The pilot of a South Korean F-35A jet fighter made an emergency "belly landing" at an air base on Tuesday after its landing gear malfunctioned due to electronic issues, CNN reported quoting a South Korean Air Force spokesperson. According to experts, the "belly landing" -- touching down with landing gear retracted -- was an unprecedented event for the $100 million US-designed stealth fighter now in use or on order by more than a dozen countries. "The jet did an emergency landing as the landing gear did not extend. This would mean the jet did the 'belly landing,'" said a South Korean military official, who would not confirm whether the aircraft suffered any damage in the incident. Even if it did, it would demonstrate superb flying skills by the pilot, whom officials said walked away from the landing, according to a South Korean military official. "A gear-up landing on the F-35 may be quite difficult and dangerous because of the angle of attack the aircraft has on approach to touchdown," said David Cenciotti, a former Italian air force officer and editor of The Aviationist blog. "The F-35 lands really fast. It's not an F-16, 18 or 111," said Peter Layton, a former Australian air force officer now at the Griffith Asia Institute, referring to older, less sophisticated military aircraft than the F-35. "I'm very surprised the emergency gear down systems didn't work, or weren't used," he said. Layton also expressed surprise that the South Korean pilot didn't eject, "but clearly they did the right thing," he said. An investigation into the incident was underway, South Korean officials said. South Korea received its first US-made F-35 in 2019 as part of an initial order of 40 of the single-engine jets, according to the plane's manufacturer, Lockheed Martin. Versions of the F-35 are also flown by the US Air Force, Navy and Marine Corps as well as US allies and partners including Japan, the United Kingdom, Australia, Italy, Norway, the Netherlands and Israel. More countries have orders in for the jet. Tuesday's accident is the first for a South Korean F-35, but the jets have been involved in at least eight other incidents, according to records kept by crowdsourced website F-16.net. The most recent of those was the loss of a British F-35, which crashed into the Mediterranean Sea off the aircraft carrier HMS Queen Elizabeth in November. The pilot ejected safely from that plane. In May 2020, the pilot ejected safely when a US Air Force F-35 crashed on landing at Eglin Air Force Base in Florida. The Air Force attributed the crash to a variety of a factors involving the pilot and the plane's systems. In April 2019, a Japanese F-35 crashed into the Pacific Ocean off northern Japan, killing its pilot. The Japanese military blamed that crash on spatial disorientation, "a situation in which a pilot cannot sense correctly the position, attitude, altitude, or the motion of an airplane," according to the journal Military Medicine. Lockheed Martin says the F-35 "is the most lethal, survivable and connected fighter aircraft in the world, giving pilots an advantage against any adversary and enabling them to execute their mission and come home safe."