Iran–U.S. RQ-170 incident
On 4 December 2011, an American Lockheed Martin RQ-170 Sentinel unmanned aerial vehicle (UAV) was captured by Iranian forces near the city of Kashmar in northeastern Iran. The Iranian government announced that the UAV was brought down by its cyberwarfare unit which commandeered the aircraft and safely landed it, after initial reports from Western news sources inaccurately claimed that it had been "shot down". The United States government initially denied the claims but later President Obama acknowledged that the downed aircraft was a US drone and requested Iran to return it.
Capture of the drone
The government of Iran announced that the aircraft was brought down by its cyber warfare unit stationed near Kashmar and "brought down with minimum damage" They said the aircraft was detected in Iranian airspace 225 kilometers (140 mi) from the border with Afghanistan.
The government of the United States initially claimed that its forces in Afghanistan had lost control of a UAV on 4 December 2011 and that there was a possibility that this is the vehicle that crashed near Kashmar. According to unnamed U.S. officials, a U.S. UAV operated by the Central Intelligence Agency was flying on the Afghan side of the Afghanistan-Iran border when its operators lost control of the vehicle. There have been reports that "foreign officials and American experts who have been briefed on the effort" state that the crashed UAV was taking part in routine surveillance of Iranian nuclear facilities inside Iranian airspace.
The drone appeared to be largely intact, except for possible minor visible damage on its left wing. Dan Goure, an analyst at the Lexington Institute, stated the largely intact airframe ruled out the possibility of an engine or navigational malfunction: "Either this was a cyber/electronic warfare attack system that brought the system down or it was a glitch in the command-and-control system." Some US officials stated the drone broke into three pieces during impact. They claimed that it was reassembled for display purposes and was painted by Iran to hide the damage.
The Department of Defense released a statement acknowledging that it had lost control of a UAV during the previous week, claiming that it was "flying a mission over western Afghanistan" when control was lost. The statement did not specify the model of the aircraft. The U.S. government also stated that it was still investigating the cause of the loss.
A Christian Science Monitor article relates an Iranian engineer's assertion that the drone was captured by jamming both satellite and land-originated control signals to the UAV, followed up by a GPS spoofing attack that fed the UAV false GPS data to make it land in Iran at what the drone thought was its home base in Afghanistan. Stephen Trimble from Flight Global assumes UAV guidance could be targeted by 1L222 Avtobaza radar jamming and deception system supplied to Iran by Russia. In an interview for Nova, U.S. retired Lt. General David Deptula also said "There was a problem with the aircraft and it landed in an area it wasn't supposed to land".
American aeronautical engineers dispute this, pointing out that as is the case with the MQ-1 Predator, the MQ-9 Reaper, and the Tomahawk, "GPS is not the primary navigation sensor for the RQ-170... The vehicle gets its flight path orders from an inertial navigation system". Inertial navigation continues to be used on military aircraft despite the advent of GPS because GPS signal jamming and spoofing are relatively simple operations.
Later reports claimed that the capture of the Sentinel drone aircraft was a two-pronged operation which involved penetrating the command and control center running the drones from CIA Headquarters at Langley in McLean, Virginia, while reprogramming the directives guiding a satellite and the RQ-170 stealth drone by falsifying the images appearing on the screens at Langley.
On 6 December 2011, U.S. officials acknowledged that a drone crashed in or near Iranian airspace and that this belonged to the CIA and not to ISAF as was earlier stated. U.S. officials did not state that the drone shown on Iranian television was actually a real RQ-170 (which has been public knowledge since 2009), although a former U.S. official confirmed that the drone shown on the Iranian state media was a U.S. RQ-170, used for surveillance of Tehran's nuclear facilities.
On 5 December 2011, U.S. military sources confirmed that the remains of an RQ-170 had been captured by Iranian forces. Media reports indicated that various U.S. officials declined to confirm whether or not the drone in the video released by Iranian state television was authentic. On 8 December 2011, a senior U.S. official, speaking on condition of anonymity, told the Washington Post that the U.S. cannot be certain the drone shown was real because the U.S. does not have access to it, but also stated that "We have no indication that it was brought down by hostile fire." A second senior U.S. military official said that a major question is how the drone could have remained "virtually intact," given the high altitude from which it is said to have crashed. U.S. Navy Captain John Kirby, a Pentagon spokesman, told a news conference on 8 December 2011 that Pentagon analysts were examining the video. Both Kirby and fellow spokesman George Little would not comment further on whether the U.S. military believed the drone was the one missing, both did say that the missing drone had not been recovered. Later that day, CBS reported that the US officials had confirmed in private the authenticity of the drone shown by the Iranians.
Complaint to UN Security Council
On 9 December 2011, Iran lodged a formal complaint to the United Nations Security Council over the UAV violating its airspace. Iran's U.N. ambassador stated in the letter that "My government emphasizes that this blatant and unprovoked air violation by the United States government is tantamount to an act of hostility against the Islamic Republic of Iran in clear contravention of international law, in particular, the basic tenets of the United Nations Charter."
Request for return by the United States
On 12 December 2011, U.S. administration asked Iran to return the captured U.S. drone. The day before, on 11 December, General Salami stated that "no nation welcomes other countries' spy drones in its territory, and no one sends back the spying equipment and its information back to the country of origin." On 13 December 2011, Defence Minister of Iran, dismissed the request and said "Instead of apologising to the Iranian nation, it is brazenly asking for the drone back." And the ministry spokesman, Mehmanparast, stated that "it seems he [Obama] has forgotten that Iran’s airspace was violated, spying operations were undertaken, international laws were violated and that Iran’s internal affairs were interfered with. ... Instead of an official apology and admitting to this violation, they are making this request."
Former U.S. Vice President Dick Cheney criticised Obama's decisions on the drone, saying that, after the aircraft went down, the president should have ordered an air strike within Iran: "The right response to that would have been to go in immediately after it had gone down and destroy it. You can do that from the air ... and, in effect, make it impossible for them to benefit from having captured that drone." Instead, "he asked nicely for them to return it, and they aren't going to".
Reverse engineering of the drone
On 10 December 2011, Iran announced that it intended to carry out reverse engineering on the captured RQ-170 Sentinel stealth aircraft. In April 2012, the Army of the Guardians of the Islamic Revolution claimed to have succeeded in extracting the entirety of the data collected by the drone and are currently in the process of building a replica of the aircraft. Iran claimed to have been approached by countries, including China and Russia, seeking information on the drone. Although U.S. officials expressed concern over the possibility of China or Russia receiving the drone's technology, they cast doubt on whether Iran could replicate the technology of the aircraft, as well as the amount of intelligence data available, due to the precautions instated for malfunctioning drones. On May 2014 Iran shows on state TV that has built a copy of RQ 170. 
Decoded footage obtained from captured US drone
On 7 February 2013, Iran released video footage allegedly from the RQ-170 stealth plane. They claim the footage shows the drone coming in for a landing at the Kandahar base. Commander of the Aerospace Division of the Islamic Revolution Guards Corps (IRGC) Brigadier General Amir-Ali Hajizadeh said in February that all the data on the downed drone were “fully decoded.”
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