B/CA Pilot Report May 1983

F
CF34upgrades
Challenger capabilities
David M. North/Montreal
May t6, t9g3
Replacement of Avco Lycoming ALF502L turbofan engines with higher
thrr,rst General Electric Cp34s on the CL-601 has transformed the
Canadair Challenger into the corporate aircraft the manufacturer originally promised its customers in the late 1970s.
This Auiation Week I Space Tecbnologt pllot had an opporttrnity
to crompare the flight performance of the new Challenger with that of
the Challenger CL-500 flown in 1980 from the Cartierville Airport
(A\)/&ST Sept. 22, 1980, p. J+1.
The disparity between the performance guaranteed by Canadair
to operators with the Avco-powered Challenger 600 and the performance attained was not the fault of the engine. The Challenger 600
originally was envisioned as a maximum 32,500-Ib. aircraft. The maximum gross weight increased from 36,000 lb. in 1980 to 38,500 lb. in
7987 and 47,250 Ib. this year.
Canadair had evaluated both the Avco ALF502L and the General
Electric CF34 turbofan engine for the original Challenger in the mid1970s. A decision was made to install the 7,500-lb. thrust Avco turbofan engine rather than the 8,650-lb.-thrust CF34 engine when Federal
Express, which had 25 orders, specified the Avco Lycoming engine.
Another factor in the choice of the Avco engine was the inability of
General Electric to meet the overoptimistic schedule set by Canadair for
the Challenger.
The performance shortfall from what Canadar had guaranteed it.s
early customers in the Challenger 600 was primarily in range, not
overall handling characteristics,which are excellent for both the Challenger 600 and the 601.
Canadair increased the instrument flight rules 2,800-naut-mi.
range of the Challenger 600 by adding a 1,800-lb. capacity fuel tank
in the fuselage. The National Business Aircraft Assn. instrument flight
rules ranfae of the Challenger 600 with the additional tank is 3,150
naut. mi. However, Challenger 600 operators, on a ratio of five to
one, are not opting for the fuselage fuel tank.
The range of the Challenger 601, while flying at a long-range
cruise of Mach 0J4 and its higher 42,250-lb. gross weight, is approximately 3,500 naut. mi. All Challenger 601s have the fuselage fuel tank
122
cL-601
123
.ffi
External dffirences betuteen tbe Auco Lycoming-potaered Cballenger
600 and. the Challenger 601 includ.e tbe installation of 4-ft. uinglets on
tbe new Cballenger, ubicb ispouered by General Electric CF34 turbofan
engines. Installation of tbe CF34 engines prouides tbe Cballenger 601
witb a 15o/oincrease in static tbrust on two engines, compared uitb the
7,500-lb. tbrust of tbe Auco ALF5O2L turbofan engines.
installed during production. tVith the tank, the aircraft's fuel capacity
is increased from 14,900lb. to 16,725 lb.
Canadair met all of its scheduled dates for first flight and certification of the Challenger 601, which had been set almost fwo years
ago. First flight was on Apr. 10, 1982, five days ahead of schedule.
Both the Canadian and Federal Aviation Administration rype certification of the aircraft were granted in the months predicted, February
and March, respectively.
Canadair also was able to exceed performance guarantees set for
the Challenger 60t. tn many cases, the guarantees were met and bettered at the higher takeoff gross weight certificated for the Challenger
6Ot. the performance goals for the 601 were set at a maximum ramp
weight of 41,800 lb. The aircraft was certificated at 42,250 lb., and ramp
weight is scheduled to increase to 43,250lb. later this year.
The flight in Challenger N601CL was with F.D. Adkins, Canadair's
director of flight operations and chief test pilot, as was the case during the earlier evaluation of the Challenger 6OO.the Challenger 601
flown during the evaluation flight was No. 3001, the first production
aircraft. Canadair had modified its third protofype Challenger 600, No.
1003, to the 601 configuration to conduct early flight testing.
Fr
124
Jets
During preflight of the aircraft, Adkins detailed some of the differences between the Challenger 600 and the 601. The mosr obvious
one is the installation of the 4-ft. winglets on the newer aircraft,
Canadatr is still evaluating whether it will offer to install the winglets
on the earlier Challenger 600s or future production 6OO aircraft.
Addition of the winglets affords a crurise efficiency increase of
J10/o, Adkins said. At a higher weight-to-pressure ratio, the cruise efficiency gain is 4o/o,while at a lower weight-to-pressure ratio, the winglets add 30/0.Adkins also said addition of the winglets had given the
ailerons a slightly higher power control, especially noticed during crosswind landings.
During earlier flight testing, Adkins discovered there was a slight
turbulence felt in the atcraft at a long-range cruise speed of Mach
0.74. Further testing revealed there was a shock wave produced at the
juncture of the wing and the winglet. Modifications made to the wingto-winglet fairing eliminated the turbulence.
Another obvious change is the engine nacelles on the Challenger
601. The Avco ALF502L's nacelle is one piece throughout the length
of the engine, while the nacelle of the CF34 has two different noticeable diameters. The suspension and pylons of the 601 also have been
changed to accommodate the heavier engines.
Canadair has been able to remove the stall strip from the 601's left
wing, as it has from the Challenger 600s that are under FAA registration.
The stall strip removal has reduced the landing reference speed of the
aircraft by B-9 kt. and improved the field performance. Adkins said a
change in policy at the Canadian Transportation Dept. recognizing the
reliability of the Challenger's stall prevention system was the reason for
the removal of the stall strip. Challenger 600s with Canadian registration also will have their stall strips renoved, Canadair officials said.
Balance changes
The Challenger 601's auxiliary power unit was moved forward to
counter some of the additional weight of the CF34 engines. Another
change in the 60t is the addition of a replenishment engine oil system in the aft system compartment. \fhile the atcraft is on the
ground, oil can be added to the CF34s without opening access doors
in the engine.
The N601CL did not have an interior installed and still had some
test equipment in the cabin area. The ramp weight of the aircraft was
2B,BI7 lb., or 68.20/oof its 42,250 lb. maximum. Included in the total
was 6,400 lb. of fuel and two pilots. Another 1.0,325Ib. of fuel could
have been added to the arcraft to achieve its maximum fuel load.
cL-601
125
Canadatr has an outfitting allowance for interior fittings and adclitional avionics of 4,100 lb. for the Challenger at its higher planned
gross weight.
From the right seat, Adkins described a few of the internal differences between the 601 and the 600. gleed air is taken from two different stages of the General Electric engines for pressurrzatron and
anti-icing, while on the Avco engine one stage of bleed air was used
for both functions. An extra set of switches has been added for control of the additional bleed air.
Engine start
Both of the General Electric engines were started by bringing the
throttle to the flight idle position once the N2 high-pressure turbine
speed reached l4o/o. At idle, the N1 fan speed was 24o/oancJthe ftrel
flow was 430 lb./hr./engine. Fuel flow of the Avco-powered Challenger at idle in the earlier evaluation was 395 Lb'/hr'/engine' However, fuel consumption of the General Electric engines at cruise
power is slightly less than that of the Avco-powered Challenger, including the fuel efficiency derived from the installation of the
winglets on the Challenger 601.
At the relatively low gross weight of the prototype, Adkins calculated the V1 critical engine speed to be 105 kt. on the 77F day. V. rotation speed was established at L27 kt., and V2 takeoff safety speed
was found to be 132 kt.In the case of a flight emergency after V1, the
V,.psp€ed would be 119 kt.
The automatic power reserve system was electrically tested while
still at the ramp. Once the system is armed, the static thmst will increase from 8,550Ib. to 9,,140Ib. if N1 decreasesto less than 80% on
one engine during takeoff.
During the taxi to Runway 28 at Cartierville, another of the
changes from the 600 to the 601 was apparent. The nosewheel steering control is the same half circle on the pilot's left side, but a steerby-wire and hydraulic system has replaced the mechanical and
hydraulic system on the 600. Steering was more positive, with less
slack and tendency to overcontrol than in the Challenger 600.
Takeoff roll was approximately 2,000 ft. with a normal rotation tc-r
approximately 15 deg. on the attitude gyro. To appreciate the performance of the new aircraft, Adkins had asked that we receive an unlimited climb and that initial climb speed be kept at approximately
150 kr. To maintain the 160 kt., the attitude was finally increased to
more than 30 deg. The aircraft's landing gear and 20 deg. of flaps
were raised bv Adkins shortly after takeoff.
126
Jets
The climb-out speed was increased to 180 kt. while the aircraft
passed through 5,000 ft., but the rate of climb indicator was pegged
beyond 5,500 fpm until after 10,000 ft. It took 6.3 min. from brake release to reach 25,000 ft. while climbing at 250 kt. Rate of climb passing through that altitude was 3,000 fpm and the fuel flow was 1,620
lb./hr./ enqine.
An altitude of 30,000 ft. was reached in 8.3 min. The fuel flow had
dropped to 1,400 lb./hr./engine, and the rare of climb had declined to
2,000 fp*. Climb speed at this point was 245 kt. Another 3 min.
elapsed before the Challenger was passing through 35,000 ft. at a
climb speed of Mach 0.69. Rate of climb was 1,500 fpm, and the fuel
flow had decreased to 1,140lb./hr./engine.
Visibility from the cockpit, as it is in the 600 aircraft, was excellent throughout the flight. The wrap-around, sloped windows afford
good outside visibility during flight and landing.
The Challenger 60t is limited to 4I,000 ft. for the presenr. The restriction has been imposed because of concerns about what an engine rotor burst might do to elevator control. However, Adkins said
the improbabiliry of a rotor burst and the redundancy in the elevator
system has been shown to the Canadian Transportation l)ept., and
the clearance to 45,000 ft. should be granted soon.
Final cruising altitude of 4I,000 ft. was reached 16.8 min. after
takeoff. Outside air temperature at that altitude was 10 deg. warmer
than standard. Total fuel used from departure from the ramp was
L,400 lb., leaving 5,000 lb. of fuel remaining. Adkins calculated that
with a 1,000-lb. reserve and flying at a long-range cruise setting, we
still had a 1,300-naut-mi. rarrge with the Challenger at 4I,000 ft. edkins also said he has found that the Challenger 60t is able to climb
initially to an altitude 2,000-4,000 ft. higher than rhe 600 ar comparable fuel and passenger payloads.
The N1 was set at"84.40/o
to approximate along-range cruise setting.
At that power setting, the 601's speed was Mach 0.70, and the fuel flow
was 710 lb./hr./enqine. Canadat has discovered that the difference between fuel flows from Mach 0.69 to 0.74 is small, so now the company
is advocating the higher Mach number for long-range cruise.
Maximum cruise thrust was set at 93.2o/oNr by Adkins. The internal turbine temperature at that power setting was 805C. The fact that
the temperature limit of B38C was not reached at that power setting
allows for growth in thrust or longer engine life, Adkins said.
Cruise speed
A cruise speed of Mach 0.80 was attained at the 93.2o/osetting. Fuel flow
was 980 lb./hr./engine. The pressure differential of B.B psi. provided a
6,800-ft. cabin altitude at 4I,000 ft. \fhile still at this altitude, a wingover
cr-601
127
was made to the opposite direction to stay within Canadat's operational
test area. Elevator and aileron control at this altitude was excellent. The
stability and control performance of both aircraft are identical.
A descent was made through 30,000 ft. at the aircraft's certificated
maximum Mach number of 0.85 and slightly beyond. There was no
buffet or any appreciable increase in the noise level in the cockpit at
the higher speeds. \Tithout the normal soundproofing and an interior
in the prototype, the sound levels coming from the cabin were higher
than would be found in an arcraft in corporate configuration.
The spoilers were deployed to their maximum extension while the
aircraft was still at the maximum Mach. There was little buffet or pitch
attitude change. Spoilers were retained until reaching 16,000 ft. The
flaps were extended to the 20-deg. position and the power was set to
give a l-kt/sec, decrease in speed. The stick shaker in the 601 activated
at 105 kt., and the stick pusher activated at 100 kt. with 80 lb. of force,
Stall recovery
Another stall was attempted with the landing gear extended and the
flaps set at their 45-deg.landing position. The shaker was hearcl ancl
felt at 95 kt. and the stick pusher forced the nose of the aircraft over
at 92 kt. Both approaches to stalls were straightforward with elevator
and aileron control avarlable throughout the approach and recovery.
Adkins demonstrated the response of the CF34 engines at the
higher altitudes and at 16,000 ft. by retarding and advancing the fuel
controls rapidly. In all instances, the engines responded quickly without any indication of a stall. During the flight testing of the two 601
Challengers, the CF34 engines were never removed frotn the aircraft,
even after undergoing hard usage during stalls and testing of the automatic power reserve system, Adkins said.
One turbine module was removed from one engine as a precatltionary measure when it was thought there could be some damage
following a small tailpipe fire. There was no damage found in the engine. A total of 448 hr. was accumulated in the flight testing program
prior to certification.
En route to Mirabel Airport at 6,000 ft. and 240 kt., the fuel flow
of the Challenger 601 was 900 lb./hr./engine. An instrument landing
system approach was made at Mirabel with a touch-and-go landing.
The landing was routine except for my flaring slightly high initially
and then searching for the runway. Both the landing at Mirabel and
the full-stop landing at Cartierville were smooth. The Challenger gives
the impression of a heavier aircraft than it is upon touchdown.
The Challenger 601 prototype was stopped within 3,000 ft. by the
use of the spoilers and moderate pressure on the brakes. The aircraft
has an antiskid system, but the limited brake pressure ttsed on land-
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Jets
Interior dimensions of tbe Cballenger 6oo and 6o1 are identical.
Canadair estimatestbat a customer ulill spend an additional $ 1.i-l.7
million beyond tbe cost c,f tbe aircra.ft tct instcrll an interior ctncl a clual
long-range nattigation sltstem. Maximum passenger capacity of tbe
cballenger is 19, bnt most cotporate aircra.ft purcbased are bauing
nine-ten-passenger interiors installed.
ing did not activate the system. The landing clistance of the aircraft at
its maximum 36,000-lb. landing weight is 3.950 ft.
A total of 3,000 lb. of fuel was consLuned during the 1.9 hr. from
start of the auxiliary power unit to engine shutdown. Total flight time,
including the two landings, was 1.3 hr.
There are only two other systems yet to be certificated on the
challenger 601, and those are planned by canadair to be completed
after type certification. The aircraft's thrust reversers are scheduled for
certification next rnonth and the wing anti-ice system certification is
planned for Augr-rst.
Canaclair is building both rnodels of the Challenger at a rate of
three per month and plans to continue this fcrr the rest of 1983. pacing the challenger 600 production schedule is the lack of Avco Lycoming ALF502L engines. Avco is behind schedule in delivery ro
Canadair's facility here. The shortage has requirecl Canaclat to switch
cL-601
129
engines from aircraft to aircraft as they undergo testing and clelivery
to completion centers.
A total of 27 Challenger 601s are .scheduleclfor delivery in 1983,
while Canadair estimates that it will deliver 72-74 Challenger 600s
dr-rringthe year. Some of thc>se600 dehveries will come frorn the for-rr
aircraft held in inventory. The company als<>estimates that there are
five or six Challengers for sale by other than Canadair.
The price differential of approximately $1.7 million between rhe
cost of the Avco-powered Challenger 600 and the higher priced Challenger 601 has led Canadair officials to believe there will be a market
for both aircraft for some time. The price of the Challenger 600 is $8.5
million with an escalation clause, while the 601 is priced at $10.2 million. Interior and long-range navigation installation costs add $ 1.5-1.7
million to the Challenger, Canadair officials saicl.
Canadair redesigns Challenger flap vane
twashingten-[2nadair
is redesigning a vane in front of the challenger's double-slotted flaps following an incident in Canacla resulting in airworthiness directives issuecl by the Canadian Transportation
Dept. and the Federal Aviation Administration.
The incident involving a Transport Canada Challenger occurrecl
on Mar. 31 while the aircraft was making an approach to ottawa Airport. A failure of an inboard flap vane support beam assembly
caused the corporate jet to bank 70 cleg. before being brought uncler control. The atrcraft was lanclecl with the flap.s retractecl without
further inciclent.
An investigation of the incident by Canaclian officials found that
the vane assembly had failed, and inspections of other Challengers
revealed some vane assemblies with cracks.
The FAA's emergency airworthiness directive requires inspection
of the vane assembly after reaching 150 hr. of flight, and every 50. hr.
thereafter, unless cracks are found, and then the assemblies are to be
replaced. Canadair expects to issue the redesigned vane assemblies
within the next two months.
CHALLENGER 601, 600 SPECIFICATIONS
60L
POWERPIA,NT
Two General Electric CF34-1AS turbofan engines rared ar 8,650-lb.thrust each at takeoff. An automatic power reserve feature boosts the
takeoff thrust to 9.740 lb. for one engine operation.
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130
Jets
\vEIGHTS
Maximum ramp weight
Maximum takeoff weight
Maximum landing weight
Maximum zero ftrel weight
Typical operating weight empty
Maximum fuel load
Outfitting allowance
Maximum payload
Payload with full fuel
4 2 , 2 5 0 I b (. 1 9 , 1 6 5k g . )
42,100lb. (19,097kg.)
36,000Ib. (16,330kg.)
31,000lb. (14,062kg.)
24,525lb (11,L25kg.)
75,725Ib.(7,586kg.)
4,700Ib.(1,860kg.)
6,475lb. (2,937kg.)
1,000lb. G54 ke.)
PERFORMANCE
Range with five passengers at Mach
0.74long-range cruise, no wind.
NBAA instrument flight reseryes
Range with five passengers at Mach
0.77, no wind. NBAA instrument
flight reserves
Balanced field length at maximum
takeoff weight
Landing distance, sea level at 36,000 lb.
3,500naut. mi. (6,482km.)
3,320naut.mi. ( 6,149km.)
5.150ft. (1,570meters)
3,950ft. (1,204meters)
NOISE LE\rEI^s
Takeoff
Approach
Sideline
BO.3EPNdb.
s9.9 EPNdb.
86.0 EPNdb.
DIMENSIONS
Wing span
Length
Height
\Wing area
Cabin length excluding cockpit
Cabin height
Cabin width
Cabin volume
54.3 ft. (19.61meters)
68.5 ft. (20.85meters)
20.8 ft. 6.30 meters)
450 sq. ft.
28.3 ft. (8.61 meters)
6.7 ft. (1.85merers)
7.2 ft. (2.78meters)
1 , 1 5 0c u . f t .
600
POW'ERPIA,NT
Two Avco Lycoming ALF502L-2 turbofan engines rated at 7,500-lb.thrust each at takeoff.
131
cL-601
WEIGHTS
Maximum ramp weight
Maximum takeoff weight
Maximum landing weight
Maximum zero fuel weight
Typical operating weight empty
Maximum fuel load
Outfitting allowance
Maximum payload
Payload with full fuel
47,250Ib.(18,711kg.)
47,100lb. (1.8,643
kg.)
(16,329
lb.
kg.)
36,000
(L4,062
lb.
kg;)
31,000
(
1
0
,
5
1
0
23,t70Ib
kg.)
14,900Ib. (6,759kg.)
4J00lb. (1,860kg.)
7,830Ib. (3,552kg.)
3,180lb. (1,442kg.)
PERFORMANCE
Range with five passengers at Mach
0.74long-ranfle cruise, no wind.
NBAA instrument flight reserves
Range with five passengers at Mach
0.77, no wind. NBAA instrument
flight reserves
Balanced field length at maximum
takeoff weight
Landing distance, sea level at 36,000 lb.
3,900 ft. (1,189meters)
NOISE LEVEIS
Takeoff
Approach
Sideline
84 EPNdb
91.5EPNdb.
87.2 EPNdb.
2,800 naut. mi. (5,188 km.)
2,625 naut. mi. (4,861 km.)
5,700 ft. (1,737meters)
DIMENSIONS
67.9ft. (18.85merers)
\X/ing span
68.5 ft. (20.85meters)
Length
20.8 ft. (6.30 meters)
Height
tVing area
450 sq. ft.
28.3 ft. (8.61 meters)
Cabin length excluding cockpit
6.1 ft. (1.85meters)
Cabin height
Cabin width
7.2 ft. (Z.B meters)
1 , 1 5 0c u . f t .
Cabin volume
Veight and performance figures for the Challenger 600 are based on the
maximum ramp weight of 47,250Lb. to be certified within the next few
months. The 600 figures do not include the fuselage ftlel tank installed
in the 601. \7ith the optional fuselage fuel tank, the 600 has a usable fuel
capacity of 76,725Ib. and a maximum payload with full fuel of 1,055 lb.
Range of the 600 with the additional fuel tank is 3,150 naut. mi.