To mitigate delays to the combination of the SPEAR 3 missile, the Ministry of Defence confirmed plans to acquire SDB II munitions from the U.S. via a Overseas Army Gross sales (FMS) program have been given the go forward.
First reported by our pals on the UK Defence Journal, a letter revealed on Could 14, 2026, dated Apr. 30, 2026, from the Ministry of Defence’s Everlasting Secretary to the UK’s Public Accounts Committee (PAC) states “approvals have been given to proceed with a Overseas Army Gross sales (FMS) procurement of the precision-guided munition, Small Diameter Bomb (SDB-II). This acquisition will present the F-35 with an interim stand-off functionality till the introduction of SPEAR-3 into service”.
The Ministry of Defence has permitted the procurement of the Small Diameter Bomb II as an interim standoff weapon for the F-35. Click on picture for extra.
— UK Defence Journal (@UKDefJournal) Could 14, 2026
The assertion was made in response to the PAC’s earlier suggestion that the MoD “ought to set out within the Defence Funding Plan the way it will guarantee a standoff functionality within the coming years earlier than Spear 3 is totally built-in onto the plane”. The Nationwide Audit Workplace (NAO) had beforehand reported that whereas plans to amass SDB II had been mooted, funding had but to be permitted.
Whereas we nonetheless look ahead to the total, closely delayed Defence Funding Plan (DIP) to be revealed, the acquisition of the SDB has beforehand been all however confirmed to be a part of the plan.
🇺🇸🇬🇧 The UK’s Nationwide Audit Workplace advisable, and (per Aviation Week) the upcoming Protection Funding Plan will fund the procurement of GBU-53/B StormBreaker (Small Diameter Bomb II) for that reason.
Spear 3 may be very similar to SDB II, whereas SDB I would offer… pic.twitter.com/8TuYVT2DHp
— Colby Badhwar (@ColbyBadhwar) December 11, 2025
As The Aviationist and plenty of others have reported beforehand, the UK’s fleet of F-35 Lightning IIs is severely under-equipped with air to floor weaponry. Regardless of the plethora of choices out there to the plane elsewhere, in UK service the jets at the moment rely solely on the Paveway IV precision guided bomb. Whereas the Paveway IV is properly regarded with wonderful efficiency, as an unpowered bomb with no glide equipment it is rather a lot a stand-in weapon and is riskier to make use of in contested airspace.
In the meantime, the GBU-53/B StormBreaker, or SDB II, makes use of deployable wings to increase its endurance past 100 kilometres in very best circumstances. Whereas shorter in vary than the turbojet powered SPEAR 3, it nonetheless supplies a invaluable interim functionality which can certainly be preserved even as soon as SPEAR 3 enters service.
GBU-53/B #Stormbreaker pop up air turbine alternator. pic.twitter.com/Vpqdy5i7X2
— Air-Energy | MIL-STD (@AirPowerNEW1) March 10, 2025
Like SPEAR 3, every F-35B is ready to carry eight SDB IIs internally at anyone time – 4 munitions in every inside bay. This exceeds the full payload of Paveway IVs carried even within the ‘beast mode’ configuration which sees 4 bombs carried externally on the wings in addition to two internally. This implies SDB II may turn into the weapon of alternative even in some conditions the place most stealth just isn’t required, permitting a single jet to strike extra targets throughout every sortie (and, if all weapons are carried internally, moreover making the plane extra aerodynamic and gas environment friendly).
#F35 BF-5 twin GBU-53/B SDB-II #Stormbreaker launch. April 2023. NAS Patuxent River. Presently being built-in on all F-35 variants, the StormBreaker is an all-weather precision guided munition able to performing in GPS degraded or denied environments. Its tri-mode seeker… pic.twitter.com/RCLkCWcRrJ
— Air-Energy | MIL-STD (@AirPowerNEW1) February 21, 2026
F-35 Spares State of affairs
The Everlasting Secretary’s letter additionally reveals that when F-35Bs have been deployed on board HMS Prince of Wales throughout Operation Highmast, also called Service Strike Group 25, the quantity of accessible spares have been beneath the ideally desired degree. Even whereas 24 F-35Bs have been deployed on board the ship – a surged drive supposed to fulfill the necessities for declaring full working functionality – the spares pack on board remained at a degree normally designed for 12 jets.
Spares packs are standardized units of spare elements designed to help the routine operation of an plane away from its residence base. For the UK’s F-35B drive there are Deployable Spares Packs (DSPs) tailor-made for land-based deployments and Afloat Spares Packs (ASPs) for on board the plane carriers. To mitigate the lowered variety of spares, further supplies have been pulled from DSPs and from RAF Marham to complement the service’s shares. Nevertheless, the character of a service deployment and difficulties with sustaining a provide chain to the ship led to issues making certain these have been delivered on time.
Plans are in place to double the capability of the ASP, and procure a further DSP. These are anticipated to be confirmed within the Defence Funding Plan (DIP).
Letter reveals points with corrosion and confirms earlier Aviation Week reporting that the UK will go and buy the Small Diameter Bomb (SDB-II) to offer UK F-35Bs some semblance of stand-off air-to-ground functionality. And the much less mentioned about #Marham, the higher.
— Tony Osborne (@Rotorfocus) Could 14, 2026
The Secretary says that classes have been taken on board following these difficulties, with new planning processes now in place – already put into motion for the deployment of F-35B plane to RAF Akrotiri.
Mission succesful (MC) charges for the F-35Bs on Operation Highmast have been similar to the worldwide common for the variant, at some factors exceeding the common. For the reason that finish of the prolonged deployment, charges have fallen because the F-35B drive regenerates and jets are rotated via corrosion restore applications.
