There's a long tradition of over-promising and under-delivering in business aviation, but it's still a surefire way to disappoint customers and sour an aircraft's reputation. The 45, as an example, promised more than it could ever deliver, according to some longtime Learjet operators. The Learjet 75, the latest derivative of the Model 45, reverses most of those past shortcomings and delivers new levels of performance, cabin comfort and cockpit capabilities.
The Learjet 45 fell short of expectations because it gained empty weight during development and there was virtually no allowance for optional, but almost essential, equipment.wanted to keep the spec BOW at 12,100 lb. and the base price below $6 million, so FMS, GPS, TCAS, GPWS and ELT all were options. Also left out were typical upgrades such as IFE, air-to-ground phone and APU. The installed weight of the APU alone is about 210 lb. As a result, the heft of the average Learjet 45 grew to be a ton, or more, above Bombardier's advertised spec weight.
A series of post-certification weight increases improved the aircraft's tanks-full payload but sapped its takeoff performance. Being so bloated, takeoff field length ballooned from 4,200 ft. to 5,040 ft.
The Learjet 75 has sportier perform–ance, mainly due to a 10% throttle push that bumps up engine thrust from 3,500 lb. to 3,850 lb. Most valuable to operators, TOFL is reduced by as much as 12%. The new aircraft gets new canted winglets that effectively increase span by 3 ft., thereby decreasing wing loading, which also improves takeoff performance. Their blended radii also reduce transonic drag for more efficient high-speed cruise.
Garmin G5000 flat-panel avionics replace thePrimus 1000 gear, adding new capabilities and shrinking empty weight by 200 lb. Almost all that weight comes out of the nose, so c.g. shifts aft, resulting in less trim drag, further improving cruise efficiency.
The 200-lb. avionics weight loss also enables Learjet 75 operators to fill the tanks and fill the seats, as promised by the original Model 45. And the combination of the new winglets and reduction in trim drag also boosts range by 4%.
Unlike the original Model 45, the Learjet 75 comes loaded with a full complement of standard equipment, including dual FMS with WAAS, TCAS II, SVS and electronic charts. The Honeywell RE100 APU remains standard equipment, as it was aboard the 45XR. It's almost essential for ground ops, because prior to engine start, it produces the bleed air needed for the air-cycle machine to warm and cool the cockpit and cabin. You can't plug in a GPU and heat or cool the airplane.
The aircraft also has several cabin upgrades inspired by the Learjet 85, a transcontinental U.S. range business jet being developed by Bombardier. Double club seating is the only configuration offered. Each chair pivots, moves laterally and has a retractable, aisle-side armrest. The center four seats have optional fore/aft tracking, providing additional room for four passengers if the other half of the cabin is unoccupied.
The forward galley has 27% more catering storage volume and a third more trash container capacity. There are separate clean- and dirty-ice containers, considerably better space utilization in the various compartments and even an optional, galley rest seat next to the entry door.
supplies its nice HD IFE system for the cabin. Standard kit includes an LHT niceview moving map and flight data system. Options include a Blu-ray player, XM satellite radio receiver and video-on-demand file server, along with iPod interface, single 12.1-in. monitor on the left forward cabin bulkhead and individual, 7-in., pop-up passenger seat monitors. Wi-Fi Internet access is available through optional Aircell ATG and Inmarsat SwiftBroadband transceivers. Also optional is a 12.1-in., slide-out monitor for the aft cabin bulkhead, ahead of the lavatory.
Retaining Proven Design Features
The Learjet 75 retains all the best original design features of the Learjet 45. It was certified in 1997 as an all-new FAR Part 25 transport category aircraft, through Amendment 77. This means it has damage-tolerant structure, 2-sec. engine failure recognition time built into takeoff performance computations, more robust flutter margins and jammed flight control protection, plus separated, redundant control linkages, 16-g passenger seats, enhanced ice protection and improved cabin fire protection, among other improvements. The only part it has in common with previous Learjets is the nosewheel.
The primary airframe is time-proven aluminum alloy, with a three-spar wing having single piece upper and lower skins, along with a semi-monocoque fuselage and empennage. Composites are used for secondary structures. The windshield outer ply is glass for durability.
The wing has a modifiedsupercritical airfoil designed by Bombardier using advanced computer tools. It has a far higher lift-to-drag ratio and it is much larger in area than the 1940's-vintage 64000 series NACA airfoil used for all previous Learjets.
Each leading edge has two “sawtooth” or offset breaks, plus four vortilons and other boundary layer control devices to enhance low-speed handling qualities. We know of no other business jet with a “hard” leading edge wing that has more docile stall characteristics.
Systems are simple but amply redun–dant. The primary flight controls are manually actuated, with hydraulically powered spoilerons adding roll control authority. A DC-powered rudder boost system reduces pedal effort below 180 KIAS. A computer-controlled flaps/spoilers/stab interconnect neutralizes pitching moments with configuration changes. There is a three-axis electric trim system. Trimming the stabilizer nose down with increasing speed also increases pressure on the up/down elevator spring force system to prevent pitch-over control at high speeds.
The 28-VDC split-bus electrical system is supplied by left and right starter-generators, plus dual 24-volt, 38-amp-hour batteries in the tail and an emergency battery in the nose. The architecture includes automatic load shedding, starter to generator switching and bus tying. AC alternators supply power for windshield anti-icing and defogging. But the alternators can't serve as backup power sources for other systems as they do aboard theCitation CJ4.
Fuel is stored in left and right wet-wing tanks, plus an aft fuselage tank, in keeping with long-standing Learjet design protocol. A single-point pressure refueling receptacle ports fuel into the fuselage tank, which then flows by gravity into the wing tanks. DC boost pumps supply fuel for engine start, APU operation and cross flow. After start, left and right jet pumps, using motive flow from the high-pressure engine-driven fuel pumps, transfer fuel to the feeders and supply the engines.
Bleed air is used for wing, engine inlet and horizontal tail anti-ice protection, plus air-conditioning and pressurization. As noted, the APU supplies bleed air on the ground for heating and air-conditioning. DC electric heaters are fitted to the probes, sensors, windshields, cockpit foot warmers and the baggage compartment.
A single, 3,000-psi hydraulic system using conventional mineral MIL-H-5606 red fluid, powered by left and right engine-driven pumps, supplies actuators for landing gear, spoilerons, flaps and thrust reversers, plus the wheel brakes. A DC aux pump provides power for the brakes prior to engine start, plus the landing gear and flaps if the engine-driven pumps fail in flight.
The Learjet 45/75 are the first Learjets to be fitted with trailing-link landing gear. Rolling stock, including carbon disc/rotor brake heat packs, is considerably larger than in any previous Learjets, providing excellent stopping power.
Let’s Go Flying
The Learjet 75 has excellent cockpit ergonomics, having 220 deg. of visibility out of the windshields and side windows. The quiet, dark cockpit design of the Model 45 is carried over to the Learjet 75. But the main lighting switches have been moved to an overhead panel, a first for a Learjet. They're still toggle switches. We'd prefer the quiet/dark annunciator light switches as used aboard some other business jets.
Bombardier's Vision flight deck, fea–turing Garmin G5000 avionics, uses three, portrait configuration, 14-in. displays that provide a wealth of information, especially compared to the original Primus 1000 avionics package. A pair of touch-screen controllers (TCSes) replaces the conventional FMS CDUs, radio tuning units, audio control panels and display controls, plus the rotary system test knob.
Building a flight plan is more akin to using an iPhone or iPad as compared to punching in characters on a traditional FMS keyboard. TCS icons pretty much guide you through the process. The touchscreen virtual keypad, concentric knob controls or graphic flight planning can be used to select waypoints, procedures and airways. As with all Garmin navigation systems, comm frequencies are part of the database and they can be selected for use by the VHF comm transceivers at the touch of a virtual button.
Bombardier sales engineer Matthew St. Cyr aptly describes the system as “Apple for avionics” because Vision using G5000 is easily discoverable and seldom leaves the crew asking, “What's it doing now?” More features will be added after deliveries begin in early 2014, including full takeoff and landing performance computations and full FANS-1/FANS-A functionality.
Virtually all of the systems functionality is carried over from the Model 45 to the Learjet 75. Automated functions are retained but so are some manual functions. Boost pump operation, for example, is completely automatic unless cross flow is needed. But the pressurization system still requires the crew to program in the landing field elevation. That function is not linked to the new Garmin FMS.
Taxiing out of the chocks, the wheel brakes felt smooth and responsive. Not so, the nosewheel steering. It still takes some practice to make smooth turns at low speeds because the rudder pedals provide little or no centering feedback.
Demonstration pilot Greg Eastburn in the right seat conservatively computed 113 KIAS for the V1/Vr decision and rotation speeds, 123 KIAS for the V2 one-engine-inoperative takeoff safety speed and 148 KIAS for flap retraction based on the 18,000-lb. takeoff weight, Wichita Mid-Continent Airport's 1,333-ft. field elevation, 29.83 barometer setting and 31C temperature. Takeoff field length was 4,260 ft. When the aircraft earns certification, it's likely that 2 to 4 kt. will be shaved off those V speeds, according to Bombardier's flight test data.
Once cleared for takeoff on Runway 19R and I pushed up the power levers to the takeoff detent, it was immediately apparent that this aircraft may resemble the Model 45, but it doesn't perform like one. The combination of 10% more thrust and 200 lb. less weight had a palpable effect as the aircraft accelerated.
Rotation forces were as hefty as those of the Model 45, as were roll control forces. Control feel was much lighter in the old Model 20 and 30 series aircraft.
Once we stabilized at 250 KIAS, the aircraft settled into a 6,000- to 7,000-fpm initial rate of climb. Safety pilot Lyn Jacques logged our passing through FL 350 in 14 min. since beginning takeoff roll, even though we were climbing in ISA+12C to ISA+20C conditions.
We leveled at FL 430 in 19 min. and settled into Mach 0.78 normal cruise. At a weight of 17,000+ lb., the aircraft zipped along at 444 KTAS at ISA-4C while sipping 1,040 lb./hr. Pushing up the thrust levers to cruise at the Mach 0.81 redline, we trued at 460 KTAS at the same OAT while burning 1,240 lb./hr. Operators choose Learjets for speed and fuel efficiency and the Model 75 delivers.
We then headed to Hutchison, Kan., Municipal Airport (HUT) to fly the RNAV (GPS) Runway 13 LPV procedure. During the descent, we encountered a TCAS traffic advisory alert. Unlike some other Garmin display systems, the G5000 in the Learjet 75 does not provide 3-D traffic imagery on the PFD. Instead, a small bird's-eye view chart inset pops up, showing traffic in two dimensions with the intruder's altitude differential shown in numerical digits.
Eastburn requested clearance for the full RNAV procedure to demonstrate Vision's ability to compute the required guidance maneuvers to enter a procedure turn and fly the entire procedure. We flew most of the procedure with the autopilot coupled and the system guided the aircraft smoothly and precisely throughout.
At minimums, we executed a missed approach. Pressing the Go Around button on the throttle disengages the autopilot, thus initially the missed approach must be flown by hand. After the appropriate lateral and vertical flight guidance modes have been programmed, the autopilot again may be coupled.
We headed back to Wichita for a couple of touch and goes, followed by a full-stop landing. The long travel, trailing-link landing gear made for cushy landings and the wheel brakes were powerful, smooth and chatter-free.
Worth the Money?
The Learjet 75's B&CA sticker price is close to $14 million, so it's not the least expensive competitor in the light jet class. It's $4.5 million more costly than a typically equippedPhenom 300 or Cessna Citation CJ4. It's even $700,000 more expensive than the midsize Cessna Citation XLS+.
But Bombardier believes buyers will perceive the value of an aircraft that straddles the boundary between light jet and midsize business aircraft, having 2,000+ nm legs at long-range cruise, Mach 0.80 normal cruise speed and an APU as standard equipment.
Glance please at the accompanying Comparison Profile. The big spike on the chart represents tanks-full payload. It's 57% higher than the second-place Phenom 300 and 68% greater than the composite average of the group.
At 4,440 ft., standard day takeoff field length performance is competitive. Departing from B&CA's 5,000-ft. elevation, ISA+20C airport, the Learjet 75 stands out as a superb performer. But the aircraft does need somewhat more runway for takeoff on 600-nm trips. Speed and fuel efficiency remain two of its strongest selling points.
Its cabin is 2.5 ft. longer than competitive light jets and 15 in. longer than that of the Citation XLS+, so the Learjet 75 is the only light jet that can offer double club seating for eight passengers. It's also the only aircraft in its class with a flat floor.
While double club seating is standard, that configuration affords scant legroom if all seats are full. We recommend the seat tracking option that affords generous space in a single club section if only four passengers are aboard. One sore point of interest to chiropractors: The sidewall arm rails are higher than the armrests on the seats, so passengers' left and right forearms and shoulders aren't level.
Up front, pilots will find Bombardier's Vision cockpit, using Garmin G5000 avionics, a breeze to use compared with the Honeywell Primus 1000 gear in the Learjet 45XR.
Overall airport performance, especially at hot-and-high airports, is considerably better than that of the Learjet 45. It's still not as good as most other light jets, principally because of the aircraft's 68.9-lb./sq. ft. wing loading, which is much higher than that of most competitors. Then again, higher wing loading makes for a more comfortable ride in turbulence.
Still, we have a few brickbats:
Although Garmin is developing an auto-throttle system for the G5000 kits being fitted to the Citation Sovereign and the new Citation X, it's not available aboard the Learjet 75. We believe it should be optional, if not standard, considering the aircraft's price.
It's not easy to be smooth and precise with the nosewheel steering because there's little centering feedback through the rudder pedals. The Learjet 75's pitch and roll control force, unchanged from the Model 45, is ponderous by legacy Learjet standards.
No pilot's fingertips will confuse the Learjet 75 with Model 20 or 30 series Learjets. Even so, the Learjet 75 is a much stronger contender in the light to midsize jet class than its predecessor, the Model 45XR. It can operate from 10-12% shorter runways and it flies 4% farther than the Model 45 because of its new lower drag, canted winglets and reduced trim drag. It also has the most advanced cockpit and cabin environments of any Learjet yet produced.
Is it worth the money? Bombardier won't disclose its order book for the Model 75, but its extra pep, improved takeoff field performance, superbly capable avionics package and new cabin amenities surely enhance its appeal. Most of all, Bombardier's new aircraft offers classic Learjet loading flexibility. Fill the tanks, fill the seats and fly the mission.
Tap the ICON in the digital edition of B&CA to watch our video pilot report on the Learjet 75 or go to AviationWeek.com/video
|B&CA Equipped Price||$13,793,000|
|Engine||2 Honeywell TFE731-40BR|
|OAT°C||3,850 lb. ea./ISA+23C|
|Payload With Max Fuel||1,798/816|
|Fuel With Max Payload||5,750/2,608|
|Fuel With Executive Payload||6,260/2,840|
|Time to FL 370||15 min.|
|FAR Part 25 OEI Rate||NA|
|FAR Part 25 OEI Gradient||NA|
|Certification||FAR Part 25 pending|