Developing a new business jet takes years—up to 16 in the case of the recently unveiled (though not yet customer-ready) Gulfstream G400, and only if everything goes smoothly from here on out. Part of that has to do with timing and market positioning—the G400’s larger G500 and G600 siblings, with which the latest plane shares roughly 80 percent common parts, were also conceived in 2009 but certified and delivered in 2018 and 2019, respectively—but it’s a hell of a long runway, regardless. If you’ve never considered what goes into creating the best and brightest new business jet, here’s the timeline for a much-awaited upcoming model.
-
Concept
Image Credit: Courtesy of Gulfstream 2009
Gulfstream begins planning a new aircraft family by first assessing what the market needs, then polling its clients about the best way to achieve it. In 2009 it was clear there was a gap in smaller large-cabin jets that still offered transcontinental range and decent speed, and so that’s what the G400 was designed to deliver, with a 4,200-nautical mile range, a wide cabin that has the same cross-section width as the G500 and G600 and the same cruise speed of Mach 0.85. Other amenities, such as its two and a half living zones, large galley, ergonomic seating and low-altitude pressurization are the result of those extensive customer conversations.
“We designed the G400 for a market that was underserved,” says Mark Burns, president of Gulfstream Aerospace. “There really hadn’t been a new design in that category for 20 years.”
-
Preliminary Designs
Image Credit: Courtesy of Gulfstream 2009 – 2014
The company consults with a client advisory board that delivers detailed customer feedback on a range of features, from air purification to advanced connectivity to window size. This preliminary design review then becomes the starting point for the designers and engineers. For a process that will ultimately require tens of thousands of man-hours, a large chunk of time is spent on this crucial early phase.
-
Critical Design Review
Image Credit: Stephanie Lipscomb 2019
“The completion of the critical design review represents the aircraft we will build,” says Burns. By this point, he says, “we’ve completed all the engineering and know exactly how much every part weighs and have the range, climb performance, stopping performance and many other data points.” Dozens of fabrics, veneers and leathers allow clients to choose a customizable aesthetic for their G400. “We look for new materials years ahead of certification,” says Tray Crow, director of interior design.
“We look at materials from other fields, including residential and yachting, as possible sources, but we always have to be cognizant of weight.”
-
Public Unveiling
Image Credit: Chris Pearce 2021
On October 4, 2021, Gulfstream showed the G400, along with its G800 hangar-mate, in a Hollywood-style debut at its headquarters in Savannah, Georgia. The unveiling included a G400 interior mockup (pictured above) alongside existing interiors of the G700 and G600 in a sprawling showroom. “Having a full-scale mockup gives clients a better ability to imagine the layout and customize their own cabins,” Crow says.
-
Flight Testing
Image Credit: Paul Bowen 2022 – 2025
“Once we’ve manufactured the first aircraft, we plan to move into testing later this year,” Burns says. The flight-test program will consist of four test aircraft and one production-test aircraft that’s outfitted to put the new interior through its paces. The first test aircraft will perform aerodynamic testing as well as help sort out flight controls and flying qualities. The second will test systems, particularly flight-deck avionics, while the third plane will concentrate on both systems and engines.
The fourth aircraft will focus on icing, hot and cold operation, cooling and ventilation. It will face extreme heat in desert areas as well as fly through frozen regions during the winter. By certification, the G400 will likely have completed more than 600 flights and over 2,500 flying hours. “We also take it into a US Air Force base chamber, where the temperature drops to 60 degrees below zero,” Burns says. “We put the aircraft into situations that the customer will never see.”
-
Certification and First Customer Delivery
Image Credit: Andrew Hertzog 2025
Gulfstream works closely with the FAA on certification, of both the aircraft and its Savannah manufacturing facilities. Because the G500 and G600 have already been certified and entered service, some of the testing will be credited toward the G400. “That process, which is rigorous, allowed us to have a more condensed test schedule with the G400 based on their experience with the airframe,” according to Burns. In the end, hundreds of test points must be completed for FAA certification before the G400 can go into service.
