German airline Lufthansa said several employees were injured on Thursday after the nose gear of a Boeing jet collapsed while the aircraft was parked at a gate at Frankfurt airport.Only crew members and ground staff were on board the Boeing 787-9 Dreamliner when the front tip of the plane crashed to the ground ahead of passenger boarding for a scheduled flight to Los Angeles. The flight was later canceled.“Several employees were injured and are currently receiving medical attention,” Lufthansa said in a statement, adding that it and relevant authorities were investigating. The aircraft is just over a year old and was delivered to Lufthansa in January, one of the newest additions to the airline’s wide-body fleet, according to Flightradar24. Since entering service in February, the plane has operated 137 flights, the flight-tracking website said.Boeing said it is “aware of the incident” and "supporting our customer.”Video footage from the scene appeared to show the front wheels of the aircraft sliding forward and the plane's nose falling several meters (yards) as a ground crew member standing nearby quickly backed away. The doors to the nose gear bay broke off upon impact.Jeff Guzzetti, a former U.S. federal aviation crash investigator, said it is “very unusual” for a nose landing gear to collapse while an aircraft is at a standstill. He cautioned it is too early to speculate on the cause of the incident, but he said potential factors could include prior damage to the landing gear, a mechanical failure or issues related to maintenance work.Investigators, he said, will be looking closely at the plane’s maintenance history and system records, and may also review flight data to understand how the aircraft’s landing gear had been operating in previous landings.“They’re going to look at every square inch of that nose landing gear strut and the mechanisms that operate it,” Guzzetti said.A 2021 incident at London’s Heathrow Airport also involved the nose landing gear of a Boeing 787. According to a report by the UK’s Air Accidents Investigation Branch, a 787-8 was undergoing maintenance at a gate when its nose landing gear retracted during testing, causing the aircraft’s nose to drop onto the pavement. Investigators found that a locking pin intended to prevent retraction had been inserted into the wrong position, allowing the gear to fold despite safeguards designed to keep it extended.The 787 Dreamliner, a wide-body twin-aisle aircraft used primarily on long-haul international routes, first entered service in 2011. The version involved in Thursday’s incident can carry up to 296 passengers, depending on configuration.Popular ReadsIn recent years, the 787 program had been plagued by production flaws and quality-control issues, with shipments of the large plane temporarily halted on multiple occasions.Issues with the 787 started in 2020 when small gaps were found between panels of the fuselage that are made of carbon composite material. That prompted inspections that turned up problems with a pressurization bulkhead at the front of the plane.In May 2021, Boeing halted 787 deliveries while U.S. federal regulators looked over documentation of work that was done on new planes.In June 2023, Boeing said 787 deliveries were delayed again while it inspected fittings on part of the aircraft’s tail — the horizontal stabilizer — after identifying a “nonconforming condition.” The company said at the time that the issue would affect near-term deliveries but was not considered a safety risk for aircraft already in service.___Yamat, AP's airlines and travel writer, reported from Las Vegas.