COMAC ARJ21 ARJ21-900

The ARJ21 family was laid out with room to grow. In June 2018 Comac floated an ARJ21-700+ for 2021 with weight and drag reductions, and then sketched a -900: the same aircraft lengthened to take extra seat rows. The fuselage went from 33.46 to 36.35 m while keeping the 27.28 m wing, the 8.44 m fin height and the two rear-mounted engines. The commercial target was the hundred-seat bracket contested by the Bombardier CRJ900, the Embraer E175-E2 and the Mitsubishi MRJ90.

The manufacturer's tables describe a noticeably heavier aeroplane. Operating empty weight rose to 26,270 kg in standard-range trim and 26,770 kg in extended-range trim, with maximum take-off weights of 43,616 and 47,182 kg and take-off runs of 1,750 and 1,950 m. Range worked out at 1,200 nautical miles for the basic version and 1,800 — some 3,334 km — for the extended-range one, slightly short of the -700 ER despite the extra fuel, and the CF34s had to be uprated from 17,057 to 18,500 lbf to carry the weight. Ceiling and speeds were unchanged at 11,900 m, Mach 0.82 maximum operating and Mach 0.78 cruise.

No -900 was ever built. The programme's order tables list not a single aircraft in that configuration; the business stayed with the -700 and its derivatives while Comac poured its resources into the C919. The silence is doubly telling because the stretch is absent from the post-rebranding catalogue of November 2024 too, which lists the C909 in STD, ER, CBJ, CCF, EMJ, FFJ and MSJ forms and nothing longer. In practice the -900 served as a statement about what the Chinese industry believed it could do rather than as a product: the real step up in size came instead from the single-aisle C919.