air
defence
Raul Colon
e-mail:rcolonfrias@yahoo.com
PO Box 29754
Rio Piedras, Puerto Rico 00929
In the last two decades, only a handful of
combat aircraft have been downed by anti aircraft systems. This has more
to do with the fact that the majority of the high intensity conflicts
during that time mostly involved the use of aircraft designed in the
United States. These aircraft were employing the latest in electronic and
avionics packages as well as more advanced electronic countermeasure
systems. Add to this fact the new air tactics developed and you have a
combination of circumstances that had enable Western aircraft to defeat
and, in most cases, destroy enemy’s anti aircraft systems (AAS).
Not since the early days of the Korean War
(almost fifty years ago) had any US Army or Western-equipped ground force
been attacked from the air. In fact, today the US Army maintains only a
two level air defence system instead of the multi layer umbrella it used
to have since World War II. Today’s Army uses the short range, shoulder
firing Stinger missile as its only short area air defence platform. For
longer range, the Army employs an upgraded version of the Patriot system.
The fact that the US Army only employs these two systems is a testament to
the US Air Force ability to achieve and maintain air superiority over its
enemies during the past six decades. It also a rebuff of the gloomy
predictions made after the Great War in 1918.
During the first three decades of air
traffic, military commanders thought that early air platforms such as the
famous German, British or French mono and biplanes were easy prey to
ground based gun fire. They believed that due to the fragility of those
early aircraft, they would be shattered by a powerful, ground delivery
shell or shells. But to the amazement of many commanders and visionaries,
those gloomy scenarios never materialized over the Western or Easter
front. Nevertheless, Luftwaffe leaders in Germany prior to the start of
World War II still clung to the idea of shooting down a high percentage of
enemy aircraft with AAS fire. At the centre of their assumptions was
famous German 88mm anti aircraft gun shell.
Engineers and commanders alike believed that
it would take only fifty rounds of this impressive shell to down an
incoming plane. Unfortunately for the Germans, the reality turned out to
be very different. Between the summer of 1940 until the end of hostilities
in May 1945, the German rate of AAS successes remained remarkably constant
at 12,000 shells per aircraft. Again, the prognostication of the demise of
the aircraft proved to be greatly exaggerated. Notwithstanding the German
experience, commanders of all nations again asserted the demise of the
aircraft when the first anti aircraft missile batteries began to appear in
the early 1950s. But again their confidence in those ground based system
was misplaced. During the 1960s and 1970s and in the mist of highly
involved conflicts such as the Vietnam War and the series of wars between
Israel and its Arab neighbours played out during those years the missile
to downed aircraft ratio was about one per fifty launched missiles.
Although the ratio appears to have decreased dramatically, close
examination of the data shows that the improvement was not as great as
originally believed. Firstly, the fifty missiles used to down an aircraft
was the same cost as 12,000 of the dreaded 88mm shells used in the early
1940s. Second and more importantly to the development of AAS is the fact
that for the first time in history, incoming aircraft had developed the
tactic of engaging AAS instead of going around them.
Although the ratio may not show it, AAS has
proved to be a real defensive deterrent, but not the all stopping platform
early visionaries thought it will be. As it is currently employed, a
sophisticated AAS is developed with the idea of attrition. To make
aircraft packages suffer as many losses as possible in order to deter
further incursions. It is also designed to manoeuvre the aircrafts’ path
towards a designated “target’ area where a concentrated fire could be
mustered on only one sector. A by-product to these two factors is the
profile of the aircraft approach that the AAS forces it to follow. In
order to avoid heavy saturated AAS sectors, an incoming aircraft must
follow a low altitude flight profile. Such a profile will expose the
aircraft to a heavy concentration of small arms fire. It is in this, low
level profile, that the majority of aircraft are shot down by small
calibre, ground based fire. Case in point: North Vietnam.
In that high intensity conflict, over eighty
percent of all aircraft loss was due to low altitude gun fire. The ratio
was somewhat smaller in the 1973 Israeli-Arab war. Almost fifty percent of
Israeli jets lost were by heavy machine gun fire. One statistic that
remained very similar in both conflicts was the shell-to-down aircraft
ratio. Almost 10,000 machine gun shells were needed to shoot down a single
airplane. A ratio closely similar to that achieved during Word War II.
Fixed wing aircraft are not the only flying platform affected by low-level
ground fire. Helicopters are probably the most exposed flying machine.
Their profile: a low flying pattern cannot be altered to counter AAS’
small calibre fire. They run low to the ground to avoid such systems, thus
making them perfect targets for small fire. Unlike the fix wing aircraft,
their main threat does not come from heavy machine gun fire, but from RPGs
(rocket propelled grenades). For RPGs to work, they need the helicopter to
be very close (one hundred metres or closer) to have any opportunity to
engage an incoming helicopter. Helicopter pilots know this. They know that
the most likely areas for RPG attacks are city streets, canyons and river
lines. Pilots also change routinely their takeoff and landing patterns
while operating from forward bases. They don’t use the same incursion
pattern twice and when they fly in formations, they do it with a 500 meter
+ gap between air platforms.
No matter which system the ground defence
units utilize, there are four procedures that will always be employed.
It’s a four step defence drill aimed to shoot down an incoming aircraft.
The first step is to detect the air platform. Any aircraft, no matter how
big they are, is just a “blip” in the vastness of the sky. It is also
because of this vastness that AAS’s radars cannot cover the entire skyline
forcing AAS’s managers to select entry points. These “points” represent
the expected incursion areas an incoming aircraft might take. Planners as
well as pilots know this and they try to minimize the detection area by
engaging AAS’s radars with advance electronic countermeasures (EC). If ECs
did not suppress the enemy’s ability to read the aircraft, then the pilot
will use the old age trick to “decking his airplane”. Most conventional
radars arrays can not look below their profile scope altitude (usually
between 100 and 300 meters from the ground) thus providing the aircraft
with an invisible window.
But this window is not without peril. It is
in this low altitude area were the heavy concentration of small arms
ground fire occurs. The third measure an aircraft can employ to avoid
detection is stealth. A technology currently use by the United States in
its massive B-2 Stealth Bomber, the new F-22 Raptor air superiority
fighter and to a lesser extent, on the broad based, F-35 Lighting II
program. Others countries are now poised to break into the US stealth
monopoly mainly with unmanned platforms. To counter the low flying tactic,
in the early 1960s the US developed the concept of the Airborne Warning
and Control System (AWACS). AWACSs platforms not only can be
forward-looking posts, but because they are airborne, they have look-down
capabilities as well. Unfortunately, the sheer vastness of the earth comes
into play here too. It is virtually impossible for any current radar
system, ground based or airborne, to cover the complete spectrum of the
sky.
If an incoming aircraft is detected, the next
step is to acquire it. Before engaging any aircraft, AAS’s operators must
make sure that the plane is either a friend or foe and then proceed to
chart a flying course for it. The charting of the course is one of the
most important aspects of the AAS procedures. In order to engage the
aircraft, the AAS needs to have it within range of its surface to air
(SAM) batteries. Detection and acquisition of target have a longer range
spectrum than that of the aircraft’s weapon package. This is significant
because the AAS is designed to engage and destroy any aircraft as far from
its territory or defence area as possible. Most conventional ground radars
can detect an aircraft up to 550Km away and at a top altitude of 30Km. On
the edge of the 550 spectrum, the probability of making an accurate
identification of the aircraft is between 45 to 55 percent. The percentage
improves as the aircraft move forward the radar covering zone.
For example, at 375Km, the probability ratio
jumps to 90%, a high percentage, but one that still leaves a substantial
margin for error. This “probability window” between the top operational
range of the radar and the 90% point is the area where pilots begin to
implement their countermeasures (EC or low flying patterns). An advanced
AAS can detect and acquire an aircraft within one minute of the incursion.
If both areas are successfully taken, then the AAS shifts towards the
tracking phase. Is essential for the AAS to track the inbound aircraft
long enough until System’s batteries can be brought to bear. The tracking
aspect of the AAS engagement begins while the aircraft is outside the
System’s weapon platforms operational range. Once inside the weapons’
spectrum, the first platform to be employed are the long range SAMs.
Afterwards, the guns aspect of the system is engaged. Because guns are
shorter range weapons, their radars have to track the aircraft the
longest. The last step of the AAS procedure is the destruction of the
aircraft. Even if the AAS is successful in detecting, acquiring and
tracking and incoming plane, this does not translate into a successful
engagement. In fact, the majority of engagements favour the aircraft.
Modern flying machines are built with very advanced defensive systems that
it makes it difficult to shoot down even by a direct hit.
Air defence systems are built around various
sub-systems such as missile, small calibre projectiles and even nuclear
weapons. The size and complexity of the missile system varies depending
upon the warhead. The smaller missiles, primarily the low altitude, short
distance portable systems utilize a small warhead (5-7 pounds). These
missiles are very limited due to their lack of size and proximity fuse (a
radar mechanism that allows the missile to explode near the target). The
smaller missiles are heat seeking devices that most of the time can only
be fired from behind the aircraft’s tail. Frequently, portable operators
have only a few seconds (10-12) to fire the missile before the aircraft is
out of the weapon’s range. This kind of missile operates at an altitude no
greater than 1,000 meters. Because of the smallness of the warhead, the
portable missiles have to hit the target almost in the middle of the
fuselage or on one of its engines in order to be able to shoot it down.
Meanwhile, Anti Aircraft Artillery (AAA) gun’s shell range between 20 and
57mm in size.
The gun shells need a direct hit to cause any
type of damage. With a single hit, it probably will not be enough to bring
down the plane. This is why gun shells are use in high quantities. Shells’
sizes also vary. A regular 20mm shell weighs in at around 3.5 ounces, 23mm
weight 7 ounces, 40mm weight 30 ounces and a much powerful 100 ounces. The
guns are usually aligned in a multi-barrelled configuration. Two prime
examples of these platforms are the well regarded Russian ZSU-23 which
mounts four 23mm guns and can fire up to 60 shells per second. The second
battery is the Swiss-made GEPARD. The GEPARD consists of two 35mm guns
delivering a rate of 18 shells per minute. These weapons and others like
them are used primarily against helicopters and slow moving, fixed wing
aircraft. But upgrades in helicopter armour has made the use of the lower
calibre guns almost obsolete. AAS also deploy some of the largest guns
ever devised. The much discussed 75mm (and even larger systems) are a real
threat to any airborne platform. These large shells usually have a
proximity fuse and fragmentation warheads. 75mm and beyond shells are
expensive to develop, thus they are not widely available. Also, as with
the other shells, although not in the same ratio, 75mm shells need to be
used in numbers to achieve the AAS objective.
Gun engagement procedure has not changed much
since the days of Word War II. A massive barrage of shells is thrown up in
the area where the radar predicts an aircraft will be appearing. The main
user of these high calibre weapons are the Russians along with many of
their client states. The AAS also employs a large number of small calibre
weapons. This use goes all the way back to the Great War when attacked
ground troops would fire machine guns, rifles and even handguns in the
air. This was not only done to down an aircraft but also to boost morale
at the dreaded Western Front. The “fight back” idea behind the small
calibre attack still permeates battlefields today. Although it is
extremely rare to bring down an aircraft utilizing such mechanism, most of
the times pilots are unaware of small calibre action, it still can inflict
some damage to the airframe.
The other spectrum of the weapons employed by
an advanced AAS is the large warhead area. Larger missiles are often more
elaborate in design and weigh more than its portable counterparts. Their
warheads are designed to, not only hit the target with more accuracy, but
in a case of a near miss, to inflict as heavy damage to the aircraft as
possible. Some large warhead missiles utilized a shaped charge to direct a
flight of high velocity metal fragments towards and aircraft. These types
of warheads can be a deadly weapon if it makes it to within a 100m radius
of the aircraft. These warheads also carry the much used proximity fuse
which detonates near, not directly, the aircraft. Heavy or large warheads
are also use to shoot at helicopters. In fact, the use of dedicated
anti-tank weapons is being closely studied by military planners as a way
of shooting slow moving, low flying air platforms. The same reverse
concept was utilized by the Germans during WW II. On that occasion, the
Nazis employed their excellent 88mm AAA in the tank busting role with
great success.
The deployment of an integrated AAS is done
accordingly to the System’s operational range and mobility profile. The
shorter range weapon platforms always accompanied the combat formations
while the lesser mobile systems are set up around 100Km behind the front
in order to protect supply depots and other rear area installations needed
for the continuation of the war effort. The main key for an effective AAS
alignment is the layer concept. The saturation with multiple depth areas
at different altitudes is what it makes the AAS concept work more
proficiently. Case in point: the USSR. During its hey day in the Cold War,
Russian generals and commanders were well aware that in a case of war,
they would most likely lose control over the skies, so they developed a
multilayer integrated system to deter allied incursions. The first layer
was saturated with ZSU-23 cannons with a 2Km firing range augmented by a
variety of less accurate shoulder fired missile systems. After the
cannons, lay the once feared SA-9 (8Km range) missile batteries. The
ground troops were covered by SA-7/14 and its 4Km practical range.
Immediately after the front, the Soviet placed SA-8s (12Km range) and
SA-10s (50Km) to protect the more sensitive areas supplying and
maintaining their front line troops. Today’s pragmatic budget realities
have made such multilayer systems almost obsolete in the East. Today, much
of the former USSR’s supplied countries still use some kind of layering
systems based on portable SAMs, small number of medium-to-long range
missile batteries and a few cannons. Their Western counterparts on the
other hand, rely on an integrated system of short-medium and long range
missile batteries augmented by the ultimate air defence weapon system: air
superiority.
During the past five decades the only
interaction between aircraft and AAS has pitted Western-developed air
platforms against Soviet design air defence systems. These encounters have
demonstrated to some extent the ineffectiveness of the Soviet designed
systems. During the past fifty years, the hit, not the shutdown, ratio for
a Soviet-made SAM was 50-1. Meanwhile, the Western’s SAMs ratio is almost
65% hit ratio. This is an amazing difference that speaks volumes of the
technological development of each side. In the 1970s Israel-Arab wars,
Israeli Hawk SAM batteries required less than five shots for every hit on
a Soviet-build, Arab operated combat jet. While the Arabs in the 1973 war
fired 2,100 missile hitting 85 (4%) aircraft. Unfortunately 45 of the hit
aircraft were Arabs. The US developed Stinger missiles have an even more
impressive hit percentage (near 50%) in an impressive twenty plus year
career.
The incredible success ratio of Western
aircraft against Soviet-developed AAS is the product of two converging
forces. First and foremost, the Western aircraft are more advanced than
the AAS they are facing. They also are usually fitted with the latest
electronic countermeasure packages reducing the effectiveness of the AAS’
radar arrays. Finally, the Soviet/Russian AAS developed systems are
designed with a more “fixed” operational profile than mobile providing the
incursion aircraft with a window to operate in. In the late 1980s the USSR
constructed the most advanced AAS network outside the one operated by its
satellite states in Eastern Europe. Seventy six radar arrays, twenty four
missile batteries locations and one hundred interceptor missiles were
erected and deployed in the African country of Angola. Manned by East
German technicians, the defences proved worthless against the incursions
of South Africa’s more westernised Air Force. The trend continued in both
Gulf Wars (1991-2003) and the Afghanistan operation (2001) where the
United State’s Air Force was able to suppress Russian developed AAS with
amazing accuracy.
The chart below list the most utilized air
defence systems. The Soviet/Russian developed weapon platforms are named
after NATO’s codenames. The Effectiveness Ratio is a 1 to 100 scale that
estimates the weapon’s combat accuracy and reliability. The Maximum Range
is the top altitude a system can operate without loosing its overall
capability.
WEAPON DESCRIPTION COUNTRY
E. RATIO MAX ALTITUDE RANGE
Avenger Self Propelled
System US 37
4800m 5Km
Chaparral Self Propelled System
US 18
1000 5
Hawk Mobile System
US 45
11000 30
Advance Hawk System
US 70
18000 40
M/42 Self Propelled System
US 10
1500 3
Nike/Hercules Mobile System
US 51
50000 150
Patriot Self Propelled System
US 100
24000 60
Phalanx Naval-Based System
US
47 2000 2
Sea Sparrow RIM-7h Naval System
US 32 5000
5
SM2 ER Aegis Naval-Based System
US 104
28000 180
SM2 MR Naval-Based System
US 94
25000 150
Stinger Mobile System
US 31
4800 5
Tartar RIM24b Naval-Based System
US 33 20000
20
Vulcan Self Propelled System
US 10
2000m 2Km
Rapier Self Propelled
System Great Britain 28
3000 7
Roland Self Propelled System
Germany 39
3000 6
Regular .50 caliber gun mechanism
Germany 5 1000
1
AMX 30SA Self Propelled System
France 27
2000 4
Crotale Self Propelled System
France 29
3550 9
SA-6 Self Propeller System
Russia 36
2400 28
SA-9 Self Propelled System
Russia 12
6100 8
SA-7 Fix/Portable System
Russia 11
4500 6
SA-15 Self Propelled System
Russia 21
6000 12
SA-8 Self Propelled System
Russia 26
12000 15
SA-14 Fix/Portable System
Russian 16
6000 6
SA-11 Self Propelled System
Russian 48
14000 30
SA-18 Fix/Portable System
Russia 25
3500 5
SA-17 Self Propelled System
Russia 31
3500 32
SA-16 Fix/Portable System
Russia 20
3500 5
SA-4 Mobile System
Russia 32
20000 50
SA-13 Self Propelled System
Russia 20
3500 5
SA-19 Self Propelled System
Russia 24
8000 12
ADMG-630 Naval-Based System
Russia 28
2000 2
SA-3Self Propelled System
Russia 32
25000 25
SA-5 Self Propelled System
Russia 65
30500 250
SA-10 Fix/Mobile System
Russia 45 30000
45
SA-10(MU2) Self Propelled System
Russia 94
24000 200
SA-12 Fix/Mobile System
Russia 36 25000
100
SA-N3 Naval-Based System
Russia 35
25000 30
SAN3 Upgraded Naval-Based System
Russia 38 25000
55
SA-2 Fix/Mobile System
Russia 23
24000 50
ZPU-4 Self Propelled System
Russia 10
1400 1
ZSU-23 Self Propelled System
Russia 19
2000 3
ZSU-57 Self Propelled System
Russia 14
4000 6
Gepard Self Propelled System
Switzerland 23
2000 4
Today’s air forces dedicate a great deal of
training to the suppression of AASs. Suppression of Enemy Air Defences or
SEAD is one of the most sophisticated missions any aircraft can undertake.
But, as important as SEAD is, the mission is not undertaken without
extensive research. Like air forces, AAS are encountering a greater threat
from incoming cruise missiles such as the US Tomahawk. The US and Russia
to a lesser extent, are either upgrading existing platforms or are
developing new Anti Ballistic Missile Systems (ABMS). One example of this
latest development is the much publicized Patriot System. The Patriot
first demonstrated its ability to, not only shoot down incoming aircraft,
but to intercept ballistic missiles. A trend that should continue to
develop as the situation in the air changes from the current,
aircraft-based profile.
Jane’s Aircraft Recognition Guide,
Gunter Endres and Mike Gething, HaperCollins Publishing 2002
Skunk Works, Ben R.
Rich and Leo Janos, Back-Bay Books, 1994
US Strategic and Defensive Missile System 1950-2004, Mark
A. Berhow, Osprey Publishing 2005
Russian Aviation and Air Power in the 20th
Century, Robin Highanm (editor), Frank Cass
1998
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