Travels 5,000 Nautical Miles Nonstop At Mach 0.90 On Fifth Test Flight

Just before the NBAA Meeting and Convention in Atlanta, Gulfstream test pilots and engineers made a compelling demonstration of the Gulfstream G650's exceptional high-speed cruise capabilities, flying a 5,000-nautical-mile closed circuit at Mach 0.90 over the Atlantic Ocean in 9 hours and 45 minutes.

G650 File Photo

"Never has a business jet flown so far, so fast, so flawlessly," said Pres Henne, senior vice president, Programs, Engineering and Test, Gulfstream.  "This airplane defines a new level of productivity. Part of that is the ability to move executives in comfort swiftly around the world."

Aircraft Serial Number (S/N) 6004, the fourth test aircraft in the flight-test program, and the first with a full interior, departed Savannah at 0957 EDT on October 9 for the fastest ultra-long-range flight ever flown by a business jet. The aircraft had flown a total of only 12 hours previously, including seven hours with a fully installed interior. The jet is on display for order holders at the NBAA industry conference in Atlanta this week.

Weight at take-off was 99,538 pounds. The aircraft has a maximum take-off weight of 99,600 pounds, allowing it to operate from weight-restricted airports such as Teterboro and Aspen.

A crew of six manned the aircraft: Senior Experimental Test Pilot Tom Horne; Production Test Pilots Al Moros and Rick Gowthrop; Flight Test Engineer Michael Brinley; and Interior Specialists Allen Blaylock and Mike Phipps. Blaylock and Phipps used the time aloft to examine the new cabin installation under cold-soak conditions, evaluating the many new features of the G650 cabin, including communications and entertainment equipment and the airplane's advanced Gulfstream Cabin Management System (GCMS).

Although six were aboard, the aircraft was ballasted to simulate a crew of four and eight passengers.

Climb out was at 250 knots to 10,000 feet, then 300 knots, transitioning to Mach 0.85 until reaching cruise altitude. Twenty-three minutes after brake release, the aircraft leveled off at its initial cruise altitude of 39,000 feet and accelerated to Mach 0.90, later making step climbs to a final cruise altitude of 45,000 feet.

Due to the aircraft's experimental status and its current lack of reduced vertical separation minimum (RVSM) approval, there were some restrictions to the route that could be selected for a high-speed demonstration. Therefore, the aircraft flew in an offshore warning area in a 200- nautical-mile race-track pattern with 70-mile turns flown at an approximate bank angle of 12 degrees. Temperature along the route was close to ISA with the worst case being ISA+7.

G650 Landing In Atlanta

Descent was at Mach 0.90, transitioning to 300 knots and then 250 knots at 10,000 feet with a return landing with NBAA IFR reserves in Savannah. "At those speeds, we could have been in Buenos Aires for dinner, or in Hawaii for lunch due to the time zone change" said Horne. "We continue to be impressed by the reliability and capability of this airplane at this early stage in its development."

The G650 has a range of 7,000 nm at Mach 0.85. It is the largest, fastest, longest-range purpose-built business jet. Certification is planned for 2011 with customer deliveries beginning in 2012.

The speed demonstration was one of a number of tests being performed on the aircraft as it moves towards that certification date, and Gulfstream announced Monday that the aircraft recently completed several tests required as part of its certification by the FAA and EASA, including flutter, in-flight loads, flammable fluid drainage and ingestion, and water ingestion.

Initial certification tests were conducted during envelope expansion when the absence of flutter was shown out to the design dive speed (Vd) and design Mach dive speed (Md). During these tests, the aircraft achieved a top speed of Mach 0.995 and demonstrated acceptable damping responses following an input from an external test device.

In addition, certification data has been obtained for the in-flight measurement of aerodynamics loads on the wing, tail and fuselage.

The FAA began participating in certification testing of the G650 when it issued the first Type Inspection Authorization (TIA) in late August. The document authorizes the regulatory agency to conduct the tests required as part of the effort for the aircraft to receive its type certificate, which Gulfstream anticipates receiving in 2011. The FAA issued the TIA for the flammable fluid drainage and ingestion test, which demonstrates that fluids will drain properly from various zones around the aircraft and will not accumulate in excessive quantities.

Gulfstream Plane View Flight Deck

"This shows that we've reached the point in the flight-test program where FAA test crews are flying on the aircraft and collecting the data necessary to support certification," said Barry McCarthy, director, Flight Test, Gulfstream. "It also means that our product development team has satisfied a number of engineering pre-requisites. On all fronts, our test program is progressing in support of our aircraft certification schedule."

The fluid drainage and ingestion testing was conducted using the second aircraft in the flight-test program, Serial Number (S/N) 6002. After entering flight test on February 25, the aircraft completed initial anti-skid brake tuning and ram-air turbine testing. Earlier this year, the aircraft traveled to the Climatic Testing Facility at Eglin Air Force Base to test component cooling and system operations during weather extremes ranging from -40 to 55 degrees Celsius.

Since making its flying debut on November 25, 2009, S/N 6001 has performed a number of tests, including aerodynamic stall testing to validate low-speed limits and stall characteristics. It has also been involved in parameter identification testing to validate the aerodynamic models used for engineering analysis for control-law development. The aircraft has also confirmed a wide range of data, including minimum control air speeds, initial cruise performance, and flight-control system/flight-control law performance. The program's second TIA for water-ingestion tests was recently completed at NASA's facility at Wallops Island, Va. These tests demonstrated that on a runway with standing water, the aircraft and engine operations were not appreciably affected by water ingestion.

Since joining flight test in May, S/N 6003 has been used to measure in-flight loads and validate the initial PlaneViewTM avionics, auto-pilot and flight management systems.

"As the test program continues, the outstanding performance of the flight-control and fly-by-wire systems has been one of the highlights," said Pres Henne, senior vice president, Programs, Engineering and Test, Gulfstream. "The absence of any serious issues attests to the investment we made into the Iron Bird, a ground-based test structure designed to replicate the actual aircraft. The Iron Bird has allowed our engineers and suppliers to verify and validate the system design requirements and identify and resolve issues well in advance of the flight-test program."

G650 First Flight File Photo

For the first time, Gulfstream is also testing an aircraft outfitted with a full interior. S/N 6004, which flew for the first time June 6, had its interior installed over the summer and has resumed flight test.

Since the flight-test program officially began on Novomber 29, 2010, the four aircraft in the program have accumulated more than 700 hours over more than 200 flights, as of October 12.

"We are encouraged at the overall reliability of the G650," Henne said. "As the test aircraft continue to fly, they are coming back without squawks. That's a very good indication for our program and customers."

Testing also continues in the G650 Integration Test Facility (ITF) at Gulfstream's Savannah headquarters. Engineers have been using the facility to integrate the software and hardware for the aircraft's systems and to perform the human-factors testing required for certification. For the first time in Gulfstream's history, the ITF also includes a full-size mock-up of the G650 cabin systems to support Gulfstream's Cabin EssentialTM design philosophy, which ensures that systems are designed with redundancy to prevent single-point failure.

FMI: www.gulfstream.com