F-35, F-22 and B-2 vs China's Underground AIrbases

2011-02-17 (China Military News cited from ausairpower.net and written by C. L. Mills) -- 16 October 1964 was a momentous day of China. At 07:00 GMT, it exploded its first nuclear bomb called '596' – named after the year and month the nuclear weapon program started. On 17 June 1967, China successfully exploded its first Hydrogen Bomb. It took the United States more than seven years from its first A-bomb test to its first hydrogen bomb test, the USSR, four years, and the UK, four and a half years. In China, it only took two years and two months.

After the ravages of World War II, China made a remarkable recovery. However, after assessing the devastation at Hiroshima and Nagasaki, and participating in the Korean War where USA forces pushed back to the 38th parallel and monumental air battles raged, the Chinese leadership must have felt that their country, and especially their armed forces, people and cities, were nakedly exposed to conventional and nuclear attack.

Chinese Fighters entering underground Hanger

Their response was breathtaking in its scope and execution – tunneling into many mountains and building airbases with underground hangars, equipped with blast doors at the entrances. Aircraft could be hidden, maintained, armed and launched in complete safety from attack by period nuclear weapons. Personnel and armaments have a place safe from attack. No doubt the Chinese were aware of the use of the 'Tallboy' to attack the German submarine pens and underground factories, and would have made provision in the design for resistance to attack from 'earthquake' bombs. The use of licensed T-14/VB-13 "Grand Slams" dropped by B-29s in Korea by the US Air Force would have been observed very carefully by the PLA.

In terms of effective military defences, these airbases with underground hangars rank with the Great Wall of China, built to hold back the barbarians invading from the north. The Great Wall was a huge impost on the population in terms of cost of construction and cost of garrisons; in the case of airbase with underground hangars, the cost is 'sunk' and the cost of these defences is a fraction of equally safe protection of military assets exposed on the surface – an ongoing military bargain. Sun Tzu had some advice, not for China, but for a nation contemplating attacking the installations:

Thus the highest form of General-ship is to balk the enemy's plans; the next best is to prevent the junction of the enemy's forces; the next in order is to attack the enemy's army in the field; and the worst policy of all is to besiege walled cities.

The rule is, not to besiege walled cities if it can possibly be avoided.

The monograph 'Assessing PLA Underground Air Basing Capability' by Sean O'Connor and Dr Carlo Kopp is a seminal study of the history and modern use of China's Super-Hardened Underground Basing. Far from being a relic of the Cold-War, these facilities confer a substantial capability to China in its ability to generate substantial air power and protect the force-in-being. In an era of 'Spy Satellites', the recording of normalcy patterns and observation of preparation for offensive and defensive air and aerospace operations is completely denied. If a country wishes to effect a 'capability and operational surprise', underground basing is an invaluable resource. Air Power Australia's recent 'Long March' NOTAM illustrates this point.

However, there is no such state as 'invulnerability to attack'. An assessment of weaknesses in these underground installations can be made by Western observers using a process called 'Red Force Analysis' in which the vulnerabilities to attack are examined, likely attack profiles assessed, and necessary responses identified – all from a Chinese perspective. This process is repeated until the Analyst is satisfied that one of two conditions is reached: the installations are acceptably safe from attack, or that they cannot be reasonably or economically defended, and alternative military capabilities are sought. The process is often called 'Capability Gap identification and closure'.

We can return to Sun Tzu's 'The Art of War' for guidance:

Now the general who wins a battle makes many calculations in his temple ere the battle is fought. The general who loses a battle makes but few calculations beforehand. Thus do many calculations lead to victory, and few calculations to defeat: how much more no calculation at all! It is by attention to this point that I can foresee who is likely to win or lose.

In respect of military method, we have, firstly, Measurement; secondly, Estimation of quantity; thirdly, Calculation; fourthly, Balancing of chances; fifthly, Victory.

Using this discipline is called 'Weaponeering' which is part of the 'Targeting Cycle':

Targeting Cycle Phases

If the Commander's Objective is to neutralize or destroy PLA-AF air combat capability, it will be necessary to destroy aircraft in the air or on the ground. With China's air combat fleet becoming more numerous, more survivable and lethal, and more youthful by the day, and the USA's fewer, less survivable and lethal, and more geriatric and/or uncompetitive by the day, destroying aircraft on the ground is more likely to succeed. This objective inherently requires attacking the underground bases.

Attacking mountains, even with airburst nuclear weapons, is futile. The entrance to an underground base is its weakest point, and the US has several weapons for the task, and recent experience in successful attacks on Hardened Aircraft Shelters (HAS). Generally, these are a bomb or warhead with a hardened case capable of penetrating several metres of rock before delay-fusing an 'energetic' explosive. The Monograph identifies several weapons ranging from the 285 lb GBU-39 Small Diameter Bomb, through larger bombs in the 2,000-4,800 lb class which can be delivered by some tactical aircraft, to the modern equivalent of the 'Grand Slam' - the Massive Ordnance Penetrator GBU-57A/B, only deliverable by large bombers such as the B-52, the B-1B and the B-2.

The US also has cruise missiles such as the RGM/UGM-109E Tomahawk Land Attack Missile and the AGM-158 JASSM with specially designed penetrating warheads.

Defence against these weapons starts with passive measures such as blast doors, tunnel design that blocks overpressure waves, and 'burster slabs' that deflect the bomb and blast away from vulnerable areas of the underground bases. While videos of the penetrating weapons look impressive, passive defences such as burster slabs and deflection grids are cheap, effective and quickly replaceable.

Using a 'layered' system of defence, China might employ active point defences with systems such as the LD-2000, based on the Type 730 CIWS "Sino-Goalkeeper", or imported Russian Tor-M2E and Pantsir S. Adaptations of the HQ-6D Aspide and HQ-7B Crotale are also feasible.

Such "Counter-PGM" systems are designed to detect, track and destroy swarms of Precision Guided Munitions (PGMs). Placing systems such as the Pantsir S in pre-determined locations with good detection-views and arcs-of-fire would destroy inbound PGMs during an attack with a high kill probability. Some would still get through the defences, but in terms of the Targeting Cycle, this would increase the number of attacks needed to achieve the required level of effectiveness.

Therein lies the next problem for US Air Campaign Planners – surviving the ingress and egress. For air-delivered weapons, current planning says they will have a choice of aircraft such as: F-15E, F-22A, F-35A/C, B-52H, B-1B and B-2. China has an extensive and highly Integrated Air Defence System (IADS), and with sensors operating on frequencies from HF to X-Band. Only 'Low Observable' aircraft with the necessary combination of range and payload are employable, as early detection and well prepared and capable air forces will detect and destroy 'strikers' inbound and the survivors outbound. Depth-of-penetration matters in deep strike, creating many more opportunities for detection and fire against threats compared to the environment of fighting along a FEBA (Forward Edge of Battlefield Area). An attacker also exposes the rear hemisphere of the aircraft as defences are bypassed and any weaknesses in observability from these aspects, as is the case of the from-below-abeam and back-end views of the F-35 JSF, increases the chances of loss. This survivability requirement effectively limits the choice to the B-2A, F-22A and the F-35, if escorted by F-22As to clear defences along the way.

Each aircraft has its own strengths and vulnerabilities. The B-2A has the size to achieve the necessary 'Low Observability' across the spectrum of IADS search frequencies, and has the necessary range and payload, and can carry the vital GBU-57/B MOP "earthquake bomb". But with less than 20 operational aircraft and a requirement for many sorties, tactically repeated as the attacked facilities are repaired and reopened, mounting a successful campaign with such a small number of platforms is problematic at best. The aircraft is large and limited to about Mach 0.85, so intercept, while having a low probability of success, is possible and would have dire consequences in a fighter versus unarmed bomber engagement.

Tactical planners would quickly find that 20 B-2As is insufficient to mount a campaign against a target set of more than 40 airbases with underground hangars. Fortunately, there is a simple, low cost and timely solution: build more aircraft. The tooling is intact, and with the high development cost 'sunk', the cost of 'new-build' B-2Bs would be a fraction of the cost attributed to B-2As, where the huge development cost was distributed across only 21 aircraft.

Employment of high-value assets such as the B-2 generates a unique set of risks – a baited trap being one. Sun Tzu advised:

All warfare is based on deception.

Hold out baits to entice the enemy. Feign disorder, and crush him.

By exposing high levels of activity at a particular air base and revealing a set of attractive targets, plus some inventive cyber-war mis-advice, could entice an attack. A B-2's attack, like that of a silent submarine is an 'indiscretion', and when the bomb-bay doors open and the weapons fall, the attacked then know that a B-2 is in the vicinity. Swarms of fighters can then be launched and seek out the B-2 Spirit. Even though the probability of an intercept by an individual aircraft is low, when that probability is multiplied by the number of interceptors, the chances of the B-2 being intercepted become significant. This is another argument for additional aircraft – an ability to sustain losses and maintain an effective capability.

Such "Counter-PGM" systems are designed to detect, track and destroy swarms of Precision Guided Munitions (PGMs). Placing systems such as the Pantsir S in pre-determined locations with good detection-views and arcs-of-fire would destroy inbound PGMs during an attack with a high kill probability. Some would still get through the defences, but in terms of the Targeting Cycle, this would increase the number of attacks needed to achieve the required level of effectiveness.

Therein lies the next problem for US Air Campaign Planners – surviving the ingress and egress. For air-delivered weapons, current planning says they will have a choice of aircraft such as: F-15E, F-22A, F-35A/C, B-52H, B-1B and B-2. China has an extensive and highly Integrated Air Defence System (IADS), and with sensors operating on frequencies from HF to X-Band. Only 'Low Observable' aircraft with the necessary combination of range and payload are employable, as early detection and well prepared and capable air forces will detect and destroy 'strikers' inbound and the survivors outbound. Depth-of-penetration matters in deep strike, creating many more opportunities for detection and fire against threats compared to the environment of fighting along a FEBA (Forward Edge of Battlefield Area). An attacker also exposes the rear hemisphere of the aircraft as defences are bypassed and any weaknesses in observability from these aspects, as is the case of the from-below-abeam and back-end views of the F-35 JSF, increases the chances of loss. This survivability requirement effectively limits the choice to the B-2A, F-22A and the F-35, if escorted by F-22As to clear defences along the way.

Each aircraft has its own strengths and vulnerabilities. The B-2A has the size to achieve the necessary 'Low Observability' across the spectrum of IADS search frequencies, and has the necessary range and payload, and can carry the vital GBU-57/B MOP "earthquake bomb". But with less than 20 operational aircraft and a requirement for many sorties, tactically repeated as the attacked facilities are repaired and reopened, mounting a successful campaign with such a small number of platforms is problematic at best. The aircraft is large and limited to about Mach 0.85, so intercept, while having a low probability of success, is possible and would have dire consequences in a fighter versus unarmed bomber engagement.

Tactical planners would quickly find that 20 B-2As is insufficient to mount a campaign against a target set of more than 40 airbases with underground hangars. Fortunately, there is a simple, low cost and timely solution: build more aircraft. The tooling is intact, and with the high development cost 'sunk', the cost of 'new-build' B-2Bs would be a fraction of the cost attributed to B-2As, where the huge development cost was distributed across only 21 aircraft.

Employment of high-value assets such as the B-2 generates a unique set of risks – a baited trap being one. Sun Tzu advised:

All warfare is based on deception.

Hold out baits to entice the enemy. Feign disorder, and crush him.

By exposing high levels of activity at a particular air base and revealing a set of attractive targets, plus some inventive cyber-war mis-advice, could entice an attack. A B-2's attack, like that of a silent submarine is an 'indiscretion', and when the bomb-bay doors open and the weapons fall, the attacked then know that a B-2 is in the vicinity. Swarms of fighters can then be launched and seek out the B-2 Spirit. Even though the probability of an intercept by an individual aircraft is low, when that probability is multiplied by the number of interceptors, the chances of the B-2 being intercepted become significant. This is another argument for additional aircraft – an ability to sustain losses and maintain an effective capability.