The Chronic Problem of F-35 Aircraft: Why Do Nose Landing Gear Collapse?
In fighter jets like the F-35, as long as the main landing gear does not collapse (which is not common), the nose landing gear, which is generally produced in a weaker structure, can survive collapse incidents without much damage.
How did the January 24, 2024 nose landing gear collapse incident happen?
A U.S. Marine Corps F-35C Lightning II, which took off from Miramar Air Force Base in San Diego, unexpectedly suffered a nose landing gear fold failure while exiting the aircraft after the pilot shut down the engine in the parking lot after landing at Fallon Naval Air Station in Nevada. The aircraft incident occurred after an exercise flight on January 24, 2024.
This unexpected failure occurred on an F-35C aircraft, tail number CF-89/170109. After safely arriving at the parking lot at the end of the sortie, after silencing the aircraft's engine and shutting down all systems, the pilot encountered this incident while descending the stairs of the aircraft. It is stated that the pilot, who jumped to the ground from the stairs of the airplane, whose nose section suddenly started to collapse, and thus escaped unhurt, naturally experienced a great surprise after the incident. Looking at the photographs taken after the accident, I believe that in addition to the nose landing gear, the EOTS (Electro Optic Targeting System) targeting system was also partially damaged. Similar landing gear folding problems have been experienced in the F-35A and F-35B variants before. However, it is stated that this is the first time such an incident has occurred in the F-35C variant.
Designed for carrier operations, the F-35C aircraft are known to have more durable landing gear than the F-35B and F-35A variants, in accordance with the requirements of the catapult/launch and capture system. Normally, the nose landing gear is designed to carry up to 15 percent of the aircraft's weight. Therefore, as long as the main landing gear does not collapse (which is not common), the nose landing gear, which is generally produced in a weaker structure, can survive collapse incidents without much damage.
Have there been other nose collapse failures?
In 2022, a similar incident to the one on January 24 occurred in Japan, when a US Marine Corps F-35B aircraft made a precautionary landing at Kadena Air Base due to an electrical malfunction in the air. After the pilot handed the aircraft over to the aircraft maintenance team, the nose landing gear collapsed for an unknown reason while the aircraft was being towed on the taxiway, causing minor damage to the aircraft.
A similar nose landing gear incident occurred on an F-35A aircraft of the US Air Force in 2018. The F-35A belonging to the 58th Squadron Command came to land due to an emergency during the flight, and after landing safely, the nose landing gear folded in the parking lot. On June 8, 2020, the F-35A of the US Air Force, which experienced the nose landing gear incident, landed safely at Hill Air Base. However, at the end of the landing, while the aircraft was taxiing on the main runway, the nose landing gear suddenly collapsed and the pilot had to leave his aircraft on the runway.
The 'flying computer' F-35 program has been focused on solving technical problems encountered since the first flight in 2006. Since 2012, the F-35s have been in the inventory of many countries, including the US, and Turkey took delivery of the first one in 2018, but Turkey was definitively excluded from the program as of 2021 under the pretext of the S-400. More than 1,000 F-35s have already been put into service and Lockheed Martin, the aircraft's manufacturer, plans to produce around 3,500 F-35s in total. Dubbed by some as the 'problem aircraft', the F-35 has been criticized by many in Washington over the last decade for the program's high costs and frequent 'unforeseen' technical and mechanical problems, such as nose landing gear collapses. In particular, the ongoing nose landing gear problems are demanded to be resolved as soon as possible.
The U.S. Government Accountability Office (GAO), through its routine F-35 review and evaluation reports, shares the progress made in the F-35 program and the logistical, technical, financial and user problems experienced with the American and therefore the world public in line with the principles of transparency and openness. GAO's last report, dated April 28, 2023, drew attention to the low aircraft activity rates. It appears that users will have to put up with this low activity rate for some time due to technical problems, particularly with the engine, glitches in the global logistics support system designed for this aircraft, and 'disagreements' between Lockheed Martin and the F-35 program office in the flow of parts. On the other hand, the program office is working on a new approach and aims to establish a mechanism similar to the one that provides logistical support for conventional aircraft for the F-35. Thus, it is aimed to increase aircraft activity rates and to ensure uninterrupted operations by monitoring parts activity rates, parts and system failures more closely. However, considering that improved engines will be put into operation with the Block 4 modernization/improvement process, which is planned to be completed in 2029, users should wait a little longer to resolve the malfunctions, especially in the engine aspect.
Some fighter jets have more complex-looking landing gear, such as the F-16, while others, such as the F-35, have a flatter landing gear. This is because these jets have different requirements to balance. For example, the F-16 has a conventional landing gear with two main wheels under the wings and a smaller wheel in the nose. This type of landing gear allows the aircraft to operate on the ground without problems and allows pilots a more balanced operation during the take-off and landing phases. After take-off, the landing gear of the F-16, which is brought up (inside) by the pilot command, is partially parallel to the outer surface while the landing gear fits into its slots on the bottom of the aircraft. Although this causes negligible friction caused by the wheel surfaces, it is not a limiting factor in the maneuvering of the aircraft. In addition, the fact that the F-16 is not a 'low visibility' aircraft like the F-35 has allowed for a more 'operational' design of the landing gear.
Although the F-35 also has a landing gear design similar to the F-16, it results in a narrower stance than the F-16 in terms of their placement. The distance between the main landing gear is closer than that of the F-16 compared to the size of the aircraft. However, this design is an advantage for the F-35 design as it reduces weight and drag. Again, this is a design requirement that supports easier carrier operations for the F-35C. When the landing gear is raised at the pilot's command, the F-35's main landing gear folds outward into the wing, allowing it to fit 'invisibly' into its slot and avoid friction.
Conclusion
I believe that the frequent occurrence of malfunctions in the nose landing gear of the F-35s and the persistence of instability damage the aircraft's image and its reliability and airworthiness in terms of flight safety. I believe that these landing gear malfunctions point to a holistic problem and a design flaw. It is understood that the fact that the nose landing gear folds forward during give-and-take causes the landing gear to fold easily, especially when the aircraft is towed in the parking lot and during towing operations. Probably there is a sensor arrangement on the bottom of the aircraft that prevents the nose landing gear from folding back. In this case, I believe that the nose landing gear safety pin must be installed at least during ground operations. I even think that installing this pin in the take-off pool at the end of landing may be a standard flight and ground safety practice until a definitive solution to this technical problem is found. Otherwise, I do not think it is very likely that an airplane of this weight, with a 'spring-loaded' nose landing gear design to fold forward, together with factors such as material fatigue that may be experienced in the connection apparatus in the nose slot, will always be able to taxi and tow in a way that will guarantee 100% safety.
References
Stefano D'urso, David Cenciotti, "Exclusive: U.S. Marine Corps F-35C Suffers Nose Landing Gear Collapse While Parked", February 13, 2024, https://theaviationist.com/2024/02/13/f-35c-nose-landing-gear-collapse-while-parked/
Thomas Novelly, "Marine Corps F-35 Damaged After Landing Gear Failure in Okinawa", Military.com, December 2, 2022, https://www.military.com/daily-news/2022/12/02/marine-corps-f-35-damaged-after-landing-gear-failure-okinawa.html
Clement Charpentreau, "US Marine F-35B suffers nose gear collapse after emergency landing", Aerotime, December 2, 2022, https://www.aerotime.aero/articles/32809-usmc-f-35-nose-gear-collapse-japan
