During celebrations held in November 1983 to mark the 25th anniversary of the F27 entering airline service, Fokker announced the launch of a 50-seat follow-on to be known as the Fokker 50. Based on the proven F27 airframe, but fitted with more fuel-efficient engines, six-bladed 'quiet' propellers, improved aerodynamics, a redesigned cockpit incorporating digital avionics and a new cabin interior, the external differences include extra windows, twin-nosewheel landing gear and upturned wingtips. Much use is made of lighter composite materials, and F50 commonality with the F27 is only 20%. Production is shared with Dassault, Fuji Heavy Industries, Deutsche Airbus, SABCA, Dowty Rotol and Pratt & Whitney Canada with final assembly, systems integration and flight test carried out by Fokker at Schiphol. The first two prototypes were conversions of F27 airframes, with the first (PH-OSO), flying on 28 December 1985 followed by (PH-OSI) on 30 April 1986. The first production aircraft (PH-DMO) flew on 13 February 1987 and first delivery made (to DLT), on 7 August 1987. By mid-1991 Fokker held firm orders from 18 customers for 132 Fokker 50s, and had delivered 116. The standard production variant is the 46/50-seat Fokker 50-100 and the current build rate is 30 aircraft per year.