The hostages were eventually released after extensive diplomatic negotiations on January 20 1981, Carter's last day in office, after 444 days of captivity. Jimmy Carter was determined to ensure the release under his administration, particularly as the Democratic nomination for the 1980 presidential election neared, but the release did not occur until immediately after Reagan had taken the oath of office.
After flying in under radar and landing at Desert One, the C-130 Hercules would off-load men and equipment and refuel the arriving helicopters, which would undertake the actual rescue operation. After refueling the helicopters at Desert One, the plan was for the ground troops to board the helicopters and fly to Desert Two near Tehran the same night where the helicopters would be concealed. The next night, the rescuers would be transported to the embassy by assets in place and overpower the hostage guards and extract the hostages across Roosevelt Boulevard (the main road in front of the embassy) to a soccer stadium, where the helicopters would land and retrieve the entire force.
The assets in place were a Tehran CIA team led by Richard Meadows, who were there for two purposes: (1) to obtain information about the hostages and the embassy grounds, and (2) to transport the rescuers from Desert Two to the embassy grounds with pre-staged vehicles. In reality, the most important information came from an embassy cook who was released by the Iranians and discovered on a flight from Tehran at the last minute by another CIA officer, and who confirmed that the hostages were centrally located in the embassy compound - this was a key piece of information long sought after by the planners.
The assault on the embassy compound would occur after eliminating electrical power in the area in order to disrupt military and civilian capabilities, communications, and any counter-attacks attempted by the Iranians. AC-130 gunships would also orbit overhead to provide supporting fire against reacting forces. The helicopters would transport the rescuers and hostages from the soccer stadium to Manzariyeh Air Base outside of Tehran where a Ranger force would have captured the airfield and C-141 transports would be waiting to remove the entire contingent out of the country under the protection of fighter aircraft.
However, only the delivery of the rescue force, equipment and fuel by the C-130 Hercules occurred according to plan. An unexpected low-level intense sandstorm of the kind known as a haboob contributed to the loss of three of the eight RH-53D helicopters by the time the helicopter squadron reached Desert One, behind schedule. The first helicopter was grounded and abandoned in the desert with equipment indicating a cracked rotor blade, and its crew picked up by another helicopter that continued the flight. The second helicopter abandoned the flight and returned to the Nimitz with reported erratic instrumentation blamed on the highly elevated temperatures inside the haboob. The third helicopter arrived at Desert One with a malfunctioning primary hydraulics system and insufficient confidence in the secondary (backup) hydraulics system to continue. The first and third helicopters, which were abandoned, now serve with the Iranian Navy.
Meanwhile, a fuel-smuggling tanker truck was blown up nearby with a shoulder-fired rocket as it tried to escape the site shortly after the first crews landed and began securing Desert One. The resulting fire illuminated the night-time landscape for many miles around, and actually provided a beacon to Desert One for the disoriented and dehydrated incoming helicopter crews, who flew in lower than the undetected C-130 Hercules flight because of miscommunicated instructions and faulty communications equipment, and subsequently encountered the sandstorm. The passenger in the tanker truck was killed in the attack, while the truck's driver managed to escape in an accompanying pickup truck, and was considered to pose a security threat to the mission, although subsequent evaluation realized that the clandestine smuggling nature of the tanker truck posed no immediate threat. Soon after the truck driver escaped, a civilian Iranian bus with a driver and 43 passengers travelling on the same road, which served as the runway for the aircraft, was forcefully halted and held until the site was fully evacuated.
With only five helicopters remaining for transporting the men and equipment to Desert Two, and needing a predetermined minimum of six helicopters at that stage (Col. Beckwith's plans anticipated losing additional helicopters at later stages, especially as they were notorious for failing on cold starts and they were to be shut down for almost 24 hours at Desert Two), Col. Beckwith recommended that President Carter abort the mission, and Carter did just that on April 25, 1980. While maneuvering the helicopters from refuelling positions directly behind the C-130 Hercules fuel aircraft so the C-130s could taxi out and take off, one of the helicopter pilots attempted to hop over its C-130 and became disoriented in the dust cloud raised by its rotors and crashed onto the C-130.
In the ensuing explosion and fire, eight US servicemen died: five USAF aircrew in the C-130, and three USMC aircrew in the RH-53D, with only the helicopter pilot surviving. During the following frantic evacuation of the scene by the C-130s, with many of the helicopter aircrews believing they were under attack due to munitions cooking off in the fire, five RH-53D helicopters were left behind mostly intact, some damaged by shrapnel, with the sixth helicopter on top of the C-130 where it crashed and was being consumed by the fire. Iranian gains from the failed operation total between four and six RH-53D helicopters. In their haste to evacuate the helicopters, the Marine aircrews inadvertently left behind classified plans that identified the Tehran CIA agents.
The C-130s carried the remaining forces back to the intermediate airfield at Masirah Island where two C-141 medical evacuation aircraft from the rear staging base at Wadi Kena, Egypt picked up the injured personnel, helicopter crews, Rangers and Delta Force members and returned to Wadi Kena. The injured personnel were then transported to Ramstein Air Base, Germany. The Tehran CIA team fortuitously exfiltrated Iran, unaware that their presence had been compromised.
The failure of the various services to work together with cohesion forced the establishment of a new multi-service organization. The United States Special Operations Command (USSOCOM) was established and became operational on April 16, 1987. Each service now has its own Special Operations Forces under the overall control of USSOCOM. For example, the Army has its own Army Special Operations Command (USASOC) that controls the Army Special Operations Forces (ARSOF). The Air Force special ops unit that supplied the C-130 elements of the rescue attempt, and was awarded the AF Outstanding Unit Award for both that year and the next, was assigned its own squadron of HH-53H Pave Low (Super Jolly) helicopters for long-range low-level night flying operations, and became co-hosts at its home base of Hurlburt Field with the Air Force Special Operations Command (AFSOC).
The lack of highly trained Army helicopter pilots that were capable of the low-level night flying needed for modern special forces missions prompted the creation of the 160th Special Operations Aviation Regiment (SOAR) (Night Stalkers).
A second rescue mission was planned under the name Operation Credible Sport (a.k.a. Operation Honey Badger), but was never put into action. This second rescue attempt was planned using highly modified YMC-130H Hercules aircraft. Outfitted with rocket thrusters fore and aft to allow an extremely short landing and take-off in a soccer stadium, three aircraft were modified under a rushed secret program. One aircraft crashed during a demonstration at Duke Field at Eglin Air Force Base Auxiliary Field 3 on October 29, 1980, when its landing braking rockets were fired too soon. The misfire caused a hard touchdown that tore off the starboard wing and started a fire. All on board survived. The impending change in the White House led to the abandonment of this project. The two surviving airframes were returned to regular duty with the rocket packages removed. One is now on display at the Museum of Aviation located next to Robins Air Force Base, Georgia.
Retired Chief of Naval Operations Admiral James L. Holloway III led the official investigation in 1980 into the causes of the failure of the operation on behalf of the Joint Chiefs of Staff. The Holloway Report primarily cited deficiencies in mission planning, command and control, and inter-service operability, and provided a catalyst to reorganize the Department of Defense, and the Goldwater-Nichols Act of 1986.