The F-35 Still Has a Long Way to Go before It Will Be Ready for Combat
None of the three F-35 models in the current fleet can use cannons in combat. In fact, none of them are even close to completing their developmental flight tests—much less their operational suitability tests—for airframe safety, accuracy, and target lethality. Even worse, based on preliminary test experience, it appears that the severe inaccuracy of the helmet-mounted gunsight on all three F-35 versions that makes the cannon ineffective in air-to-air combat will also make it ineffective in CAS—and that the helmet’s accuracy problem may be technically inherent and incurable. Note that the cannon accuracy requirements for CAS are considerably more stringent than for air combat: when shooting in close proximity to friendly troops, even minor accuracy problems can have tragic consequences. As mentioned before, the gun pods for the Marines’ F-35B and the Navy’s F-35C will likely add another source of inaccuracy—also possibly incurable—and remain untested for CAS. The combat suitability of F-35 cannons for CAS will not be known until the end of Block 3F IOT&E, which is unlikely before 2021. Failure to complete these CAS tests realistically—a distinct possibility given JPO mismanagement and delaying of test resources—will certainly jeopardize the lives of American troops.
In addition to the critical cannon inaccuracy problem, the error-inducing chaos of symbol-clutter in the pilot’s helmet display is particularly dangerous in the CAS role. DOT&E says the current system is “operationally unusable and potentially unsafe to complete the planned testing due to a combination of symbol clutter obscuring the target, difficulty reading key information, and pipper [aimpoint] stability.” Even when the symbols being displayed by the helmet do not obscure the pilot’s ability to see the target, the F-35’s canopy might. The jet’s canopy is a thick acrylic material with a low observable coating to preserve stealth. This makes the canopy less transparent and according to the DOT&E appears to be distorting the pilot’s view.
Further limiting the cannon’s effectiveness in each version of the F-35 is the number of 25 mm rounds it carries—182 for the F-35A and 220 for the B and C. This is grossly deficient for CAS, especially when compared to the over 1,100 30 mm shells carried by the A-10. While the A-10 has enough cannon rounds for between 10 and 20 attack passes, any variant of the F-35 will only have enough for two, maybe four, passes.
Even more limiting in the effective use of any CAS weapon, cannon or other, is the F-35’s inability to fly low and slow enough to find typical hard-to-see CAS targets and safely identify them as enemy or friendly, even when cued by ground or air observers. Due to its small, overloaded wings, the F-35 cannot maneuver adequately at the slow speeds that searching for concealed and camouflaged targets requires—and being completely unarmored and highly flammable, it would suffer catastrophic losses from just the small rifle and light machinegun hits inevitable at the low altitudes and slow speeds required. In sharp contrast, the A-10 was specifically designed for excellent low and slow maneuverability and, by design, has unprecedented survivability against those guns, and even against shoulder-fired missiles.
Air Force officials have often argued that the lack of an effective gun or inability to maneuver low and slow won’t matter in future wars because the Air Force intends to conduct CAS differently—that is, at high altitudes using smaller precision munitions. But the F-35 will not be cleared to carry those weapons for at least five years.
In the meantime, the F-35 can carry only two guided bombs right now, and those are 500 pounds or larger. None of those models are usable in proximity to friendly troops. According to the military’s risk-estimate table, at 250 meters (820 feet), a 500-pound bomb has a 10 percent chance of incapacitating friendly troops. This means that within that bubble, the enemy can maneuver free from close air support fires. A 250-pound Small Diameter Bomb II is now in low rate production and cleared for use on the F-15E; even that, though, is much too large to be used near friendly troops in “danger close” firefights, and the software and bomb racks necessary to employ it on the F-35 will not be available and cleared for combat until 2021 at the earliest.