Development has been a challenge, pushing sensor fusion and miniaturisation to the limits

After a slow start, the Eurofighter development programme has hit high gear, accelerating from 500 flights to 1,000 in less than half the time it took to accumulate the first 500 missions. The pace is increasing as all seven development aircraft (DAs) get to grips with the task of clearing the initial production configuration.

Although less than a quarter of the way through the total 4,800-flight programme, Eurofighter says testing to date has cleared the initial air defence configuration throughout a large part of the flight envelope. "Flight test has cleared the envelope well," says managing director Brian Phillipson. "Now we are shifting the focus to avionics work."

Already, software for the initial operational capability (IOC) standard aircraft is running in simulators and flight testing is scheduled to begin by year end. This software will be "productionised" for the five instrumented production aircraft (IPAs) which Eurofighter will fly, beginning in August 2001.

The IPAs will be used to verify the production standard and complete flight testing, which began in March 1994 with the flight of DA1 in Germany. A month later, the second aircraft flew in the UK, setting the stage for programme that has divided flight testing tasks between the four partners:

• DA1, based at Dasa Manching, is assigned to handling and engine tests;

• DA2, based at BAe Warton, is tasked with envelope expansion and carefree handling (CFH) clearance;

• DA3, based at Alenia Caselle, is dedicated to engine, stores and gun testing;

• DA4, a two-seater based at BAe Warton, is assigned to avionics and radar development;

• DA5, based at Dasa Manching, is tasked with avionics, radar and weapons testing;

• DA6, based at Casa Seville, is dedicated to two-seater CFH clearance and systems tests;

• DA7, based at Alenia Caselle, is responsible for weapons and performance testing.

This division of labour reflects the workshares agreed when the four nations signed the development contract in 1988 - 33% each for Germany and the UK, 21% for Italy and 13% for Spain, based on each country's share of a planned 765 aircraft. These workshares have been adjusted for production.

"During development, all of the partners wanted to participate in the technology," says development phase director Martin Friemer. Each company was assigned system design responsibility for an element of the aircraft. Then four major joint development teams were formed, each led by one partner, involving all the companies and their key suppliers. Alenia leads the utilities control system joint team, BAe the avionics team, Casa the structural team, and Dasa the flight control system team.

Development has proved a challenge. "We took an extremely large step in technology on all fronts," says Phillipson. "The Eurofighter went to the edge of what was possible. We've had to push technology a long way in development, which has made it more than just an EMD [engineering and manufacturing development] programme."

The Experimental Aircraft Programme (EAP) paved the way for development of the Eurofighter, "but did not develop mature enough technologies," he says. Although the EAP demonstrator proved the air vehicle aerodynamics, Eurofighter was faced with substantial development work in flight controls and other areas. "We've had to develop a lot of technology in sensor fusion and miniaturisation," says Phillipson.

The first two development aircraft were flown with RB199 engines, as used in the Tornado and EAP. "Starting the programme with RB199s, to decouple aircraft and engine development, in hindsight was the best idea we had,"says Friemer. "We've had a much better experience than the Tornado, with no major engine problems." All seven DAs are now flying with EJ200 engines.

While problems with the digital flight control system (FCS) slowed early flight testing, the subsonic carefree handling envelope has been cleared and work begun on supersonic CFH. Autopilot/autothrottle testing is under way, and flight testing of FCS software for the IOC aircraft will begin later this year.

Two development aircraft are flying with what is essentially the IOC standard radar. The ECR90 has been installed in DA4 and DA5 since they first flew in early 1997. These aircraft have flown co-operative missions with the BAC One-Eleven radar testbed, which has been flight testing the ECR90 since mid-1996.

Because of delays in development of the forward-looking infrared (FLIR) sensor, flight testing in a "hack" aircraft will not begin until later this year. "The FLIR is a problem area, but the basic sensor performance is known and it's a relatively low risk," says Phillipson.

Flight testing of the defensive aids subsystem (DASS) is still a year away, but ground tests are already under way and the towed decoy has been deployed successfully by DA4 during manoeuvres and supersonic flight. Clearing the DASS will be among tasks assigned to the IPAs.

All software is being developed in blocks. Eurofighter plans to complete development of the IOC standard software by the end of next year, ready for installation in the IPAs. The company will then move on to the full operational capability (FOC) software, which it plans to have developed well before the first FOC aircraft is delivered in late 2003.

Eurofighter plans to convert four development aircraft to production standard, for early demonstration of the FOC software. "We want to fly the FOC software in production hardware in the DAs and IPAs," Phillipson says.

"Over the next two to three years, we want to get the ground rigs running production equipment, and convert some DAs to production hardware, to get some time in the air," he says. "We are driving our suppliers to provide equipment early for the rigs. We want it a year from now, way ahead of when it is wanted for production aircraft."

There have been some significant avionics changes during development, where the original equipment was found to be inadequate. "In some areas, we have gone through two generations of development," he says. As a result, the transition to production is now viewed as relatively straightforward.

Persuading suppliers to write off their investment in development and sign tough fixed-price contracts for production equipment is not proving so easy, Phillipson admits. "Development was basically fixed price, and nobody will make money out of it," he says. "Industry will have to write off its investment in development; the partners just faced up to it sooner."

Making a profit from production is high on the agendas of the Eurofighter partners and their suppliers, and that means delivering on cost, on schedule and to specification. While development continues to be demanding, Phillipson appears confident of delivering an aircraft meeting those requirements.

"We've flown the basic standard of all the systems, and we're ground testing the IOC systems. We know the basic performance, and we know we have the capability we need," he says. "It will be tough getting that first aircraft out the door, but it does not look impossible."

Source: Flight International