Cross Gulfstream’s long-running GIV with thetop-of-the-line G550 and you get the G450 – and a smooth entry into service

G450Entry into service of Gulfstream’s G450 has been the smoothest yet for any of the company’s large-cabin business jets. The G450 entered service in May and despatch reliability is above 99%, the company says, with some customers so confident that they took their aircraft overseas in the week they took delivery.

A smooth service introduction could be expected because the G450 is the latest version of the long-running GIV, and most of the changes come from its larger GV/G550 stablemate, but to Gulfstream it is more than just an upgrade. “This is a new model. The system changes are substantial,” says Jim Gallagher, director, entry into service, for both the G450 and the shorter-range G350.

Eleven G450s were in operation by the end of September, plus four G350s, with the initial aircraft going to a variety of customers: some upgrading from earlier Gulfstreams like the GII, some from the GIV, some from other manufacturer’s aircraft, and some for whom the G450 is their first business jet, says Gallagher.

Service introduction has not been trouble-free. “There are a couple of issues we are working through, and for which we have fixes in place,” says Gallagher. Both involve components unique to the G450: an elevator servo and the new lightweight thrust reverser for the upgraded, digitally controlled Rolls-Royce Tay 611-8C engines.

The servo issue is caused by built-in test tolerances that are too tight, and supplier Honeywell is introducing a software fix, says Gallagher. The thrust-reverser problem is a tolerance mismatch between an isolation valve and the new full-authority digital engine control (FADEC), and the short-term fix is to screen the valves to ensure they meet the required tolerance.

Concerns addressed

One reason for the G450’s smooth introduction, Gallagher says, is that Gulfstream used an integrated test rig and four flight-test aircraft to shake out a lot of the system issues before delivery. Another is that the G450 draws heavily on the GV, which has been operating since 1997, and the G550, which entered service in 2003. The improvements incorporated in the G450 also tackle many concerns customers had expressed about the GIV and GIV-SP.

The G450 is the latest in a line of long-range business jets the stretches back to the original GIV, first flown in 1985. Compared with the earlier GII and GIII, the 7,800km (4,200nm)-range GIV had new R-R Tay turbofans, a stretched fuselage, improved wing and Honeywell SPZ-8000 glass cockpit. The aircraft was built until 1992, and 214 remain in service. Production then switched to the improved GIV-SP, its higher weights increasing payload with full fuel. The GIV-SP was built until 2002, and 286 are in service.

In 2003 Gulfstream rebranded its product line, and the GIV-SP became the G400, which had more standard equipment and a slightly reduced range of just under 7,600km. But the G400, which retained the GIV-SP’s upgraded SPZ-8400 avionics, was a gap-filler while Gulfstream executed a strategy of equipping all its large-cabin jets with the PlaneView integrated flightdeck.

PlaneView, based on Honeywell’s Primus Epic integrated avionics, was first certificated on the ultra-long-range G550 and is now fitted across the company’s expanded, four-aircraft large-cabin line, which includes the G350, G450 and G500. All of these aircraft, and the earlier GV, now share a common type rating.

Concept commonality

One of the changes from the GIV to the G450 is a reduction in stick forces to make them the same as in the GV/G550. “It feels different, it feels that same as a GV,” says Gallagher. Early customers are taking advantage of the commonality, says Gallagher, with several operating mixed fleets of G450s and GVs, G550s or G350s.

Operators “are blown away by the cockpit”, says Gallagher. PlaneView features four 355mm (14in) liquid-crystal displays side-by-side across the cockpit. The displays are managed using sidearm cursor-control devices mounted on the cockpit walls. These allow graphical “point-and-click” flight planning, navigation and radio tuning using pull-down menus. The LCDs can display uplinked weather graphics, moving maps and electronic charts.

The third iteration of PlaneView software, called “Cert Charlie”, has just been certificated and is being retrofitted into aircraft in service, says Gallagher. This adds take-off and landing performance computer, vertical situation display, uplinked weather and the display of winds aloft. The vertical situation display shows a vertical profile of terrain below the glideslope.

Although PlaneView can display geo-referenced electronic charts, Gulfstream does not yet have “paperless cockpit” approval. The charts database is a single unit and not dual-redundant as required for approval to remove paper charts from the cockpit. Meanwhile, Cert Charlie can print charts from the cockpit printer.

Like the G550, the G450 is equipped with head-up display (HUD) and enhanced vision system (EVS) as standard. This allows an approved operator to descend below decision height to 100ft above touchdown using the EVS infrared image of the runway displayed on the HUD. Feedback from US operators indicates they are using the capability, says Gallagher.

The G450 is more than just an avionics upgrade. Structural changes include a 305mm longer fuselage. The forward fuselage is now common between the G350/G450 and G500/G550, and provides 30% more flightdeck space. The main entry door is moved 0.91m aft to improve access. As in the G550, cabin altitude is reduced to 6,000ft at the aircraft’s 45,000ft maximum altitude and there are three seating zones.

Gulfstream has included the most-requested customer options as standard on the G450, and offers cabin layouts that can be tailored. Gallagher says most customers have opted for the packages. Several of the G450s in service are among the first aircraft to be equipped with Gulfstream’s BroadBand MultiLink (BBML) high-speed internet connection, which uses Arinc’s SkyLink satellite communications service. BBML service is limited to North America, “but next quarter we turn on Europe and the North Atlantic tracks,” says Gallagher.

The Tay 611-8C produces 5% more hot-and-high thrust, and has a 2% better fuel efficiency. Coupled with a higher maximum take-off weight of 33,500kg (73,900lb), this increases the G450’s range by 450-900km over the GIV – to 8,050km at Mach 0.8 and 6,480km at M0.85, with eight passengers. FADEC improves engine reliability, and the Tay 611-8C has a 12,000h time between overhauls.

The biggest changes from the GIV to the G450 are in the systems, many addressing reliability issues experienced with older aircraft. The top 10 high-removal components in the GIV-SP have been replaced in the G450 with systems developed for the G550. These include the variable-speed constant-frequency converter. This has been replaced with the G550’s integrated-drive generator, which has an 18,000h mean time between failures.

Other G550 systems used include the digital environmental-control system, nose landing gear and nosewheel steering, and even the heated cabin windows, which overcome fogging. Other changes to increase reliability include the new Honeywell 36-150 auxiliary power unit, which is also quieter and has improved high-altitude operation, as well as new wheels and brakes with digital anti-skid.

Early operational experience with the G450 indicates the reliability improvements are paying dividends. “Despatch reliability is above 99%,” says Gallagher. “We are looking for 99.75%”, he says, but adds, even with the early issues, “this is our cleanest entry into service yet”.

GRAHAM WARWICK / WASHINGTON DC Cutaway drawing / Tim Hall

Source: Flight International