By FRED GEORGE
Leatjet60The largest Learjet lives up to theperformance legacy of its much
smaller ancestors.
, he 12-year wait finally is over. Business aircraft operators have beenchomping at the bit for more than adecade, awaiting the arrival of a largecabin Learjet that would measure upto the performance legacy of its muscular predecessors. The Learjet 60finally is here, with performance,cabin size and fuel efficiencythat waswell worth the wait.
Why so long a delay? Learjet simplydid not have the money to develop anairplane to succeed the Model 55C,which had been the firm's roomiestbusiness airplane. Lean times causedthe large Learjet development program to be postponed during the1980s.
Changes started to happen rapidly,however, in spring 1990when Montreal transportation equipment conglomerate Bombardier bought LearjetIncorporated. Well before the ink wasdry on the acquisition agreement,Learjet launched the ambitious $100million Learjet 60 development program, with the goal of certifying it byJanuary ofthis year.
The development delay had majorunanticipated benefits, since it allowedLearjet engineers to take advantage ofnew technology aerodynamic designtools along with next-generation turbofan engines and avionics.
The result? The new Learjet 60 ismarkedly superior to the Model 55C.For example, when loaded to maximum takeoff weight (MTOW), theLearjet 60 will climb directly to FL 430in less than 14 minutes. This is not the
e result of simply bolting huge engines~ onto a stretched Model 55C airframe.~ The Learjet 60's performance results~ from a balanced blend of more8- thrust-especially at cruise altitude.w better specific fuel consumption and~ more refined aerodynamics when com-
50 Business& Commercial Aviation. July 1993
pared with the Model55C.No business jet with a competitively
sized cabin can beat the Learjet 60 atthe fuel pump; its block-to-block fuelconsumption almost equals that of thenotoriously fuel-miserly Learjet35N36A business airplanes. Comparedwith the Model 55C, some operatorsare chalking up 10 to 12 percent lowerfuel consumption numbers, accordingto Learjet.
Just as importantly, the Learjet 60'slonger cabin, now comfortably seatingsix or more people, makes the airplanea real contender in the highly competitive mid-sizebusiness jet class.
EVOLUTIONARY, BUTSUBSTANTIVE PHYSICAL
CHANGESThe newest Learjets sport one additional cabin window on each side of
Stretching the fuselage 28 inches and moving the door forward eight inchescreates a truly mid-size jet cabin.
the aircraft, as compared to the Learjet 55. That is a byproduct of stretching the fuselage 28 inches forward ofthe wing. To balance the airplane, theaft fuselage was lengthened 15 inches.
The cabin door was moved forwardmore than eight inches, but thatchange is tough to notice without atape measure-at least until passen-
gers board the airplane. Together withthe fuselage stretch, the repositionedcabin door makes a big difference incabin comfort.
The size ofthe vertical and horizontal stabilizers is identical to the Learjet 55's. To preserve the samenose-down pitching moment, the areaof the ventrally mounted anhedral
"delta fins" was increased 20 percent.The Learjet 60 has a slightly narrowerc.g. envelope than its predecessor, butits higher basic operating weight actually makes it easier to load the airplane within the weight and balanceenvelope. While remaining within theC.g.limits, the airplane can carry fullfuel and six passengers or virtually
Business& Commercial Aviation. July 1993 51
any combination of fuel and payload.Larger delta fins also help improve
the directional stability of the Learjet60 compared to the Learjet 55C, whichitself has earned high marks for docilehandling. Overall, the Learjet 60 ismore stable than the Model 55C,according to the firm's flight test engineers.
The Learjet 60 retains the basic airframe structure of the Model 55, but itwas the first business aircraft to haveits shape honed by using theNASA/Boeing Tranair computationalfluid dynamics (CFD) software. Modelling aircraft transonic airflow, theTranair CFD program identifies thelocal Mach number at any point on theairframe. That allows designers to spotexcessively strong local shock wavesthat cause excessivedrag.
Starting in September 1990, Learjetinvested in 50 hours of NASA Amescomputer time that slashed overallcost and time from the developmentprogram. Among other things, thecomputer indicated that a small cusphad to be added to the leading edgesection of the wing root in order toreshape the upper wing surface. Thewing-to-fuselage fairing was also modified to lower interference drag. Ogeeshaped trailing edge extensions wereadded to the winglets near the rootsections partially to decamber thewinglet airfoil. Modifications also were
52 Business& Commercial Aviation. July 1993
B/CAANALYSIS
The Learjet 60's contours were made
slipperier by using NASA/BoeingTranair software to reduce the dragassociated with the nacelles, enginepylons and wing lets, among otherdetails.
made to the shape of the enginepylons.
Changes yielded almost four percentless drag in. cruise, allowing the aircraft to climb to a higher initial cruisealtitude and burn less fuel.
NEW GENERATION TURBOFANSThe Pratt & Whitney Canada PW305Aengines, having a substantially largernacelle diameter than the AlliedSignalTFE731-3AR-2B turbofans on theLearjet 55C, produce significantlymore drag. To preserve the same wingand fuselage clearances as on theLearjet 55, the nacelles have beenmoved up and out, thereby preventingan increase in interference drag.
The engines enclosed within thosenacelles represent a new generation ofturbofan powerplants designed forbusiness aircraft. The PW305As havea wide chord fan with improved aerodynamics, a fan-to-corebypass ratio ofmore than 4.5:1 and a core compression ratio of almost 18:1. The enginehas a standard-day output of 5,225pounds-thrust, but each is flat-rated to4,600 pounds-thrust in the Learjet 60.Rohr target-type, hydraulically actuated thrust reversers are standardequipment, but certification is notscheduled to be completed beforeAugust.
The engines' conservatively flatthrust rating assures excellent hothigh airport performance, an initialTBO of 4,500 hours and, according toLearjet engineers, helps make possiblethe quietest FAR Part 36 takeoff noise
signature of any business jet yet certified. (The final Part 36 noise levels aresignificantly improved over the preliminary levels shown in B/CA's 1993Planning & Purchasing Handbook.)
Full Authority DigitalEngine Controls, orFADECs, control theengines. These electronicengine computers use adual channel, control-bywire design. The thrustlevers are electrically, notmechanically, linked tothe engines, and theysend electrical signals tothe FADECs. In turn, theFADECs control allengine functions.
The thrust levers havegated detents for idle cutoff, idle, maximum cruisethrust, maximum contin
uous thrust, takeoff thrust and automatic power reserve thrust. Auxiliarypower reserve (APR)does not increasethe PW305A's thrust output, but itmakes the full 4,600 pounds availableat higher ambient temperatures.
As we explained in the September1992 issue of B/CA,the FADECs slashpilot workload from setting takeoffpower amounts to simply pushing thethrust levers forward into the detentmarked "Takeoff." After departure,the thrust levers are pulled back onenotch into the maximum continuousthrust detent for climb-out. Duringthe climb, the engine computers handle all aspects of engine management.The pilot needs only to pull the thrustlevers back to an appropriate intermediate cruise thrust setting after reaching level-offaltitude.
SYSTEMS AND ERGONOMICIMPROVEMENTS
Pilots of early Learjets, especially the20-series models, are accustomed to arather quaint, seemingly "designed byexpedience" array of cockpit controlsand gauges.
The Learjet 60's cockpit, along withthat of the Learjet 31A, offers arefreshingly modern contrast now thatfunctional layout and easy access havebecome top design priorities. Customers had plenty of input before anycockpit metal was cut for the Model60. Much less cockpit clutter is theresult.
The instrument panel is dominatedby four large-format electronic dis-
j
Four Collins Pro Line 4 large-format CRTs dominate the instrument panel, providing more usable information than dozens ofconventional instruments. B/CA believes the avionics suite makes the Learjet 60 easier to fly than the Learjet 55.
.-'
plays that replace a dozen and a halfseparate indicators, including theradar display. A pair of radio tuningunits control all the comm/nav/identavionics, except the HF that has itsown control head in the console. Aswith all previous Learjets, there is nooverhead panel.
Similar to previous models, theLearjet 60 has round, two-inch analogdisplay engine instruments, but thenew design gauges have digitalinnards for reliability and secondarydigital displays for precision readability. To alert the crew to emergency andabnormal conditions, red MasterWarning lights and amber MasterCaution lights are included in theannunciator panel.
The system controls and circuitbreakers are grouped together in functional sections that are outlined andlabeled by name. On the console, the·fuel system control panel uses aschematic graphic design that hasdark face annunciators. They illuminate only when needed to alert thepilots to an other-than-normal condition or transient function. A digitalwings/fuselage tank/total fuel quantityindicator is mounted in the instrument panel.
Many other controls and indicatorsalso have been updated, including acomposite electrical system indicatorthat replaces the array of gauges
found in the Model55C.Overall, the layout ofleft- and right
side controls puts them within easyreach of the pilot and copilot, according to duty assignments. Allmajor systems controls and indicators are closeenough to the center so that bothpilots can monitor them.
The systems themselves also havebeen upgraded, and here are someexamples: The wheel brakes on thedual wheel main landing gear aremore powerful, and they use improvedalloy steel disks that dissipate heatbetter and are not subject to warpingor cupping. A full-time, speed-proportionate steer-by-wire nosewheel steer-
ing system helps to make the airplaneeasy to handle on the ground. Thestall warning system has beenreplaced by a true angle-of-attack reference system that is fully compensated for configuration changes. Thespoilers now can be deployed in smallincrements, rather than being eitherfully extended or retracted.
An added rudder boost system yieldsa two-fold benefit. Compared to theModel 55, the system reduces the rud-
Ease-of-use features, such as the
graphic design fuel panel (left) andFADEC click-detent thrust levers (below),reduce flightcrew workload.
Business& Commercial Aviation. July 1993 53
B/CAANALYSIS
The Learjet 60, when configured with seven seats, has ample interior storagespace for passengers, business materials and carry-on luggage.
der pedal pressure by up to 75 pounds,and it slightly increases the rudderauthority.
The cabin environment now is easierto control. A new, fully automaticAlliedSignal digital cabin pressurization system requires only one input:destination airport elevation. TheFreon air conditioning system hasbeen made more efficient by increasing the ambient air flow through thetailcone, where the condenser is located. Defogging of the windshields isaccomplished by electric heatingrather than by defogair.
Learjet is developing an auxiliarypower unit installation as part of anFAA contract for two special configuration Learjet 60 airplanes that will bedelivered in 1995. No firm date orprice has been set regarding the availability of an APU for regular production airplanes. However, Learjetengineers would like to persuadeWilliams Research to develop the newAPU because it looks like a lighter,more efficient candidate than existingAPUs that might otherwise beinstalled in the Learjet 60.
COLLINS PRO LINE 4 AVIONICSThe Learjet 60's integrated Pro Line 4avionics system ,isbased on a hub-andspoke design. An Integrated AvionicsProcessing System (lAPS) box formsthe hub, and ARINC 429 interfacescomprise most of the spokes leadingout to various components, controlsand displays.
Among other components, the central IAPS computer box contains flightguidance components and an FMS.The Collins FMS uses DME for shortrange navigation and a VLF/Omegasensor as the standard long-rangenavaid.
The standard package contains dualattitude-heading reference systems(AHRS), dual digital air data computers, dual comm/nav/ident radios(including an AlliedSignal HF commtransceiver), a single Collins<FMSwitha Canadian Marconi VLF/Omega sensor, a radio altimeter and a soIrd-stateweather radar. Optional componentsare, among others, a Canadian Mar"coni combination VLF/GPS sensor,Collins TCAS, a TWR-850 solid-stat~Doppler turbulence detection weatherradar and various second systembackups.
The Collins FMS is well-suited tolong-range enroute navigation, but not
54 Business& Commercial Aviation. July 1993
terminal area and approach navigationtasks. The FMS has no vertical navigation mode, contains no SIDs or STARsand has no holding pattern, roll-steering command guidance mode. A second Collins FMS is available as a$101,700 option. Upgrades to theCollins FMS are under study.
Learjet will offer dual UniversalNavigation UNS-lB FMS boxes starting with serial number 17 for an additional $167,400 in October. TheUNS-1B also will be offered as aretrofit package. The UNS-1B, in contrast to the Collins FMS, is a full-function system that offers SIDs, STARs,multiple waypoint vertical navigationand holding pattern guidance amongits range of features.
Largely because of the human factors design features of the large format CRT displays, the Learjet 60 iseasier to fly than the Model 55. ThePrimary Flight Displays-incorporating airspeed, attitude, altitude andcourse guidance functions-makeeffectiveuse of color and pattern visual cues. The rolling drum type airspeed scale, for example, has amagenta trend vector bar that shows ifthe airplane is accelerating or decelerating. In our opinion, the airspeedtrend vector is the next best thing toauto throttles because it makes it easyto spot small deviations in speed.
The altitude scale also uses a rollingdrum type display, but it has an
expanded scale that makes it easy tospot small deviations. Color bars andgraphs alert the pilot when the airplane is approaching a preset baro altitude or flight level and when theaircraft nears a preset altitude-aboveterrain on the radio altimeter.
The Navigation and Multi-FunctionDisplays graphically show weatherradar, moving map and waypointinformation as well as alphanumericdata. Everything that appears on theelectronic displays is easily interpreted, easing the transition for pilots whoare new to the Learjet 60.
lt takes time, though, to learn howto program the electronic displayssince it is first necessary to master thenuances of the console-mounted AMS850 Control Display Units. The CDUsare used to control and program manyavionicssubsystems, such as the EFIS,weather radar, flight management system and also the radios, backing upthe panel-mounted radio tuning units.In essence, the design causes a separation between many hand/eye functionsthat takes a while to overcome. Learjetflight test pilots told us that with a little practice, using the AMS-850to program the subsystems becomes quiteeasy.
PASSENGERACCOMMODATIONS
The Learjet 60 is delivered as a finished aircraft, including a six-place
The emergency exit door provides access to the aft cabin
luggage compartment in the lavatory; the aft externalcompartment, though, holds most of the baggage.
interior. The repositioned cabin doorand lengthened fuselage increase leftside passenger legroom by more than ayard, compared with the Model 55.Although the aircraft optionally maybe configured for up to 10 passengers,we feel the interior is better suited to amaximum of seven for long-rangetrips.
The fit and finish of the interior ofthe LR60-005 that B/CA flew wassuperb. Standard in the passengercabin are two forward-facing seatsahead of an aft club section of four
seats. Business-related carry-on luggage can be easily accommodated bythe slim clothes closet forward of therefreshment center, briefcase stowagebehind the seat backs and a 27-cubicfoot, 260-pound capacity inflight-accessible compartment aft of the lavatory.The Model 55's capacious 44-cubicfoot, 500-pound capacity luggage compartment failed to make the cutbecause of new engine rotor burst containment rules and the need for a larger fuselage fuel tank.
On the LeaIjet 60, the 5.5-cubic-footforward external luggage compartment of the Model 55 has been eliminated. The aft external luggagecompartment holds 28 cubic feet ofgear (versus 17 cubic feet in the Model55). The result is that the LeaIjet 60has a total luggage capacity of about10 cubic feet less than its predecessor.
Hot and cold water and an externally serviced flush potty are provided ina full-width lavatory located in the aftcabin. The emergency exit door islocated in the lavatory area, on the aftright side of the airplane. The doorswings up and out, providing the crewwith ready access to the aft cabin luggage compartment during groundoperations. This feature allows thelavatory door to remain closed whileluggage is loaded or unloaded from theaft cabin compartment, thus protecting any passengers on board from theweather. (The high-density seatingversions eliminate the aft lavatory infavor of a three-place aft divan. A pullout lavatory is positioned forward insuch configurations.)
The passenger cabin is designed forwork as much as comfort. Chairs arewell-shaped and padded for transconti-
nental flights,the fold-outtables are amplysized, and aradiotelephoneis included asstandard equipment. A faxmachine,microwave ovenand drip coffeemaker are available options.
Learjet couldnot supply B/CAwith Learjet 60interior noisemeasurements,but, subjectively,
the airplane seems at least as quiet asa Model55.
FLYING THE LEARJET 60Walking around the airplane, we madesome notes regarding servicing. A single-point refueling system is located onthe right side of the aircraft, aft of thewing. The airplane also may be fueledover the wing. If pressure refueling isnot available, the Learjet 60 has a5,012-pound fuselage tank that can befilled by transferring fuel from thewings.
The engine oil level may be checkedby looking at sight gauges visiblethrough slots in the nacelles. Addingoil, though, requires access to a ladder.Most other systems, including oxygenand hydraulics, may be serviced fromground level.
Landing lights are located on themain landing gear, so they are onlyfunctional on final approach and whentaxiing. A high intensity recognitionlight is mounted in the vertical fin,thus providing enhanced see-and-avoidvisibility in high traffic density areaswhen a pilot is flying with the landinggear retracted.
Quite possibly, the Learjet 60 hasthe lowest workload of any LeaIjet thefirm has yet built. Many pre-startchecks have been automated. Pilotsshould plan on spending about half asmuch time doing checklist items priorto takeoff, according to Learjet engineers.
For example, the FADECs set theN1 bugs on the fan speed tachometers.If the computer-programmed N1 bugson the left and right gauges concurwithin one percent, there is no need tolook up a takeoff power setting in the
Business& Commercial Aviation. July 1993 SS
B/CAANALYSIS
LEARJET 60
14.7'(4.48 m)
1
14.7'14.48 m}
_1
-r
Baggage
28.0 k.' 18.5 m'J
58.7' (17.9 mJ
43.8' (13.4 m)
17.7' 15.4 m)
7 Passenger Floor Plan
flight manual.The FADECs are so sophisticated
that the engine could be started at thetouch of a button, if long-standingLearjet cockpit design conventionscould be set aside, such as the startoff-generator switches that stillrequire three separate switch movements during start.
Once the engines are started, ittakes a healthy push on the thrustlevers to start taxiing. Our basic operating weight was 14,028 pounds. Asafety pilot and 3,440 pounds of fuelbrought the total taxi weight to 17,640pounds.
Up to 24 degrees of nosewheel steering are available at low speed by moving the rudder pedals gently to thestops. Pressure transducers sensewhen the pedals are pushed againstthe stops, causing the nosewheel tomove up to 60 degrees, proportionateto pedal pressure. The net effect issmooth, precise control during taxi.
The wing flaps are normally set to20 degrees for takeoff, but eightdegree flaps may be used for hot/highdepartures if FAR Part 25 second segment, one-engine-inoperative (OEI)climb performance is a prime consideration. We opted for 20 degrees flaps forour departure from Napa, Californiaat 17,500 pounds, resulting in a Part25 scheduled takeoff field length of3,325 feet. We set the VI decisionspeed bug at 112 KIAS,rotation speedwas pegged at 124, and the V2 takeoffsafety speed was set for 133 KIAS.
Pushing the thrust levers to thetakeoff detent left no doubt that theairplane is very much a Learjet. Ourlight takeoff weight yielded a 1.9:1weight-to-thrust ratio on the day ofour flight.
The pitch force at rotation was moderate, but notable, reflecting our forward e.g. A typical long-range missionwith full fuselage fuel and passengerswould result in a more aft e.g., withcorrespondingly lighter pitch forces.
The lightly loaded airplane climbedto FL 430 in 16 minutes, burning 690pounds of fuel from the start of thetakeoff roll, in spite of three intermediate level offs for ATC. At that altitude, the airplane that now weighedslightly less than 17,000 pounds stabilized at 432 KTAS,burning 1,090pph.
Because of the aircraft's low drag,Learjet 60 crews can plan on startingthe descent for the approach to thedestination airport sooner than they
56 Business& Commercial Aviation. July 1993
LEARJET 60
TIME AND FUEL VERSUS DISTANCE
Source: Leariet Incorporated
5 6
460 480
High-Speed Cruise
Long-Range Cruise
420 440
Speed (KTAS)
SPECIFIC RANGE
2 3 4
Time (hrs)
Conditions:
18,000Ibs;zero wind; ISA
Conditions: 800-lb
payload; NBAA IFRreserves (200-nmalternate); zero wind;ISA
0.40
0.35
0.25380 400
0.45
1,000
::ii':::::.
E£.
Gl
IIICII
Ill:"Ii:";:;
Glll.III 0.30
o
2,500
500
2,000
E 1,500£.Gl"c.2IIIis
Source: learjet Incorporated
These graphs present range, fuel and payloadinformation that is designed to show the capabilities of the Leariet 60. Do not use these data forflight-planning purposes.
Time and Fuel Versus Distance-This graphshows the plot of two missions: the first flown athigh-speed cruise and the second at long-rangecruise. The numbers at the hour lines indicatecumulative miles and fuel burned for each of the
two profiles. While the intermediate points onthese lines are accurate only for the full trip, theycan provide the user with a rough idea of the timeand fuel required for trips of intermediate length .
Specific Range-The specific range of an aircraft, a measure of its fuel efficiency, is the ratio ofnautical miles flown to pounds of fuel burned(nm/lb). Higher specific fuel consumption (SFC)numbers indicate better fuel efficiency. This graphshows SFC values at six altitudes for the Leariet 60at an intermediate l8,000-pound cruise weight.For example, while flying at FL 350 the specificfuel consumption at high-speed cruise is 0.281nm/lb and at long-range cruise it is 0.383 nm/lb.A close look at the charts reveals that fuel efficien
cy actually drops above FL 430, which in part indicates that flight at higher altitudes should beattempted at lower weights, if fuel efficiency is thegoal. The Leariet 60 at 18,000 pounds achieves along-range SFC of 0.410 nm/lb at FL 430, forexample, but only 0.404 nm/lb at FL 450.
Range/Payload Profile-This graph is intended to provide rough simulations of trips under avariety of payload and airport density altitude conditions, with the goal of flying the longest distance.For the Leariet 60, we use a relatively constantangle-of-attack, maximum range profile that causesthe long-range cruise speed to vary with altitudeand aircraft weight. The payload lines-intendedonly for gross evaluation purposes-are each generated from a dozen or more points. Time and fuelburns, shown at the top of the chart, only are plotted for the longest mission. Keeping these limitations in mind, it is possible to get a "feel" for theairplane's capability. If, for example, you want tosimulate a 2,200 mile trip (slightly more than thedistance from Los Angeles to New York) with a fivepassenger, 1,000-pound payload, the graph indicates that the time required is 5+20, the fuel burnwould be about 6,150 pounds and the sea level,standard day takeoff field length would be about5,100 feet.
RANGE/PAYLOAD PROFILE
2,800
6,622
2,400
5,732
2,000
Conditions: four passengers; NBAAIFR reserves (200-nm alternate); zerowind; ISA; 0.72 Mach cruise
4,527
4
3,379
3
II!
1,200 1,600
Range (nm)
800
2,302
2
400
1,282
Fuel
Balanced Field LengthGross
Burn
SLI
5,000 ftTakeoff(Ibs)
TimeISA
ISA+20°CWeight (Ibs)(hr)
5,350
8,47523,000
4,840
7,54422,000
4,402
6,74421,000
4,023
6,06820,000
3,674
5,43519,000
3,354
4,89018,000
3,154
4,65217,000
2,995
4,43616,0000
Source: learjet Incorporated
Business & Commercial Aviation. July 1993 57
B/CAANALYSIS
B/CA COMPARISON PROFILE"'(% Relative to Average)
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Designers attempt to give aircraft exceptional capabilities in all areas-ncluding price-but the laws of physics do not allowone aircraft to do all missions with equal efficiency. Tradeoffs are a reality of aircraft design.
In order to obtain a feeling for the strengths and compromises of a particular aircraft, B/CA compares the subject aircraft'sperformance to the composite characteristics of aircraft in its class. We average parameters of interest for the aircraft that aremost likely to be considered as competitive with the subject of our analysis, and then we compute the percentage differencesbetween the parameters of the subject aircraft and the composite numbers for the competitive group as a whole. Those differences are presented above in bar-graph form, and the absolute value of the parameter under consideration, along with itsrank with respect to the composite, are given.
For this Comparison Profilee, we present selected parameters of the Learjet 60 in relation to a competitive group consistingof the BAe 125-800, BAe 125-1000, Cessna Citation VII and IAI 1125. It should be understood that this Comparison Profilee ismeant to illustrate relative strengths and compromises of the subject aircraft; it is not a means of comparing specific aircraft toeach other.
58 Business& Commercial Aviation. July 1993
Competitors may have larger cabins, but the Learjet 60 hasfew performance equals.
SPECIFICA liONSLEARJET 60
FAR Part 36 noise levels(TO/Land) 70,8/87.7 EPNdB
PERFORMANCEPASSENGER SPACE
AND PRICELearjets have always beendesigned for distinct marketniches, especially those inwhich high performance is amajor advantage. The Learjet60 continues this tradition.Other midsize business jetshave larger cabins and somecompetitors have longerrange, but when time toclimb, initial cruise altitude,operating economy and reliability are prime factors, theLearjet 60 has few equals.
It will climb directly to lowto mid-40 cruise altitudes atmaximum takeoff weight,while the passengers enjoy a6,000- to 7,000-footcabin alti
tude. It has nonstop U.S. transconti-nental range except againstunseasonably strong headwinds. Itshefty wing loading makes for a comfortable ride, especially in turbulentair. Its low noise signature surely willmake it a goodneighbor at noise-sensitive airports.
Ample new technology in the Learjet60's design will keep it fresh for manyyears. No midsize business jet in production has more advanced engines.The avionics suite, when configuredwith the optional dual Universal FMSand other additions, is unsurpassed forcapability by comparably sized competitors. The Learjet 60's airframe systems have been substantiallyimproved and updated, making themmore reliable and easier to use.
The flagship Learjet 60 may not become an instant classic as did theLearjet 24, but it is destined to markan important turning point in thehistory of the company. It unmistakably identifies Learjet Incorporated'srenewed commitment to designingnew technology aircraft-those thathave power and range, reliability andeconomy,comfort and capacity-to carry forward the business jet legacy ofcompany founder William P. Lear, Sr.
And traditional Learjet customersseem to agree. Learjet Incorporatednow has more than 25 firm orders forthe Learjet 60, more than enough tocreate a backlog through most of 1994.That's fairly clear evidence of a company making a healthy recovery afterlanguishing for so many years in the1980s. B/CA
(See charts)
(See charts)
4,500/1,5751,340/469340/56
51,000/17,85043,000/15,05025,000/8,75025,700/8,995
Airport performance
Range performance
PerformanceClimb
All-engine (fpm/mpm)Engine-out (fpm/mpm)Gradient (ft/nm, m/km)
CeilingsCertificated (ft/m)Service (ft/m)Engine-out (ft/m)Sea level cabin (ft/m)
B/CA equipped price $8,886,000
Seating
2+6/10
EnginesModel
2 PW305APower
4,600 Ibs eoTBO
4,500 hrs
Dimensions
(See three-views)
Weights (Ibs/kgs)Max ramp
23,350/10,591Max takeoff
23,100/10,478Max landing
19,500/8,845MaxZFW
16,500/7,484BOW
14,240/6,459Max payload
2,260/1,025Useful load
9,110/4,132Max fuel
7,910/3,588
Payload w/max fuel
1,200/544Fuel w/max payload
6,850/3,107
LimitsMMO
0,810VMO
340 KIAS
VFE(app,)
250 KIASPressurization
9,4 psi
would in a Model 55. Thedescent profile specifics werenot available in time for thisreport, however.
We continued to explorethe airplane's handling characteristics, after leveling offat 12,000 feet. The airplane iswell damped in all three axes,particularly in the long periodpitch mode. The natural aerodynamic Dutch roll dampingmakes it possible to fly theairplane at all altitudes without a yaw damper, but passengers, in our opinion,would be uncomfortable if thestability augmentation system were inoperative.
The Learjet 60 has a crisproll rate in both clean andflaps-down configurations.Spoilerons augment the roll controlauthority when the flaps are extendedbeyond 25 degrees.
The delta fins tame the Learjet 60'sstall characteristics, as they have onthe Learjet 31/31A and 55C. We heldfull aft yoke, with the yaw damper off,in both clean and dirty configuration,during full aerodynamic stalls. Thenose mushed over at the stall, and theairplane's roll attitude easily could bemaintained by using roll controlinputs. Exiting the stall amounts toreducing the AOA and shoving thethrust levers forward into the takeoffdetent until the airplane recovers.
Such docile handling should givecrews confidence that the publishedapproach speeds may be flownwithoutextra padding. Our VREF landing reference speeds varied from 124 to 127KIAS. VREF at the maximum landingweight of 19,500pounds is 139 KIAS.
The approach and landing characteristics of the Learjet 60 are quitesimilar to those of the Model55, whichmay be chalked up as a plus for thenew airplane. It is quite stable onapproach, and it is easy to 'make precise corrections to keep the aircraft oncourse. The landing flare is flat,requiring small adjustments to thenose attitude for smooth touchdowns.
Simulated OEI operations requireless effort in the Learjet 60 comparedto the Model 55, because of the aforementioned rudder boost system. Wefound that, compared to the Learjet 55, it is much less tiring to fly thenew airplane during simulated OEIoperations.
Business & Commercial Aviation. July 1993 59