F-35 Lightning II – Can it Fire all its Weapons?

The weapons used by the F-35 Lightning II are capable of destroying targets in the air and on the ground with great accuracy. When combined with the advanced sensors, superior situational awareness and stealth, you will have lethal fighter/attack aircraft.

Or so the marketing goes.

What do you really know about the weapons? Can they be used today or sometime in the future? The purpose of this post is to provide information to allow you to answer these questions.

1/ Weapons Capability (Missiles & Bombs)

The F-35 will use the full range of weapons available for the current fleet of fighters such as the F-15, F-16 F-18 and F-22 including:

  • Advanced Short Range Air-to-Air Missiles, E.G. AIM-9X Sidewinder and AIM-132 ASRAAMweapons
  • Advanced Medium Range Air-to-Air Missiles, E.G. AIM-120 AMRAAM
  • Cruise Missiles, E.G. the Storm Shadow and AGM-158 Joint Air to Surface Stand-off Missile (JASSM)
  • Bombs, E.G. Paveway Laser Guided (GBU), Unguided (BLU), Joint Direct Attack Munitions (JDAM) [GPS Guidance Kits attached to unguided bombs].


 2/ Weapons Capability (Machine Gun)

The machine gun to be used on the F-35 is the GAU-22/A. It is a four barreled version of the General Dynamics GAU-12 (5 Barrel) 25mm, Gatling Type, Rotary Canon.

The gun is the same for each F-35 variant however there is a major difference.

  • F-35A (CTOL) – The gun has a permanent mount inside the plane above the left air intake. This design allows the F-35 to maintain its stealth capability.
  • The F-35B (STOVL) & F-35C (CV) – These variants do not have a permanently mounted gun. In its place both the B&C variants have access to a removable gun pod containing the same machine gun as the A variant. The Pod sits in the central external mount located underneath the plane.

To understand the guns capability a comparison to existing US fighters is below. You can also click this link if you would like to download a simple PDF version: US Fighters – Machine Gun

Fighter Gun Model Manufacturer Size of Bullet (mm) No. of Barrels Rounds Carried Max Rounds Fired / Minute Total Fire Time (sec)
F15/A-D M61A1 General Electrics 20 5 940 6000 9
F15/E M61A1 General Electrics 20 5 450 6000 5
F16 A-D M61A1 General Electrics 20 5 940 6000 9
F16/E M61A1 General Electrics 20 5 511 6000 5
F18A/B M61A1 General Electrics 20 5 578 6000 6
F18E/F M61A2 General Electrics 20 6 578 6000 6
F-22 M61A2 General Electrics 20 6 480 6000 5
F35A GAU-22/A General Dynamics 25 4 182 3300 3
F35B&C GAU-22/A General Dynamics 25 4 220 3300 4
A-10 GAU-8/A General Electrics 30 7 1100 3900 17
AV-8B GAU-12 General Dynamics 25 5 300 4200 4

Key Insights from the Gun Comparison

  • The F-35 carries less rounds of ammunition than every fighter listed;
  • For close air support the A-10 carries four times the ammunition of the F-35;
  • The air superiority fighters (F-15A-D, F-16A-D, F-22) carry, on average, double the ammunition of their multi role cousins (F-15E, F-18, AV-8B).

With these insights the F-35 gun falls well short of my expectations. It even raises the question why there is a gun at all?  At least the Marines and Navy have the option to fit the gun if the mission calls for it.

3/ Are all these Weapons Available Today?


The Marines declared Initial Operating Capability (IOC) for the F-35B Short Take Off and Landing Fighter on 31 July 2015. This was a great day for all associated with the F-35 Program but what does this really mean?

Essentially the Marines have approved the F-35B to be an active aircraft that can be used in operations the same way as any other Marine aircraft.

Declaration of IOC for the Marines provides a great story however it does not give the Marines the ability to use the full weapons suite available to the F-35. Far from it in fact.

Many of the capabilities of the F-35 rely on software to work. To effectively control development of this software the F-35 weaponsProgram created “Software Blocks” that will allow systems to be updated on a semi-regular basis rather than all at once.

The latest Software Block release is known as “2B”. This software block provides the first war fighting capability for the F-35 and this has allowed the Marines to declare IOC. The software however provides a limited war fighting capability.

Block 2B Software key points:

  • Weapons can only be fired from the four weapon stations within the Internal Weapon Bays of the F-35B;
  • Block 2B software also limits the mix of weapons that can be carried:
    • 2 x AIM-120 Advanced Medium Range Air-to-Air Missiles (AMRAAM) used for beyond visual range engagements; and
    • 2 x Bombs. There is a choice of three bomb types that can be used.
  • The Machine Gun cannot be fired;
  • The 7 external weapon stations are not operational.

General Joe Dunford, the outgoing Marine Corps Commandant stated:

“I am pleased to announce that VMFA-121 has achieved initial operational capability in the F-35B, as defined by requirements outlined in the June 2014 Joint Report to Congressional Defense Committees. VMFA-121 has ten aircraft in the Block 2B configuration with the requisite performance envelope and weapons clearances, to include the training, sustainment capabilities, and infrastructure to deploy to an austere site or a ship. It is capable of conducting close air support, offensive and defensive counter air, air interdiction, assault support escort and armed reconnaissance as part of a Marine Air Ground Task Force, or in support of the Joint Force.” Source Defence News

Given the weapons capability of Block 2B, the General really needed to precede each capability with a bolded “limited“.

“Limited” may also be stretching the truth as the Marines first planned deployment of the F-35B takes place in 2017 when Unit VMFA-121 moves to Iwakuni, Japan. Source Defence News.  Not surprisingly this schedule aligns with the planned roll out of Software Block 3F in 2017.

According to Janes:

What will Block 3F Software enable?

“Block 3F provides 100% of the software required for full war fighting capability, including but not limited to data link imagery, full weapons, and embedded training……it is due to be rolled out in the third quarter of 2017.”

The F-35 Program has a history of delays, should we expect Block 3F to be released on time with all the functionality planned? I will let Major General Jeffrey Harrigan, director of the Air Force’s F-35 Integration Office answer this:

“Some capabilities that had been planned for Block 3F – the software and hardware standard that is the end point of the F-35’s system development and demonstration (SDD) phase – are at risk of slipping into Block 4” Maj. Gen. Jeffrey Harrigian continued by saying “Goal 1 would be to keep [capabilities] in 3F and understand what we can do now to drive the risk down, versus sliding them to Block 4. We are working really hard with the JSFPO and industry to understand why we can’t fix this now,” Source: Aviation week

Current plans for Software Block 4 show it being released in four stages between 2019-2025. If, as Gen. Harrigan has suggests, some functionality from Block 3F slips to Block 4 there is a real possibility that the F-35 fleet will not have full war fighting capabilities until the next decade.

Delays will also create problems for any allies buying the F-35 such as Australia. I wrote about Australia’s risks in my post titled “Lockheed Martin F-35 Lightning II – An Australian View

 4/ Weapons in Development

With the visual engagement (dog fighting) capabilities of the F-35 well reported as average at best, there is development underway for new and improved Beyond Visual Range (BVR) missiles that are all too important to the success of the F-35. These new weapons are planned for introduction with the Software Block 4 Program (2019-2025), all things going well.

SOM-J Air-to-Surface Standoff Cruise Missile

Lockheed Martin has signed a contract with Turkish company Roketsan to jointly develop the SOM-J for integration into the F-35 internal weapon bays. 

“The SOM-J integration on the F-35 will enable pilots to engage targets from long ranges while maintaining the aircraft’s critical stealth capabilities,” said Frank St. John, vice president at Lockheed Martin Missiles and Fire Control. Source: Lockheed Martin

Key Specifications of the SOM-J:weapons

  • Guidance –  Primary is GPS , secondary is an advanced Inertial Navigation System and a radar-based Terrain Referenced Navigation system;
  • Range – 130 nm
  • Warhead – Semi-armour piercing type with blast/fragmentation

Small Diameter Bomb (SDB II)

Raytheon’s GBU-53/B SDB-II is an air launched precision guided glide bomb. Designed to find and strike moving targets in any weather.

This bomb is mission critical to the Marines due to its accuracy, stand-off range and, due to its size, eight bombs can be carried in the internal weapon bays. As with many things F-35 there is a but…… in this case the SDB II does not fit in the F-35B internal weapon bays as hardware is taking up some critical space. The result is that the internal weapon bays need to be redesigned and refitted. This upgrade cannot happen until Software Block 4 implementation taking place between 2019 and 2025.

Key Specifications:weapons

  • Guidance – Primary, Tri-mode (laser, IIR, radar) seeker, secondary, a GPS receiver;
  • Range – 40-60 nm;
  • Warhead – Blast & Fragmentation

Joint Strike Missile (JSM)

The JSM is being developed from the Naval Strike Missile (NSM) which is a surface launched anti-ship and land-attack missile developed by the Norwegian company Kongsberg Defence & Aerospace.

Two JSM’s will be carried in the F-35 internal weapon bays as well as the external weapon stations. It will be weaponscapable of attacking both sea and land based targets.

Key Specifications

  • Guidance –  Inertial, GPS, terrain-reference navigation, imaging infrared homing, target database.
  • Range – 160 nm
  • Warhead – Blast & Fragmentation

Meteor – a Beyond-Visual-Range Air-to-Air Missile (BVRAAM)

The Meteor will be carried in the F-35 internal weapon bays. It is an active radar guided missile being developed by the European missile manufacturer MBDA. The Meteor will offer a multi-shot capability against long-range manoeuvring targets in a heavy electronic countermeasures (ECM) environment.  It will enter service with the Typhoon, Gripen and Rafael fighters in 2015/2016 before it is integrated with the F-35 in the next decade.


Key Specifications:

  • Guidance – Inertial guidance, mid-course update via data link, terminal active radar homing;
  • Range – 60-160 nm;
  • Warhead – High Explosive Fragmentation


We have seen lasers used for decades in the movies and on TV. It is science fiction right? Wrong, and thanks to Lockheed Martin the laser will soon become a military weapon when its 60kW laser is delivered to the army in late 2016. Not to be outdone Boeing has its own vehicle based laser technology it is testing.

Laser technology has matured to a point that allows Lockheed Martin to start considering applications of a laser on the F-35. Early ideas consider the Laser a defensive weapon that would allow the F-35 to shoot down missiles and other airborne threats.

Lockheed Martin’s, Rob Afzal, Senior Fellow for Laser and Sensor Systems said at a media briefing on 5 October 2015 “Absolutely, we’re looking at concepts for the integration of a laser weapon onto the F-35,”. Source: Flight Global

Although a long way off, could a laser weapon be a practical addition to the F-35 to increase its Lethality and/or Survivability? This is one weapon I want to keep an eye on.

Report Card

With a greater understanding of the weapons associated with the F-35, I have provided my subjective four pillars rating below.

My Four Pillars Rating = 65%F-35 Program

(With concurrency and Software Blocks in mind, I suggest 50% is a pass, 75% & above is excellent)

Affordability – 4/5 – Utilises existing weapons. Some development underway to redesign existing missiles.

Lethality – 2/5 – Today it only carries four missiles with no gun. New BVR missiles to be introduced with Block 4, a functioning set of external weapon stations and the machine gun will significantly increase this score. The question is when?

Survivability -2/5 – Carries only 2 Air-to-Air Missiles and no gun. Same problems as Lethality.

Supportability – 5/5 – Utilises existing weapons. The gun is a new model however it is based on the existing Gun used by the AV-8 Harrier II and AC-130U Gunship.

Following full implementation of Block 4 the F-35 will be a lethal weapon. The problem as always is the need to be patient. Are the decision makers willing to wait or is their patience running out?

How would you score the weapons? I encourage you to post your rating in the comments.


Leave a Reply

Show Buttons
Hide Buttons
%d bloggers like this: