Cessna's Ultra has all of its family's virtues, and more.
Harry Hopkins/WICHITA
FLIGHT INTERNATIONAL, over the years, has flown several members of Cessna's family of straight-winged business jets, including the Citation II, IIS and V. The latest member of that family is the Ultra, a higher-powered, value-for-money, derivative of the Citation V. It incorporates as standard many of the most popular optional extras offered on that model, along with an improved electronic flight-instrumentation system (EFIS) and a myriad of detail improvements.
Single-point refueling had already been made standard on the Citation V this year (from airframe 307 on); now the vapour cycle cooling unit is standard, too.
The Ultra has the first application of the Honeywell Primus 1000 EFIS. Each Pratt & Whitney Canada JT15D-5D engine delivers 13.53kN (3,045lb) thrust to 27¡C; the -5A variant powering the Citation V delivering 12.89kN to 15¡C. The nose section is manufactured to a closer fit and better finish. Cockpit-voice recorders and in-flight telephones (Flitephone VI - two handsets) are standard, as are a radio-altimeter, dual altitude reporting and dual distance-measuring equipment (DME). A flight-data recorder is optional. The optional 5,540kg maximum zero-fuel weight is now available using the normal Vmo of 292kt (540km/h), without the previous 276kt restriction, after a little local wing strengthening.
CABIN LAYOUT
A typical layout for the 5.18m-long cabin is a club four with two forward-facing single seats behind. There is room for a seventh seat or second refreshment centre against the right cockpit bulkhead. The lavatory, behind sliding doors at the rear of the cabin, has a toilet unit, the top of which can be used as an extra seat. The seats have recline, sideways and 30°-swivel controls and retractable headrests, and there is a storage drawer underneath each seat. Regular options, such as a deep carpet from sunken aisle up the side panels, hardwood veneer and gold-plated metal fixtures, create a most agreeable atmosphere. Nose and aft baggage compartments provide 1.16m3 (41ft3) of space, and up to 390kg in weight. A further 0.74m3/270kg space can be fitted in lieu of the lavatory unit.
The cockpit bulkhead has been moved back just 75mm, but this makes a lot of difference to getting into the pilot's seat and gives noticeably better foot-room in flight. Cessna demonstration pilot Leroy Herrman and I went through the cockpit changes before start-up.
The simple, old-fashioned trim indicators - white pins running in slots - are retained. An angle-of-attack (alpha) indicator for the pilot and extra pilot/static sensors are standard.
The three 200 x 180mm EFIS displays are more exotic, and dominate the modest-sized cockpit. There are obvious similarities with the Primus 2000 system fitted to the Dornier 328 and similar displays will also be fitted to the Citation X. Appropriately, the three previous separate avionics units have been replaced by a dual-channel integrated avionics centre.
Each pilot has a comprehensive primary flight display (PFD) with attitude, airspeed, altitude, vertical speed and heading. The barometric setting control is neat - in the lower frame under the altitude tape. Engine data are separately displayed as vertical strips on three mechanical displays,
The central multi-function display (MFD) is used mainly for large-scale display of route and navigation data. An optional checklist display is available. Its controller, immediately behind the engine control's quadrant, and ahead of the control panel of the Global GNS-X/ES advanced navigation and flight-management unit, includes a joystick for cursor control. The Primus 650 (or optional 870) colour radar display can be overlaid on any of the three screens.
GLOBAL NAVIGATION
The Primus and Global, which incorporate both global positioning and Loran-C (Omega is an option), operate closely with the MFD. Navigation functions include DME/DME position calculation in the global-navigation system (GNS), Mode S responder capability and an emergency-location transmitter.
In the aircraft flown, six separate Collins navigation and communications frequency controllers, were grouped to the right of the MFD. A Primus II integrated radio tuning system, as fitted to the Dornier 328, is optional.
After a simple push-button start, the engines idled at 28.8%N1 (low-pressure rotor speed) 320/360¡C ITT (inter-turbine temperature), and 51% N2 (high-pressure rotor). Each was consuming 110kg/h. On moving off I used the useful switch, which reduces idle thrust on the ground for taxiing at lower weights.
As I steered the nose-wheel with the rudder pedals, the rudder/aileron coupling showed up in sympathetic movement of the control wheel. This device is used in several medium-sized business aircraft, to counter any adverse bank upon initiation of yaw.
The new digitally controlled brakes start operating at a light touch on the pedals, which do not release so much pressure in the anti-skid operation, which becomes effective at 12kt, so improving runway performance.
Hydraulically powered flap (less usual in lighter aircraft) was lowered to 15¡, while 7¡ flap can be used to improve the climb-out gradient after take-off from longer runways, with the penalty of a 4kt increase in take-off reference speeds. Reference speeds are selected using a knob at the left base of the MFD. Selection of cleared altitudes, is dialed in on the right knob - a neat arrangement.
TAKE-OFF
At 6,200kg, with 1,800kg fuel, the aircraft was 1,200kg below maximum take-off weight. Reference speeds were, decision speed (V1) 88kt, rotation speed (Vr) 93kt and safety speed (V2) 105kt. It took just 9s to reach 70kt and 11s to Vr. After 30s, flap was selected up at 145kt.
The airspeed tape on the PFD leads with a speed vector, showing speed change over 6s at the current rate, rather than the more common 10s interval. A very nice addition is a similar altitude vector, with the same lead.
On the altitude scale, the selected altitude changes to amber at 1,000ft (300m) before cleared altitude, and the whole scale is made especially clear by marking it with large single notches at 500ft intervals and double ones each 1,000ft.
Wichita is 2,000ft above sea level. We reached an altitude of 14,000ft in 6.5min, climbing at 250kt indicated airspeed (IAS) and 18,000ft in 8.5min; 42,000ft was passed after 24.5min, to reach 45,000ft in 27min, burning 370kg fuel. In the climb, ITT was kept at 600¡C. By the top of the climb N1 had risen from 95% to 99%, and N2 decreased from 91.5% to 89%. Fuel flow, shown both on the engine instruments and a page of the GNS unit, reduced from 440kg/h each at 20,000ft to 260kg/h at 40,000 and 210kg/h at 45,000.
The auto-pilot mode indications at the top of the PFD, with lateral modes to the left and vertical modes to the right, are clearly readable and well coded for the selection, capture and hold phases. At altitudes above 34,000ft, available bank through the auto-pilot is reduced by half, but full bank is still available on the flight director for manual flight.
The GNS, as good as an FMS in cruise on auto-pilot, set up precise leads into the turns for two 140¡ changes of track. Go-direct selection, does not cancel any part of the flight plan, so bypassed way-points can be simply reinstated.
With all fan engines, acceleration to cruise speed can be slow at high altitudes. It was worth waiting 10min to reach cruise speed. Once the wing was over a sort of "step" and the nose angle came down to 1¡, 45kt was gained in true airspeed (TAS). Even in light turbulence (noticeable with the stiff wing) cruise settled at 192kt IAS (Mach 0.721) 408kt TAS, with fuel flow 185kg/h per engine.
The Ultra like the Citation V, is cleared to operate to 45,000ft, but its best high-speed cruise at mid-weight is at 35,000ft instead of 33,000ft and 5kt faster, at around 430kt TAS.
The supplementary air cooling can be used in the air, but it automatically shuts down, on climb through 17,500ft. When I selected one air bleed "off", the cabin altitude rate of climb reached 1,500ft/min (2.5m/s) and fell back to normal in 15s.
Alpha changed quickly in turns, and the straight wing "started to talk" at 35¡ bank. Roll-reversal through 70¡ was timed at a fairly fast 4s. With IAS now 175kt in descent, extending the air brake caused a slight rumble. A slam acceleration from flight idle to full power at altitude took 10s, a time halved at lower altitudes.
Air-traffic control required us to drop from 37,000ft, to cross 33,000ft in 1min. Accelerating in descent, with air-brakes out, we were through 33,000ft in 35s, and passed 29,000ft in 70s. At 45¡ bank, still using air-brake, the Ultra could be flown at 220kt hands-off.
In a clean stall at 15,000ft, the stick-shaker operated at 10¡ alpha, and the Ultra stalled at 85kt with the right wing slightly down. Recovery took just 400ft. Rapid rolls were made at 110kt, and turns at just 30¡ bank pulled the alpha indication into its amber sector.
Landing reference speed (Vref) was set at 97kt, for approach at 107kt. Speed can easily rise with the low drag, and control is slippery until full flap is selected. I used airbrake once or twice, until "in the slot".
The generous window area, which is a feature of the series, is ideal for tight turns in the circuit, but I needed to re-adjust to the wide vision angles in feeling for the right approach attitude. I tended to duck under at first and needed to trim more nose-up.
My first touchdown was solid - I simply did not pull enough on the control column in the flare. Herrman re-selected flap and trim as I wound up power and, in 6s we reached Vr, the right engine being idled back after lift-off.
THE APPROACH
For a single-engine landing, approach speed was 117kt at 15¡ flap, with a weight of 5,500kg. This time I was ready for the increasing nose-heaviness as speed bleeds off in the flare - and used the electric trim right through the flare, to counter the quite rapid change in trim.
The undercarriage is quite stiff. It gives a good ride on taxiing, but reminds you if the touchdown is other than feather-like. The rudder-pedal steering took the nose smoothly round the taxiway corners, which can be tightened up with a dab of (snatch-free) inside brake.
This satisfying evaluation confirms that, after nearly 20 years, the Ultra is still an economically sized business jet with a well-provisioned cabin, whose appeal is enhanced by a relatively high-technology cockpit. It keeps the good low-speed qualities, which allow it to use the shorter runways of local airfields. (In sea-level standard conditions it requires a field length of just 970m for a maximum-weight take-off and a landing distance of 855m, without credit for the reverse thrust.) It can transport five passengers 3,330km (1,800nm) in just over 4h 30min - carrying maximum fuel, with a reserve at destination of 45min - gaining two passengers and 185km over the Citation V.
Source: Flight International
