Why an Aircraft Carrier

Opponents of the carrier maintain that there are alternative ways and means of providing the capabilities afforded by MELBOURNE. The Navy contends that a new aircraft carrier is required to replace MELBOURNE’s capability. It is a complex and intriguing debate. But why an aircraft carrier?

Unique Qualities of an Aircraft Carrier

An historical examination of the employment of naval forces reveals a number of special advantages that make ships uniquely valuable to governments. In the main, these advantages originate from the long used and widely recognised principle of free use of international waters. By lawful use of the oceans of the world, navies have been able to achieve military advantages which are denied to other military forces. These special advantages are fundamental to the use of an aircraft carrier which can further enhance the advantage gained from being at sea by the projection of air power, either strike, air cover or air assault in the right place at the right time.

Political flexibility

Naval forces are ideal for governments to use as an instrument of foreign policy. A naval force may sail subsequent to an external event which a government sees as a possible threat to specific national in­terests in a particular area. The government then has a number of op­tions open ·10 it.

It can announce that the sailing of the naval force is a direct response to the event, it can deny that the sailing is a direct response but is merely a part of a naval exercise or it can remain silent and allow the antagonist to ponder on what course of action, if any, is be­ ing taken.

The naval forces once at sea can proceed to position themselves near the potential trouble spots without the political impediments associated with land based forces. Naval forces, unlike land-based forces, do not rely on prior international agreements before taking a position in an area of potential crisis. They do not have to “live off the land” while they wait. By remaining in the proximity of a potential or real trouble spot, naval forces display a capability for action which ground or air forces can achieve only by landing or entering the sovereign air space of another nation. The naval force provides the government with the option of influencing events without aggressive commitment of forces and allows a flexibility of options in commit­ ment or withdrawal that is not available when deploying other forces.

Base mobility

Modern aircraft can be quickly deployed from one area to another but such deployments are of little value unless the new base from which they are to operate is equipped with internal and external communications, command and control arrangements, accommodation, facilities for its own defence, workshops, ammunition stocks, spare parts and stores necessary to operate modern aircraft and a logistic train to support them. In recent times, despite the resources available in terms of transport aircraft, air mobile workshops and air portable runway strips, the US Air Force in setting up new bases in Vietnam did not achieve the planned operational sortie rate from such bases for months after the forecast target date. It is pertinent to mention here that over 90 per cent of the military and other stores moved to Vietnam were carried by sea.

Sometimes discussed as a means of shortening the time to reach operational status, is the “bare base” concept. This entails a com­pleted runway and hardstanding complex, but requires all the major facilities to be brought in to bring the base to an operational standard. The vast quantities of fuel, and indeed air weapons, cannot be flown in so a decision must be made to stockpile, or to judge to a nicety the lead time to provision with fuel and many other heavy lift re­quirements before the aircraft arrive.

A point often overlooked is the need to protect bases, whether permanent, or merely a “bare base” likely to be used at some future date. It would be exasperating to plan a deployment to a remote area bare base” only to find on arrival that the runway has a large hole in the centre, or the fuel stockpile destroyed by mortar fire.

An assessment of the ground forces required to secure an air base from mortar attacks by determined groups in the Vietnam situa­tion, was once stated by an eminent Australian Defence Scientist who had studied the matter, as “Three divisions!”. In open terrain this figure could undoubtedly be reduced, but it serves to illustrate the difficulties, particularly in the remote areas of the North West coast where small parties can be landed undetected.

This is not to suggest that shore bases are not needed, but the problems of insuring they are fully stocked, immediately available for operations, and adequately protected, even in a low level situation, places constraints on the numbers which can be guaranteed available.

The aircraft carrier is a fully operational base and has the advan­ tage of being mobile. It is fundamental to the understanding of the value of carrier air power to distinguish between the ability merely to fly aircraft, and the ability to operate control, service and rearm military aircraft effectively in an environment which may be hostile. Additional capability can be provided where necessary by destroyers in company, and logistic support by underway replenishment ships. This mobility of a fully operational air base is a great asset to defence planners and politicians. It can provide a lawful demonstra­tion of military force near a centre of crisis without commitment or involvement.

Proximity

The need for proximity of the tactical air base to the area of operations is not peculiar to maritime operations. The value of tac­ tical air defence or ground support is heavily dependent upon such defence or support being readily available when required. Availabili­ ty depends upon the number of aircraft available and the distance from the air base to the scene of action. In real life circumstances, there are never sufficient aircraft available to meet all requirements and so the solution to the problem is to bring the air base closer to the scene of the action thereby reducing the time aircraft spend in transit. This is the major advantage of Vertical/Short Take Off and Landing aircraft. Such aircraft can be positioned briefly near to the scene of action thus reducing transit time and hence provide a quick reaction to the commander on the spot. With naval aircraft, the transit time is reduced further by moving the airfield (carrier) closer to the scene of operations.

JOHN GOBLE retired from the RAN in 1976-after 35 years service. Retiring with the rank of Commodore, John Goble enjoyed a distinguished career which included Chief of Staff to Fleet Commander, Commander HMAS Vampire, Executive Officer HMAS Tobruk, Air Officer HMAS Melbourne, Com­ mander of 817 squadron in addition to attending the US Arm­ ed Forces Staff College in 1960. We feel that John Goble can speak with authority on the future of naval aviation at a time when many less informed persons are ridiculing the viability of a replacement to HMAS Melbourne.

When operating at sea, a naval force would make good use of any tactical aircraft available from land bases within range for its defence and support. However, such bases could be hundreds of miles away from the naval scene of operations and transit time and availability of aircraft could mean a fleet without air cover and sup­ port unless it could provide its own.

Integration of forces

As stated above, the prime benefit of tactical air power is rapid reaction with the right force in the right place at the right time. The high speed of modern aircraft and missiles coupled with the difficulty in achieving long-range detection can result in a very short period between initial detection and missile delivery/impact. Swift reaction is thus crucial to success. Because of the large ocean area in which our maritime forces operate, this swift reaction can only be achieved if the aircraft are provided as an integral element of the force.

During combat operations, aircraft from within a naval force can be fully briefed up to the minute on the tactical situation. This is not so easy if the aircraft are provided by some separate or remote agen­cy. To communicate with other commands or bases and with ap­proaching friendly aircraft, a naval force must make radio transmissions which immediately advertise the ships’ general loca­ tion. If a decision were made for some reason to break radio silence in order to pass information to co-operating aircraft, the aim may be frustrated by communication and transit delays and misunderstan­ dings could occur. Experience has shown time and time again that the quick reaction and flexibility so necessary for the application of tac­ tical air power at sea will not be achieved unless it is organic to the naval force.

Readiness for operations

The mobility of the carrier as a floating airfield has already been discussed but complementary to that attribute is the advantage of combat readiness that exists in an aircraft carrier. It is a major advan­ tage of the aircraft carrier that when it reaches a crisis location, it is immediately ready to commence operations. There is no require­ ment for advance parties, no setting up of facilities, and no_ im­ mediate logistic problems with a carrier. It arrives in the area fully prepared to commence and sustain operations.

Versatility of aircraft carriers An aircraft carrier provides the defence forces and the govern­ment with a valuable military unit that can be moved without blatant political involvement to areas of crisis, and allows a government to keep its options open until the very last minute. It can provide a power base in the right spot at the right time and, by covertly positioning itself near the scene of action, retain an element of surprise. In operations, a carrier can provide a concentration of force and, by keeping transit time to a minimum, enable more sorties to be flown by a given number of aircraft. However, the unique qualities of a carrier do not end there. By adjusting the outfit of aircraft carried, the role of the carrier can be varied. The carrier aircraft can be used for long range reconnaissance, surveillance, anti-submarine operations, air strike, ground support, air defence, airborne assault by troops and in assisting the civil community in times of natural dis­ asters. No other military unit or equipment can provide such a range of options.

Relevance To The Australian Scene

Critics may argue that Australia will never need to deploy a naval force in the type of situations discussed, this however, overlooks the principles in the use of naval forces, whether considering the protec­tion of Australia’s interests in the nearer ocean waters of the resources zone or further afield. The questions which invariably arise in any discussion on aircraft carriers, are not so much centred on the principles but relate to the usefulness of a carrier in Australian defence scenarios, the vulnerability of a big ship (too many eggs in one basket) and the survivability of carriers.

Australia is an island state and any future conflict that involves the Australian Defence Force would be initially maritime in character and would necessarily remain so unless the maritime elements of our defence force were defeated. It is quite possible that a threat that was wholly maritime in character could develop and persist. The per­ suasive argument for an aircraft carrier is that it would be valuable in any situation in which Australia were required to display or use military force. The carrier, with its aircraft, is a weapon system which is ideally suited to the Australian scene. Expensive, yes – but defence does not come cheaply, and the capabilities and options an aircraft carrier gives to our nation’s defence make it a cost-effective weapon system.

Vulnerability

It is a misconception, unfortunately widely held, that a carrier is disadvantaged by its vulnerability. This vulnerability is said to exist because it is assumed a carrier can be sunk by a relatively small number of modern powerful missiles. This statement warrants further consideration. All weapons systems and bases are vulnerable in some degree to the offensive measures used against them. This applies throughout the whole range of military equipment. The real issue centres on survivability.

Vulnerability can be divided into three distinct phases. Firstly, there is the question of how the enemy is to find the carrier; second­ ly, he has to get into an attacking position; and lastly, there is the question of what is required to sink a carrier or at least render it out of action in the face of the defences available to the force.

Locating the carrier

The ocean is a vast area and history has shown how difficult it is to find ships at sea if they have no wish to be found. In fact, it is often difficult to find ships that wish to be found.

The advent of satellite surveillance has not made the oceans an open book. The so called “geo-stationary” satellite does not possess the degree of discrimination to be of any value in a surveillance role. A single satellite will “sweep” a particular strip of ocean only once every day and a half. Satellite ocean surveillance systems are enor­ mously expensive. A six satellite system to allow a single sweep of an area every six hours would cost of the order of $250 million a year for satellites alone, assuming the ground stations were available. They certainly do not provide the up to the minute data needed in tact_ical situations. Furthermore a satellite’s telemetry systems are susceptible to jamming by electronic means, and it has been acknowledged in the Australian defence scene that undue reliance should not be plac­ ed on satellite information in the event of hostilities. In six hours, a carrier can cover a considerable distance and the satellite information is not good enough for a blind missile launch. The enemy may know of shipping in an area, but he needs much more accurate and up to date information to launch an attack.

How is he going to acquire such information? It must come from a tactical source such as reconnaissance aircraft, a surface ship or sub­ marine. Any one of these vehicles will need to close the carrier to ob­tain the required information. In the case of the submarine, an ade­ quate level of Long Range Maritime Patrol support backed up by the carrier’s own aircraft would make this task difficult and the earner has the option of avoiding submarine probability areas. This, combined with the use of speed, evasive steering and ant1-subma_nne measures give the carrier a high degree of protection from a possible successful submarine attack.

Attacking

A maritime task force with an integrated defence system which includes tactical naval air power poses a serious problem for a wouId­ be attacker. For example, a missile-firing ship or patrol craft would have to survive attacks from tactical nava! aircraft before it reaches a position to launch its missile. Similarly, reconnaissance aircraft would be subjected to air attacks whilst attempting to obtain the informa­tion required for an air or surface strike on the carrier. Should, however, the enemy gain a firing or attacking position, this missile would then have to successfully defeat the force’s missile, gun and electronic defences.

THE SKI-JUMP STO LAUNCH This very important contribution to the operation of fi><ed-wing jet V/STOL aircraft from decks stems from an idea first s::ub­ lished, in 1973, by Lt. Cdr. D. R. Taylor, AN. He showed that by curving up the front end of a flight deck runway so that the Harrier is launched on an upward trajectory, very considerable performance gains become available compared with the corresponding flat-deck STO launch. Because of the upward momentum im­ parted by the ramp, the Harrier can be launched with less speed than from a flat deck. Just after leaving the Ski-Jump, the Harrier is not, in fact, truly flying. There is a deficiency of vertical support, and this curves the flight path towards horizontal. But, due to the high thrusUweight ra i of the aircraft, there is nevertheless suff1c1ent thrust to accelerate the Harrier along the-­ upward-inclined flight path. After a part­ ballistic trajectory of about 10 sec, there­ fore the Harrier will have picked up30 knots or ore additional airspeed and is fully sustained in 1g flight. Transition to wing­ borne flight with jets aft can commence at the top of the trajectory, and the aircraft will be fully wingborne some 15 sec later, exactly as in the flat-deck STO launch. The pre-requisite for Ski-Jump launch is the The diagram compares the same Harrier in ability of the aircraft to continue to accel­ a flat-deck and a Ski-Jump STO launch. erate with initial flight path angles up to Sufficient analytical studies, simulator and about 25 deg. and be controllable at full-scale test work has now been done to sub-stall airspeeds. It is therefore insepar­ give great certitude to this revolutionary able from – and applicable wholly to – technique. The numbers quoted in the vectored thrust V/STOL configurations: diagram have been rounded for simplicity Harrier, Sea Harrier, AV-8A, AV-88, etc. but the examples are based on accurate predictions for an STO weight near the maximum normally used for the Harrier flying from existing flat decks. SKI-JUMP BENEFITS As shown in the diagram. a 20 deg. Ski-Jump offers a launch speed reduction of 30 knots, at given aircraft weight, compared with a flat deck. At the highest launch weights this represents a 30% reduction in launch speed which, because distance depends on speed squared, reduces the deckrun by over 50%. At lower launch weights, 30 knots less endspeed represents over 40% reduction in velocity, needing a deckrun only about one third that of the flat deck launch. Alternatively, at constant deckrun, the endspeed achieved remains almost the same in the Ski-Jump launch as in the flat deck. Only 2 to3 knots of speed (at most) are lost by the Harrier “climbing the hill’. The aircraft is therefore launched with an effec­ tive 30 knots excess speed compared with the same deckrun off a flat deck and can thus carry 30 kts x 66 lb/kt (20 kg/kt) – 2 000 lb (900 kg) more payload from the same deck. This can be extra fuel or weapons or some of each. Even when at anchor, the Ski-Jump ship enjoys the launch benefit of this 30 knot effective Wind-Over-Deck (WOO). Alternatively, at constant deckrun, the endspeed achieved remains almost the same in the Ski-Jump launch as in the flat deck. Only 2 to3 knots of speed (at most) are lost by the Harrier “climbing the hill’. The aircraft is therefore launched with an effec­ tive 30 knots excess speed compared with the same deckrun off a flat deck and can thus carry 30 kts x 66 lb/kt (20 kg/kt) – 2 000 lb (900 kg) more payload from the same deck. This can be extra fuel or weapons or some of each. Even when at anchor, the Ski-Jump ship enjoys the launch benefit of this 30 knot effective Wind-Over-Deck (WOO).

Assuming that all the countermeasures discussed above are not 100 per cent successful and the enemy is able to hit the carrier, the question then becomes one of survivability.

Survivability

In the latter stages of World War 11, the Japanese introduced the Kamikaze aircraft. The Kamikaze was the forerunner of the cruise missiles of today, controlled by the most sophisticated and reliable guidance system yet conceived – the human brain. Although the Kamikaze had considerable success with hits, they failed to sink one allied carrier. A case for example, was the USS SARA TOGA. Built in 1927, she was in 1945 an old ship, but despite being hit by four Kamikazes, the ship was ready to land on aircraft within some four hours. A more recent example is the experience of USS ENTERPRISE in 1969. An accident on the flight deck of ENTERPRISE caused the detonation of nine major calibre bombs. This is the equivalent of more than half a dozen cruise missiles, yet the ship could have resum­ ed her scheduled air operations within hours, as soon as the debris was cleared from the after end of the flight deck. The damage control measures which can be built into an aircraft carrier hull make it a particularly tough nut to crack and the figures on the losses of aircraft carriers in World War II lend weight to the statement. Statistics com­ piled from a number of different sources show that only 11 per cent of allied carrier were sunk compared with about 33 per cent of cruisers, 36 per cent of destroyers and 37 per cent of submarines.

What type of carrier and aircraft?

Having established beyond. afly reasonable doubt the value of an aircraft carrier and its outfit of aircraft, the question of what type of earner and what type of aircraft are available, and can be afforded by Australia, needs to be examined.

Aircraft carriers come in a wide range of sizes. At the top end of the scale, there are the 91,000 ton nuclear powered attack carriers of the US Navy. These giant ships carry over 100 aircraft and a crew of some 6000 men and represent the ultimate in carrier size.

At the other end of the scale is the Vosper Thornycroft concept for a Harri r Carrier. This 8000 ton carrier has been specially designed for operating the Sea Hamer, a VSTOL (Vertical/Short Take Off and Landing) aircraft.

. To operate modern conventional fixed wing aircraft with their high landing and launch speeds and weights, a carrier must be more than about 30,000 tons in order to accommodate features such as Ca_tapults, arresting gear and decks to the necessary strength. Larger ships mean greater costs and more manpower. It is highly likely that a conventional carrier would prove to be too expensive for Australia to acquire and operate under present strategic circumstances.

Recent development of VSTOL aircraft technology has resulted

in a type of aircraft which can be effectively operated from a much shorter runway than required by conventional aircraft. When part of the fuel and weapons load has been expended, the aircraft can make a vertical landing thus reducing the deck area required for operations.

. . An interesting concept under trial in Britain is the “ski-jump”, an inclined ramp to be fitted to the bow of a earner. At the end of its deck run, the aircraft would be launched with a slight upward trajec­ tory, thus allowing an increase in the payload of a vectored thrust air­ craft by a considerable margin and making it more comparable to its conventional counterpart.

Just as the angled deck and steam catapult gave the navies of the world the technological breakthrough necessary to permit naval avia­ tion to continue into the jet age, the advent of VSTOL aircraft and the ski-jump may provide the breakthrough to allow continuation of naval aviation from reasonable sized carriers.

The way ahead

Following the Government’s statement in the Defence White Paper that it proposed to institute funded project development at an appropriate time, the first step was to issue a world-wide invitation to companies to register interest in funded carrier Project Investigation. The approval of the Minister of Defence for this action was given on 12th September, 1977.

Sixteen companies responded to this invitation and these responses are currently being evaluated and examined within the Defence Department. No funds have yet been approved for any stage of the Project.

Summary

The primary requirement for increased self reliance which Australia is seeking to achieve in its defence strategy necessarily calls for a defence force which can operate with substantial independence in our own environment. The island nature of our country and its dependence on sea lines of communications for trade, call for a strong emphasis on maritime strategy in our overall defence posture. Australia cannot hope to provide defence cover for all the sea ap­proaches at the same time but it is not envisaged that this would be necessary. The maritime area of operations would change from time to time and it is important that the defence umbrella shifts to cover the area where it is needed most. This calls for mobility of assets and the carrier as a mobile airfield provides this all important factor.

Carrier borne air power forms a fundamental part of the Navy of our island nation. Without this critical element of our defence force, independent operations of our seaborne forces would be severely circumscribed; our maritime lines of supply upon which the defence force and our national economy so heavily depend could be easily broken. • The navies of the western world are no longer alone in possessing the ability to deploy tactical aircraft at sea.

The strategic and tactical arguments in favour of naval air power for Australia are clear. It is not a case of “can we afford it”, but one of “can we afford not to have it”. On all the evidence the decision is overwhelmingly in favour of maintaining naval air power in Australia’s defence inventory.