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Tougher tucano


Developing the Super Tucano for the hostile Amazon basin has given Embraer an aircraft with unique selling points

Entering production deep in the rural heartland of Brazil is a new aircraft that will soon be used to patrol the huge country's far-flung borders, intercept drug traffickers, hunt guerrillas and keep the peace, as well as help train the next generation of fighter pilots.

The aircraft is the Embraer EMB-314 Super Tucano, a stretched, strengthened and re-engined derivative of the Tucano trainer. It is a crucial element of SIVAM, or Amazon surveillance system. Set up in 1990 by the Amazon Protection System to counter growing problems in the unpoliced wilds of the river basin, SIVAM required surveillance aircraft to track drug producers and guerillas, while light attack aircraft would intercept them. Though derivatives of Embraer's RJ-145 regional jet provided ideal surveillance platforms for SIVAM, the operational and tactical requirements of the interceptor role made this a harder niche to fill.

"The requirements are very tough, but the dangerous elements are not necessarily the bad guys, the terrorists or the drug smugglers," says Embraer defence marketing strategist Nilton Goncalves. Equally perilous, he says, are "the environment, the dust, the humidity, the bugs. Above all, the aircraft has to be autonomous. There is no infrastructure out there and, once you are in the middle of the Amazon, you are on your own".

The baseline requirement therefore called for a rugged design and an electrical system with a 30min main battery and a 2h back-up battery system "so you can fly around for two hours on minimum instruments". An extra 300litre (80USgal) fuel tank was devised to occupy the back-seat space, augmenting the 680 litre held in the wing, the 960 litre in three external tanks, all to provide endurance times of up to 7h.

At home in the heat

Embraer realised the stringent requirements gave it a blueprint for a design that would be equally at home in the climatic extremes prevailing in the equatorial,subtropical and arid regions of the world. "This area, and its tough conditions, are basically the same throughout much of South America, South-East Asia and even places in the Middle East. They all need tough aircraft that don't need much support and will last," adds Goncalves.

In tackling the SIVAM wishlist, Embraer was luckier than most. Not only was it familiar with the operating regime of the Amazon, but it already had a suitable building block for the aircraft in the shape of the EMB-312 Tucano and, by 1990, the conceptual notion of a more powerful, armed variant.

"You can thank President Carter for the start of the Tucano," says EMB-314 product development manager Carlos Henrique Berto. "He pushed through a boycott on sales of defence materiel and equipment to Brazil in the mid-1970s and forced us to begin developing our own military aircraft." Design of a trainer to replace the Brazilian air force Cessna T-37 fleet began in 1978, leading to a first flight of the Tucano in December 1980 and deliveries to the Brazilian military as the T-27 in 1983.

The trainer won overseas orders from Egypt and Iraq before it was selected in 1985 by the UK Royal Air Force as the basis for its BAC Jet Provost replacement. As part of the modifications made to meet the RAF requirements, the Pratt & Whitney Canada PT6A-25C-powered Tucano was re-engined with the more powerful 1,100shp (820kW) Honeywell (then Garrett) TPE331-12B. The modification prompted new interest in the potential for a light attack version. "The Tucano was designed to be a trainer that could carry weapons, but it was so good from the start that it quickly evolved into an operational aircraft. It was not really designed for that role, but it became almost natural," says Berto.

By the end of the 1980s, with defence budgets under pressure, Embraer saw the potential for "filling the gap with a multi-mission aircraft", Berto adds. Studies of a counter-insurgency variant of the aircraft began as the -312F but later changed to the -312H in covert recognition of its potential role as the "helicopter killer". Work on modifying the RAF Shorts Tucano T1 development prototype into a proof-of-concept "Super Tucano" began in January 1991, leading to a first flight just eight months later. To balance out the weight of a more powerful P&WC PT6A-67R engine fitted in the nose, the fuselage was lengthened by 1.37m (4.5ft) to 11.42m overall. Two plugs made up the increase: one 0.37m section ahead of the cockpit and a 1m stretch aft.

Two prototypes

Conveniently for Embraer, this development coincided with the launch of the US Air Force and Navy Joint Primary Aircraft Training System (JPATS) competition. Seeing its potential, Northrop and Embraer agreed in 1992 to tender jointly a variant for this tightly fought contest, so work began on two prototypes. "One was an operational version and one a training version, "says Berto. "The operational aircraft became the AL-X, and the trainer became JPATS." The AL-X, or Avion Leve X (Ataque), was an easy spin-off from the JPATS/EMB-312H studies and coalesced around the Brazilian air force's growing need for a light strike aircraft to meet the SIVAM requirements. In parallel, the Brazilian forces also needed a replacement for the ageing EMB-326GB Xavante weapons trainer, adding to the impetus behind what Embraer had by now redesignated the EMB-314 Super Tucano.

The two versions were similar, but the JPATS aircraft had only two hardpoints on the wing for fuel tanks and no provision for a head-up-display (HUD), while theAL-X was fitted with five hardpoints (plus two internal for machine guns) and a fourth-generation avionics suite with multifunction displays, HUD and other advanced features. "It was intended exclusively for the Brazilian air force," says Goncalves, who recalls the subsequent mixed fortunes of the -314. "We lost JPATS in June 1995, but in August we won the Brazilian air force AL-X order and then, in September, we won the NFTC [NATO Flying Training in Canada] programme."

Despite selection by the Canadian Department of National Defence, the win was later overturned "because of our regional jet fight with Bombardier", says Goncalves. The -314s were replaced by Raytheon 7-6As (Bombardier says it changed the selection because the Super Tucano could not be delivered in time for training to start in 2000). By now the future direction of the Super Tucano was clear. "We had changed the concept. Now it was an operational aircraft with full training capabilities," comments Berto.

Work began on a proof-of-concept (PoC) aircraft that embodied the bulk of the features now evident in the production AL-X. A key feature was the PT6A-68 turboprop and a 2.36m-diameter, five-bladed Hartzell propeller.

"We needed to develop the PoC aircraft to check handling characteristics and the suitability of the more powerful aircraft to ab initio training," says Goncalves. "To be honest, we had doubts that a 1,600shp-rated aircraft would be OK for cadets," he adds. To help offset the torque of the larger turboprop, a key feature was the introduction of an automatic rudder trim system as well as a new autopilot. "The basic idea is to reduce pilot workload and to be able to manoeuvre with feet off the rudder pedals," he adds. The PoC AL-X first flew in May 1996.

Elbit was contracted in April 1997 to supply mission avionics and the baseline mission system package flew on the PoC aircraft in 1998. Meanwhile, economic problems were bedevilling Brazil and the formal acquisition of the AL-X was delayed as the nation suffered the devaluation of the Real. Although the programme slipped beyond the 1999 target date for deliveries, Embraer continued to fund development as the contract with the air force was rejigged. This was changed from 50 firm orders, plus 50 options, to 76 firm orders, plus 23 options. Delivery was rescheduled to begin from December 2003. The 100th aircraft in the contract is expected to be the refurbished PoC model.

Final assembly site

Embraer settled on its new factory at Gaviao Peixoto as the final assembly site for the aircraft, which is designated the A-29 by the Brazilian military (AT-29 for the two-seat trainer variant). Initial deliveries will be at the rate of two a month, although the factory is sized for a maximum rate of six a month to handle additional work from export orders. To date only the Dominican Republic, with a requirement for 10 aircraft, has ordered the Super Tucano, but Embraer's marketing team has been busy since the Brazilian air force's firm order commitment was announced in 2001. The United Arab Emirates and the UK have been briefed on the aircraft, while other traditional Tucano operators have all shown "great interest", says Goncalves.

The AL-X's ruggedness appears to be the key selling point. "If you are in the jungle working on counter-insurgency missions you need flexibility, "says Goncalves. That's no place to operate jets. You would need ground support, big bases and hard runways. The AL-X doesn't need all that. Our whole philosophy is aimed at keeping life-cycle costs balanced. The main point is to be affordable." He estimates the market for the $4.5 million to $5 million (depending on options) AL-X as between 400 and 500 aircraft over 10 years.

Embraer toughened the aircraft for jungle dirt strips by reinforcing the undercarriage and strengthening the leading edges and windshield to take strikes from birds weighing 1.8kg (4lb) at 300kt (555km/h). "We have very big birds here in the Amazon," says Berto.

The air intake lip design was also optimised to reduce the chances of foreign object ingestion. The canopy was changed to an electrically actuated, side-hinging design. The pressurised cockpit - to 0.345bar (5lb/in2) - is fitted with Martin Baker Mk10LCX zero-zero ejection seats.

A Northrop Grumman on-board oxygen-generation system (OBOGS) is also fitted, while an air-cycle machine provides Freon-free environmental control for the crew, which sit in a Kevlar-armoured cockpit. The use of OBOGS eliminates the need for oxygen bottles to be stored at remote locations.

The Elbit avionics suite in the AL-X "is close to that of the Block 60 Lockheed Martin F-16", says Berto. Designed for high reliability, low workload, redundancy and high commonality with state-of-the-art fighters, the multimode system is driven by two main mission and display computers via a 1553B multiplex databus. Configured for either light attack or advanced training, the panel is designed to be altered during base checks to suit the appropriate need.

The instrument panel is dominated by two 150 x 200mm flat-panel multifunction displays (MFD), an arm consent switch, a HUD and a subpanel with hands-on-throttle-and-stick (HOTAS) controls. In the advanced training mode, the fighter subpanel, HOTAS and HUD are removed and the MFDs are "frozen", says Berto. A "basic-T" made up of traditional instruments (air-speed and attitude indicators, basic flight instrument, vertical speed indicator, turn and bank indicator, standby horizon plus g meter), is dropped in its place. "The MFDs can be gradually phased in as the student gains experience," Berto adds. Only two pages are available in training mode on the MFDs - a horizontal situation display and radio page on the left, and the electronic instrument and crew alerting system on the right.

For night operations training, the aircraft can be fitted with a FLIR Systems turret-mounted forward looking infrared sensor that fuses imagery with HUD symbology. The cockpit is compatible with Generation III night-vision goggles, adds Berto. This capability is vital for the SIVAM role because, says Goncalves, "most illegal operations take place at night in the Amazon".

The aircraft is being developed with a UHF digital datalink with future satellite communications and high-speed 10Mbit/s datalinks as growth options. It is also provided with IFF transponders operating in modes 1, 2, 3 and C, as well as a data transfer system for mission planning.

Weapons systems

The armament system can handle a total of 1,500kg external loads in the form of weapons or reconnaissance pods. Internal FNH 0.5in machine guns are capable of 950 rounds a minute, while external options include a GIAT M20A1 gun capable of 650 rounds a minute or an HMP podded gun. Up to 10 115kg or five 250kg bombs can be carried, or four LM70/19 unguided rocket pods.

Primary air-to-air armament is the Brazilian MAA-1 Piranha short-range infrared guided missile, but versions of the Raytheon AIM-9 Sidewinder and equivalents can also be carried.

Although 200-300h of flight testing remain, Embraer is confident it will achieve certification to US Part 23 standards without difficulty. The certification standard is modified to accommodate specific Brazilian air force requirements in areas such as spins, with particular stores configurations. "However, based on what we know, the aircraft is ready to go today," adds Berto. "We are sure we are offering the market a remarkable aircraft."

As the first aircraft fly next year to Brazilian operational bases in Natal, and later Boa Vista and Porto Velho, Embraer is bound to believe its $60 million investment will be well worthwhile.