Top Gun: A Case of F-35 for Taiwan

Written by Liao Yen-Fan*

Despite its critics, F-35 remains an ideal solution to problems faced by ROCAF

A review of the deteriorating situation and the struggle for F-35

F-35B trials aboard USS Wasp, source:

F-35B trials aboard USS Wasp, ROCAF expressed interest in this STOVL version. Source:

The deteriorating situation in the Control of the Air across the Taiwan Strait has, in the past few years, become a major concern for the Republic of China Air Force (ROCAF). The People’s Liberation Army Air Force (PLAAF) has deployed a significant number of advanced fourth-generation air superiority assets, such as the J-10 and the J-11, coupled with the acquisition and integration of advanced Airborne Warning and Control Systems (AWACS). This means that even with the superior training enjoyed by ROCAF pilots, with a higher than NATO average of 180 hours of flight time logged per year, can no longer hope to maintain a Favourable Air Situation[1], even Air Parity with China. Indeed, the ROCAF is fast approaching an Unfavourable Air Situation, with the unpleasant implication of allowing the PLAAF to prosecute successful air operations over the island in support of an invasion.

The failure to acquire advanced models of F-16 C/D as an interim measure further tilted the already dangerous balance toward the PLAAF, and hence as early as 2009,ROCAF Command was actively entertaining the possibility of acquiring the F-35, specifically the short take off and vertical landing (STOVL) B-model, going so far as to include it in ROCAF’s Ten-Year Force Buildup Concept and Five-Year Force Construction Plan.

On 29 April 2013,Deputy Defense Minister Andrew Yang, in a conference held jointly by the Brookings institution and the Center for Strategic and International Studies, stated that the ROCAF would need advanced fighters with capabilities “beyond the current models of F-16 C/D”. Defense Minister Kao Hua-chu clarified the statement a few weeks later during a legislative session, affirming MND interest in acquiring the F-35 as a long-term objective.

The Role of ROCAF

The mission of ROCAF is a defensive one, as reflected in the mission statement

“…During wartime, to gain control of the air to the best of its abilities,to collaborate with Army and Navy in various forms of joint operations, in orderto fully realize its effectiveness in neutralizing invading threat forces, and safeguard the integrity of national territory”

The “defensive weapons” clause as presented in the Taiwan Relations Act (TRA) restricts America’s sale of arms to Taiwan to those which are defensive in nature has had severe consequences for the operational doctrines of the ROCAF.

These restriction range from the initial software restrictions on the take-off engine power of the F-CK-1 Ching-kuo[2] (also known as the Indigenous Defense Fighter), to the deletion of certain air-to-ground modes in the F-16’sAN/APG-66(V3) radar.

And hence the primary focus of ROCAF has always been air defense.

In this article I will first respond to some of the criticisms directed against the performance of the F-35 as an air-superiority fighter, and then I will elaborate upon the fundamental conceptual differences between the lightening and 4th generation fighters such as the F-16 it’s replacing, and finally I will offer some observations as to why F-35 is suited for the ROCAF’s tactical requirement.

The Myth of Kinematics

The most common criticism leveled against the performance of F-35 is it’s kinematics -the maneuverability of the aircraft. In most cases of criticism been simplified into various performance metrics, and in some worst cases, just Key Performance Indicators (KPI).Commonly used performance metrics include the Thrust-weight ratio, combat radius, max instantaneous turn rate, Maximum G-load, Wing-loading, among many others.

Criticism arises when people discovers that some of these performance metrics does not seem to measure up with the 4th generation fighters they’re replacing, such as the drop of a maximum G-load factor to 7G instead of 9G, and the apparent low thrust to weight ratio, and whereas some of the other criticisms were pure fabrications made without any basis in fact — such as Pierre Sprey’s interview with the Canadian documentary program The Fifth Estate — others were genuinely ignorant of the implications behind performance metrics.

The problem of utilizing performance metrics as basis for comparison is that they are used only as proxies for what is important in a weapon system. The metrics are never important in and of themselves. They exist only to inform developers and operators on the system’s true versus desired capabilities. In other words, taking indicators out of context would at best create misleading impression, and resulting in bad policy decisions at worst, as evidenced by the selection of A-7 by the USAF during the Vietnam War[3]

Graph 1: Sample "doghouse" plot of F-16 C/D Block 52 at 10,000 feet

Graph 1: Sample “doghouse” plot of F-16 C/D Block 52 at 10,000 feet

Take thrust and weigh ratio for example, the importance of this particular indicator did not come into being until the Energy-Maneuverability diagram, also known as a ‘doghouse’ plot came into vogue partially through the effort of the ‘Godfather of Fighter Mafia’[4], United States Air Force(USAF) Colonel John Boyd. Who devised a way to describe the potential and kinetic energy in a quantitative manner convenient for ‘paper airplane’ [5] comparisons, where every line delineates the iso-specific energy of the aircraft (in other words, what the aircraft could do without losing/gaining energy either through decreasing speed and gaining altitude, or increasing speed/gaining energy by diving).

Rudimentary calculations[6] conform to traditional E-M plot using publicly available information on the lightning II falls in line with Project Executive Officer Lt General Christopher Bogdan’s statement that the maneuverability of the F-35 would be “at least as good as the F-16”.

And while the E-M plot is a useful tool in understanding and discussing air combat. The rapid pace of development in weapons capability, such as the increasing importance of beyond-visual-range(BVR) combat and the advent of full-aspect seeking missiles has rendered the original interpretation – that a merge of two fighters inevitably result in a protracted dogfight with each competing to gain a rear-aspect position – obsolete. More recent literature suggest new metrics such as Befecadu Tamrat’s 1988 Combat Cycle Time (CCT), which calculate and compare the time of an aircraft to point its nose (but not flight path) toward the enemy, unload ordinance, and regain lost energy (speed) under various different conditions (Graph 2), which means the traditional focus on the aircraft’s performance within the plot no longer applies (energy conservation’s no longer the major focus, reaction time is.)

The F-35, as reported by test pilot Lt. Col. Matthew Kelly, has a very similar E-M diagram to the F/A-18, but offers better acceleration at certain points of the flight envelope. The F/A-18, been another aircraft capable of high alpha maneuvers[7] and a 7-G load factor as oppose to the F-16, which has a dangerous pitch-up tendency that forced the designers to limit its AoA to 30 degrees, and hence possessws an inferior CCT.

Graph 2: The shift of focus onto the boundaries of the E-M plot under the CCT metric

Graph 2: The shift of focus onto the boundaries of the E-M plot under the CCT metric

This metric perfectly illustrates the superiority of the F-35 within the context of the ROCAF’s potential engagements with the PLAAF, as the lack of any serious SEAD (Suppression of Enemy Air Defense) capability on ROCAF’s part meant any engagement will quickly degrade into WVR (Within Visual Range) engagement due to the relative distance between Taiwan and China, in which the famous post-stall characteristics of the Su-27 family and the canard-equipped J-10 would allow them to enjoy significant kinematic advantages over ROCAF’s existing combat assets within the majority of the air combat regime.

Situational Awareness and the attention of the pilot as a finite resource

We’ve established so far that the kinematics of the F-35 according to traditional E-M was at least “as good as the F-16”, with far superior CCT. However the true strength of the Lightning II lies in its unique approach on the subject of Situational Awareness (SA).

SA has been an important part of air combat since the dawn of aviation in WWI, most of the top fighter Aces throughout aviation history – such as Manfred von Richthofen (80 kills), Hans-Joachim Marseille (158 kills), and Robin Olds(16 kills), all agree that been able to spot the enemy first was the deciding factor in their victories.

Quantitative studies conducted in the SEA theater (Vietnam Conflict) by the USAF (Project Red Baron) also indicate the significance of SA, with regards to initial target acquisition, whereas initial acquisition in all quarter but the rear results in the U.S. aircraft gaining most of the first firing opportunities (132:23), while rear quarter acquisition resulted in mostly the Migs gaining first firing conditions (7:37)[8].

Under these conditions, the SA factor almost determines the first firing opportunities irrespective of other factors such as aircraft type.[9]

In most of the situations mentioned above, target acquisition usually relies on what the pilots’ termed “Mk.1” eyeball or using un­aided vision (i.e. no radar, binoculars, etc…) to spot the enemy, – WWII and before as a consequence of the pre-radar days and the SEA theater as a consequence of the rules of engagement, low visibility due to weather conditions resulting in visual acquisition usually within 5 miles, and the limitation of early onboard radars combined with a conscious effort by the North Vietnamese Air Force (NVAF) Ground Control Intercept (GCI) to exploit the blind spots of these radar.

And while the Mk.1 remains an important asset even to this day, the limitation of human attention was discovered during the Air Combat Evaluation(ACEVAL) and Air Intercept Missile Evaluation(AIMVAL) from 1974-78, whereas any 4 on 4 engagement the pilots would quickly lose the ability to keep track of each other’s relative position and descend into a ‘furball’ where the formation lost all coordination and combat effectiveness.

On the F-35, these two issues were approached through the incorporation of the AN/AAQ-37 electro-optical Distributed Aperture System (DAS), which not only provides the pilot with a real-time unobstructed spherical view of around the entire aircraft, both day and night, through helmet mounted displays, essentially allowing the pilot to “see through” the aircraft, but also provide aircraft/threat detection/tracking and cueing using both visual and audio means.

The Cockpit itself is composed of one 8″ x 20″, configurable touch-screen Multi-Function Display that allows the pilot to focus on the task at hand, the display also filters all the intelligence gathered by friendly assets and display them in a coherent, easy-to-comprehend manner[10]. Link-16 compatibility allows the lightning II to communicate and share intelligence with other assets such as ROCAF F-16s, E-2Ts, Kidd-class destroyers among many others, while MADL (Multifunction Advanced Data Link) capability between the F-35s allows them to act as intelligence gathering platforms through synchronizing the information gathered by all onboard instruments, from DAS to the AESA radar, effectively acting as a local force multiplier.

OODA loop, Kill Chain and Stealth

Of all the characteristics of the Lightning II, Stealth is probably the least understood yet most criticized one. However these two concepts might aid in understanding the benefit of stealth.

Incorporating his experience during the Korean War, Colonel Boyd also came up with the concept of the OODA loop – observe, orient, decide, and act. While the interpretation of the loop varies with application, the implication for air combat is rather straight forward – observe the incoming threat, orient yourself according to your training, personality, and even culture, make a decision on the maneuver you’re going to take, and act on it. So what does stealth means in the OODA loop? What does a lower RCS actually represents? The answer lies in merging the concept of SA with the OODA loop. A lower signature, be it RCS, thermal, audio, or visual, allows you a better chance to cut into the enemy pilot’s OODA loop, and continues to interfere with the observation and orientation process.

The Kill Chain presented another way to understand the utility of stealth aircraft in military operations. The Kill Chain represented all 6 stages of the target cycle – Find, Fix, Track, Target, Engage, Assess (F2T2EA), with the usual focus been to compress the time spent in each of the stages[11]. For a threat force encountering a stealth asset, it undermines and prolongs every single stage of the Kill Chain., and hence compromising the threat force’s effectiveness in dealing with not only the asset, but also other friendly units

Limited Airspace, limited manpower, and Strategic Initiative

At any given day, ROCAF has about 2-3 sorties of combat patrols consisting of 2 flights of 2-ship formation over the island, with additional 5-minute and 15-minute stand by aircrafts on the tarmac. Considering the strategic initiative possessed by the attacker, and the relatively limited endurance of combat aircraft, especially the F-CK-1, the importance of each and every one of these airborne asset could not be overstated.

The limited manpower, more specifically the pilots. Reflected on a cockpit ratio[12] of less than 1.5 as oppose to 2.5 enjoyed by the USAF could spell serious problems in the form of insufficient sortie generation down the road.

The limited airspace, as represented by both the physical space and the PLAAF’s practical capacity to direct attack waves on the other hand, provide more benefits to the defender then the attacker, as the attacker enjoys the relative freedom of movement unimpeded by escort/SEAD duties or the ordinance load.


Although the horizon for delivery even if Taiwan were to order the F-35s today remains distant at 10-15 years depending on negotiation and the decision made by tier3 /SCP partners such as Singapore and Australia, this could actually work to Taiwan’s advantage by allowing or prices as low as 85 million per aircraft at 2019 dollars (for the Australian Air Force), and since F-35 has consistently come in under the estimated budget, with LRIP 7 (2015 delivery) budgeted at 126.8 million and cost 98 million instead per aircraft, one could expect a total program cost of 60 aircraft at somewhere around 5.5 billion dollars for the ROCAF. A very reasonable amount considering the F-16 A/B “Peace Phoenix” program cost of 60 billion at 1992 dollars spanned over 9 years of special budget.

Concerns for the Lightning II’s potential “offensive” characteristics violating the TRA originated from a fundamental misunderstanding of the spear and shield paradox. Just as the examples mentioned earlier in this article, sensitive characteristics could often be limited through software modifications while the stealth technology was always considered fit for potential export, and without proper SEAD, AWACs, EWOPS support and proper munitions, even the F-35 would suffer unsustainable losses within a short timeframe in any sort of offensive operations, limiting its potential utility for the ROCAF strictly at air superiority.

The above mentioned factors influencing the Cross-Strait air balance all points toward a qualitative improvement with a quantitative reduction in ROCAF combat aircraft, with the difficult situation Taiwan faced on the international stage, the F-35 remains te only viable option possessing 5th generation capabilities delineated in previous paragraphs. While the timetable for F-35’s development might not be compatible with the immediate needs of ROCAF (currently in LRIP, with IOC expected in 2015 for the US), there is little doubt that the F-35 lightning II will eventually join the ROCAF order of battle.

*Liao Yen-Fan is a graduate of National Chengchi University and former intern with the Formosan Association for Public Affairs. He can be reached for comment at

This piece is a version of an article written for Strategic Vision for Taiwan Security, published by Center for Security Studies at the Institute of International Relations, National Chengchi University in cooperation with National Defense University. Electronic version of Strategic Vision 16 can be accessed here.


[1]According to the British Air Power Doctrine AP3000, Control of the Air assert itself through 7 degrees ranging from Air supremacy, wherein the enemy air force is incapable of effective resistance, to Air Paralysis, where friendly forces are totally incapable of offering resistance to enemy Air Power.

[2]Initially the static thrust of the F-CK-1 when landing gears are down were limited by software to 8350lb, which indirectly limited the role of F-CK-1 into little more than air defense.

[3]The A-7 was forced upon the air force in the name of commonality by McNamara, which created various problems that wasn’t solved until the end of the McNamara era and the decline in power of OSO/sd.

[4]Fighter Mafia was an unofficial lobbying group within the Air Force centered around Boyd, Riccione and Pierre Sprey advocating the adoption of an aircraft completely conform to the requirement of the E-M theory, which influenced the establishment of the LWF program – F-16.

[5]A leftover term from McNamara’s reign as the Secretary of Defense, in which the system analysis approach became infamous for comparing aircraft based on out-of-context performance metrics on paper. Performance requirements for new projects were also set on paper without any development phase, hence the name “paper aircraft”. once the project commences it was next to impossible to stop it.


[7]Maneuvers conducted under High Angle of Attack (AoA), which describe the angle between the vector of incident airflow and the chord line of the airfoil, a high AoA will often create high induced drag which eventually slows the aircraft down enough to cause stall.

[8]Project Red Baron Vol. IV

[9]“It was determined that on this subset of encounters, four factors were correlated with the results in a complex way – enemy aircraft type, quadrant [Acquisition clock position], relative altitude, and acquisition range. (The latter two factors, while statistically significant, had a small effect upon results compared to quadrant). No significant statistical difference was noted between the results achieved by the different U.S. aircraft types, when adjusted for relative starting position. No significant difference could be detected among the three non-rear quadrants….” Project Red Baron Vol. IV

[10]Employees of the Lockheed Martin’s flight demonstration center spoke at an interview that some of the kids were doing much better than a lot of trained pilots as a result of this intuitive display.

[11]” Compressing the Kill Chain”, Air Force Magazine March 2003

[12]The ratio of the number of active-duty pilots divided by number of available aircrafts.

2 responses to “Top Gun: A Case of F-35 for Taiwan

  1. Pingback: Taiwan’s fighter jet fleet: Inventory and Procurement Options (2015 update) | Taiwan in Perspective·

  2. Pingback: Defense of Taiwan Post-2016 Elections: Legacy and New Challenges of Military Transformation | Taiwan in Perspective·

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