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