Paris Air Show

A350 to set an Airbus record, as program marches forward

 - June 16, 2013, 1:00 AM
Final preparations for the new Airbus A350’s flight-test program began in earnest earlier this month with the first running of its Rolls-Royce Trent XWB engines, of which 12 development examples had previously logged more than 250 hours flying and a further 4,200 hours/7,400 cycles in ground running.

As launch customer Qatar Airways prepares to receive new Airbus A350s next year, the Arab operator will train using an operations department at the manufacturer’s Toulouse factory in southwest France. Until then, Airbus plans to conduct flight-test activities to mirror airlines operations at that facility.

The flight-line buildings are being fully refurbished as the A350 begins its initial flight test campaign, according to executive vice-president and A350 program head Didier Evrard. New hangar construction also is under way at Toulouse, while an existing building will house airline-like operations, including provision for working parties and daily maintenance in the run-up to the new twin-aisle twinjet’s entry into service in the second half of 2014.

Final preparations for the A350’s first flight began in earnest at the beginning of June, following handover of the first aircraft to the Airbus flight-test department on May 31. In the ensuing two days, Airbus ran the Rolls-Royce Trent XWB engines, of which 12 development examples had previously logged more than 250 hours flying on the A380 flying testbed (FTB) and a further 4,200 hours and 7,400 cycles in ground running.

The time from last Friday’s first flight to service entry will be a record for Airbus of a little over a year, according to A350 project test pilot Frank Chapman. He said that Airbus has “tried to front-load [flight-test] as much as possible to ensure maturity, de-risk [the program] and increase efficiency.”

Chapman, who earlier this month was expecting to fly the A350 on its third flight (and was earmarked to bring it to Le Bourget if the program allowed), said that the A350 program involves carefully managed risk to avoid flying a new engine on a new platform. Hence, the manufacturer has been using a suite of ground-test rigs that became increasingly busy from early last year. For example, A350 landing gear zero entered service at Airbus UK in March 2012, not long after the Trent XWB first flew on the A380 flying test bed. In September, the adaptive dropped-hinge flap, a high-lift device said to combine the advantages of a tracked Fowler flap with a variable-camber function, completed tests on the high lift zero rig.

By the beginning of June, Airbus had accumulated some 13,280 hours of tests on equipment that included cabin and cockpit simulators, fuel-system rigs and the iron bird test rig used for electrical, hydraulic and mechanical system functions. In July the cabin mock-up will be used to conduct trials with a full load of passengers, said Chapman.

As A350 flight-testing gets under way, the aircraft will initially be operated with a mixed crew of experimental test pilots for development and operational evaluation. Test-flight engineers are responsible for aircraft configuration, while design evaluation and validation follow-up are handled by flight-test engineers.

Flight testing of the new Airbus A350-900 involves incremental development away from an initial combination of medium-weight and centre of gravity position, according to Chapman. For the maiden flight, Airbus chose a minimum height of 20,000 feet and a speed of 200 knots to provide plenty of margin for handling and control checks, followed by various configuration changes, including flap settings and landing-gear function checks.

With the aircraft cleaned up, aero-elastic response will be compared with predictions based on ground simulator work before speed and altitude are increased to 430 knots and 25,000 feet, respectively. Typically, early flights are to use one test-flight engineer to track the aircraft and constantly identify its status and three flight-test engineers to run the flight profile and direct operations from the rear of the aircraft.

Five A350-900s are involved in the “relatively standard” overall flight-test program that for each comprises five phases of development and certification flying, followed by a buffer period before entry into service, according to Chapman. He said that the first several flights constitute an initial development phase during which Airbus will analyse the A350’s flight characteristics and behaviour before beginning more formal activity.

A350 manufacturer’s serial number (MSN) 001 is one of two aircraft carrying heavy flight-test instrumentation (FTI) and will perform flight-envelope, powerplant and systems work, including natural icing trials after the aerodynamic configuration has been frozen. MSN 003, the second to fly and also heavily instrumented, will be used for high-altitude and high- and low-temperature campaigns during its development and certification flying, which covers performance, engines and systems activity. One of a pair of lightly instrumented A350s, MSN 004 will be used for avionics development and certification and its duties will include external noise measurement and analysis.

MSN 002, which is scheduled to fly shortly after MSN 004, will sport a medium test-instrument fit and is one of two machines to be furnished for passenger cabin development and certification. It is earmarked for partial evacuation trials and hot- and cold-chamber climate tests in its initial program, which will be followed by early long flights in its third test phase to assess the A350’s endurance with a full load.

Finally, the lightly instrumented MSN 005, another furnished-cabin A350, is scheduled to conduct route-proving trials towards the end of the type-certification period in mid-2014. Its duties cover function and reliability (or operability), training and extended-range twin-engine operations performance as well as the first customer crew-training sessions.