The Armed Helo In The Land Battle

Fortunately, the Hughes Tow guided weapon system was at that time on a demonstration tour in West Germany and was promptly flown out to Vietnam to help stem the invasion from the north. In the ensuing action a total of 89 rounds were fired, mainly from two Bell UH-1Bs fitted with XM26 fire control systems. Most of the targets were in scrubland (not jungle) and only a few were on the road, hence low-level attacks in the European fashion were generally impossible. In any event, US Army tactics at that time called for sufficient height to keep the Tow guidance wires clear of the trees, hence the weapons were delivered in long, shallow dive attacks. Some were released outside the maximum firing range, but 73 hits were scored (an 82 per cent success rate), all resulting in target kills. The vehicles knocked out included 10 T-54s (36-tonne main battle tanks), eight M-41s (old US-built 23-tonne light tanks) and six PT-76s (14-tonne light amphibious tanks). The helicopter was well and truly launched as an anti-tank weapons platform!

The Vietnam War is better remembered for the US Army’s widespread use of gun- and rocket-armed Hueys, initially squad-carrying helicopters with door-mounted guns (as applied with modified mountings to RAAF Hueys), and later as dedicated Cobras with miniguns and rocket batteries. Ballistic weapons are now fitted to the helicopters of many services (for example, French Army Aviation uses Pumas armed with 20 mm cannon), but shortly around 20 of the more serious operators will possess helicopters with anti-tank guided weapons (ATGW).

Since Australia has so far shown no interest in the use of helicopters as tank killers, it may be worth reviewing the services that are adopting this new weapon system. France’s Army Aviation (Aviation Legere de l’Armee de Terre) has six 72-aircraft helicopter combat regiments, each of which has 30 machines armed with ATGW. The ALAT fleet includes 70 Alouette Ills, each capable of carrying four SS. 11 s, in addition to which some 11O early-model SA. 341F Gazelles have been modified to take four Euromissile Hot, and the service is now receiving 128 purpose-built SA. 342M Gazelles, each of which can carry six Hot. France is planning a third-generation anti-tank helicopter (HAC=Helicoptere Anti-Cha. r) in collaboration with West Germany, where it will be the PAH-2 (Panzerabwehrhubschrauber 2). The PAH-1 is the Bo105P, of which Germany’s Army Aviation (Heeresflieger) is receiving 212 examples, the first having been delivered in September 1979. Each of the three army corps will have a regiment of 56 of these aircraft, operating in flights of seven, each aircraft carrying six Hot missiles.

The Iranian Army has had 202 Tow-capable Bell AH-1J Cobras, some of which have been employed in the war with Iraq, which has 40 Hot-armed SA. 342L Gazelles. The Israeli Air Force has 30 AH-1 Cobras and is receiving 30 Hughes 500 MDs, the two types being used in an anti-tank high-low mix, both with Tow missiles. The Italian Army (Aviazone Leggera dell’Esercito) is carrying out trials with five Agusta A. 109s armed with Tow, and three prototypes of the A. 129 Mangusta dedicated attack helicopter are on order, with a large production order in prospect.

Japan’s GSDF is testing a pair of Tow-armed Bell AH-1S in the anti-tank role, and is planning to have 56 such aircraft produced by Fuji under licence. Kenya has 15 Hughes 500 MDs with Tow. South Korea is taking delivery ot 73 Hughes 500 MD Defenders, also armed with Tow. Kuwait has 12 Hot-armed SA. 342 Gazelles, while Lebanon has four similar helicopters fitted with 20 mm cannon and AS. 11 or 12s. Libya has an unknown quantity of Mi-24 gunships, and Morocco has 24 Tow-armed Hughes OH-6. Roumania has approximately 47 Alouette Ills operating in the anti-tank role, although the armament has not been published. Syria is in the course of receiving 16 SA. 342L Gazelles, some of which will be armed with Hot. Spain’s Army Aviation (Fuerzas Aeromoviles de/ Ejercito de Tierra) will have 60 examples of the Bo105 assembled by CASA, for use both in liaison duties and as Hot-armed anti-tank systems.

Turning to the UK, the main anti-tank aircraft is to be the Tow-armed Lynx, of which 114 are on order. Each of the four BAOR divisions in Germany and the Corps HQ will have a Lynx squadron of 12 aircraft, in addition to 12 Gazelles for the LOH role. Small in comparison with the French helicopter force, the British Army complement will in fact be roughly one-third of the helicopters requested by MoD.

The US naturally has the largest force of ATGW-equipped helicopters in the Western World. Including conversions from earlier Cobra models, by 1984 the US Army will have 987 Tow-capable Bell AH-1S. In the US Marine Corps, at least 23 AH-1Ts Improved Sea Cobras will have provision for Tow.

In the USSR, battlefield helicopters largely come under the command of the Air Force’s Frontal Aviation (Frontovaya Aviatsiya), although there are more than 3000 helicopters in Air Transport Aviation (Voenno-transportnaya Aviatsiya). The Mi-8 Hip, of which over 6000 have been built, is the principal troop-carrying assault helicopter, and the Hip-E variant is generally regarded as the world’s most heavily armed rotary-wing aircraft, having a 12. 7 mm machine gun in the nose, a total of 192 rockets of 57 mm in six pods, and four AT-2 Swatter ATGW. The more recent Mi-24 Hind is a smaller aircraft (with cabin space for eight troops, rather than up to 28), but it has armour protection for the pilot and gunner and is a much faster vehicle, with a multi-role capability. A Hind-C still holds the world’s helicopter speed record with a figure of 198. 9 kts (368. 4 km/hr). The Hind-E carries up to 128 rockets in four pods, four AT-6 Spiral laser-guided ATGW, and a nose-mounted twin-barrel 23 mm cannon. The Mi-24 has been employed operationally in both Afghanistan and the Ogaden.

In considering how the various battlefield helicopters are employed, it is noteworthy that only in the British and Australian services is control divided between the army and air force. There are also fundamental differences in the attitudes of the operators toward the armed helicopter. In the British Army, for example, it is regarded as an expensive weapons system for emergency use only. Its cost is justified in containing an enemy armoured breakthrough when the helicopter’s mobility and firepower may be the only means to delay the enemy until more conventional anti-tank forces (ie, tanks, artillery and fixed-wing aircraft) can be brought into action.

The US Army, having far more armed helicopters available, sees them in a more general application, including use in close support. This is completely contrary to the British philosophy, which regards the helicopter as survivable only when firing from behind cover, preferably in a thoroughly known defensive position, attacking fast-moving tanks that have only limited support from self-propelled flak (ZSU-23-4 and -57-2).

As dedicated tank killers, the ATGW-armed helicopters will normally operate with LOH support, a combat unit typically consisting of two or three LOHs to spot enemy armour and guide six armed helicopters into firing positions. The helicopter is a relatively small target in head-on view, but its rotor is a sore-thumb target for pulse-doppler radars. The need to minimise exposure has led to higher sight mountings, the present widely-used roof sights possibly being superseded in the longer term by mast-mounted sights (MMS) over the rotor, although all high-set sights restrict weight and sophistication, and require an initial “jump” by the missile.

Soviet plans for the employment of armed helicopters are believed to cover several roles, including the neutralising of NATO tank-killing grounds, attacks on second-echelon forces and on nuclear artillery and tactical GW, the seizure of airfields, and the insertion of sabotage teams and troops to secure landing zones. In recent military exercises, the Russians have used the Mi-24 in GW attacks on armour, the close support of advancing tanks and motorised rifle units, and fire support for assaults by the Mi-8 troop transport and the equipment-carrying Mi-6. It is conjectured (largely as a result of the 23 mm cannon on Hind-E) that the Mi-24 also has an anti-helicopter role.

Chopper vs Tank

There are several ways in which a helicopter can exploit its mobility and load-carrying capacity in the battle to stop the tanks. Firstly, it can mount a stabilised sight and a number of ATGW (some helicopters are also able to carry further rounds in the cabin) and engage enemy armour directly. This type of attack currently applies to daylight conditions with reasonable visibility and with the target vehicles on the move over open ground.

Under Central European conditions the helicopter (eg, Lynx, Gazelle, Bo105) would normally fire hull-down from behind trees or buildings, although the US Army’s forthcoming Hughes AH-64 will not have this facility, being fitted with a chin-mounted sighting system (and with considerably more armour than contemporary European helicopters). Conversely, desert or snow conditions rule out a low hover due to the potential sand/snow storm, and firings would probably take place in forward flight at 30-40 kt (55-75 km/hr) in order to avoid this problem, yet none come too close to the enemy. Such conditions make ground movements much easier to see, hence the lead vehicle is an easy target, but those following May well be obscured.

The visibility restrictions on the helicopter’s use of ATGW militate strongly in favour of it having alternative methods of attacking armour. For example, a considerable effort is currently being directed at the development of small mines that can be dispensed from helicopters. Although not a complete substitute for the much larger mines laid by ground vehicles, these new lightweight mines can disable an AFV and thus deny selected areas to the enemy, deflecting his armoured thrust into an open killing ground.

In addition, an anti-tank helicopter with full operational flexibility can carry infantry teams that are able to attack under conditions that rule out the aircraft’s own ATGW. For example, the Lynx can carry 6 troops with four Milan missiles and launchers. If necessary, further mobility can be provided by a sling-carried, lightweight, multi-terrain vehicle such as Saboteur. Men on the ground are probably a better way to attack a stationary, camouflaged vehicle or one hidden by darkness, fog or the smoke of battle. In night attacks (when today’s helicopter can navigate, but not deliver ATGW) infantry can destroy armour by the light of flares. In desert or snow, the anti-tank section of men can make use of the helicopter’s mobility without exposing it to enemy fire.

The helicopter’s survival in the face of enemy defensive fire requires the minimising of the probability of detection and of being hit (once detected), and maximising the aircraft’s ballistic tolerance and crashworthiness. Reducing detection probability is partly a question of sighting system location (the higher the better) and the use of concealment tactics, but it also depends on the nature of the ATGW, the cruise speed of which determines the helicopter’s exposure time and rate of firing. For example, Tow currently has a maximum range of 3750 m and a corresponding flight time of 21 sec (although Tow-PIP would introduce an uprated rocket motor), while Hot has a range of 4000 m and a flight time of 17. 3 sec.

Whereas first-generation ATGW used command guidance to line-of-sight (CLOS), second-generation weapons such as Tow and Hot use semi-automatic guidance (SACLOS), the operator simply holding the stabilised sight on the target and the fire control system generating corrective signals according to the distance of the missile flares from the line-of-sight. This system is said to raise hit probability from around 50 to 95 per cent. The helicopter’s exposure could in principle be reduced by the development of homing missiles, although this raises the threat of decoys.

The forthcoming Rockwell Hellfire reduces exposure time by the use of a supersonic cruise, but it can also be operated in a fire-and-forget mode, homing on to a target illuminated by other laser sources. With different laser codings, Hellfire can attack multiple targets simultaneously, the Hughes AH-64 firing up to 16 of these missiles in a single salvo. It can also attack over-the-horizon targets up to ranges of 5000 m by virtue of its ability to search for the laser reflection after launch.

Small aircraft size reduces the chance of detection and also the probability of being hit by ballistic rounds. Long ATGW range also reduces the effectiveness of return fire from automatic weapons. For example, the ZSU-23-4 Shilka has a maximum range of 5000 m, but its effective range is roughly half of this. Whether there is any point in producing ATGW of extremely long range is open to question since target detection range will normally limit the conditions of engagement. In ideal visibility, a tank in the open country may well be detected (and identified by means of a stabilised telescopic sight) at 6000 m, but in Europe the probability of a sighting beyond 4000 m is slight.

Other important factors in minimising the chance of being hit by return fire include aircraft agility (ie, acceleration and g-capability), engine plume suppression, and the use of IA-decoys and chaff dispensers. The probability of surviving hits is basically a matter of armour protection for the crew, engines and transmission, plus flight control system duplication, self-sealing fuel tanks and the use of composite blades, which appear to absorb machine gun hits reasonably well.

To summarise the present situation, the armed helicopter (as demonstrated in many field exercises) can achieve an excellent kill-ratio in daylight, and clear weather conditions against the moving, buttoned-down tank by using guided missiles for stand-off attacks from outside the effective range of return fire, and by concealment techniques which are made possible by high-mounted sighting systems and which benefit from close control by escorting LOHs. However, most present-day attack helicopters would benefit from modification programs to improve survivability.

Future helicopters, notably the Hughes AH-64 (which is scheduled for first delivery to the US Army in November 1983, given a production go-ahead in December this year), are aimed at extending anti-tank capability into night/adverse weather conditions. However, until a full all-weather capability is achieved, there will be a strong argument in favour of helicopters that are highly flexible operationally, able (when necessary) to attack armour by landing anti-tank teams or by laying minefields. Indeed, this approach may yet prove to be more cost-effective than the highly sophisticated, dedicated attack helicopter in the anti-armour role. It may also be argued that, for smaller countries in particular, the multi-role helicopter provides valuable economies by reducing the number of types in the inventory, and by facilitating inter-service commonality.

Chopper Against Chopper

Since the introduction of Hind-£ early in 1979, there has been considerable talk in the West about the use of helicopters against helicopters. If the attack helicopter can standoff outside the effective range of automatic weapons and can present a difficult target to ground-launched missiles by virtue of a hull-down firing position and IA suppression, then the obvious defence for the advancing tank is to send some form of aircraft after its attacker, eliminating the latter’s disadvantages of firing range and terrain/building/vegetation screening.

In open terrain it may well be that the best answer to the anti-tank helicopter is a fixed-wing aircraft, as West Germany’s Luftwaffe proposes to use the Alpha Jet, and Britain’s RAF and the USAF are considering using the Hawk and A-10 respectively. However, in circumstances in which the attack helicopter can hide, the fixed-wing aircraft is at a disadvantage, being forced to circle at low speeds, yet sufficiently high to be an easy target for lightweight SAMs or opposing fighters. The best answer to the anti-tank helicopter is then probably another helicopter, and the main question is how to arm it. The primary armament of Hind-E (as stated earlier) appears to be a 23 mm cannon and AT-6 Spiral missiles. It is conjectured that both types of armament could be used against helicopters, implying that a laser designator for AT-6 could be held on the target by means of a stabilised sighting system, or held on automatically by means of a TV-sight with optical contrast lock-on, or perhaps that a different form of guidance can be fitted for the air-air role Gust as a different type of warhead might well be preferred). It is noteworthy that the AT-6 is credited with a range of 7500-9000 m.

Considering firstly the cannon as an anti-helicopter weapon: it is relatively inexpensive, fires a round that (in the event of a hit) has a good chance of inflicting serious damage on any aircraft, and has the major advantage that it can be flexibly mounted on the aircraft. On the other hand, a rotary-wing aircraft is not the ideal platform for an automatic weapon that is to be used for anything but area suppressive fire (the purpose of the 30 mm Chain Gun on the AH-64), hence its effective range is severely limited in the air-air role, perhaps to as little as 1500 m. Nonetheless, in the event of two low-flying helicopters sighting each other at short range, a flexibly mounted cannon could well prove the decisive armament.

In the more general case, a missile armament is to be preferred for effectiveness at longer ranges and is easier to install than a remotely-controlled barbette. Infra-red or laser-spot homing produces a reasonable probability of a direct hit which, in turn, gives a virtually certain kill due to the sheer weight of the explosive. Because of the helicopter’s warlord restrictions, attention has turned to the adaptation of lightweight SAMs to the air-air role.

At Farnborough last year, Hughes showed the 500 MD Defender 2 equipped with a 30 mm Chain Gun and a pod containing two General Dynamics FIM-92A Stinger missiles. The US Army replacement for Redeye, the IA-homing Stinger weighs 15. 1 kg and has a range of 5000 m. In the UK, Shorts are proposing the use of the CLOS-guided Blowpipe, which weighs 11 kg and has a range of over 3000 m. At the Paris Show in June, Sweden’s Bofors proposed the use of the beam-riding ABS70 round, which weighs 15 kg and has a range of 5000 m. On the Soviet side, the SA-7 Grail weighs 9. 2 kg and has a range of 3600 m, while the SA-9 Gaskin is reported to weigh approximately 30 kg and has a range of 6000 m. Having witnessed the helicopter usurping to some extent the roles of the tank and the armoured personnel carrier, it thus appears that we are about to see the missile-armed helicopter taking over at low altitude from the fixed-wing aircraft in the fight for control of the air over the battlefield.