Gulfstream G650 Business & Commercial Aviation (cover story)
BY FRED GEORGE Publication date: October 2010
The G650 is arguably Gulfstream Aerospace's most ambitious technological leap since
Grumman, the line's progenitor, introduced the GII in 1965. The newest, top-of-the-line
Gulfstream will cost nearly $1 billion to bring to market, by some industry estimates. In
return, the G650 will offer passengers the largest cabin of any purpose-built business
aircraft yet introduced. It will have the highest cruise speeds, longest range and best fuel
efficiency of any business aircraft cruising at Mach 0.85.
It also has the most-sophisticated systems of any model yet designed by Gulfstream,
along with a space-efficient, non-circular fuselage cross section, the highest cabin
pressurization of any large-cabin business aircraft, new wing contours producing lower
drag at high-speed cruise and considerably more composite content.
Gulfstream has kept its clean-sheet ultra-jet on schedule since its inception, even though
the aircraft embraces several technological advances compared to its predecessors. The
most notable advance is its digital fly-by-wire (FBW) flight control system, but this
newest Gulfstream also will feature the firm's patented Standby Multifunction Controller,
a new triplex FMS, automatic emergency descent mode, PlaneView II and fully
automatic, 3-D weather radar. Electronic circuit breakers will be used for non-critical
systems, thereby reducing weight by 300 lb.
Maintaining the certification schedule with an all-new aircraft is a rare distinction among
most civil aviation companies. Some firms have suffered two- to 10-year delays in their
new aircraft development schedules.
Keeping the G650 program on time even represents a major culture change at
Gulfstream. Development and certification of some of its legacy products, most notably
the GIV, ran late, gained weight and fell short of initial expectations. It took five years
after the GIV initially entered service in 1987 before it lived up to its billing.
"We've been pretty successful up to this point with the G650. But I don't want to say
anything that might jinx something. A little talk goes a long way," said Pres Henne,
Gulfstream's senior vice president, programs, engineering and test.
"But I've got to tell you this airplane is doing great. It's behaving well up to almost Mach 1
and the performance looks smack on target. The high-speed lift-to-drag ratio is dead on.
And serial number 6004, our first production aircraft fitted with an interior, looks to be
very close to design basic operating weight. You would be hard pressed to find any
weight variances."
Wing contours were refined using four different CFD software packages. More than
1,400 hr. of wind tunnel testing, including cryogenic flow tests at the German-Dutch wind
tunnel lab in Cologne to compensate for scale effect, were completed before full-scale
aircraft construction began. Gulfstream engineers wanted no surprises during the flight
development program that would require aerodynamic bandages, such as vortilons,
vortex generators or leading-edge stall strips. As of early September, flight testing
verified that no aero mods will be needed.
Such detailed planning and testing have been major factors in keeping the G650
program on schedule, on weight and on spec to meet Gulfstream's goals for the
program.
Four of five flight test aircraft had entered the flight test program as of mid-September
and had logged about 600 hr. of the 1,800 hr. scheduled for the certification campaign.
Thus, Gulfstream appears to be right on track for 2011 certification and initial customer
deliveries in 2012.
Although formally announced in March 2008, the G650 has been five years in the
making. It has benefited from the most thorough preflight planning and testing of any
Gulfstream yet introduced. Gulfstream parent General Dynamics approved program
launch in May 2005. The wing contours were frozen in September 2006 and preliminary
design review was completed in June 2007.
Meticulous Program Planning
While it's always good to be lucky, the success of the G650 to date is not by chance.
The aircraft is the product of broad-based and in-depth program planning and execution
that Henne practiced at Douglas Aircraft when he was in charge of MD90 development
and also from his involvement with the C-17 Globemaster III program.
For instance, a 10-ft. coupon test section of the new four-radii fuselage, including the
16% larger windows, was subjected to ultimate overpressure tests well before
Gulfstream started full-scale manufacturing of the aircraft. Testing was completed in
April 2007, almost one year before the program was unveiled.
"The G650 development plan is aggressive, but achievable. It's challenging, but doable.
The entire team bought into it," Henne said, adding that he's "planned for surprises" and
that both the development schedule and budget have adequate buffers to accommodate
contingencies.
"A whole bunch of elements are involved," he explained. "You need a highly motivated,
experienced, small team of people, many of whom have been through previous
programs."
The challenges borne by the team are manifold. Parts count on the G650 is being
slashed in half and, for the first time on a Savannah-built aircraft, adhesive bonding is
being used for fuselage skin and substructure components. To reduce risk, Gulfstream
built a 10-ft. fuselage cross section, complete with six windows, and subjected it to all
required pressure and stress tests prior to beginning construction of the full-scale
aircraft.
The G650 is Gulfstream's first aircraft to be fitted with digital fly-by-wire flight controls.
The aircraft's PlaneView II cockpit features four, 14-in. flat-panel displays, plus standard
synthetic vision, a second-generation enhanced vision system, a larger, sharper HUD
and 3-D weather radar.
The G650's FBW system breaks new ground in business aviation. It has only two sets of
electrically controlled, hydraulically powered flight control actuators. But it also has a
third set of electrically controlled and powered backup flight control actuators, a first for a
business aircraft.
No element of the G650 development program has taken higher priority than cabin
design. What Gulfstream terms its Cabin Essential design concept includes redundant
water, waste and communication systems, plus lighting, power and entertainment
equipment. The goal is to provide 10-7 essential level reliability for cabin systems.
Transoceanic communications are increasingly important to Gulfstream operators. The
G650 will feature a redesigned satcom radome atop the empennage that will offer more
clearance for the antennas, thereby increasing the range of movement and line-of-sight
signal connectivity with communications satellites.
"We're more than happy to embrace advanced technology, but we have to test it before
it goes into a production aircraft," Henne said. The G650's complete three-channel FBW
flight control system, for instance, went through extensive inflight testing aboard a GV
and ground testing in an "iron bird" mock-up. "We had it all trucked up before we ever
put it on the G650," he noted.
Hands-on internal management also is an essential element. Henne's G650 program
team has been directed to manage two levels below their accountability. "Each team
member has to know the 10 tasks performed by each of his or her direct reports. And
they also have to know the 10 tasks assigned to each of those persons' direct reports.
You must trust, but verify. When you've got that kind of granularity, you can plan for
contingencies."
That same two-level management granularity extends to Gulfstream's suppliers for the
G650. "That way," he said, if a supplier derails, you got to know it ASAP. Then, we
swarm 'em." This enables Gulfstream to dispatch troubleshooters to vendors that are
experiencing problems and get those suppliers back on track in time to meet the G650
development schedule.
Henne recalled an instance during MD90 development, when he dispatched Jack
Pelton, then one of his senior engineering managers, to go "swarm" Douglas' enginedriven
generator supplier. Pelton, who is now chairman, CEO and president of Cessna
Aircraft, ended up running that vendor's plant for almost two years, Henne claimed.
Gulfstream similarly has had to "swarm" some G650 suppliers, but Henne declined to
identify which ones.
The G650 also has benefited from more customer focus group participation than any
previous Gulfstream model. Starting in 2006, G650 program managers began meeting
with an Advanced Technology Customer Advisory Team (CAT) every quarter. As a
result of CAT inputs, the passenger chairs were widened, the galley was redesigned and
cabinets were modified to accommodate customer needs.
Progress to Date, Challenges Ahead
Gulfstream built one static test and one fatigue test article for the certification program.
All required static tests are slated to be completed by the end of October 2010, including
the 167% over-pressurization check and stress loads. The fatigue test article is on track
to complete 5,000 flight cycles prior to the aircraft's entering service in 2012. Dozens of
components, such as the flight control actuators and landing gear, are undergoing
intensive operational wear tests at Gulfstream's integrated test facility, according to Kurt
Erbacher, Gulfstream's G650 program vice president.
Accelerated life-cycle testing on the fatigue test article will lead the fleet by at least a
factor of two. By 2014, Gulfstream expects to have logged 80,000 flight hours and
34,000 flight cycles, thereby validating the 20-year, 40,000 flight hours, 17,000 flight
cycle initial design life expectancy for the G650.
Parts count has been slashed by 50% compared to previous large-cabin Gulfstreams.
The large aluminum components assemblies have precisely positioned, full-size, predrilled
mounting holes for fasteners. This slashes assembly time because no custom
fitting, machining or filing is needed to build the primary airframe structure
Most of the heavy lifting in the flight test campaign is still to occur and involves
qualification testing of components including the quad-channel Thales flight control
computers, Honeywell PlaneView II cockpit systems and Parker flight control surface
actuators, Erbacher explained. Most critically, each of these systems must demonstrate
immunity from interface caused by lightning and high-intensity radio frequency sources,
such as ATC radars, commercial broadcast transmitters and long-range military
communications systems.
"The FAA won't get on the airplane to begin type inspection authorization until all these
systems have passed qualification tests," Erbacher explained. "If any system fails a test,
we have to go back, redesign hardware or software and retest."
Normal flight control laws also are being refined so as to provide a consistent stick force
per g pitch control feel. The G650 also will have low- and high-speed envelope
protection, plus an automatic trim function to compensate for pitching moments caused
by air brake and wing flap extension and retraction. In addition, there will be an
automatic pitch trim function to counter pitching moments caused by speed changes so
that the crew won't have to trim out pitch forces as the aircraft accelerates and
decelerates.
However, there will be a speed stability function once the landing gear and flaps are
extended, assuring a natural pitch control feel with speed changes. Gulfstream
engineers believe that, once the landing gear is extended, it will allow the crew to feel
and trim out speed-induced pitching moments.
Sea level, standard-day runway performance appears to be on target, thereby enabling
the aircraft to depart 6,000-ft. runways at its 99,600-lb MTOW. At its 83,500-lb max
landing weight, the G650 should have a 3,000-ft. landing distance. Most operators,
though, are likely to use runways that are least 5,000-ft. long, the minimum runway
length needed for landing the aircraft in accordance with FAR Part 135 rules.
Hot-and-high performance initially will be verified at Roswell, N.M., later this year. In
2011, the G650 will undergo comprehensive hot-and-high airport testing at Roswell,
Telluride, Colo., and in Mexico, Erbacher said. Engineers predict that the aircraft will be
able to depart our 5,000-ft. elevation, ISA+20°C airport and fly eight passengers 6,200
nm at Mach 0.85. Unlike the G550, though, the G650 may be
weight/altitude/temperature limited when departing our hot-and-high airport, and thus
perhaps unable to fly its maximum 7,000-nm range under those conditions.
Gulfstream believes that cabin development is on track to meet the design goals of 10-7
essential-level system availability and a 5- to 6-dB reduction in sound levels compared to
the G550. Cabin Essential systems have been tested to assure they'll meet the
availability specification and new insulation materials and cabin shell isolators have been
developed to help quiet the cabin. In addition, the cabin air distribution system has been
upgraded to reduce air noise.
Program managers still are negotiating with the FAA about certification requirements for
the aircraft's four Type IV over-wing emergency exits.
Perhaps as important to operators, Gulfstream's maintenance-friendly MSG-3
certification is on schedule, according to Erbacher. Dozens of working groups have been
convened and a final MSG-3 team meeting will be held before the end of this year.
Erbacher said that all MSG-3 documents will be submitted to the FAA in early 2011.
Company officials confirmed that G650 pilots will need a separate type rating, but those
holding G450/G550 type ratings will undergo an accelerated initial training program
because of systems and PlaneView avionics similarities.
As of mid-September, the newest Gulfstream appeared to be on target to fly eight
passengers at Mach 0.85 from New York to Nanjing, Delhi to Detroit or St. Petersburg to
São Paulo, should the need arise. Just as importantly, the G650 will be the most
thoroughly tested aircraft ever produced by a general aviation manufacturer when it
enters service in 2012. Thus the G650 also could set new reliability and maintainability
standards. That may score more points with operators than the aircraft's speed, range
and cabin comfort.
Henne said that Gulfstream has 200 firm orders for the G650 out of an estimated 500
letters of intent the company held in mid-2008. The net $13 billion order book still is a
respectable number, considering the state of the world economy and the aircraft's $65
million price tag. Assuming both that the G650 meets its design goals when it enters
service and that the world economy continues to improve, Gulfstream's order book could
swell considerably. BCA
