Leaked F-35 Report Confirms Serious Air Combat Deficiencies

F-16 (foreground) and F-35 (Photo: U.S. Air Force)

A new leaked test, which was first exposed by War is Boring, provides more evidence that the F-35 Joint Strike Fighter’s demonstrated performance is inferior to the current fighters it is designed to replace. Specifically, the report finds that, in a series of 17 dogfights, the F-35 was consistently outmatched by an aging F-16.

An F-35A test pilot with extensive dogfighting experience in F-16s and F-15s wrote the report, detailing his cockpit observations during the January 2015 maneuvering combat tests of the F-35 against a 30-year-old F-16 at Edwards Flight Test Center in California. The report, marked for official use only (FOUO), highlighted serious concerns about the plane’s performance in this key mission.

One of the significant new issues raised by the report was the F-35’s difficulty in sustaining energy in close-in maneuvering combat—that is, the energy needed to turn and accelerate. The test pilot found this to be “substantially inferior” to older planes like F-15s, F-16s, and F-18s. In the tests, the F-35’s maneuverability against the F-16 was so limited that it could only point quickly enough to achieve a missile shot by executing one specific maneuver. But this move consumed so much energy that if the shot failed the F-35 would “ultimately end up defensive again”—which is to say, at the mercy of any opponent.

The report also homed in on flight control problems in the 20 to 26 degrees angle of attack zone, crucial for hard maneuvering. The pilot described the F-35’s computer-controlled flying qualities as “sluggish” for evasive maneuvering and “not intuitive or favorable.” This echoes information in a recent report from the Director of Operational Test and Evaluation (DOT&E) that described severe flying quality problems in this high angle of attack region—including uncontrollable wing drop and heavy buffeting (shaking) “that degraded the flight control system (two of three flight control channels become disabled), requiring a flight abort.”

Fixing these earlier flight control problems identified by DOT&E required new flight control software modifications that significantly shrank the F-35’s maneuvering limits while slowing control response—leading to exactly the problems uncovered in the recent January dogfight tests. The F-35, like most modern aircraft, uses fly-by-wire technology. Such technology depends on software to translate the pilot’s control stick inputs into flight surface movements. According to the DOT&E report, the F-35’s then-current software limited the maneuverability of the plane in an attempt to avoid placing extreme dynamic stress on the aircraft in flight. The January tests showed the new F-35 software control system changes further limited the flight controls so that the pilot could pull no more than 6.5gs in hard defensive turns, even though the F-35 design and contract specifications call for 9gs.

The F-16 Should Have Been the Underdog

F-16 with two external fuel tanks under the wings
F-16 with external fuel tanks (Photo: Dvids / Flickr)

“The F-35A remained at a distinct energy disadvantage for every engagement,” against the test F-16, the Air Force report noted. The F-16 was a mid-1980s vintage F-16D two-seater, suffering the drag penalties and the extra weight added by a second seat. Its maneuverability was further degraded by the drag of two 370 gallon underwing drop tanks (each about 3200 pounds with fuel and pylons), while the F-35 was permitted to fly with empty weapon bays and clean wings—hardly a level playing field. The test pilot noted the F-35 would suffer similar maneuvering disadvantages against the F-18 and F-15. For instance: “The EM [Energy Maneuverability] of the F-35A is substantially inferior to the F-15E with PW-229s [engines] due to a smaller wing, similar weight, and ~15,000 lbs less in afterburner thrust.” In addition to its thrust deficiency, the F-35’s acceleration is hampered by a relatively wide, heavy, high-drag fuselage and its turn performance suffers from comparatively small wings. This creates the highest wing loading (weight per square foot of wing) of any contemporary fighter, significant because the higher that measure, the poorer the plane’s maneuverability.

Test Report Blowback

Since the test pilot’s report surfaced, F-35 program apologists have come out with a series of articles claiming that the plane was never supposed to dogfight. But Bill Sweetman at Aviation Week details how previous statements from the program office and prime contractor flatly contradict those claims. F-35 advocates and industry spokesmen quickly rushed out with additional excuses for the $1.4 trillion dollar program’s poor showing. A few of the explanations from the Joint Program Office include:

The lack of software for the F-35’s long range sensors does nothing to explain maneuverability deficiencies inherent in the aircraft’s basic design, deficiencies critical in the air battle’s unavoidable close-in fights. Further touting the primacy of long range combat only serves to bolster the argument that the F-35 was never meant to be as maneuverable as our current inventory of fighters in the first place.

F-35 in flight
F-35 in flight (Photo: U.S. Air Force)

Unfortunately, it is patently untrue that this kind of maneuverability was never intended for the F-35. In August 2002, then-Colonel Dwyer Dennis of the Joint Strike Fighter Program Office said that the Joint Strike Fighter’s capability, “as far as aerodynamical handling as a minimum, is an S-16 (sic), F-18 type of aerodynamic performance.” That claim has been consistently reiterated by the program office ever since. In 2013 a Lockheed Martin test pilot claimed the F-35 E-M would be “comparable or better than every Western fourth-generation fighter out there.” He continued, “in terms of instantaneous and sustained turn rates and just about every other performance metric, the F-35 variants match or considerably exceed the capabilities.”

The claim that the F-35 will avoid close-in combat and defeat all comers by using its dazzling sensors to shoot them down beyond visual range also fails to hold water for several reasons:

First, in full scale air battles with near-peer enemies, the sky will almost certainly be full of intermingled friendlies and enemies. In all such combat, the hackability and unreliability of Identification Friend or Foe (IFF) gear since its introduction has forced our combat leaders to impose strict positive visual identification rules to avoid shooting down friendly pilots. Such identification requires flying within a quarter mile or less of a target aircraft, thereby making maneuvering fights impossible to avoid. Once a pilot closes to visually confirm a target, it is too late to retreat beyond visual range and fire a missile.

Second, what happens if the promised 90 percent kill rate of the long range missile proves to be one fifth or one tenth of that in combat—exactly as happened in Vietnam air combat? Or if the near-peer enemy turns out to be smart enough to outmaneuver, jam, or spoof our missiles—as we and the Israelis did to Soviet air defense missiles in the Vietnam and Yom Kippur wars? Or, if combat shows that two to four missiles per F-35 are too few to handle swarms of enemy fighters? Clearly each of these eventualities forces the F-35 right into the heart of the close-in maneuvering fight.

Lacking the ability to use radar not only locks the F-35 into close-in fighting, it also means modern European, Russian, and Chinese fighters will detect the F-35 first with passive infrared sensors."

Lastly, we know the Russians and the Chinese are producing quantities of modern, networked long wavelength search radars that are not deceived by the stealth shaping and stealth skins of our bombers and fighters. Stealth invisibility is non-existent: those radars will warn enemy fighters of the F-35’s position, speed, and direction of flight from more than 200 miles away. And those enemy fighters will be equipped with—among other weapons—missiles with passive seekers that can identify and home in on our fighter’s radar signals. Since the F-35 is being sold as a beyond visual range platform, a high-powered radar system inside the plane is needed to guide its missiles to enemy fighters. After the enemy fires a home-on-radar missile, F-35 pilots will be forced to turn off their radar systems to avoid being shot down. Those passive home-on-radar missiles always detect at ranges well beyond those of our own active radar missiles.

In every generation of air-to-air missiles manufactured for the last 40 years, the Russians have always fielded a passive seeker option, and the Chinese are now following suit. Lacking the ability to use radar not only locks the F-35 into close-in fighting, it also means modern European, Russian, and Chinese fighters will detect the F-35 first with passive infrared sensors. Their infrared search-and-track detectors can detect engine heat up to 70 miles away and the F-35 has a particularly hot and visible exhaust plume.

It is vitally important that any aircraft with a designated air-to-air role, whether designed for beyond visual range or not, be capable of prevailing in a dogfight. A 2008 RAND study analyzing 588 air-to-air kills since the 1950s demonstrates how the tactical circumstances of air combat and the technical shortcomings of beyond-visual-range missiles combine to make beyond-visual-range combat extremely rare. In fact, the study found that only 4 percent (24 of 588) of all those air combat kills occurred with the attacker firing from beyond visual range. While there may be improvements in the reliability and accuracy of radar guided missiles, they will not change the tactical circumstances of air combat that inherently limit the missile’s viability beyond visual range.

This is not the first time planners have declared the end of the dogfighting age. Decades ago, Pentagon decision-makers fell for the myths the defense industry was selling about the effectiveness of air-to-air missiles and decided the F-4 did not need a cannon because beyond visual range missiles had rendered it obsolete. Combat experience over North Vietnam proved them disastrously wrong and a bolt-on gun pod was hastily rushed into production for existing aircraft while new F-4s were eventually fielded with an internal 20 mm cannon.

As for the claim regarding the absence of special stealth skins on the test F-35, it should go without saying that these skins don’t contribute to winning dogfights. Stealth skins or coatings deal only with radar detection. They do not make the plane invisible to the enemy’s naked eye, the sensor of choice for dogfighting. The Joint Strike Fighter Program Office’s comment regarding the test aircraft’s lack of stealth seems an obvious ploy to distract attention from the F-35’s poor showing in the test dogfights.

A Plane Without a View

F-35 Helmet
F-35 Helmet (Photo: U.S. Air Force)

The new report also puts a finer point on previous CDI reporting about the F-35’s inability to detect rear hemisphere threats. The aircraft’s unusually wide fuselage and solid bulkhead directly behind the pilot’s head means he cannot see enemies below or behind him if his helmet’s complex video display system fails, or has inadequate resolution. The new report observes that the bulky helmet hitting up against the canopy even further restricts the pilot from turning his head to look to the rear, and that the helmet’s protruding front visor makes it difficult for the pilot to look up and behind, also essential in dogfight maneuvering. In CDI’s previous reporting, a pilot said it was “nearly impossible to check [the six o'clock position to the rear] under g” and concluded that “Aft visibility will get the pilot gunned [down] every time," in close-range combat. In this latest report, the test pilot wrote, “in general, it took a lot of physical effort to turn around for the visual.”

Significantly, this crippling lack of rearward visibility is the direct result of the technical compromises inherent in designing an airplane for three disparate missions and for three services with vastly different requirements. The original F-35 was designed to meet Marine Corps demands for a supersonic, short takeoff/vertical landing plane. That vertical landing requirement dictated an extremely wide 50 inch fan blowing straight down for lift and sucking air through a huge intake door on top of the fuselage directly behind the pilot. That, in turn, led to an unusually fat fuselage that is so high it completely obstructs the rear of the canopy.

Subsequently, when the Air Force and the Navy were enticed into joining the F-35 program—supposedly to benefit from the “savings” of a large 2500 unit tri-service buy (savings that quickly turned into huge cost overruns)—they both had to accept the fat fuselage and lack of rearward visibility of the Marine Corps version. Both services inherited other severe effectiveness penalties stemming from the Marines’ demand for vertical landing. For one, the fat fuselage’s weight and drag leads to the F-35’s poor range and sluggish acceleration. Similarly, the small wing area needed to keep the aircraft’s overall weight light enough for vertical landing is another key contributor to the plane’s inadequate dogfight and close support turning performance.

When the helmet fails in flight, F-35 pilots will be unable to fire weapons and defend themselves."

According to F-35 advocates, the plane’s poor aft field of view doesn’t matter because the pilot’s helmet mounted video displays provides all the rearward visibility needed. This $600,000 helmet system (not including cost of the hardware and software needed to integrate the helmet into the F-35’s computers, nor the cost of R&D) projects images onto the pilot’s visor from six TV cameras all around the aircraft, and additionally projects flight instrument displays, radar/infrared displays, and other target information displays. The resolution of these projected video images on the pilot’s visor is significantly poorer than the flat panel screen displays used on current A-10s and F-15s. Reports from pilots say that makes the helmet video display hopelessly inadequate for reliably seeing against a hazy sky the tiny, low contrast, extremely dangerous dot of an enemy fighter 1 to 5 miles behind the F-35. One F-35 pilot recently confirmed that a camera could not replicate the ability to judge aspect and distance closure the same way he can by just looking for himself. “I’ll use my eyes,” he said. “I need to see things with my own eyes.”

The problems of making this complex helmet work are severe enough that it is now into its third generation design. It also still displays excessive false targets, is years behind schedule, and is way over cost. Even if the system eventually works, there will still be severe operational penalties. When the helmet fails in flight, F-35 pilots will be unable to fire weapons and defend themselves. And because the plane doesn’t have backup instruments, pilots will also not be able to land at night or in weather if the helmet malfunctions. Equally serious, when the helmet fails, the pilot is grounded. It’s not just a matter of simply borrowing another helmet—each one has to be custom-fitted. So pilots must be issued a new $600,000 helmet and then go to a specialized helmet calibration laboratory to have it precisely aligned and fitted to their head before they can fly again.

The costs and capability shortfalls become more staggering when you compare the F-35’s helmet to the Scorpion Helmet Mounted Cueing System, which is already being successfully used in combat on the F-15, F-16, F-18, and A-10. It is a much simpler and smaller design than the F-35’s bulky helmet, does not require lengthy calibration, and costs only $85,000. The Air Force has also been testing it for use on the F-22. The F-35 helmet appears to be another example of developing an expensive, do-everything, overly complicated product when a combat-proven system already exists at a fraction of the cost.

Clearly, the over-the-top complexity of the F-35 helmet mounted display system does not compensate for what all fighter pilots over the last 75 years—though few technologists or designers—have understood clearly: first-rate fighter planes must have high bubble canopies with superb 360-degree visibility. The legendary WWII P-51 Mustang had dangerously poor rear visibility until pilot demands forced a switch to the bubble canopy.

MiG-15 and F-86
Mikoyan-Gurevich MiG-15 and F-86 Sabre (Photo: Daniel Grazier)

In Korea, the F-86 outfought the slightly better-performing MiG 15: Col. John Boyd’s meticulous analysis showed that a key advantage was the F-86’s bubble canopy’s visibility compared to the restricted view from the MiG 15’s more buried-in-the-fuselage cockpit. As in every air war before and since then, a rearward visibility advantage yields fewer losses from unseen enemy ambushes and more kills due to achieving surprise.

A Plane That Makes It Impossible To Turn Out Winning Pilots

As Col. Boyd’s and every other careful analysis of historical combat outcomes have shown, pilot skill always dominates fighter technical differences in achieving aerial victories. In every first rate air force, turning out superior fighter pilots has always required at least 40 sorties per month of realistic, intense air combat training to hone fight-winning skills.

Here lies the single largest—and clearly incurable—cause of the F-35’s lack of combat effectiveness. Because of the plane’s unprecedented complexity and the corresponding reliability and maintenance burdens, it simply cannot fly often enough to train pilots that are clearly better than any possible adversary.

F-35 with overlay of computer code
(Modified U.S. Air Force photo)

The F-35 has nearly 30 million lines of constantly changing aircraft and support system computer code, a maintenance-intensive stealth skin, a problem-ridden helmet system, excessive engine failure rate, significant maintenance burdens, constantly emerging structural defects, and continuing reliability problems throughout the all-electric control and integrated power generation systems. All of these factors will combine to turn the F-35 into what is known as a “hangar queen.” The plane will have limited operational availability for flight training because maintenance crews will find it difficult to keep up with the inevitable mechanical failures.

According to the most recent DOT&E report, the F-35A has only been able to fly 55 percent of its planned flying hours because maintenance crews cannot repair failed aircraft systems any faster. So far this year, F-35As at operational squadrons at Nellis and Luke Air Force bases have been able to fly no more than 6.1 and 6.4 sorties per plane per month (9.4 and 10.4 hours per month respectively). The Nellis operational pilots only fly about 4 to 5 sorties per month, while pilots at Luke fly 5 to 7 per month--demoralizing for pilots and dangerously short of the 40 per month that first-rate fighter forces have found necessary to turn out pilots that can dominate every fight, and below the number of sorties per month needed to be safe.

With less than one-fifth the number of sorties per month they need, F-35 pilots called to war will be inadequately trained and under-skilled. They will be forced into the dangerous practice of completing their training during combat. And that will inevitably entail avoidable losses of scarce $200-million-dollar aircraft and a tragically unnecessary waste of American lives.


The technical problems and combat ineffectiveness of the F-35 are fundamental to the concept and basic design of the airframe, avionics, and engine, as well as the acquisition schedule’s extreme concurrency. The significance of these deficiencies will continue to be confirmed with more tests. As the program approaches the most demanding stage of testing and software development, the pace of uncovering serious new technical problems—requiring massively expensive, schedule-slowing fixes—will likely continue to increase.

Pentagon, congressional, and defense industry defenders of the F-35 are fond of reiterating that the program is “too far along” for any major changes at this point in the process. There is clearly a straightforward, practical alternative to the reckless acceleration of the annual F-35 buy, which could also halt the Air Force’s rapid shrinking of its fighter force: simply refurbish and upgrade some of the large numbers of F-15s, F-16s, and A-10s that the Air Force is rushing off to the boneyard in the hopes of offsetting a small fraction of the F-35’s costs.

The January dogfight tests go a long way to showing that a refurbished F-15C or F-16 C/D is, plane for plane, a better air-to-air fighter than an F-35, to say nothing of their larger payload capacity and longer range.

As for close support, combat-experienced ground controllers favor the A-10 by a huge margin over the F-35 or any other thin-skinned, fast jet. A truly combat-realistic close support operational test evaluating the two would quite certainly support the user’s educated assessments.

Equally obvious is that refurbishing any of these legacy aircraft—even ones retrieved out of the boneyard—is far cheaper than buying F-35s.

Before stampeding into the F-35 production “ramp-up” dictated by the FY 2016 and FY 2017 budgets that the Pentagon and Lockheed are selling hard, Congress must seriously reassess the number of F-35s being bought, and the expensive risks of increasing those buys while test failures accumulate. The test pilot’s report should serve as a clarion call for decision-makers to rationally and conservatively reformulate the program. Simply going along with the “too big to fail” procurement plan means acquiescing to shrinking air forces, growing defense budget shortages, and the likelihood of disastrous failures in combat—failures that will come with a high cost in the lives of American warfighters in the air and on the ground.