The Gulfstream G400, G500, and G600 (GVII) are twin-engine business jets designed and produced by Gulfstream Aerospace. The aircraft are designated Gulfstream GVII-G500 and GVII-G600 in their type certificate. The two larger models were unveiled on October 14, 2014 and the smaller G400 was unveiled on October 4, 2021. The G500 was first delivered on September 27, 2018, and the longer G600 was first delivered August 8. The G500 will replace the G450 while the larger G600 will succeed the G550. The smaller G400 meanwhile has not yet been certified, and is not expected to go into production until 2025. Powered by two Pratt & Whitney Canada PW800 turbofans, the MTOW G500 has a range of while the G600 can cover at a speed of Mach 0.85. Development Both aircraft were unveiled by Gulfstream Aerospace on October 14, 2014 During the second quarter of 2017, 80% of Gulfstream orders were for the G500/G600. G500 The G500 was taxiing under its own power at its unveiling on October 14, 2014, and it first flew on May 18, 2015. The model was initially planned to be certified in 2017. In May 2017, the test fleet of four G500 prototypes and the first production aircraft, made over 745 flights in two years for 2,900 flight hours, on track for the certification by the end of the year. In August 2017, the FAA issued the G500 a type inspection authorization to allow in flight evaluation. The five G500 test aircraft have logged more than 3,100 hours over 820 sorties and completed cabin systems, brakes, lighting, fly-over noise and fuel systems tests. The fifth G500, with a complete interior, will be the first to enter service, as a demonstrator, before customer deliveries in early 2018. Through August 20, the G500s had flown 3,460 h over 905 flights, reaching Mach 0.995 and FL530. For the October 2017 NBAA show, the five G500s were completing their campaign with 995 flights and 3,690 h - 10 h 19 min for the longest - the first delivery schedule was maintained as certification was pushed until early 2018. Mach 0.85 range for the G500 was extended by 200 nmi to 5,200 nmi/9,630 km and by 600 nmi/1,111 km to 4,400 nmi/8,149 km at Mach 0.90. The 300 flights hours of function and reliability testing required for FAA type certification was to be completed in summer 2018 after 240 were done