Citation XLS+

The fact that Cessna has been building aeroplanes for over 80 years definitely has its advantages. Beyond the credibility that often comes with age, there is a genuine sense of how to go about the job. Through the passage of time and customer feedback, manufacturers can gain a better grasp of what actually works well in their aeroplanes. This is no more evident than in the Cessna Citation range.

Cessna have been building business jets since 1968 and in that time have grown from the original six passenger Citation to true inter-continental machines cruising at Mach 0.92. Along the way they have identified a spectrum of requirements in the marketplace and consequently developed an entire range of jets. These span from the small single-pilot Mustang, right through to the impressive ‘Citation X’ and most importantly, all levels in between.

It is this heritage that has given life to the Citation XLS+. The aircraft boasts the large stand-up cabin of the top of the range, but holds onto the simplicity of those jets that sit in their lighter Citation range. The resulting XLS+ is an aircraft that offers the big cabin luxury at a more affordable price and while it may not nudge the speed of sound like the ‘X’, it has an equally impressive set of performance figures that offer true versatility.

The Look.

My first glimpse of the Citation XLS+ came at some distance, through the glass walls of the passenger lounge at Canberra Airport. Immediately, the aircraft gave a real sense of size that caught me off guard. Having flown the ‘Citation X’, I had preconceived that the XLS+ would have the presence of an aircraft sitting a little further down the Citation range; but I was wrong. In profile, the XLS+ is far more closely related to its bigger brothers with its commanding fuselage and sleeker nose-cone. This looks the part of a big bizjet and in the corporate world, first impressions count.

It is only on closer examination that the hybrid nature of the XLS+ becomes evident. Attached to the commanding cabin is the empennage of the C560 and the straighter wing of the Cessna light jet range. This meeting of design features is seamless and balanced and combines to create a genuinely individual aeroplane.

Walking around the aircraft at close quarters, Cessna’s heritage and know-how becomes immediately apparent through a number of tell-tale features. Fundamentally, the fuselage is that of the ‘Citation X’. It shares the same strong air-stair combination that is both light to operate and sealed through multiple means to both pressurise and minimise cabin noise levels. The faired lower fuselage also does more than simply differentiate the larger Citations from the more tubular fuselage of their lighter jets. Beyond its aerodynamic considerations, the faired fuselage provides an easy means to run systems, cables and hoses along the aircraft without challenging the integrity of the pressure cell that constitutes the cabin. Aft of the wing, as the form blends into the tail-cone, this space facilitates a large door and 80 cubic feet of baggage space including a coat rack.

At the other end of the aircraft, the nose of the XLS+ is aesthetically sharper than the lights jets and functionally is home to the aircraft’s avionics and computing capacity. The cockpit windows are electrically heated and cleverly possess a cross-over arrangement to allow the continued heating of both front windows in the event of a single generator loss. The side windows are also able to be opened on the ground to allow those last minute items and paperwork to be handed up to the aircraft once the door has closed. These are simple features that can make the job that bit easier.

Simplicity is a frequently used term when describing the XLS+ and additionally flows onto the big ticket items, such as the undercarriage and wings. The nose gear utilises a chined tyre for water and slush deflection, with the main wheels boasting a trailing arm undercarriage that offers every opportunity for the pilot to land this aircraft smoothly. Electrically controlled, but hydraulically actuated, the undercarriage is depressurised in the up position and held in place by mechanical uplocks. In the event of an emergency, the gear can be extended by hydraulic or mechanical means with the further back-up of a ‘blow down’ system. You would really be having a bad day not to get the gear extended on this aeroplane!

The straight wing design is familiar to the Citation family. Incorporating a more highly swept leading edge at the inboard section, it is a wing that has an Mmo of Mach 0.75, a stall speed of 90 knots and the ability to fly slow enough to land in under 1,000m at maximum landing weight. In addition to the wing’s shape, this speed range and performance is facilitated by graphite-composite trailing edge Fowler flaps. The flaps extend to 35 degrees for landing and have a limiting initial extension speed of 200 knots, so combined with effective speedbrakes; this aeroplane is a breeze to slow down. The leading edges are protected against icing by hot bleed air from the engine which, in the case of engine-out operations, automatically ‘crossfeeds’ to the affected side. The wings also house integral fuel tanks which hold up to 3,057kg of jet fuel. The XLS+ can be pressure refuelled through a single point forward of the wing, although traditional fuel caps are available for overwing fuelling should a particular port of call require the old style hose.

The aft end of the XLS+ in many ways typifies what the aircraft is about; efficiency. On the starboard side is an inspection port which allows crews and engineers to easily stand up inside the rear fuselage for inspection and maintenance purposes. Similarly, everything that needs to be inspected on the two Pratt & Whitney engines can be done so without a ladder as caps and indicators are all comfortably at eye height. The rear-mounted PW545C engines produce over 4,000lb of thrust each and feature FADEC to optimise both the efficiency and ease of engine operation.

The tail section is a tried and trusted design with a reasonably swept fin and 9 degrees of dihedral on the horizontal stabiliser. The horizontal stabiliser has two position settings; take-off/landing and cruise. This is automatically adjusted without pilot input as a function of flap setting and airspeed in an effort to counter pitch changes associated with configuring the aircraft. Below the fuselage at the rear are two small strakes which serve to extend the useable Centre of Gravity range of the aeroplane. Like the ailerons, the rudder and elevator are actuated by a pushrod and cable system. It is a simple system that keeps maintenance at a minimum and undoubtedly contributes to the aircraft’s dispatch reliability. Even though this aircraft can operate at nearly three-quarters of the speed of sound, it possesses a simple, functional design philosophy.

Another great feature housed in the tail section is the Auxiliary Power Unit, which is certified for operations up to 30,000 feet. The corporate world of the XLS+ does not always mean that ports of call are major destinations and consequently, full ground services are not always available. The APU provides a level of autonomy in cabin air conditioning, electrical power and engine starting when away from base. Furthermore, the APU can be used to supplement the bleed air system to condition the cabin airborne, hence not detracting from the engines’ output.

On the ground, the XLS+ is a ‘4 point aeroplane’. Without any additional equipment such as ladders or stairs, the XLS+ can receive people, baggage, fuel and servicing with consummate ease. Its appearance speaks of flair, but at its heart is proven functionality. With so much to impress an onlooker, it was time to observe its potential in the sky.

From the Ground Up.

Entering the XLS+, the cabin height is immediately apparent. This aircraft bridges the light jet gap by offering a spacious ‘stand up’ cabin. While internally the cabin is 5 feet shorter than the ‘Citation X’, it possesses the same width and height as its top-of-the-range sibling. Functionally, sharing the same cabin with the ‘Citation X’ also means that the cabin is built to 51,000’ standards but the XLS+ is only certified to 45,000’. The result is a lower operating cabin differential within the XLS+.

Potentially the XLS+ can carry 2 crew and 12 passengers, although the luxurious cabin layout is more likely to be found hosting 6 to 8 passengers. The new seats are slightly wider and very comfortable, while all of the other cabin appointments are in keeping with the highest standards of finish. As impressive as this classy cabin may be, it is the cockpit that has gone a long way towards putting the ‘plus’ in XLS+. Specifically, the inclusion of the Collins Pro Line 21 avionics suite and the FADEC controlled engines.

Easing into the left hand seat, the correct seating position is found very easily and feels very natural. The outlook is higher than traditional light jets, while within the cockpit four 8 x 10 LCD screens dominate the panel. The entire layout is very clean, from the centre pedestal and thrust lever quadrant, past the two CDUs, central standby instruments and onto the expansive instrument panel and upper mode control panel (MCP).

Everything about the layout is in keeping with the clean, efficient philosophy of this aeroplane and carries through to a start procedure that is as simple as they come. Following adequate rotation and airflow through the engine, fuel is introduced by lifting the thrust levers out of ‘Cut Off’ and up to the idle detent. From there, the pilot’s job is to monitor the engine as FADEC goes about its work. Following engine start, the Collins avionics are brought to life in a large, crystal clear display of colours and fonts. There seems to be limitless options available in the displays with all manner of flight, engine, navigation and communication at the fingertips.

To my right sits Cessna Flight Supervisor, Mike Walton and between us we decide upon the displays, flight director bars and Jeppesen charts that will colour our screens. Through the CDUs we enter the performance data for today’s flight and it in turn generates our critical speeds. The Jeppesen charts are particularly useful for the world-travelling corporate pilot as they are not only projected clearly on the LCD, but show the aircraft’s current location. And for those late nights and weary eyes, you can even ‘zoom in’ on the chart. Choices, choices…

With clearance from Canberra Ground we move off from the Fairbairn hardstand. The thrust levers are very well positioned in terms of comfort and have a substantial, yet sporty, feel to them. There is no tiller, so ground steering is through the direct-linkage rudder pedals and asymmetric thrust as needed. The XLS+ is very easy to manoeuvre on the ground by virtue of this and complemented by the toe-actuated carbon brakes. A tight turning radius and 17 metre wingspan means that the aircraft will be at home on smaller aprons relatively narrow runways. However, today we are lining up on the grand width of Canberra’s runway 35 with flaps set at 15 degrees.

We are at a mid-range weight of 18,500 lb today and in round figures V1 is 95 knots, rotate at 105 knots to achieve a V2 of 115 knots. Once cleared for take-off, advancing the thrust levers through the cruise and MCT detents to the take-off setting results in a pleasing push of acceleration in the lower back. The initial force to ‘unstick’ the nosewheel is a little heavier than usual, but once the nose has lifted the control forces feel very well balanced. Climbing out and cleaning up, the aircraft is very stable to fly and that translates into both a good IFR platform and a smooth ride for the valued customers in the cabin. The automatic change of the stabiliser position to cruise goes unnoticed, so it’s doing its job nicely in cancelling out pitch changes.

I hand fly a standard climb profile of 250KIAS/0.65M and the aeroplane is a joy to handle. Additionally, the flight information supplied by the large LCD screens is absolutely intuitive. It is the first time I have flown the Collins format, but my instrument scan has adapted in a matter of minutes due to the logical layout. Passing through FL200, I decide to let the automatics do some work while I sit back and absorb the scenery both inside and out. As we enter a 140 knot jet stream there is some turbulence associated with the transition, but the ride remains relatively smooth until we are established in the fast-moving air.

Without step climb, the jet flies straight to FL400 in 18 minutes. Levelled out, we accelerate to Mach 0.72 before reducing thrust and settling in the cruise where we have a True Air Speed of 425 knots and a fuel flow of 1270lb/hr. Mike pulls out the books and the aircraft is sitting right on the advertised numbers. Depending on the settings and configuration, this aircraft can cruise at up to 440 knots TAS or be tasked with a sector in excess of 1,800 nautical miles. Versatility is another feature of the XLS+.

Having whisked our way well towards Melbourne past the snow-capped mountains, we reluctantly decide to return to Canberra. During the turn, the automatics possess a ‘half bank’ function to avoid reducing margins in turns up in the thin air. With the arrival programmed through the CDUs, a vertical navigation (VNAV) profile is generated, so at the calculated top of descent the thrust levers are simply retarded for a 280 knot descent.

The aircraft sits very comfortably at this speed and ‘lumps’ out of the jet stream without undue discomfort. The deceleration below 10,000 feet is cued by the VNAV and we start to ready the aircraft to fly the ILS on Runway 35. Hand flying again, we start to configure for the approach. This time as flap is extended there is a slight pitch noted as the horizontal stabiliser changes position. It is not an issue and would be anticipated as second nature with only a few hours experience on the aeroplane I suspect.

The aircraft is very stable throughout the ILS and makes the pilot look good. With a Vref of 120 knots, it is easy to see how this aircraft benefits from its straight wing with impressive landing performance. Subtle thrust lever movements allow the speed to be maintained within a knot or two of the desired approach speed all the way down final. However, on this occasion we decide to execute a pre-arranged missed approach from the approach minima.

Pressing the TOGA buttons and advancing the thrust levers, the aircraft leaps back to the skies and flaps and gear are retracted in sequence. With a level-off of 1,500’ AGL approaching rapidly, it is obvious that ‘go-around’ thrust is no longer needed and throttling back, the aircraft is easily levelled off and brought to bear in a visual left hand circuit. The ‘go-around’ sequence all takes place quite quickly but without undue forces and pitch changes, so it is quite a manageable exercise.

The visual circuit was a lot of fun to fly over our nation’s capital and was of a lot of interest to my American counterpart. The aircraft itself made the experience very enjoyable as it handles with a big jet feel blended with a sportier responsiveness. Extending flap and gear presented no undue ballooning or sink and circuit altitude was managed without too much effort at all. As we rolled out on final and the threshold grew bigger in the window, the only disappointment was that this Air Test was nearly over. Over the fence, landing was very straightforward. I took care of the airspeed and minimal attitude change and the trailing arm undercarriage took care of the touchdown.

As we taxied back to the parking area, ably assisted by the Jeppesen display, I was hard pressed to wipe the grin off my face. This aeroplane felt so right in all phases of flight while the ergonomics and equipment made the job all too easy.

Simply Excellent.

Cessna have a winning combination here. A cabin that the passengers will love steered through the skies on a wing that offers tremendous mission flexibility. Efficient corporate flights aren’t always about pushing the speed of sound; they can be about bypassing hubs and the need for a change of aircraft to access a smaller airfield. The XLS+ offers a lot of straight line sectors direct to the desired destination and this ultimately equates to a saving in terms of time. Once there, it has a simple support philosophy that makes the aircraft truly independent.

Its simplicity of proven systems keeps the purchase price relatively affordable and the ongoing reliability predictable. These are both critical elements in the corporate world. For pilots, the aircraft is a pleasure to fly and equipped to the teeth with the latest in flight deck technology.

It is hard to overstate the simplicity, efficiency and versatility of this aeroplane. Simply put, the Cessna Citation XLS+ is simply excellent.

By Owen Zupp
July 2010