Two more F-35Bs arrive at RAF Marham
May 9, 2025
The well-publicised problems with the F-35’s TR-3 (Technology Refresh 3) upgrade led to a halt in deliveries of modified aircraft, and meant that the RAF had not received any of its F-35Bs since the last pair of Lot 14 aircraft (ZM168 and ZM169 BK-34 and BK-35) were delivered on 16 March 2024. The six remaining aircraft expected during 2024 were not delivered.
The Royal Air Force announced the arrival of the two new aircraft (ZM171 and ZM172, BK-37 and BK-38) after what it called: “A long journey from Lockheed Martin in Fort Worth,” and said that the two new F-35B aircraft, which arrived at RAF Marham supported by an RAF Brize Norton Airbus A330 MRTT Voyager, “represented the UK’s ongoing effort to maintain advanced air power.” They represented, the RAF said: “an important step in the F-35 programme.”
What was not made clear was that the two aircraft have the interim, ‘training only’ TR-3 software load, meaning that they may not be capable of deploying on board the HMS Prince of Wales for the CSG25 deployment, and if they are, they will not be operationally useful!
The delivery brings the Marham-based fleet to 32 aircraft. ZM135, ZM136 and ZM138 (BK-01, BK-02 and BK-04) are based at Edwards AFB for test and evaluation, along with ZM165 (BK-31), while ZM152 (BK-18) was lost in an accident in November 2021, and ZM170 (BK-36) remains at Fort Worth.
This small number of aircraft means that the force is unlikely to reach Full Operating Capability during the ongoing CSG25 carrier deployment, since this is meant to be defined as being two squadrons (24 aircraft) operational on the carrier.
Retired Air Marshal Greg Bagwell observed that: “Combat aircraft fleet management is a complex equation, where the maths aren’t quite as simple as they first appear… Even getting to 18 aircraft is going to require someone throwing a lot of sixes.” Bagwell noted that No.207 Squadron, the training unit, has six aircraft, while scheduled and unscheduled maintenance and modifications and fatigue management programmes will take some aircraft away from the front-line for significant periods. The US Air Force has a target availability rate of 65% for its F-35As (and achieves about 51%). This would mean that the UK’s notional 24 aircraft fleet (32 less the 207 Squadron training aircraft and the two TR-3 aircraft) would be hard pressed to generate even 18 deployable aircraft. Even if training were to be stopped, the fleet would need to achieve 75% availability to be able to deploy 18 aircraft, while deploying 24 would be impossible without 100% availability!
“I know the RN has a lot of experienced Uckers [a board game similar to Ludo, played in the services] players, but you can’t keep throwing sixes for eight months,” Bagwell observed drily.
