wings could not stand much stress. As a
result, U-2 pilots had to approach the KC-135 tankers very carefully
in order to avoid the vortexes from the wingtips of the tanker and the
turbulence caused by the four large jet engines. During the first few
years of refueling operations, two U-2s crashed after their wings
broke off as they crossed into the turbulent area behind the tankers;
one of the pilots was killed!'
The in-flight refueling capability was a useful modification to
the U-2, but it could not dramatically extend mission length. The
main limiting factor remained pilot fatigue, which prevented missions
from lasting longer than approximately 10 hours.
U-2 Coverage During the Cuban Missile Crisis
Cuba remained a high-priority target even after the Bay of Pigs inva-
sion failed in April 1961. Soon afterward, Detachment G U-2s began
flying monthly missions over Cuba in a program known as Project
" Ibud.. p. 11-12 (TS Codeword).
ret
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