To ensure fewer will go further, reliability, maintainability and testability have been given the same priority as performance, cost and safety

Product support considerations have influenced the design of the Eurofighter Typhoon from the outset, as the consortium works to deliver on its promise of unprecedented reliability.

Reliability has a key role to play in successful deployment of the Eurofighter, because its air force customers are banking on improved availability rates, and therefore buying fewer aircraft than would previously have been required. In other words, a smaller fleet should be sufficient to maintain a large enough pool of mission-ready aircraft at any given time.

"Support considerations had to influence the design and we have had to develop support itself in an integrated way," says Eurofighter support phase programme director Massimo Tarantola. The concept of product support was re-examined during development. "We had a study with the customer and the question was that, with a new technology aircraft, no Cold War and high maintainability, did we believe that traditional support is still fit for the purpose?"

According to Tarantola, two conclusions were reached: that the air forces should concentrate on the operational aspects and delegate industrial support to industry itself; and that aircraft upgrades after delivery should be co-ordinated among all the customers so that a common technical standard is maintained.

For the first time, he says, reliability, maintainability and testability were given the same level of priority as aircraft performance, cost and flight safety. He adds that Eurofighter is contractually obliged to ensure the aircraft are fully supported when they enter service.

"The customer has recognised that you want to buy something when it is mature," he says. "If we deliver an aircraft and all of the related support is not available, we must bring in alternative means at our expense or the customer has the right to leave the aircraft at our premises while we procure the missing item."

Germany has agreed to cede all engineering support for its aircraft to Eurofighter and will pay for the service on a per flying hour basis. When a part needs repaired, the air force will hand it over to the company in exchange for a serviceable replacement. Eurofighter will own these exchangeable parts. Large and expensive items such as landing gear are likely to be owned by the air force. Eurofighter will repair and return them to their original owner.

Italy favours maintaining its own repair and overhaul capabilities where they already exist for aircraft such as the Tornado, but will rely on Eurofighter for a significant amount of support. Spain is also considering keeping a major support capability in-country, but is unlikely to pursue this option unless the UK does the same. The UK has yet to make up its mind.

The advantage for the operators of ceding some or all of their product support to Euro-fighter and paying per flying hour is that no up-front capital investment is required, Tarantola says. Over the life of the aircraft, they will end up paying roughly the same for product support as they would otherwise have done.

An important implication of such an arrangement, he notes, is that Eurofighter has a financial incentive to achieve the highest possible reliability. "The more reliable the aircraft, the more money we get," he says.

Eurofighter plans to respond to a request for quotations for spares support from the four countries by September. Per flying hour pricing for each nation will vary depending on which spares their air forces want to own and/or repair themselves. The quotes for Spain and the UK will be based on the assumption they will keep their in-house maintenance capabilities at current levels. "If they change anything I will clearly have to reshuffle," says Tarantola.

It is envisaged that around 15 support bases will be established around Europe, which will between them stock, and have the ability to repair, some 2,000 spares items.

Maintenance support by Eurofighter also has to be split between the nations according to the number of aircraft each is buying. "I will have to make sure each nation gets work in line with their share of the programme," he says.

Configuration management, meanwhile, is a first for a European collaborative military aircraft programme. A coordination centre has been set up to ensure that information on avionics upgrades carried out by the individual nations after the aircraft enters service are shared in an effort to maintain commonality between the fleets.

"It wouldn't be wise to deliver an aircraft that then goes into a base and they start modifying it as they want," says Tarantola. "We suggested to the air forces: 'Why don't we still leave you with four national centres, but we create a centralised one called the International Weapon System Support Centre [IWSSC], which will manage the four national centres?'"

Eurofighter will encourage individual air forces to proceed with any software modifications they deem to be desirable, as long as details are provided to the IWSSC afterwards. Says Tarantola: "We would then introduce all these upgrades to the other air forces and keep the aircraft common."

He says the Panavia partners "lost configuration control" of the Tornado following a series of rolling upgrades. As a result they failed to make the most efficient use of the expertise available at each of the companies. As with programmes such as Tornado, future requirements for other Eurofighter upgrades, such as integrating a new missile, will also be captured centrally so that a solution can be offered to all the partners.

Framing agreements covering integrated logistics support (ILS)were signed by Eurofighter and Eurojet in January 1998. Two procurement contracts, PC1 and PC2, were also signed. PC2 contained "preparatory work to go to contract for major support items", Tarantola says. Work was split in line with the workshare set for the overall Eurofighter programme.

Consequently Dasa is responsible for the aircrew synthetic training aids, Casafor the ground support system, Alenia for technical ground training aids and BAe for the International Weapon System Software Support System.

Three additional ILS procurement contracts were signed in September 1988. These cover design and demonstration of high-value aircraft ground equipment (AGE); development of medium-value "off aircraft" AGE; and the "enabling contract" for the future procurement of all spares, plus "on aircraft" line-replaceable items for the first 148 aircraft. "We are in the process of concluding the other contracts," says Tarantola.

Target operational reliability for the Typhoon is fewer than 400 "attributable" defects per 1,000 flying hours, with a less than 5%chance of a mission being aborted for technical reasons. Euro-fighter is aiming for fewer than nine maintenance man-hours per flying hour, with 50% of defects being rectified within 45min and 95% in less than 3h. An engine change should be possible in just 45min using four people. Testability targets call for a "false alarm" (or "no fault found") rate of below 5%, plus the ability to detect all safety-critical failures.

Tarantola says the Eurofighter has been designed so that only safety-critical components must be removed regularly for inspection, at intervals of 400h, 800h or 1,600h. "All the rest we know by design don't need to be removed, until they fail." Air force field teams helped ensure that those components most likely to fail are mounted for easiest access in case they have to be removed.

The aircraft's ability to meet the reliability, maintainability and testability targets will be assessed in detail by Eurofighter after service entry. "Compared with programmes such as the Tornado they are definitely very ambitious to achieve," says Tarantola. "This means very little maintenance activity."

Source: Flight International