Texas. Although Lockheed modified six CIA aircraft into the aerial refueling-capable U-2F model in 1961, permitting some Cuba missions to originate from Edwards, pilot fatigue limited flights to about 10 hours. An August 1962 flight showed Soviet SA-2 SAM sites on the island; later overflights found more sites and MiG-21 interceptors. The increasing number of SAMs caused the United States to more cautiously plan Cuban overflights. USAF U-2s did not conduct overflights, but officials believed that it would be better for a military officer to be the pilot in case he was shot down. Following one last Cuba overflight that originated from Edwards and ended at McCoy Air Force Base, Florida on 14 October 1962, all further U-2 operations over Cuba originated from a detachment operating location that was established at McCoy. Cuban Missile Crisis After receiving hasty training on the more powerful U-2F under the cognizance of the Weather Reconnaissance Squadron Provisional (WRSP-4) at Edwards AFB, Major Richard S. Heyser flew over western Cuba on 14 October 1962 in a U-2F; his aircraft was the first to photograph Soviet medium-range ballistic missiles (MRBM) in San Cristóbal before returning to McCoy AFB, Florida. Prior to the launch of all Cuban sorties, the two U-2F aircraft possessed by WSRP-4 and flown by 4080th Strategic Reconnaissance Wing personnel had USAF insignia and tail numbers. SAC received permission to fly as many Cuban overflights as necessary for the duration of the resulting Cuban Missile Crisis. On a 27 October sortie from McCoy AFB, one of the U-2Fs was shot down over Cuba by an SA-2 Guideline surface-to-air missile, killing the pilot, Major Rudolf Anderson; he posthumously received the first Air Force Cross.Correll, John T. "Airpower and the Cuban Missile Crisis." Air Force Magazine, August 2005. Retrieved: 27 June 2009. Soviet leader Nikita Khrushchev was dismayed, warning President John F. Kennedy in a private message that U-2 overflights could inadvertently cause WWIII: "Is it not a fact that an intruding American plane could be easily taken for a nuclear bomber, which might push us to a fateful step?" Fulfilling CIA officials' fears of a USAF takeover, CIA pilots never again flew over Cuba; SAC retained control over Cuban overflights, which continued until the 1970s under the code name OLYMPIC FIRE. At the same time as the Cuban crisis, Royal Air Force (RAF) English Electric Lightnings of the Air Fighting Development Squadron made several practice