Airbus is conducting a second round of cold-weather trials as part of its A321XLR flight test programme, to assess the narrowbody's cabin interior. The European airframer says its A321XLR flight-test vehicle Number 3 (FTV3, registered F-WWAB) has arrived in Iqaluit, Canada's northernmost city, for a week of cold-weather trials. The twinjet, powered by CFM International Leap-1A engines, is the only one in the campaign equipped with a cabin and primarily used to test the narrowbody's interior for long-haul operations. In February, the manufacturer completed a week of ground and flight tests with its Pratt & Whitney PW1100G-powered FTV2 (F-WWBZ) in Iqaluit, located on Baffin Island, to check other aircraft systems in such conditions. The airframer says it is standard practice to complete multiple rounds of cold-weather trials during flight-test campaigns. Among the aims of the current cabin cold-weather trials is to check the freezing protection and insulation of water lines and the functionality of lavatories and the aircraft's waste tank system. "This is a big campaign for the team," Airbus says.
The cold-weather programme follows previous FTV3 trials to assess cabin temperature control, with passenger heater dummies in November 2022, and interior noise. New, visually improved sidewall and ceiling panels have been developed for the A321XLR, Airbus highlights. "We have added insulation in the forward fuselage section and developed a new lining as standard within the door and door-surround structures," states cabin and cargo engineering project leader Mehmet Altay. "We have also developed an optional thermal/acoustic 'textile door cover' for Doors-1 and Doors-4, which can be attached via magnets to each door by the crew during flight." He adds that heated floor panels have been introduced in the entrance and galley areas at Doors-1 and -4, and that a quieter fresh-air vent outlet has been installed. The airframer says the thermal and noise improvements in the door and galley areas have been developed based on "airlines' valuable in-service feedback from their A321neos featuring the more recent ACF [Airbus Cabin Flex] configuration. "This would bring benefits in particular for the cabin crews' working environment, especially during long range flights." In 2018, Airbus introduced the ACF layout which features no additional doors immediately ahead of the wing – standard on earlier A321s – and instead includes new over-wing emergency exists. ACF has since become standard for the A321neo. As part of cabin noise assessments, Airbus says it is looking at the sound of new fuel pumps that have been introduced as part of the A321XLR's rear-centre-tank, in the fuselage under the floor, aft of the central wing structure. "Any acoustic energy they emit is monitored closely monitored," Airbus says. It asserts that design changes from previous A321 versions are "now being fine-tuned for the best possible in-flight experience". Later this year, Airbus intends to complete flight tests with passengers and flight attendants as part of route proving. "This will include a dedicated flight of up to seven hours with Airbus employees – acting as passengers – on board," states Tuan Wei Chung, cabin and cargo lead for A321XLR cross functions. "Various comfort aspects will be asked, not only from the passengers, but also for the crew. We will conduct surveys, to assess the passenger comfort level on the aircraft during the long flights with regards to temperature and noise." The next step in the A321XLR's flight-test campaign is described as Maturity Gate 13. "That means everything that we have developed is now in the phase to obtain EASA [European Union Aviation Safety Agency] type certification, and then to hand it over to the series production organisation for entry into service," Altay explains. "This is the main milestone we're heading for now." Airbus declined to specify a timeframe for MG13 and its requirements.