Airbus plans a 1,600-hour flight-test schedule for the three A350-1000s that it will use to certify the new stretched variant of the widebody twinjet, the first of which flew on November 24. The scheduled first-flight profile took the initial aircraft – manufacturer's serial number (MSN059) – to an altitude of some 25,000 feet and up to the maximum operating limit speed.

Between FL100 and FL150 crewmembers explored the aircraft flight envelope in both direct and normal control law as the A350 flew in all configurations, according to Airbus chief test pilot Christophe Cail. Tests included, for example, handling at maximum flap extension speed (VFE) and at low-speed in landing configuration.

A crew comprising Airbus head of flight and integration tests flight-test engineer (FTE) Patrick du Ché, FTEs Emanuele Costanzo (head of A350 development flight tests)  and Stéphane Vaux, test-flight engineer Gérard Maisonneuve, and experimental test pilots Frank Chapman and Hugues van der Stichel flew the A350-1000 while accompanied by Dassault Falcon 20 executive-jet chase aircraft. Chapman performed the initial landing when the aircraft returned to the Airbus final-assembly plant and test center at Toulouse in southwest France more than four hours after take-off.

Airbus has split the three-aircraft A350-1000 flight-test program into five phases covering initial development, development and initial certification flying, final certification work, preparation for entry into service (EIS), and support following EIS, although Airbus has not published target dates associated with each phase.

Initial operations with MSN059, equipped with heavy flight-test instrumentation, involve further exploration of the flight envelope and trials of handling qualities and systems, engines, loads, and braking, according to Cail and Airbus marketing senior vice-president François Caudron. Schedules call for MSN059 to complete about 600 hours of flight-tests, including all the EIS support flying.

An early program key point with MSN059 will involve freezing of the aircraft aerodynamic configuration, nominally expected almost halfway through the first phase. That milestone will come as second aircraft MSN071 – another heavily instrumented machine that faces 500 hours of flight-testing – joins the program. Airbus expects the third A350-1000, MSN065 to fly a 500-hour schedule toward the end of initial development.

Plans call for MSN071 to accomplish performance, powerplant, systems and autopilot trials. In the first half of second-phase flight-test work, it will conduct the cold-weather campaign, followed by airfield performance at high altitude and in warm conditions, according to Cail. 

This second phase will see MSN065, the cabin-development aircraft fitted with light flight test instrumentation and a representative passenger interior, involved in cabin-air and external noise-emission measurement. All three A350-1000s will participate in the third phase of testing, scheduled to lead to final airworthiness approval ahead of EIS in the second half of next year.

Among final duties, MSN065’s fourth-phase flight testing will begin with route proving, followed later by initial extended-range operations and confirmation of EIS performance. The A350-1000, which accommodates 41 passengers more than does the baseline A350-900, uses a reinforced structure that allows it to operate with increased design weights (including higher maximum takeoff weight) and payload. The stretched fuselage involved the insertion of six forward and five aft frames into the fuselage parallel section and an improved wing that includes aerodynamic changes such as an extended wing trailing edge to support higher-weight approach speeds.

The heavier aircraft sits on new six-wheel main landing-gear bogies to reduce airport pavement loading, while more-powerful Rolls-Royce Trent XWB-97 engines each provide 97,000 pounds of thrust. Ahead of last week's maiden flight, Airbus and Rolls-Royce have performed two rounds of Trent XWB-97 trials on a flying testbed (A380 MSN001) that should accumulate some 305 hours of flying by the end of next month. The first campaign, between November 2015 and April this year, logged 148 flight test hours that included Rolls-Royce “certification specification for engine (CS-E)” operability tests, according to Cail.

A second round of testing that began at the end of July is set for completion after 157 flight hours. The sequence will cover de-risking, maturity, and items for certification specification for engine integration, including hot weather, natural icing, drainage and fire extinguishing.