Andrew Doyle/TOULOUSE
The start of final assembly of the first Airbus Industrie A340-600 is four months away, but the consortium is ensuring that its latest widebody derivatives have an unprecedented level of service readiness.
First deliveries of the 380-seat -600 are due from the second quarter of 2002, followed by those of the shorter, ultra-long-range -500 in September of that year.
At the end of this month, Airbus is to complete flight tests of several A340-500/600 systems conducted with the A340-300 prototype. The aircraft will then be modified for use as the flight test and certification platform for the new A340 models' Rolls-Royce Trent 500 engines.
"We've been taking the opportunity to test some systems beforehand," says Gordon McConnell, Airbus vice-president for A340-500/600 development. "We're trying to ensure that when our customers get the product it's as mature as we can make it. It's about finding things early and fixing them early."
Airbus is focusing on three main tasks: to influence the design, based on lessons learned with previous aircraft; to enhance the support services, with the provision of technical documentation, tools and training; and to "improve the product development and verification process to demonstrate maturity before service entry". The programme is designed to encompass the activities of all Airbus vendors, as well as those of partner companies.
Dispatch reliability
Airbus' goal is a dispatch reliability level of at least 99% for the A340-500/600 after the first year of service, when the consortium believes that sufficient numbers of aircraft will have been delivered to provide a statistically representative sample. "When you've only got a few aircraft in the fleet you won't achieve 99% straight away," says McConnell.
The A340-300 testbed has been used to validate the -500/600's taxi-aid camera system, nosewheel steering damper and take-off rotation and flight control system laws. These systems are required because of the aircraft's increased size - the -500 and -600 will have a substantially bigger wingspan than that of the -300, while the -600 will supersede the Boeing 777-300 as the world's longest airliner.
Control laws
As a result of testing control laws designed to prevent tailscrapes on the A340-600 "we've been able to delete the tail-bumper on the 600", says McConnell.
Work on the new models' flight control laws has focused on modifications to deal with the increased flexibility of the larger wing and the substantially longer fuselage of the -600, "so we can better anticipate the response of the aircraft", adds McConnell. The A340-500/600 flight control system will receive additional inputs - compared with those installed on earlier A340 models - provided by new pitch-rate sensors on the wings and fuselage.
The first Aircelle-developed thrust reverser for the Trent 500 has been delivered to R-R and will undergo a 3,000-cycle test programme before service entry.
One of the most significant examples of the way in which the maturity programme has influenced the design of the A340-500/600 is in the cargo handling system, which was changed from a six- to an eight-track design with enlarged power delivery units to boost reliability, McConnell says. The use of CADDS 5 three-dimensional, computer-aided design software in developing the A340-500/600 has also delivered benefits, says McConnell, in terms of maintenance accessibility for line engineers. "We've been able to check maintenance tasks on the computer system and make changes."
Airbus, meanwhile, is striving to iron out potential problems with cabin systems - traditionally a significant cause of dispatch reliability problems. DaimlerChrysler Aerospace will test a cabin systems integration rig in March.
"We are able to simulate the cabin systems and test them fully before we go near the aircraft," says McConnell. The third prototype will be fitted with a full passenger cabin and "will do some long-range flights to look at the cabin systems," he adds.
Source: Flight International
