The test campaign of the Airbus A321XLR that commences in 2022 will include three aircraft. The first aircraft will be powered by CFM LEAP engines and the second by Pratt & Whitney Geared Turbofans to certify the XLR with two different engine specifications. The third will have LEAPS again but will focus on certification of the fully furnished cabin. A321XLR test campaign includes three aircraft. On the sidelines of the Airbus Summit on September 21-22, the airframer had various experts on hand to update the media on the status of all its programs. One of the key focus points was on the A321neo. On-site at the Delivery Center was MSN7877, one of the A321LR test aircraft with LEAP engines. While the LR has been in service for some time and is proving its value with its extended 4.000 nautical mile range, construction of the first A321XLR is taking place in Hamburg where the 4.700 nm (8.400 kilometers)-version will be exclusively assembled. The A321XLR, which was launched during the 2019 Paris Airshow, has a higher Maximum Take-Off Weight of 101 tons, which requires a modified and strengthened main landing gear with uprated brakes. The wing has a different single trailing-edge flap configuration. The anti-icing system for the XLR is currently being tested on MSN7877, as was visible from the black padding on the leading-edge flaps. This is an A321LR, but on the XLR, the Rear Center Tank will be positioned between the black area on the right up to the middle of the door on the left. (Richard Schuurman) Giving the XLR the extra range over the LR is the addition of the Rear Center-Tank (RCT), which holds up to 12.900 liters and is the size of four Additional Center Tanks of 3.124 liters each. The RCT is positioned behind the main landing gear halfway up to the Main Doors 2 and fully integrated within fuselage sections 15 and 17. The RCT has been topic of debate earlier this year when both the European regulatory agency EASA and Boeing submitted their views on the design. Both questioned the effects that the cold fuel inside the tank would have on cabin comfort, with passengers sitting on top of it likely experiencing cold feet. But they were more worried about the safety of the big tank, which might lack sufficient space around it for fitting fire-protective panels to prevent any burn-through as well as adequate ventilation. EASA also required that Airbus makes the RCT resistant to penetration and fire hazards. The engineers on-site in Toulouse said that Airbus is dealing with all these issues and will take notice of all suggestions and remarks that have come in during the consultation phase. The airframer is confident it has produced a safe Rear Center Tank configuration that will pass the certification but is aware that regulators want to demonstrate this at length during the test and certification campaign that runs until at least mid-2023. The A321XLR test campaign includes three aircraft, but this will be tested on the first two aircraft. Software will deal with the center of gravity With the huge RCT just aft of the main landing gear, its weight could have an impact on the center of gravity and hence the stability of the aircraft. The standard A321neo was subject to an EASA Airworthiness Directive in 2019 when it was found that in special circumstances during the final approach the Elevator Aileron Computer could command excessive pitch that could reduce control of the aircraft. The issue has been solved since with a software update, but it caught media attention as it happened at the same time when the Boeing MAX hit all the bad headlines over its pitch sensitivity and the flawed MCAS system. Asked if the RCT will affect the flight characteristics in such a way that the A321XLR will need constant trimming, engineer Isabelle Bloy said: “This characteristic will be considered during the flight tests and will be adjusted at the end of the flight test campaign as in any aircraft. We will not have something drastically different on software for the XLR. The fine-tuning of the flight control modes will be done during flight testing.” A colleague added: “This is the beauty of fly-by-wire: you can tweak the laws even if the aircraft through an A319neo to and A321XLR is of a different size. They all behave the same.” Bloy added: “The only thing is how the fuel behaving during the cruise phase of the flight. In what we call the fuel vector or when and where we transfer the fuel between the tanks is part of the adjustments that we do to maintain the center of gravity during the cruise. The fuel system has been designed for this. It is nothing special for us.” It means that on the XLR, fuel will likely be transferred between tanks to optimize the CoG, but Bloy was unwilling to go into further details. No pictures were allowed inside A350-900 MSN002. (Richard Schuurman) A350 has some 'secret' cabin features Also on display was A350-900 MSN002. The media was invited to tour the aircraft but were not allowed to take pictures inside. The reason was that there are some innovations that Airbus isn’t willing to fully share yet. One of these was the 10 inch flexible and very thin screens of the inflight entertainment system that were fitted on three seats in Economy Class. The flexibility means they can easily follow different shapes of the seat. While small in size, the screens actually offered high-resolution and good-quality images. In the forward cabin, another innovation was demonstrated in the Business Class section. Three projectors in the ceiling were projecting images on the luggage bins and wall in front of the cabin, like a sky full of stars, scenic images of landscapes, or even pictures of the active crew flying the aircraft. The system has been designed by Diehl and only recently entered flight testing to see if the projectors continue to provide stable images in flight. Already available soon will be fully dimmable windows. They will be standard on the A350 AirSpace cabin from next year. Formation flying looks promising In the cockpit, Chief Test Pilot Malcolm Ridley answered a few questions on the Fello’Fly project. Announced in 2019, Airbus said it would test the effects of wake-energy retrieval when flying in formation just like geese do when they embark on a long journey. Formation flying could potentially save five to ten percent in fuel per trip. The formation flight was first tested in March 2020 with a couple of A350s, but it has been al quiet since then. While more testing needs to be done, Ridley said that initial results look promising. The projected fuel efficiency seems to be possible, especially when the trailing aircraft is some 1.5 miles behind the leading one. But it takes careful preparation, sequencing, and scheduling to get aircraft in the correct position, Ridley said, although once programmed into the flight management system, the aircraft executes all maneuvers by itself. While he was impressed, Ridley said that more testing needs to be done. We will be some years away from seeing aircraft cross the Atlantic on orchestrated formations that come out of Fello’Fly.
