XLent

Cessna delivered 372 of its impressive Excel, our subject aircraft, before switching production to the upgraded XLS in 2004, the main change being the more powerful (3990lb thrust) PW545B engines, plus upgrades to the cabin and cockpit. The further improved XLS+ was announced at the 2006 NBAA convention with deliveries due from late 2008. It “

It decreases total journey time by sprinting to high altitude and being able to operate in and out of short runways.

” will be fitted with FADEC equipped PW545C engines, a Collins Pro-Line 21 avionics suite, and further revisions to the flightdeck and cabin interior.

But even with its 3804lb thrust PW545As the original Excel is impressive. From sea level in ISA the Excel will lift up to 12 occupants off a mere 4000ft runway and fly them at 425kt over still-air stage lengths of up to 1200nm. Alternatively it will carry four executives in great comfort over 2000nm from the same small airport. Naturally, like all the other Citations, it is also a delight to fly.

While admittedly not cruising quite as fast as some of its competitors, the aircraft more than makes up for this. The roomy cabin ensures its occupants arrive un-ruffled, having travelled in comfort and style.

There will always be a market for the fastest executive jet, or the biggest, or the one with the longest range, or possibly even the least expensive, but the top seller is likely to be the model offering the best combination of all these features. Consider this: the US$11. 5m Citation XLS cruises just eighty per cent as fast as the world’s quickest bizjet (its Citation X stablemate), and may fly but 60 per cent ofits range, but it is nearly as big inside, and costs less than half the price. Put another way, for two-and-a-half times the price, you could fly the same number of people a mere 25 per cent faster. No wonder its customers deemed the Excel great value.

The Excel’s wing came from the Citation V series, retaining its trusty NACA 2300 aerofoil, but with a 1. 1m increase in span. Its aerodynamics are assisted by a swept inboard leadingedge cuff, large radius leading-edges, mid-span fences, a long line of upper surface vortex generators and a row of pyramid like boundary energisers which look like small stall strips along the leading-edge ahead of the ailerons.

The whole trailing edge is taken up with the graphite composite single-slotted Fowler flaps on their titanium tracks and the aluminium ailerons. There are speed-brakes on both upper and lower wing surfaces.

The old pneumatic wing de-icing boots have been replaced by bleed air anti-ice. Boots are retained only on the horizontal stabilisers which, like the rest of the tail, again came from the Citation V line. They are supplemented by a pair of splayed ventral strakes which improve C of G tolerance and help induce a nose-down pitch in the stall. The elevators incorporate normal trim tabs, but there is also an auto-trim system which motors the stabilisers’ leading edges downwards when the flaps are extended.

This reduces cruise trim drag while retaining good low-speed elevator authority, so dispatch is prohibited if this system is unserviceable.

The circular widebody fuselage is immediately recognisable as coming from the III, VI or VII, although Cessna prefers to say it is derived from the Citation X, but shortened by 1. 2 metres. Sitting on a centre-section saddle, the cabin has no intrusive, aisle-obstructing spar. Like the wing, I noticed the fuselage exhibited a surprising number of external lumps and bumps in the form of various avionics antennae and three pitot heads and static ports each side. Nevertheless, the aerodynamics must benefit from a large and carefully contoured wing-to-body fairing of apparent Cessna 650 (III/VI/VII) heritage, as is the trailing-link main gear, which has but one wheel per side and still lacks wheel doors, but now sports carbon brakes.

The PW545As give the Excel a great thrustto- weight ratio and good economy. Cessna quoted a NBAA IFR range of 1585nm with eight occupants. Each engine is controlled by a single-channel EEC, using throttle detents at takeoff, climb and cruise (with a mechanical get-you-home back-up) and fitted with targettype Nordam thrust reversers and bleed air anti-ice. A fluted exhaust mixer nozzle reduces noise emissions.

Purchase price and maintenance costs benefited by using mainly the simple, reliable systems from the Citation 500 family. The flying controls remain manual, with an aileron-rudder interconnect to satisfy FAA yaw/roll stability requirements. The flaps, speed-brakes, two-position horizontal stabiliser, thrust reversers and landing gear are standard Citation hydraulic, powered by 1500psi engine-driven pumps, and with manual and pneumatic up-lock releases for alternate gear extension. Braking is also hydraulic, but using a separate system, also with a pneumatic back-up; anti-skid is standard.

Fuel is carried in each wing (and only in the wings) and its supply is fully automatic, using jet pumps, with electric boost pumps and cross-feeds. Anti-icing additive is not needed, thanks to the fuel-heating oil coolers. Two engine-driven 300 amp starter/generators feed the 28-volt DC electrics and NiCad battery.

Pressurisation is by engine bleed air to give sea level cabin pressure to FL 250 and a 6800ft cabin altitude at FL 450. An air cycle machine provides separate air conditioning for the cockpit and cabin, with a refrigerative supplemental system for use on the ground and up to 18,000ft.

Much thought went into ground handling.

No ladders are needed for the pre-flight inspection, since the oil level indicators and fillers are in the lower nacelles and the hydraulics are behind the wing. All other systems are either conveniently situated behind panels in the wing-to-body fairing or easily accessed within the roomy tailcone. The quick-disconnect battery hides behind a panel ahead of the baggage compartment. Single-point pressure refuelling fills both tanks in just eight to 10 minutes, and careful positioning of the other services allows the operator simultaneously to dump the lavatory, plug in or remove external power, load the bags and board the passengers, all while the optional Honeywell APU keeps the cabin cool. Located above and behind the right engine, this can be started in flight at up to 20,000ft and used for both pneumatics and electrics up to 30,000ft – very useful attributes for trans-ocean flying.

The nose holds the radar and other avionics, which are accessible through a pair of large

I had to yank the throttles further back to prevent streaking through our cleared altitude of 3000ft. Oh boy, Excel pilots must love this!

upward-hinging doors. A big, carpeted 2. 35m3 baggage compartment under the left engine takes up to 317kg, is long enough for skis or golf clubs, and is said to have good C of G tolerance.

Unfortunately it is un-pressurised and un-heated, so hello exploding toiletries, but its 63cm wide drop-down door has useful steps inside.

The counter-balanced three-step passenger air-stair has no weight limit and is easily raised and lowered using the lever’s mechanical advantage. The door has a dual-action catch and locking pins, and is fitted with three seals: active, passive and acoustic. A plug-type emergency exit is on the right of the rear fuselage, accessible from within the toilet.

Unfortunately fog, ATC slot delays and restricted airspace combined to limit my time with the Excel, but I saw enough to convince me of its appeal.

Stepping into the cockpit reveals a clear, uncluttered flightdeck that is immediately recognisable as a Citation, and deliberately similar in layout to all the other family members. Although basically a modernised 500-series aircraft, the Excel has a 650 cockpit, and so requires a new type rating. The wide glass windscreens are electrically heated, and coated with rain repellent supplemented by air blast from the avionics bay’s cooling fan.

Both side windows can be opened. The pilots’ seats are very comfortable, with five-point inertia-reel harnesses. They are adjustable fore-and-aft, vertically and for tilt, and the rudder pedals can be moved fore-and-aft.

The ordered panel is dominated by the three 20 by 17cm CRTs (two PFDs and a MFD) of the standard Honeywell Primus 1000 EFIS. These are fed by three ADCs and triple AHRS and a single Integrated Avionics Computer (IAC) with twin Radio Management Units (RMUs). A digital AP/FD is standard, with all the usual modes and functions, including a Cat II ILS flight-director approach capability. A Meggitt multi-function EFIS standby instrument acts as back-up. The centre console FMS has a colour CDU, and incorporates position updating by GPS, double DME or VOR/DME. Vnav and GPS approaches are possible where approved. The avionics include dual VHF navcoms, dual mode S transponders, single ADF, TCAS, EGPWS, CVR, ELT, Primus 880 colour weather radar and radio altimeter.

Abbreviations over, the centre panel has two boxes of strip engine instruments (not my favourite since they are less easy to interpret at a glance than circular dials, something airliner makers learned some time ago). Above them in the glareshield is a large 42-light annunciator panel. The EFIS and audio controls are outboard, the electrics are on the far left and the controls for pressurisation, air conditioning and anti-ice are ahead of the throttles. There are circuit-breaker panels on the sidewalls, and nothing overhead, another admirable Citation tradition. The landing gear and flap levers are to the right of the centre console.

To start you just press a button, lift the thrust lever latch, move it to the first detent at 10 per cent rpm and watch the dials. Each engine took 20 seconds to start. With so much power, the aeroplane moves off as soon as the brakes are released, and I found it hard not to ride the brakes to keep our speed in check.

Typically of carbon units, these had a tiny tendency to grab, and the pedals exhibited a little lost motion. The nosewheel is steered through a 20 degree arc by the rudder pedals via ‘bungee’ springs.

Control was easy enough, but with a slight lag, and helped by a dab of differential brake or a puff of asymmetric thrust. The suspension was a significant improvement on the Citation V family, which will be noticeable to all occupants.

The Excel’s takeoff performance is impressive.

In ISA at sea level it will clear a 10m obstacle at top weight in just 1094m.

Most sea level runways are at least 1200m long, so the Excel can use them all. Even more important, at the same weight, but in hot-and-high conditions of 25oC at 5000ft it will do so in a mere 1759m.

Sea level max-weight climb is a sparkling 3790ft/min, even beating the Citation X. We flew with five occupants and 2100kg of fuel, bringing our weight to a representative 8000kg. Using the normal low altitude setting of 15 degrees of flap, and with an OAT of 15oC, a pressure of 1024 HPa and a 10kt headwind, the EECs calculated and set power to 88. 1 per cent N1 rpm. I pushed the throttles forward the three clicks to that setting and we leapt forward. Our takeoff was so rapid I only had time to note in retrospect ‘acceleration: v sprightly, pull force: not much, takeoff: v quick!’ I rotated at 106kt for a 118kt V2, easing the nose 17 degrees above the horizon. Demo pilot Steve Workman whipped up our wheels and flaps (without any noticeable trim change), and I pulled back the throttles a click to climb power as I struggled to hold our speed under control at 140kt.

A startled glance at the VSI revealed a whopping 3300ft/min before I had to yank the throttles further back to prevent streaking through our cleared altitude of 3000ft. Oh boy, Excel pilots must love this! Later I witnessed the lightly loaded Excel’s fighter-like departure for another sortie. It broke ground in under 600m and soared skywards in a 30 degree climb that would not have been out of place at an air display. It must have been 1000ft high by the airfield boundary, and yet it was almost unnoticeably quiet, and within a few seconds completely inaudible.

Neighbours must love this aeroplane too! The normal climb speed is 250kt, transitioning to Mach . 62, but speed is restricted to 260kt below 8000ft for bird protection, the Vmo increasing to 305kt thereafter. Cessna says the Excel will climb all the way to FL 430 from sea level in 22 mins at MTOW. More representatively, it will reach FL 330 in just 12 minutes. Single-engine performance is splendid too: the book quotes an engine-out service ceiling of 28,600ft at top weight. Disengaging the yaw damper and pulling the right throttle back to idle as we passed 13,000ft, we still climbed at a healthy 950ft/min at 230kt. The rudder pedal pressure was initially quite heavy, but easily trimmed out.

As our speed increased I noticed the electric elevator trim was not quite as quick as I should have liked, and I still find those distinctive squared Citation yokes a little uncomfortable to grasp for any length of time, but these are small quibbles about what was otherwise a delightful aeroplane. Overall control at all altitudes was Citation-great, predictable and safe, the aircraft feeling completely natural and easy to handle, although it needs a firm pull on the stick at over 45 degrees of bank. Visibility is also good, although of course not quite as panoramic as in the smaller 500 series.

With limited time we were constrained to just FL 250 for a brief cruise segment, at which uneconomical level we burned 935kg of fuel per hour for a 426kt TAS.

A more representative cruise would be at FL 430 where, at . 73 Mach we would have burned just 520kg of fuel per hour for a TAS of 408kt. Long range cruise at the same level would be at 365kt for 420kg per hour.

The normal descent profile at idle power loses the usual 300 feet per mile, so from FL 450 in still air it takes 140nm and 22. 5 minutes to reach sea level. At high speed these figures can be reduced to 93nm and 15 minutes, and the speedbrakes help even more. Their switch is to left of the centre console, protected by a small steel hoop, and they are either in or fully out. Extension causes a lurch, a nose-down pitch and a noticeable rumble, but produces significant deceleration and a very useful increase in descent rate.

Cracking open either throttle automatically retracts them. Using them briefly to aid our descent we seemed to be pointing 20 degrees nose-down to hold 250kt.

Slowing to 150kt at 15,000ft, I closed the throttles in preparation for a clean stall. At 105kt in good airframe buffet, the dual stick shakers started to vibrate, followed by the yoke becoming lighter.

Then the nose nodded forward at 102kt, accompanied by a 15 degree left wing drop. As I eased the back-pressure, Steve selected the flaps to 15 (standard stall recovery procedure) and I shoved the throttles forward. We lost barely 200ft before promptly regaining 15,000 with a great long speed trend vector zipping up the ASI.

The flap selector has detents at seven, 15, and 35 degrees. They run quite quickly, and extension causes a nosedown pitch, but then that automatic tailplane trim takes 22 seconds to react, so there is an odd change in feel as the aircraft pitches up again, but you soon get used to it. With gear down and full flap we got much less buffet before the stick shake at 95kt. After another lightening of the back pressure, we again saw a pitch-down and a 20 degree left wing drop at 90kt, with a slightly greater 300ft height loss during the recovery.

CITATION EXCEL

(Technical specs)
Powerplant
Two Pratt & Whitney
Canada PW545A 4:1
bypass ratio turbofans,
each rated at 3804lb
sea-level thrust. TBO 5000
hours with 2500 hour HSI.
Honeywell RE 100 (XL)
APU.
Performance
(Manufacturer’s stated)
Maximum cruise (FL 330)
431kt
Max range (VFR, 45min
reserve) 2080nm
Stall (full flap) 93kt
S/L climb 3790ft/min
Max altitude FL 450
Single-engine SL climb
850ft/min
Single-engine service ceiling
28,600ft
Take-off distance (FAR 25)
1094m
Landing distance 969m
Weights
(test aircraft)
Equipped empty 5562kg
Max takeoff 9072kg
Max landing 8482kg
Max zero fuel weight
6804kg
Useful load (over crew)
3328kg
Useable fuel 3080kg
Maximum payload 1060kg
Full fuel payload 248kg
Baggage 317kg/ 2.35m3
Dimensions
Length 15.79m
Height 5.24m
Wing span 17.0m
Wing area 34.3m2
Cabin length (inc toilet)
7.0m
Cabin width (max) 174cm
Cabin height (at aisle)
177cm

Our Vref at 7720kg was 112kt, giving us a comfortably low 118kt approachspeed. Despite being radar vectored into the circuit with a 250kt dive on to the downwind leg I quickly got stabilised without using the speed brakes. The undercarriage can be dropped below 250kt (taking six seconds, and with no noticeable trim change) and flap seven or 15 may be extended at 200kt to get things further under control. Taking full flap at its 175kt limit as I swung around base leg, we quickly reduced towards our 120kt approach speed so I spooled up the fast responding fans. It was easy thereafter to peg the speed at 120kt all down final using 45 to 50 per cent N1 rpm, despite the bumps and gusts of a 20kt wind.

Simultaneously closing the throttles as we crossed the threshold and easing the light stick back to flare by just two or three degrees, I misjudged our height and managed to float for 500m but, thanks to that excellent soft main undercarriage, eventually made a gentle touchdown. Steve extended the speed-brakes and, using full reverse as soon as the nosewheel was on the ground and gentle braking later, we rolled to a halt in under half the 2080 metre runway. Reverse thrust induced some tail rumble at the lower speeds. The Flight Manual quotes an ISA sea-level landing distance at the 8480kg maximum landing weight of a mere 969m, which is almost STOL performance for a jet, and very close to the capabilities of its four smaller siblings.

Shutting down after our brief flight, the fuel remaining was 1640kg, so we had burned just 460kg in 40 minutes. Steve told me the demo pilots plan on using 1350kg in the first two hours, and 500kg per hour at FL 410 thereafter.

Inside, the spacious cabin is a constant 174cm across, and nearly 7m long. The 33cm wide dropped aisle gives 177cm headroom, and the floor either side of the unobstructed aisle has also been lowered by 9cm, to give occupants a little more shoulder space. The testexample had eight seats, laid out as a central club quartet, with a forward-facing pair at the rear and a sideways double bench opposite the door. An additional unit can be fitted in place of the toilet, where there is already a window each side, up to 10 cabin seats are available in a high density layout, and the configuration can be changed relatively quickly.

The seats are impressively comfortable, well stuffed, upholstered in champagne hide and fitted with lap/diagonal harnesses. They swivel up to 180o, recline to the horizontal, and track 17 cm fore-and-aft and up to 8cm inboard.

Between them were four tables, two big ones forward and two smaller ones aft. The 11 elliptical triple-pane windows have lever-operated internal accordion blinds, and the interior is extremely quiet in flight.

The full-width toilet is spacious enough to change your clothes in. Stowage space includes a hanging coat closet on the rear wall, a big cupboard with a shelf that can be removed to provide more hanging space, and a little drop-down flap compartment containing moist hand wipes. This can be replaced by a sink if required. There is also a wardrobe at the front of the cabin, opposite the door, above which are the CD player and DVD player, with storage space for CDs and DVDs. Ahead of the door on the left is the large and beautifully veneered refreshment centre. The interior finish is of a high standard, with superb cabinetry and warm wood colours.

Cessna’s marketeers called the Excel “the world’s only light jet with a stand-up cabin. ” For not much more than a narrow-bodied Bravo or Ultra Encore, the Excel/XLS owner gets a significantly bigger, more comfortable aeroplane, and one that exudes real presence on the tarmac. No wonder the 500th Excel/ XLS was delivered in 2006, just eight years after deliveries began. It’s proven to be a real winner.