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Date Posted: 01-Mar-2010
Jane's Defence Weekly
Proportionate force
Counter-insurgency operations in Afghanistan are driving a revival in the use of turboprop aircraft for the armed reconnaissance role. Gareth Jennings reports
At the outset of the US-led Global War on Terror (GWOT), Donald Rumsfeld, the then US Secretary of Defense, famously said: "I don't want to put a million-dollar missile on a five-dollar tent".
In making this statement, Rumsfeld recognised the fact that, given the largely asymmetric nature of the fight to come, the force used by the United States and its allies had, for political, military and financial reasons, to be proportional to the threat faced.
From the perspective of the US Air Force (USAF), the main problem with this doctrine was that it had spent decades building up a multibillion-dollar arsenal of aircraft and munitions designed to globally project US power and to counter the conventional forces of the Warsaw Pact.
While squadrons of B-52, B-1, B-2, F-15 and F-16 aircraft may have been well suited to rolling back invading Soviet divisions from Central Europe, it can be argued that they are of limited value in countering small bands of peasant farmers-cum-guerrillas in theatres such as Afghanistan.
Modern jets are prohibitively expensive to maintain and operate for all except the most modern and developed of air arms. Even when operating from their home bases, where the infrastructure of hangars and maintenance depots are already in place, the logistical trains of parts and personnel that are needed for such aircraft to function can, in themselves, run into many millions of dollars.
When deployed operationally 'off-site' these costs only escalate, as does the logistical effort needed to maintain a viable fighting force of frontline jet combat aircraft many thousands of kilometres from their well-developed airbase infrastructure.
Announcing a presence
In addition, the noise signature of a jet, while useful for 'show of force' missions, can alert the intended target as to the proximity of incoming air support, removing the element of surprise so necessary for counter-insurgency (COIN) operations.
Also, the high speed of jet aircraft can often make target identification and the accurate dropping of ordnance problematic.
Setting aside the 'behind the scenes' support needed for modern jets and their expensive price tags, many such high-performance aircraft are simply not suited to the peculiarities of low-intensity COIN warfare. The aircraft are often just too capable. Using modern jet combat aircraft for COIN operations is like taking the proverbial sledgehammer to crack a nut. For these missions, less is definitely more.
What is required is a low-cost, low-maintenance platform that is rugged enough to operate in austere conditions close to the front line with minimal ground support, able to survive in a 'low and slow' environment while possessing a long enough loiter time to provide persistent top cover to the troops on the ground. In addition, it must have a large weapons fit, both in terms of the weight and variety of stores carried, and a sophisticated targeting system to guard against collateral damage and to allow for all-weather, day and night operations.
These requirements are indicative of a ruggedised straight-wing turboprop aircraft that is fitted with an integrated electro-optic/infrared (EO/IR) sensor, with multiple hardpoints, is well armoured and comes with a comprehensive defensive-aids suite. It will ideally be fitted with an internal or podded gun and carry the latest generation of precision-guided 'smart' munitions.
The relatively slow speed of turboprop aircraft when compared with jets is largely offset by the fact that they can operate from temporary airstrips very close to the front line. This translates into a faster response time and a longer time on station.
Time on station is further increased by the relatively low fuel consumption of turboprops when set against fuel-hungry jets. Although a jet aircraft can be aerially refuelled (an ability not shared by light attack turboprops), this can take them out of the fight at a critical juncture.
A further advantage of a turboprop aircraft is that it is easier to maintain, especially in austere conditions, and will have higher readiness rates and reduced life-cycle costs in comparison with most jet aircraft.
On the downside, a criticism often levelled against turboprop COIN platforms is that they are too vulnerable to ground fire. However, helicopters (which are slower still) are expected to routinely operate in the same low and slow environment, which they achieve through the use of appropriate tactics and defensive aids.
To protect against such dangers, a turboprop's cockpit and key systems can be armoured. Furthermore, they produce lower heat signatures than jets, which reduces the threat of IR-guided weapons (this signature can be reduced still further with the fitting of IR shrouding to exhaust nozzles). Also, if crippled, their gliding and recovery characteristics are often far better than flamed-out jets and certainly much better than auto-rotating helicopters.
Probably the greatest advantage, in terms of crew survivability, that the turboprop has over the attack helicopter is the ejection seat. With the exception of the Russian-built Kamov Ka-50/52, which features an ejection system whereby the main rotor blades are first jettisoned by means of exploding bolts, escape is not an option for stricken helicopter crews in the way that it is for fixed-wing pilots.
While any commander would think carefully before deploying turboprop strike platforms into a theatre unless air dominance is already in place, the same is also true for attack helicopters and unmanned aerial vehicles (UAVs), both of which play a key role on today's multifaceted battlefield.
Most COIN operations involve a state versus non-state scenario. While there have been exceptions, such as in Sri Lanka with the Liberation Tigers of Tamil Eelam (LTTE) and their Air Tigers, it is usually the case that the insurgency does not have an air force and possesses only a limited anti-aircraft capability.
Happy medium
Turboprops strike a happy medium between attack helicopters, which may be too slow and vulnerable for some strike missions, and jets, which may be too fast. In addition, their long endurance and high weapon loads means that, once on station, turboprops can provide a constant stream of aerial fire support without having to return to base to refuel and rearm. Furthermore, the relatively low speed and low-level manoeuvrability of a turboprop aircraft compared with a fast jet affords the pilot more time to positively identify a target, reducing the risk of collateral, or blue-on-blue, casualties. That turboprop COIN aircraft tend to rely on cannons and rockets, rather than large bombs, only diminishes still further the likelihood of the pilot inflicting civilian casualties.
As Air Commodore Julian Stinton of the UK Royal Air Force (RAF) said in May 2008, the level of accuracy required in today's COIN operations means that it is now necessary to "get the guy in the left-hand seat of the pick-up", rather than destroying the whole vehicle.
For countries that have limited defence budgets, it is paramount that they get as much 'bang for the buck' from their assets as possible. This is especially true of combat aircraft, which are among the most expensive purchases that any military will have to make.
A criticism of turboprop COIN platforms is that they are 'one-trick ponies' and have no multirole capability. Whereas, for example, an F-16 can be used for close air support (CAS) in much the same way as a turboprop, it can also, unlike a turboprop, be used for air defence and other roles such as suppression of enemy air defences (SEAD) and CAS in contested airspace.
Turboprops do have a limited multirole combat capability in that they can also be used as a training platform. Their utilisation removes an expensive and time-consuming tier of flight training where the pilot transitions from an advanced trainer aircraft to a fast jet.
In addition, the fact that the pilot fights in the same aircraft in which he has trained has all the advantages of platform familiarity and increased pilot confidence you would expect. It also reduces the required infrastructure and the logistics train needed to support a country's aircraft fleet.
Such platforms have been in service with air arms conducting COIN campaigns throughout the world for decades, most notably in the Far East and the Asia Pacific region with countries such as the Philippines and Indonesia.
In recent years the concept of operating fleets of relatively cheap turboprops for light attack duties has again become vogue, with Latin America in particular showing a renewed interest in developing and operating turboprop COIN aircraft.
The Brazilian-developed Embraer EMB-314 Super Tucano has entered service with five air forces in Central and Southern America and has been utilised as an air-to-air and aerial surveillance platform in addition to its more conventional light attack role.
However, it has only been with the wars in Afghanistan and Iraq that the use of turboprops has re-entered the thinking of US commanders in any meaningful way.
It is as a direct result of these post-9/11 conflicts that the US launched its two continuing light attack requirements, namely for the USAF and Afghanistan (Iraq is already in the process of establishing its fixed-wing light attack capability with AIM-114 Hellfire missile-armed Cessna AC-208B Grand Caravans and yet-to-enter-service Hawker Beechcraft AT-6B Texan IIs).
On 27 July 2009 the USAF released a request for information (RfI) for a light attack platform for its newly envisaged COIN air commando unit. The Air Combat Command (ACC) Light Attack/Armed Reconnaissance (LAAR) RfI spelt out what the air force is looking for in its new COIN force. According to the RfI, the USAF is looking to field 100 fixed-wing light attack aircraft with deliveries starting in Fiscal Year 2012 (FY12), with and an initial operational capability (IOC) to be declared in FY13.
The RfI set out that the tandem two-seat aircraft should be able to accommodate multiple weapon and sensor types as the mission dictates. It should be equipped with a gun and precision weapons and will have the ability to co-ordinate fire support directly with ground units through voice, video and datalinks.
Separate to, although not completely removed from, USAF's LAAR requirement for its proposed counter-insurgency units are the US-backed programmes to equip the Afghan and Iraqi air arms with a sovereign light attack and armed reconnaissance capability. Shortly after issuing its LAAR RfI, the USAF released a similar set of requirements to find an advanced flight trainer and light attack aircraft for the Afghanistan National Army Air Corps (ANAAC).
Announced on 30 October 2009, this Light Air Support (LAS) RfI comes on the back of a January 2008 statement by USAF Brigadier General Jay H Lindell, head of the Combined Air Power Transition Force (CAPTF) in Afghanistan, that the ANAAC would be looking to field its new light attack aircraft by 2013.
The RfI, for the production of six (with an option for 14 more) fixed-wing single-engine turboprop platforms, lists a number of critical requirements that the winning aircraft must fulfil. These included a rough-field capability without ground support, dual controls, ejection seats, specific air-to-ground avionics and systems and a defensive-aids system.
Critical requirements
Performance parameters include a take-off run of less than 6,000 ft (1,800 m), the ability to conduct flight operations from -54 degrees Celsius to 45 degrees Celsius and, although being a two-seater aircraft, the ability to be operated by a single pilot. No ferry or combat range was stipulated, but the RfI did say that, when fitted with external drop-tanks and loaded with maximum stores, the aircraft must have an endurance of three hours plus 30 minutes reserve.
The proposed weapons fit includes (but is not limited to) 500 lb-class munitions capable of being carried on any one of five NATO/US-compatible hardpoints and .50 calibre machine guns (MGs). The number of these, and whether they be internal, podded or stowed on hardpoints, is not stipulated. In addition, the aircraft must be fitted with a laser designator.
As the USAF has yet to issue an official request for proposals (RfP) for either the LAAR or Afghan LAS programmes, there are no official bidders at this time. As such, the USAF is unable to disclose the names of any respondents to either RfIs (although Embraer has confirmed to Jane's that is has responded to both the LAAR and LAS RfIs).
However, the popular consensus is that the two current front runners for both programmes are the Super Tucano (which has already been leased by the US Navy (USN) as a light attack platform under its 'Imminent Fury' programme) and the AT-6B Texan II (a variant of which is already in service with both the USAF and USN as a trainer aircraft).
The Super Tucano, with global sales of more than 170 aircraft, is in service with seven air arms worldwide. The aircraft differs from the baseline EMB-312 Tucano trainer aircraft in several crucial respects that make it ideally suited as a light attack and COIN platform.
Namely, it is powered by a more powerful 1,300 shp Pratt & Whitney Canada PT6A-68A engine (compared with the 1,100 shp powerplant of the EMB-312); has a strengthened airframe to sustain higher g loads and to increase the aircraft's fatigue life (to 12,000 hours in operational environments, depending on mission loads and utilisation); is fitted with five weapon hardpoints; and has a night-vision goggle (NVG)-compatible 'glass cockpit' with hands-on-throttle-and-stick (HOTAS) controls.
The Super Tucano's weapons fit comprises a .50 calibre MG (with 200 rounds of ammunition) in each wing and the capacity to carry a variety of ordnance including Giat NC621 20 mm cannon pods, Mk 81/82 bombs, MAA-1 Piranha air-to-air missiles (AAMs), BLG-252 cluster bombs and SBAT-70/19 or LAU-68A/G rocket pods on its underwing stations.
In addition, there is the provision for a datalink, a video camera and recorder, an embedded mission-planning capability, forward-looking infrared (FLIR), chaff/flare dispensers, missile approach warning receiver systems (MAWS) and radar warning receivers (RWRs). To date, the USAF has received a static demonstration of the Super Tucano at Wright-Patterson Air Force Base (AFB) in Dayton, Ohio.
In the same class as the Super Tucano, in terms of its configuration, capability, and approximately USD8 million price tag, is the AT-6B Texan II. With the 85 per cent common T-6A in service with the USAF and USN as a basic trainer aircraft, the AT-6B already meets all of the air force's requirements as laid out on the LAAR RfI.
In September 2009 Hawker Beechcraft and Lockheed Martin announced that they would jointly bid for the USAF's LAAR requirement. Hawker Beechcraft will be the prime contractor, with Lockheed Martin assuming responsibility for integrating the aircraft's mission systems.
As well as having the option of FLIR and a tactical datalink, the AT-6B is equipped with six underwing pylons (three under each wing), allowing for the carriage of up to 1,415 kg (3,120 lb) of stores, including .50 calibre MGs, Mk 82 500 lb bombs and LAU-68 seven-round 70 mm (2.75 inch) rocket pods.
The provision to carry precision-guided munitions could also be included at the customer's request and a limited self-defence capability could be incorporated with the integration of the AIM-9X Sidewinder air-to-air missile.
As well as being offered for the USAF LAAR and ANAAC LAS competitions, the AT-6B has been favoured by the Iraqi Air Force (IQAF) as its light attack platform of choice. In December 2008 the Iraqi government requested the sale of 36 such aircraft from the US.
With the IQAF also looking to buy 20 T-6A trainer aircraft, the synergies (and consequent cost savings) in logistics, maintenance, air and ground-crew training and basing infrastructure are apparent and go a long way to explaining the growing popularity of such platforms as a cost-effective alternative to jet combat aircraft.
Currently, the AT-6 prototype is undergoing flight-testing, which should last until the end of the second quarter of 2010.
Other possible contenders for both the LAAR and LAS competitions include the Air Tractor AT-802U, North American (Boeing) OV-10 Bronco and Stavatti SM-27 Machete. The AT-802U, a militarised version of Air Tractor's agricultural and fire-fighting aircraft, was first unveiled at the Paris Air Show in June 2009. At the time a company spokesperson told Jane's that it had received firm interest in the two-seat turboprop aircraft "from well over 20 countries". The example displayed in Paris was fitted with dual 12.7 mm GAU-19/A three-barrel Gatling guns mounted on the inboard wing pylons (which can carry 1,200 rounds each), two M260 rocket launchers on the outboard pylons (one on each) and representative Mk 82 freefall bombs on the two under-fuselage hardpoints.
According to Lee Jackson, a design engineer at Air Tractor, the aircraft can also be configured to carry more advanced weapon systems such as the Hellfire missile, Directional Attack Guided Rocket (DAGR) laser-guided rockets, a Sniper XR surveillance and targeting pod and a Wescam MX-10/MX-15 targeting turret for reconnaissance and target identification.
Although no unit price had been set, the company told Jane's that it should be "significantly lower" than that of both the Super Tucano and the Texan II.
A selling point for the AT-802U over its competitors is its 3,628 kg (8,000 lb) payload. This carrying capacity can translate into either more munitions carried than comparable platforms, the same carried over a greater distance (or for longer on station) or the same carried but with an increased safety margin and carry-back capability.
Perhaps the most intriguing light attack aircraft to emerge as a result of the USAF's new-found interest in turboprop COIN platforms is the resurrected Boeing (Rockwell) OV-10 Bronco. Originally conceived as a light attack asset during the Vietnam War, the Bronco was retired from the US inventory in the mid-1990s (it was retained as a forward air control and aerial surveillance platform for some years after it had fulfilled its COIN role). In September 2009 Boeing announced that it was in the process of computerising old designs of the OV-10 and would open up a production line should the USAF select it to fulfil the LAAR and/or Afghan LAS requirements.
Dubbed the OV-10X, the revived Bronco would have a payload capacity of 1,360 kg (3,000 lb). Its twin turboprop powerplants have the benefit of increased reliability and safety, enabling the pilot to return home on one engine. In addition, its widely spaced main landing gear (located on two pontoons) should greatly improve the aircraft's rough-field performance characteristics.
Although still in its developmental stages, it is thought that the OV-10X may feature helmet-mounted displays, an EO sensor, a .50 calibre gun and IR countermeasures. In addition, it should be able to carry up to 16 Hellfires.
Despite the USAF's tight deadlines, Boeing is confident it can quickly open a production line at a location to suit the air force.
The OV-10X concept "is a very modular design; it's easy to build", a Boeing spokesperson said. "There are any number of companies that can produce and assemble this airplane."
Entry level
An outsider for the LAAR and LAS requirements, in so far as it is the company's first foray into the military market and because a prototype has yet to fly, is the Stavatti Aerospace SM-27T Machete.
The original Machete concepts were developed in 2000, with actual design work commencing in 2003, company chief executive officer Chris Beskar told Jane's . In 2005 Stavatti met with USAF planners at the Pentagon as well as air force battle laboratories studying COIN operations and, based upon their suggestions, a major redesign effort was undertaken that led to the creation of the three Machete variants: SM-27S/T single-seat/twin-seat turboprop COIN/CAS platform, forward air control (FAC) and advanced trainer; SM-27J/L turbofan COIN/CAS, FAC and lead-in fighter trainer; and SM-47S/T turbofan air-defence fighter.
In 2007 the design underwent a second review that focused on increasing the aircraft's internal fuel load, weapons carriage and powerplant configuration, leading to a larger aircraft. The current design was frozen earlier in 2009 with engineering of the current design beginning in May 2009. The SM-27S/T, the subject of the LAAR bid, has been billed by the company as "a 21st century A-1 Skyraider". With a unit cost of between USD10 million and USD15 million, its performance parameters will include a tactical radius of 750 nm and the ability to carry a 2,948 kg (6,500 lb) payload (3,629 kg [8,000 lb] with 70 per cent internal fuel). Powered by a single 2,920 shp Pratt & Whitney PW127G turboprop (the same engine that powers the ATR 72 and C-295 transport aircraft), the SM-27S/T will be armed with a centreline-mounted 30 mm cannon and armoured throughout.
The SM-27 will have a maximum level speed of 360 to 400 kts, depending upon external load, and will feature a 'glass cockpit' that incorporates F-16 flight controls and reclined Martin Baker Mk 16 ejection seats. It will have an inflight refuelling capability, integrated avionics and will be able to sustain +9 g in a clean configuration.
The turboprop Machete will be available in a basic configuration without radar, as well as a more advanced variant, which will feature the Lockheed Martin AN/APG-67 radar (as developed for the F-20 Tigershark export fighter) and a comprehensive electronic-warfare (EW) self-protection suite.
According to Beskar, details of the SM-27 flight-test schedule will be released after the prototype's anticipated first flight in late 2010/early 2011.
The company intends to be able to field the SM-27S/T COIN variant some time in 2012 to 2013, which would meet the USAF's LAAR and LAS requirements. "While this schedule may seem to be ambitious, we have been performing considerable engineering development for some number of years," Beskar said.
However, even though Stavatti has submitted its designs for the LAAR competition, and is confident of meeting the programme's exacting timetable, Beskar concedes that the Machete's time may come later than the air force's current requirements: "What the ... LAAR requirement does is identify the need for a light attack aircraft and the value of COIN/CAS. We feel this is an indicator of a paradigm shift. We suspect that, due to the rapid acquisition timetable, the LAAR requirement will be satisfied by a legacy aircraft. From a strategic marketing standpoint, any legacy aircraft procured to satisfy the LAAR requirement in the near term could be replaced by Machete aircraft produced 20 to 25 years from [the] LAAR [aircraft in-service date]." He added that, with this long-term objective in mind, the Machete programme will proceed regardless of the outcome of the USAF LAAR bid.
For the USAF LAAR programme, the next step in the acquisition process is for the ACC to document a validated requirement using the official Joint Capabilities Integration and Development System (JCIDS) process. Once a validated requirement is documented, which will probably occur sometime in 2010, an official RfP can be released to industry for the acquisition of a LAAR platform.
Looming RfPs
For the Afghan LAS programme, the next step is to post an official RfP to industry, which is likely occur in early 2010, according to a USAF spokesperson.
For both the USAF LAAR and Afghan LAS programmes, the platform evaluations will take place at the air force's Aeronautical Systems Center (ASC), Wright-Patterson Air Force Base (AFB), Ohio.
The USAF would not say when the winner/s would be revealed, but said that the date for such an announcement would be contained in both RfPs.
Not even the strongest exponents of turboprop light attack platforms would suggest that they could completely replace fast jets on today's battlefield. However, as a counterpart to the jet, the turboprop does have its part to play as a hard-hitting and cost-effective light attack and ISR platform.
As recently as May 2009, a USAF spokesperson told Jane's that acquiring "single mission type aircraft may not be in our best long-term interest".
That it should now be looking to procure 100 such aircraft to fulfil just this role some 30 years since it retired its last such platform represents a paradigm shift indeed.
Gareth Jennings is Jane's Aviation Desk Editor, London
Date Posted: 01-Mar-2010
Jane's Defence Weekly
Proportionate force
Counter-insurgency operations in Afghanistan are driving a revival in the use of turboprop aircraft for the armed reconnaissance role. Gareth Jennings reports
At the outset of the US-led Global War on Terror (GWOT), Donald Rumsfeld, the then US Secretary of Defense, famously said: "I don't want to put a million-dollar missile on a five-dollar tent".
In making this statement, Rumsfeld recognised the fact that, given the largely asymmetric nature of the fight to come, the force used by the United States and its allies had, for political, military and financial reasons, to be proportional to the threat faced.
From the perspective of the US Air Force (USAF), the main problem with this doctrine was that it had spent decades building up a multibillion-dollar arsenal of aircraft and munitions designed to globally project US power and to counter the conventional forces of the Warsaw Pact.
While squadrons of B-52, B-1, B-2, F-15 and F-16 aircraft may have been well suited to rolling back invading Soviet divisions from Central Europe, it can be argued that they are of limited value in countering small bands of peasant farmers-cum-guerrillas in theatres such as Afghanistan.
Modern jets are prohibitively expensive to maintain and operate for all except the most modern and developed of air arms. Even when operating from their home bases, where the infrastructure of hangars and maintenance depots are already in place, the logistical trains of parts and personnel that are needed for such aircraft to function can, in themselves, run into many millions of dollars.
When deployed operationally 'off-site' these costs only escalate, as does the logistical effort needed to maintain a viable fighting force of frontline jet combat aircraft many thousands of kilometres from their well-developed airbase infrastructure.
Announcing a presence
In addition, the noise signature of a jet, while useful for 'show of force' missions, can alert the intended target as to the proximity of incoming air support, removing the element of surprise so necessary for counter-insurgency (COIN) operations.
Also, the high speed of jet aircraft can often make target identification and the accurate dropping of ordnance problematic.
Setting aside the 'behind the scenes' support needed for modern jets and their expensive price tags, many such high-performance aircraft are simply not suited to the peculiarities of low-intensity COIN warfare. The aircraft are often just too capable. Using modern jet combat aircraft for COIN operations is like taking the proverbial sledgehammer to crack a nut. For these missions, less is definitely more.
What is required is a low-cost, low-maintenance platform that is rugged enough to operate in austere conditions close to the front line with minimal ground support, able to survive in a 'low and slow' environment while possessing a long enough loiter time to provide persistent top cover to the troops on the ground. In addition, it must have a large weapons fit, both in terms of the weight and variety of stores carried, and a sophisticated targeting system to guard against collateral damage and to allow for all-weather, day and night operations.
These requirements are indicative of a ruggedised straight-wing turboprop aircraft that is fitted with an integrated electro-optic/infrared (EO/IR) sensor, with multiple hardpoints, is well armoured and comes with a comprehensive defensive-aids suite. It will ideally be fitted with an internal or podded gun and carry the latest generation of precision-guided 'smart' munitions.
The relatively slow speed of turboprop aircraft when compared with jets is largely offset by the fact that they can operate from temporary airstrips very close to the front line. This translates into a faster response time and a longer time on station.
Time on station is further increased by the relatively low fuel consumption of turboprops when set against fuel-hungry jets. Although a jet aircraft can be aerially refuelled (an ability not shared by light attack turboprops), this can take them out of the fight at a critical juncture.
A further advantage of a turboprop aircraft is that it is easier to maintain, especially in austere conditions, and will have higher readiness rates and reduced life-cycle costs in comparison with most jet aircraft.
On the downside, a criticism often levelled against turboprop COIN platforms is that they are too vulnerable to ground fire. However, helicopters (which are slower still) are expected to routinely operate in the same low and slow environment, which they achieve through the use of appropriate tactics and defensive aids.
To protect against such dangers, a turboprop's cockpit and key systems can be armoured. Furthermore, they produce lower heat signatures than jets, which reduces the threat of IR-guided weapons (this signature can be reduced still further with the fitting of IR shrouding to exhaust nozzles). Also, if crippled, their gliding and recovery characteristics are often far better than flamed-out jets and certainly much better than auto-rotating helicopters.
Probably the greatest advantage, in terms of crew survivability, that the turboprop has over the attack helicopter is the ejection seat. With the exception of the Russian-built Kamov Ka-50/52, which features an ejection system whereby the main rotor blades are first jettisoned by means of exploding bolts, escape is not an option for stricken helicopter crews in the way that it is for fixed-wing pilots.
While any commander would think carefully before deploying turboprop strike platforms into a theatre unless air dominance is already in place, the same is also true for attack helicopters and unmanned aerial vehicles (UAVs), both of which play a key role on today's multifaceted battlefield.
Most COIN operations involve a state versus non-state scenario. While there have been exceptions, such as in Sri Lanka with the Liberation Tigers of Tamil Eelam (LTTE) and their Air Tigers, it is usually the case that the insurgency does not have an air force and possesses only a limited anti-aircraft capability.
Happy medium
Turboprops strike a happy medium between attack helicopters, which may be too slow and vulnerable for some strike missions, and jets, which may be too fast. In addition, their long endurance and high weapon loads means that, once on station, turboprops can provide a constant stream of aerial fire support without having to return to base to refuel and rearm. Furthermore, the relatively low speed and low-level manoeuvrability of a turboprop aircraft compared with a fast jet affords the pilot more time to positively identify a target, reducing the risk of collateral, or blue-on-blue, casualties. That turboprop COIN aircraft tend to rely on cannons and rockets, rather than large bombs, only diminishes still further the likelihood of the pilot inflicting civilian casualties.
As Air Commodore Julian Stinton of the UK Royal Air Force (RAF) said in May 2008, the level of accuracy required in today's COIN operations means that it is now necessary to "get the guy in the left-hand seat of the pick-up", rather than destroying the whole vehicle.
For countries that have limited defence budgets, it is paramount that they get as much 'bang for the buck' from their assets as possible. This is especially true of combat aircraft, which are among the most expensive purchases that any military will have to make.
A criticism of turboprop COIN platforms is that they are 'one-trick ponies' and have no multirole capability. Whereas, for example, an F-16 can be used for close air support (CAS) in much the same way as a turboprop, it can also, unlike a turboprop, be used for air defence and other roles such as suppression of enemy air defences (SEAD) and CAS in contested airspace.
Turboprops do have a limited multirole combat capability in that they can also be used as a training platform. Their utilisation removes an expensive and time-consuming tier of flight training where the pilot transitions from an advanced trainer aircraft to a fast jet.
In addition, the fact that the pilot fights in the same aircraft in which he has trained has all the advantages of platform familiarity and increased pilot confidence you would expect. It also reduces the required infrastructure and the logistics train needed to support a country's aircraft fleet.
Such platforms have been in service with air arms conducting COIN campaigns throughout the world for decades, most notably in the Far East and the Asia Pacific region with countries such as the Philippines and Indonesia.
In recent years the concept of operating fleets of relatively cheap turboprops for light attack duties has again become vogue, with Latin America in particular showing a renewed interest in developing and operating turboprop COIN aircraft.
The Brazilian-developed Embraer EMB-314 Super Tucano has entered service with five air forces in Central and Southern America and has been utilised as an air-to-air and aerial surveillance platform in addition to its more conventional light attack role.
However, it has only been with the wars in Afghanistan and Iraq that the use of turboprops has re-entered the thinking of US commanders in any meaningful way.
It is as a direct result of these post-9/11 conflicts that the US launched its two continuing light attack requirements, namely for the USAF and Afghanistan (Iraq is already in the process of establishing its fixed-wing light attack capability with AIM-114 Hellfire missile-armed Cessna AC-208B Grand Caravans and yet-to-enter-service Hawker Beechcraft AT-6B Texan IIs).
On 27 July 2009 the USAF released a request for information (RfI) for a light attack platform for its newly envisaged COIN air commando unit. The Air Combat Command (ACC) Light Attack/Armed Reconnaissance (LAAR) RfI spelt out what the air force is looking for in its new COIN force. According to the RfI, the USAF is looking to field 100 fixed-wing light attack aircraft with deliveries starting in Fiscal Year 2012 (FY12), with and an initial operational capability (IOC) to be declared in FY13.
The RfI set out that the tandem two-seat aircraft should be able to accommodate multiple weapon and sensor types as the mission dictates. It should be equipped with a gun and precision weapons and will have the ability to co-ordinate fire support directly with ground units through voice, video and datalinks.
Separate to, although not completely removed from, USAF's LAAR requirement for its proposed counter-insurgency units are the US-backed programmes to equip the Afghan and Iraqi air arms with a sovereign light attack and armed reconnaissance capability. Shortly after issuing its LAAR RfI, the USAF released a similar set of requirements to find an advanced flight trainer and light attack aircraft for the Afghanistan National Army Air Corps (ANAAC).
Announced on 30 October 2009, this Light Air Support (LAS) RfI comes on the back of a January 2008 statement by USAF Brigadier General Jay H Lindell, head of the Combined Air Power Transition Force (CAPTF) in Afghanistan, that the ANAAC would be looking to field its new light attack aircraft by 2013.
The RfI, for the production of six (with an option for 14 more) fixed-wing single-engine turboprop platforms, lists a number of critical requirements that the winning aircraft must fulfil. These included a rough-field capability without ground support, dual controls, ejection seats, specific air-to-ground avionics and systems and a defensive-aids system.
Critical requirements
Performance parameters include a take-off run of less than 6,000 ft (1,800 m), the ability to conduct flight operations from -54 degrees Celsius to 45 degrees Celsius and, although being a two-seater aircraft, the ability to be operated by a single pilot. No ferry or combat range was stipulated, but the RfI did say that, when fitted with external drop-tanks and loaded with maximum stores, the aircraft must have an endurance of three hours plus 30 minutes reserve.
The proposed weapons fit includes (but is not limited to) 500 lb-class munitions capable of being carried on any one of five NATO/US-compatible hardpoints and .50 calibre machine guns (MGs). The number of these, and whether they be internal, podded or stowed on hardpoints, is not stipulated. In addition, the aircraft must be fitted with a laser designator.
As the USAF has yet to issue an official request for proposals (RfP) for either the LAAR or Afghan LAS programmes, there are no official bidders at this time. As such, the USAF is unable to disclose the names of any respondents to either RfIs (although Embraer has confirmed to Jane's that is has responded to both the LAAR and LAS RfIs).
However, the popular consensus is that the two current front runners for both programmes are the Super Tucano (which has already been leased by the US Navy (USN) as a light attack platform under its 'Imminent Fury' programme) and the AT-6B Texan II (a variant of which is already in service with both the USAF and USN as a trainer aircraft).
The Super Tucano, with global sales of more than 170 aircraft, is in service with seven air arms worldwide. The aircraft differs from the baseline EMB-312 Tucano trainer aircraft in several crucial respects that make it ideally suited as a light attack and COIN platform.
Namely, it is powered by a more powerful 1,300 shp Pratt & Whitney Canada PT6A-68A engine (compared with the 1,100 shp powerplant of the EMB-312); has a strengthened airframe to sustain higher g loads and to increase the aircraft's fatigue life (to 12,000 hours in operational environments, depending on mission loads and utilisation); is fitted with five weapon hardpoints; and has a night-vision goggle (NVG)-compatible 'glass cockpit' with hands-on-throttle-and-stick (HOTAS) controls.
The Super Tucano's weapons fit comprises a .50 calibre MG (with 200 rounds of ammunition) in each wing and the capacity to carry a variety of ordnance including Giat NC621 20 mm cannon pods, Mk 81/82 bombs, MAA-1 Piranha air-to-air missiles (AAMs), BLG-252 cluster bombs and SBAT-70/19 or LAU-68A/G rocket pods on its underwing stations.
In addition, there is the provision for a datalink, a video camera and recorder, an embedded mission-planning capability, forward-looking infrared (FLIR), chaff/flare dispensers, missile approach warning receiver systems (MAWS) and radar warning receivers (RWRs). To date, the USAF has received a static demonstration of the Super Tucano at Wright-Patterson Air Force Base (AFB) in Dayton, Ohio.
In the same class as the Super Tucano, in terms of its configuration, capability, and approximately USD8 million price tag, is the AT-6B Texan II. With the 85 per cent common T-6A in service with the USAF and USN as a basic trainer aircraft, the AT-6B already meets all of the air force's requirements as laid out on the LAAR RfI.
In September 2009 Hawker Beechcraft and Lockheed Martin announced that they would jointly bid for the USAF's LAAR requirement. Hawker Beechcraft will be the prime contractor, with Lockheed Martin assuming responsibility for integrating the aircraft's mission systems.
As well as having the option of FLIR and a tactical datalink, the AT-6B is equipped with six underwing pylons (three under each wing), allowing for the carriage of up to 1,415 kg (3,120 lb) of stores, including .50 calibre MGs, Mk 82 500 lb bombs and LAU-68 seven-round 70 mm (2.75 inch) rocket pods.
The provision to carry precision-guided munitions could also be included at the customer's request and a limited self-defence capability could be incorporated with the integration of the AIM-9X Sidewinder air-to-air missile.
As well as being offered for the USAF LAAR and ANAAC LAS competitions, the AT-6B has been favoured by the Iraqi Air Force (IQAF) as its light attack platform of choice. In December 2008 the Iraqi government requested the sale of 36 such aircraft from the US.
With the IQAF also looking to buy 20 T-6A trainer aircraft, the synergies (and consequent cost savings) in logistics, maintenance, air and ground-crew training and basing infrastructure are apparent and go a long way to explaining the growing popularity of such platforms as a cost-effective alternative to jet combat aircraft.
Currently, the AT-6 prototype is undergoing flight-testing, which should last until the end of the second quarter of 2010.
Other possible contenders for both the LAAR and LAS competitions include the Air Tractor AT-802U, North American (Boeing) OV-10 Bronco and Stavatti SM-27 Machete. The AT-802U, a militarised version of Air Tractor's agricultural and fire-fighting aircraft, was first unveiled at the Paris Air Show in June 2009. At the time a company spokesperson told Jane's that it had received firm interest in the two-seat turboprop aircraft "from well over 20 countries". The example displayed in Paris was fitted with dual 12.7 mm GAU-19/A three-barrel Gatling guns mounted on the inboard wing pylons (which can carry 1,200 rounds each), two M260 rocket launchers on the outboard pylons (one on each) and representative Mk 82 freefall bombs on the two under-fuselage hardpoints.
According to Lee Jackson, a design engineer at Air Tractor, the aircraft can also be configured to carry more advanced weapon systems such as the Hellfire missile, Directional Attack Guided Rocket (DAGR) laser-guided rockets, a Sniper XR surveillance and targeting pod and a Wescam MX-10/MX-15 targeting turret for reconnaissance and target identification.
Although no unit price had been set, the company told Jane's that it should be "significantly lower" than that of both the Super Tucano and the Texan II.
A selling point for the AT-802U over its competitors is its 3,628 kg (8,000 lb) payload. This carrying capacity can translate into either more munitions carried than comparable platforms, the same carried over a greater distance (or for longer on station) or the same carried but with an increased safety margin and carry-back capability.
Perhaps the most intriguing light attack aircraft to emerge as a result of the USAF's new-found interest in turboprop COIN platforms is the resurrected Boeing (Rockwell) OV-10 Bronco. Originally conceived as a light attack asset during the Vietnam War, the Bronco was retired from the US inventory in the mid-1990s (it was retained as a forward air control and aerial surveillance platform for some years after it had fulfilled its COIN role). In September 2009 Boeing announced that it was in the process of computerising old designs of the OV-10 and would open up a production line should the USAF select it to fulfil the LAAR and/or Afghan LAS requirements.
Dubbed the OV-10X, the revived Bronco would have a payload capacity of 1,360 kg (3,000 lb). Its twin turboprop powerplants have the benefit of increased reliability and safety, enabling the pilot to return home on one engine. In addition, its widely spaced main landing gear (located on two pontoons) should greatly improve the aircraft's rough-field performance characteristics.
Although still in its developmental stages, it is thought that the OV-10X may feature helmet-mounted displays, an EO sensor, a .50 calibre gun and IR countermeasures. In addition, it should be able to carry up to 16 Hellfires.
Despite the USAF's tight deadlines, Boeing is confident it can quickly open a production line at a location to suit the air force.
The OV-10X concept "is a very modular design; it's easy to build", a Boeing spokesperson said. "There are any number of companies that can produce and assemble this airplane."
Entry level
An outsider for the LAAR and LAS requirements, in so far as it is the company's first foray into the military market and because a prototype has yet to fly, is the Stavatti Aerospace SM-27T Machete.
The original Machete concepts were developed in 2000, with actual design work commencing in 2003, company chief executive officer Chris Beskar told Jane's . In 2005 Stavatti met with USAF planners at the Pentagon as well as air force battle laboratories studying COIN operations and, based upon their suggestions, a major redesign effort was undertaken that led to the creation of the three Machete variants: SM-27S/T single-seat/twin-seat turboprop COIN/CAS platform, forward air control (FAC) and advanced trainer; SM-27J/L turbofan COIN/CAS, FAC and lead-in fighter trainer; and SM-47S/T turbofan air-defence fighter.
In 2007 the design underwent a second review that focused on increasing the aircraft's internal fuel load, weapons carriage and powerplant configuration, leading to a larger aircraft. The current design was frozen earlier in 2009 with engineering of the current design beginning in May 2009. The SM-27S/T, the subject of the LAAR bid, has been billed by the company as "a 21st century A-1 Skyraider". With a unit cost of between USD10 million and USD15 million, its performance parameters will include a tactical radius of 750 nm and the ability to carry a 2,948 kg (6,500 lb) payload (3,629 kg [8,000 lb] with 70 per cent internal fuel). Powered by a single 2,920 shp Pratt & Whitney PW127G turboprop (the same engine that powers the ATR 72 and C-295 transport aircraft), the SM-27S/T will be armed with a centreline-mounted 30 mm cannon and armoured throughout.
The SM-27 will have a maximum level speed of 360 to 400 kts, depending upon external load, and will feature a 'glass cockpit' that incorporates F-16 flight controls and reclined Martin Baker Mk 16 ejection seats. It will have an inflight refuelling capability, integrated avionics and will be able to sustain +9 g in a clean configuration.
The turboprop Machete will be available in a basic configuration without radar, as well as a more advanced variant, which will feature the Lockheed Martin AN/APG-67 radar (as developed for the F-20 Tigershark export fighter) and a comprehensive electronic-warfare (EW) self-protection suite.
According to Beskar, details of the SM-27 flight-test schedule will be released after the prototype's anticipated first flight in late 2010/early 2011.
The company intends to be able to field the SM-27S/T COIN variant some time in 2012 to 2013, which would meet the USAF's LAAR and LAS requirements. "While this schedule may seem to be ambitious, we have been performing considerable engineering development for some number of years," Beskar said.
However, even though Stavatti has submitted its designs for the LAAR competition, and is confident of meeting the programme's exacting timetable, Beskar concedes that the Machete's time may come later than the air force's current requirements: "What the ... LAAR requirement does is identify the need for a light attack aircraft and the value of COIN/CAS. We feel this is an indicator of a paradigm shift. We suspect that, due to the rapid acquisition timetable, the LAAR requirement will be satisfied by a legacy aircraft. From a strategic marketing standpoint, any legacy aircraft procured to satisfy the LAAR requirement in the near term could be replaced by Machete aircraft produced 20 to 25 years from [the] LAAR [aircraft in-service date]." He added that, with this long-term objective in mind, the Machete programme will proceed regardless of the outcome of the USAF LAAR bid.
For the USAF LAAR programme, the next step in the acquisition process is for the ACC to document a validated requirement using the official Joint Capabilities Integration and Development System (JCIDS) process. Once a validated requirement is documented, which will probably occur sometime in 2010, an official RfP can be released to industry for the acquisition of a LAAR platform.
Looming RfPs
For the Afghan LAS programme, the next step is to post an official RfP to industry, which is likely occur in early 2010, according to a USAF spokesperson.
For both the USAF LAAR and Afghan LAS programmes, the platform evaluations will take place at the air force's Aeronautical Systems Center (ASC), Wright-Patterson Air Force Base (AFB), Ohio.
The USAF would not say when the winner/s would be revealed, but said that the date for such an announcement would be contained in both RfPs.
Not even the strongest exponents of turboprop light attack platforms would suggest that they could completely replace fast jets on today's battlefield. However, as a counterpart to the jet, the turboprop does have its part to play as a hard-hitting and cost-effective light attack and ISR platform.
As recently as May 2009, a USAF spokesperson told Jane's that acquiring "single mission type aircraft may not be in our best long-term interest".
That it should now be looking to procure 100 such aircraft to fulfil just this role some 30 years since it retired its last such platform represents a paradigm shift indeed.
Gareth Jennings is Jane's Aviation Desk Editor, London
