Gulfstream G280 Flight Test

Gulfstream G280 Flight Test

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Gulfstream G280 Flight Test

This tale of the G280 begins with a simple declaration… the 280 is an all-new airplane and not simply a derivative of the G200 that evolved from Gulfstream’s 2001 purchase of Galaxy Aerospace. Despite a resemblance to that earlier airplane, the G280 that entered service in December 2012 was for all intensive purposes, an airplane the original designers would barely recognise.

Gone, for example, was the real fuselage fuel tank, no longer necessary thanks to the new Honeywell HTF7250G, FADEC controlled turbofans. Steve Cass, Gulfstream’s vice president of technical marketing and communications explained the difference in simple terms, including the fact that all of the G280’s fuel is now carried in the wing. “A G200 would fly 3400 nm at M.75 on 15,000 lbs. of fuel. The G280 now flies 3600 nm at M.80 on less fuel.”

The Gulfstream G280 certainly fits snuggly into the super midsize category with a cabin cross section only one inch narrower per side than the G450/550 while adding an extra inch of headroom to that of the larger aircraft. The G280 incorporates much of the luxury and comfort of a large-cabin airplane, including the ability to carry four people non-stop between any two cities in the US. All that matched to the performance of a smaller, more agile, airplane.

At its maximum certified altitude of 45,000 feet, the cabin sits at about 7,000 feet while cruising at 41,000 brings the cabin up to just 6,000 feet. Up front, Gulfstream pilots will feel right at home with a Rockwell Collins-powered version of the Plane View avionics that can accommodate the same Heads Up Display (HUD) as the bigger company products, as well as an Enhanced Vision and a Synthetic Vision system.

An easy way to differentiate a G280 from earlier airplanes is to note the T-tail and the clean leading edge that replaced the de-ice boots with bleed air heat. In the cabin, configurations include seating for as many as 10 or berthing as many as four in seats that are just one inch narrower than those of the G450/550 airplanes. The G280’s ailerons are manually powered while the rudder incorporates a dual fly-by-wire system while the fly-by-wire braking system incorporates larger-aircraft like autobrakes.

Anyone familiar with the earlier G200 will be awed by the redesign of the G280 both inside and out. Pulling that rear fuselage fuel tank from the original airplane opened up a large chunk of the rear fuselage that Gulfstream designers put to good use. The extra space translated into an eight-inch stretch to the passenger compartment for starters, a move that allowed for the installation of two extra windows in the cabin to allow more ambient light. The G280’s huge 120 cu. ft. baggage compartment is capable of holding about 2,000 pounds of anything that can be crammed in. That compartment is also accessible
in flight.

As another major improvement signal, Gulfstream significantly redesigned the rear lavatory and used another nine inches of the extra space in the rear to create a facility with the look and feel of those found on the much larger G450/550/650 series, including one additional window on each side of the fuselage to make the lav seem even larger. The effort to better integrate the G-280 into Gulfstream’s family of large-cabin long-range airplanes didn’t stop with simply expanding the usable space in the lavatory. Gulfstream replaced the old chemical toilet with a new vacuum version more suitable to the needs of an airplane capable of eight-hour legs.

Stopping a G-280

Aerospace engineers will tell you that the magic V1 number used by the cockpit crew as their Go/No Go speed can be fraught with danger if the airplane must actually be brought to a safe halt from speeds approaching 150mph. Despite all the training and experience, many pilots still fail to climb on the brakes hard enough and early enough in a rejected takeoff to even have a prayer of remaining within the balanced field length numbers they have in the back of their minds. Some pilots incorrectly believe that getting the reversers out early on are better at halting the airplane.

Gulfstream engineers had a better idea to insure their airplane could stop safely in the calculated distance. Unusual for an airplane that weighs in at less than 40,000 pounds (39,600 lbs. to be precise) at maximum takeoff conditions, the G280 comes standard with an auto-braking system to handle much of the thinking and acting should a rejected takeoff event occur. A simple four-position knob placed just to the right of the landing-gear lever allows the PIC to choose any of three levels of braking pressures for landing, as well as the Rejected Takeoff (RTO) mode for departure. The moment the aircraft senses the throttles coming back prior to V1, it doesn’t wait for the pilot to cover the rudder pedals, but adds maximum braking pressure immediately, right to the limits of the system. That translates into just short of locking the main wheels in order to assist the crew in halting the airplane.

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This P1 pilot tested the RTO system in our G280 aircraft on Savannah’s 7,002-foot runway one after close coordination with the folks in the tower. Gulfstream’s mid-cabin demo pilot Mattias Fogelberg’s instructions from the right seat were pretty simple as I taxied on to the runway centerline. I was to expect a normal takeoff until he called “Abort, abort, abort.” Once I heard that call, my only tasks were to pull the throttles to idle and steer, making sure not to add my own pressures to the brakes as I kept the aircraft tracking up the centerline. The G280’s auto-brakes would handle all the work. We were relatively lightweight – approximately 34,500 lbs – after having flown for an hour and a half, so V1 would be much lower than the 129 I’d have seen at a maximum gross takeoff event.

The final advice before we began the demo was succinct … “lock your shoulder harness.”

Power levers up and quickly I heard “80 knots, cross check,” from Mattias. When the abort signal came, I hauled the throttles back and immediately felt my body being pushed forward hard against the shoulder harnesses. As instructed, my efforts were only focused on keeping the aircraft aligned with the runway centerline. Before I had enough time to take it all in, the G280 had slowed to near taxi speed allowing me to make the right turn at Bravo 1 to catch up with the camera crew that had been filming the event. From their perspective outside the airplane, they later told me the abort looked like a non-event. Inside, of course, it felt much different. I calculated the entire test from power up to stop had consumed about 2,000 feet of runway. The beauty of the autobrake system in the G280 is not only that it brings this kind of technology into a super midsize airplane, but also that it clearly demonstrates the operational value if it’s really needed. There is no way, despite the planning for our simulated abort that any pilot would ever have added the kind of pressure to the brake pedals the autobrake system does. Surprisingly, neither the G450 nor the 550 are yet equipped with autobraking. The autobraking system is also credited with reducing overall brake wear due to the uneven braking efforts by the humans in the cockpit.

A Bit of Flying

When I learned the G280 was created with a new wing designed with the G550 in mind, the first thing that ran through my mind was wondering how maneuverable the airplane would perform at high altitudes. Like other Gulfstreams, the G280 is a clean wing with no leading edge devices to maintain. I also wanted to see a demonstration of the Emergency Descent Mode that’s standard on the G280 to save the people aboard should the cabin altitude ever climb above 10,000 feet. Of course, we’d need to get the airplane started and head out east over the ocean where we wouldn’t be in anyone’s way to try out all of these systems.

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We were light when Mattias and I brought the Honeywell turbofans to life on the company ramp in October. With 6,000 pounds of fuel, our takeoff weight hovered around 36,000 pounds, well below the 280’s maximum of 39,600 pounds. Taxiing this airplane – Gulftest 78 on the radio – was a snap with a tiller that delivers 60 degrees of turn capability. At takeoff, the rudder steering of 2 ½ degrees either side of centre was more than adequate to maintain control of the airplane at full power. In the event of an engine failure, the G-280 offers a thrust compensation mode that adds about 70% of the rudder necessary to keep the aircraft racking straight, but not quite everything, leaving some room for pilot input. The APR automatic thrust increase system is armed for takeoff and adds about two percent additional thrust up to 15,000 feet if one engine quits.

Mattias mentioned I should be prepared for a rather sprightly takeoff since the outside temperature was hovering in the upper 60s F at Savannah and he was spot on. Our V1 speed turned out to be 107 knots. I held the brakes and brought the power up about 70 percent N1 as I engaged the autothrottles. I felt a bit like I was hanging on to the Gulfstream’s control wheel as the aircraft accelerated down runway 10. It took about 13 seconds from power up to rotation speed. I’d briefed the idea of hand flying the aircraft to our filed altitude of FL430 and once airborne watched at just how quickly the speed built what I’d been told, that the G280 offers the best thrust-to-weight ratio of any of the Gulfstream aircraft.

We’d initially been restricted to 10,000 feet on departure and turned toward Charleston before Jacksonville Center cleared us to FL230. The initial rate of climb settled on about 3500 feet per minute. A few minutes later ATC cleared us up to FL430. Out of 15,000, we were indicating 250 knots that produced a rate of about 4500 feet per minute while burning about 2150 pounds of fuel per side. Out of 23,000 we were still climbing at 3500 feet per minute, a rate that remained fairly constant despite an ISA +13 temperature passing through 33,000 feet. The cabin at this point held steady at 3,600 feet. Through 37,000 feet we were climbing at M0.75, translating into 3,000 fpm rate as we burned 1350 pounds of fuel per side. Our TAS looked like 441 knots. Fourteen and a half minutes later, we reached 43,000 feet and accelerated to M0.84 in preparation for some steep turns. At a TAS of 478 knots fuel flow settled down at about 950 pounds per side.

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Level at FL430, I slowed to M0.80 and turned off the autopilot as I rolled into a right turn of about 45-50 degrees of bank. Adding a tiny bit of backpressure, I trimmed and the G280 held altitude and bank angle smoothly. It felt as comfy as did the G550 when I tried the same thing at a slightly higher altitude. I pulled the headset off too and the cockpit noise level was quite comfortable. I tried another steep turn to the left and felt absolutely no different than what we later tried down low in the chunkier air.

Because we wanted to descend anyway before heading down to 15,000 feet for slow flight and stalls, it seemed like an appropriate time to test the airplane’s Emergency Descent Mode. The system was created to assure the aircraft will not be lost if the cabin rises high enough to cause the crew to pass out. In order to fool the system into believing the cabin was indeed racing skyward, Mattias manually ordered the pressurisation to bring the altitude above 10,000 feet. The cabin chimes announced the aircraft had passed through the magic number and the airplane turned left 90 degrees as the autothrottles brought the engines to idle. The aircraft pitched down to maintain a descent rate of approximately 8500 fpm all the way down to 15,000 feet a ride that consumed just less than five minutes. As the G280 leveled out, the autothrottles brought the speed up to 225 knots. The aircraft selected roll control and began a gentle orbit to offer the crew – if this had ben an actual test – a bit of time to regain consciousness.

Gulfstream says that slightly more than half of the customers who accepted one of the 75 G280s already flying around the world travel with a flight attendant on board which makes sense when some of the legs might look like New York to Milan, Lima to Los Angeles or London to Lagos. If the flight should depart Mexico City’s 8,466-foot airport, for example, the G280 can still carry four people at maximum cruise speed to Juneau with reserves. The 280 has already set more than 50 city pair speed records as well, including Paris/New York in seven hours 40 minutes, London/Chicago in eight hours 13 minutes and Dubai/Hong Kong in seven hours six minutes.

While Gulfstream owns the G280 design, the green aircraft are still built in Tel Aviv by Israel Aircraft Industries’ team and mated to a new wing constructed by Spirit Aviation and shipped to the Middle East. The green aircraft is then flown to Dallas for paint and interior, a location where Gulfstream recently opened a design centre similar to the one in Savannah for customers to choose fabrics and other interior components.

Gulfstream’s Steve Case said, “Customers like the G280 as a moveup from the midsize or from companies that use it as a supplement to their long-range airplanes for more regional work. The G280 has been certified in 13 different countries and has managed to maintain a 99.8 per cent dispatch reliability. The G280’s 2015 list price is US$24.5 million.”

Want to see more P1 flight test reports of Gulfstream aircraft?

Take a look at the G450 Flight Test Here

Take a look at the G550 Flight Test Here