MIKE GERZANICS / WICHITA, TEXAS
After a two-year delay, Raytheon has brought its first all-new jet to market. Flight International finds out if the wait was worth it
The entry-level business jet sector owes its success to a number of factors. Technological advances in aircraft and engines and increased affluence at the upper end of the owner-operator spectrum have combined to fuel demand for twinjets with a maximum take-off weight (MTOW) of 5,670kg (12,500lb) - the limit for single-pilot operation.
Cessna elected to fill this end of the market with the CitationJet, a derivative of its successful Citation series, while Raytheon sought to stake out the high ground in this segment by offering a totally new model - the Premier I. Bringing its first all-new jet to market proved a challenge for the company, and certification took 28 months longer than planned, but Raytheon finally began deliveries to customers in June. Flight International was able to sample the Premier during a flight from the company's production facility in Wichita, Kansas.
Weight is the designer's enemy, affecting cost and performance. For the Premier, weight posed an additional challenge. Raytheon wanted to give the aircraft the most spacious and comfortable cabin in the light jet category, while keeping MTOW to the 5,670kg single-pilot limit. The company's solution was a composite fuselage - the first in a business jet and the first to use fibre-placement technology.
The two-piece carbonfibre fuselage is 20% lighter and provides 13% more volume than the equivalent aluminium design, and gives the Premier a cabin with 150mm (6in) more headroom and 200mm more shoulder width than that of the latest CitationJet, the CJ2. Cabin volume is 9m³ (315ft³), almost one third greater than in the CJ2.
The cabin has four seats in a club configuration and two at the rear, facing forward. Further aft, behind a hard sliding door, are a toilet and additional baggage storage. The three large cabin windows per side are located at shoulder height, noticeably higher than in some business jets.
While Raytheon has lavished leather seats on the passengers, it has not forgotten that two-thirds of potential Premier I buyers are owner-operators. The aircraft has a flightdeck comparable to those in the latest airliners. The standard equipment list is extensive and headed by a Rockwell Collins Pro Line 21 integrated avionics suite. The basic configuration has two 250 x 200mm (10 x 8in) liquid crystal displays: one a primary flight display (PFD), the other a multifunction display (MFD). In the optional configuration the right-seat primary instrument cluster is replaced by a second PFD. GPS satellite navigation and weather radar are also standard. Two control display units (CDUs), mounted forward on the centre console, control the single flight management system (FMS) and communications/navigation/identification radio tuning.
The three-axis autopilot is controlled via a prominent glareshield-mounted flight guidance panel. This level of sophistication in an entry-level jet may seem excessive, but one of Raytheon's goals was to provide a superior level of comfort for passenger and pilot. Automation is never a substitute for basic airmanship, but anything that eases the workload on a single pilot in instrument conditions may be money well spent. While 70% of Premiers will be flown by a single pilot, 70% of buyers have opted for the optional two-PFD layout and the additional redundancy it provides.
Surprisingly big
Crossing the Beech Field ramp to board N155RM, the second production aircraft, for the test flight, we were surprised by how big the Premier I was. The large fuselage, swept wing and prominent wing-fuselage fairing combine with the T-tail to make the aircraft look like a piece of heavy iron, worthy of two pilots in pressed white shirts and neckties. Equally impressive was the smoothness of the fuselage, almost totally devoid of fasteners.
The walk around was straightforward, with all access panels readily available at ramp height. One unique feature is the two nose-mounted ice detection probes. Wing leading edges and engine inlets are anti-iced by engine bleed air. The horizontal stabiliser has a heated ice-parting strip and an electromagnetic expulsive de-icing device, controlled either manually or automatically via the nose-mounted probes. Raytheon has certificated the Premier for operation into known icing conditions.
Pre-flight inspection of the two Williams-Rolls FJ44-2A turbofans was simple. Oil level is checked via two switches in the aft maintenance bay. Not having to open an access panel or pull out a dipstick are features one would expect from an owner-operated aircraft in this price range.
While checking the condition of the engine inlets and exhaust nozzles, we noted the prominent dimples in the fuselage forward of the engines. This necking down of the fuselage was made possible by the composite construction and serves two purposes. First it allows area ruling to reduce drag at higher Mach numbers. Second it allows the engines to be mounted closer to the aircraft's centreline, reducing the yaw caused by engine failure.
Cabin entry is via an integral door-mounted airstair on the left forward side. The manual non-plug-type door has six latching points and is sealed by engine bleed air. The flightdeck is separated from the main cabin by hard partitions behind each seat and a stowable curtain.
For the flight, senior demonstration captain Mark Loyancano sat in the right seat and demonstration pilot Tom Sifford sat in the passenger cabin. Although there was room to store flight bags on the floor aft of the centre console, we put them in the aft cabin baggage area. Aircraft flight manual and approach plates were readily available behind the cockpit seats. The four-way adjustable seat and two-position rudder pedals ensured we could find a comfortable seating position.
The field of view out of the four forward, heated windows was good, a necessary feature when operating into and out of uncontrolled fields. Once strapped in with the four-point harnesses, we ran the before-start checks. Paper checklists were available, but we elected to use the standard electronic checklist. This is displayed on the centre MFD with each step colour-coded to show its status: white before accomplishment, blue during the step and green when complete.
Rather than use the aircraft's internal battery for engine start, we used the external DC power cart. After arming the ignition, we pushed the yellow start button which energised the engine's starter/generator. At 12% N2, we brought the left throttle out of the cutoff position to idle. Light off was immediate and the engine reached an idle RPM of 58.8% in less than 12s. Peak interturbine temperature (ITT) was 780°C (140°F), well below the start limit range of 900-1,000°C. Once the left engine's DC generator was brought on line, the external power cart was disconnected. Right engine start was similar, but peak ITT was about 60°C higher, typical of a start using aircraft power only.
Post-start checks were easily accomplished, with most systems controlled by logical panels located along the bottom edge of the forward instrument panel. Built-in tests called for by the electronic checklist were activated by a rotary switch on the overhead panel. Initialisation of the FMS, via the centre console CDU, was straightforward and logical.
The Premier I is certificated to operate at 41,000ft (12,500m), and we found the pressurisation system is remarkably easy to operate. After checking the automatic and manual modes from both bleed air sources, all that was required for flight was to set the landing airfield's elevation.
Heavy steering
Lowering its handle on the right side of the centre console released the parking brake and we taxied forward before turning out of the parking ramp, idle thrust sufficient to move us along at a reasonable pace. We found the manual nosewheel steering (NWS) somewhat heavy at slow speed, with the forces lightening up as speed increased. Aircraft braking is provided via toe-operated brakes using power from the two 210bar (3,000lb/in2) engine hydraulic pumps, reduced to 105bar. Should primary hydraulic power fail, emergency braking from an accumulator is available via the parking brake handle. Once under way we were able to track the taxiway centreline accurately. Several tight 180í turns were easily accomplished using a combination of NWS inputs and differential braking.
Brisk acceleration
Once cleared by the tower we lined up for take-off on runway 18. Temperature was 38íC and wind was out of the south at 13-18kt (24-33km/h). Our aircraft had an empty weight (including one pilot) of 3,855kg. With two passengers and 1,440kg of fuel, we weighed 5,450kg at brake release. Take-off decision speed (V1) and rotation speed (VR) were both 118kt indicated airspeed for our 10° flap configuration. Take-off safety speed (V2) was 122kt. Loyancano entered these into the FMS along with our initial climb-out speed of 140kt, which is also the single-engine climb speed. Once entered into the FMS they were displayed on the PFD's airspeed tape, located to the left of the ADI (artificial horizon) display.
We pushed both throttles to the electronic fuel control unit (EFCU) maximum limit stop. Once the engines stabilised we released the toe brakes and began the take-off roll. Acceleration was brisk and Loyancano called, "thrust set" at 80kt. At VR less than 7kg of aft yoke force was required to attain the initial climb-out attitude of 8-10°. The entire take-off roll used about two thirds of the 2,400m (8,000ft) long runway, or approximately 1,600m. Post-flight examination of the Premier's performance manual predicted a no-wind roll of 1,600m at Beech Field's 1,408ft elevation.
Once airborne, Loyancano retracted the hydraulically actuated landing gear. We released the yoke and with take-off trim still set the aircraft climbed out at the desired speed of 140kt. Passing 1,000ft, we decreased the pitch attitude to 5í and retarded the throttles to the maximum continuous power detent. Loyancano retracted the electrically operated flaps and we accelerated to 180kt while climbing to 4,000ft to exit the airport's traffic pattern.
Once level at 4,000ft we were able to evaluate the Premier's control harmony at 180kt. Pitch forces were light as we executed a series of gentle lazy-8 manoeuvres. Roll control was responsive, but the forces were somewhat heavier than the corresponding pitch forces. Aiding the unboosted ailerons in roll control were two hydraulically actuated spoilers. Rotating the yoke past 10í of deflection causes the progressive extension of two of the three wing-mounted spoilers per side. The inboard spoiler on each side is only for lift dumping on the ground. A control yoke-mounted pitch and roll trim switch allowed us to trim off forces generated during these manoeuvres.
Our next planned event was to be a climb to 41,000ft, but events conspired to restrict us to low altitude. A large line of thunderstorms, some to heights of 60,000ft, had developed in a north-south line between Wichita and our intended destination of Denver, Colorado. Upper level air traffic was being diverted overhead Wichita in an effort to keep scheduled flights moving. As we were a low-priority flight, we were restricted to operations below 15,000ft.
Slow-speed handling
A post-flight review of published performance data showed that, for our take-off weight, we would have covered 215km (115nm), burned 215kg of fuel and taken 21min to reach 41,000ft. Loyancano said he had performed 60í angle-of-bank steep turns at that altitude, and not encountered any buffet. A Mach 0.74 cruise at that altitude would have burned 370kg/h and yielded 424kt. Flying at the more economical long-range cruise speed would have given 368kt and burned 298kg/h. A descent from this altitude to sea level would have covered 142km and used less than 45kg of fuel.
With high-altitude operations out of the question, we started a climb to 13,500ft to evaluate the Premier's slow-speed flight characteristics, setting the power to the maximum continuous detent and starting a 220kt climb. Once stabilised at the target airspeed we engaged the autopilot in the heading (HDG) and flight-level change (FLC) roll and pitch modes.
During the climb we used the HDG knob to command heading changes. The aircraft responded by smoothly rolling into and out of turns to capture the desired heading. We could also vary the climb speed using the FLC speed knob. As power was manually set, the autopilot responded to requested speed changes by increasing or decreasing target pitch attitude.
At 12,500ft the tone sounded to indicate we were within 1,000ft of the target altitude. The autopilot smoothly pitched the aircraft over and captured 13,500ft. The indicated airspeed trend vector on the PFD made holding desired speed easy by showing the predicted future airspeed.
With the throttles retarded to set up for a clean configuration stall, we kept the aircraft level and set the power to achieve a 1kt/s deceleration rate. As the aircraft slowed, a red line showing the computed stall speed appeared on the airspeed display. At 113kt the stick shaker went off, the only indication of an impending stall. The wings remained level as we pushed both throttles up to the maximum continuous detent for recovery. As the high-mounted engines spooled up they gently helped push the nose down, a nice pro-recovery feature.
Had the shaker been ignored, a stick pusher would have helped coax even the most reluctant pilot into initiating a recovery. A landing configuration stall, gear down and full 30° flaps, was also remarkably benign. The stick shaker came on at 98kt. Pushing the power up to the maximum continuous detent resulted in an immediate recovery.
Safety featured
While still at 13,000ft we evaluated a unique safety feature of the Premier I - the rudder boost system. In the event of an engine failure, as sensed by more than a 1,100rpm difference in engine fan speeds, the autopilot servo deflects the rudder to help counteract the asymmetric thrust.
With the gear down and flaps set to 10í, both throttles were placed in the take-off detent. At 118kt we simulated an engine failure on take-off by rapidly retarding a throttle to idle. With the rudder boost system on, only about 13.5kg of rudder force was required to maintain a steady heading. With the rudder boost system off, over 40kg of rudder force was required. While the asymmetric thrust was easily controllable without the help of the rudder boost system, it should greatly reduce the pilot inputs required safely to recover the aircraft in the event of an engine failure.
Area work complete, we set up for an approach and landing at Wichita's Mid-Continent airport. During a 200kt idle power descent to the field, we extended the speedbrakes by moving a large flat switch on the throttle quadrant. Pitch attitude remained steady, and the descent rate increased from 1,300ft/min (6.6m/s) to 2,600ft/min. Loyancano selected the instrument landing system (ILS) approach to runway 19R on the CDU. The map display on the MFD showed the entire approach procedure, including the missed approach segment. The FMS automatically tuned the ILS frequency and final approach course. The approach speed of 127kt for our 30° flap landing was bugged on the PFD's airspeed display.
Once level at the glideslope intercept altitude and on a heading to intercept the localiser, we retracted the speedbrakes. As the aircraft slowed, Loyancano extended the landing gear and lowered the flaps to 30í. As was the case during clean-up after take-off, gear and flap extension caused little change in pitch trim control forces.
The flight director captured the ILS localiser and gave pitch commands to maintain level flight. At ILS glideslope capture, the flight director gave a smooth 3í pitch down command to track the glidepath. A power setting of 60% N1 was required to maintain approach target airspeed. The flight director's guidance was easy to follow and allowed us to stay on course and on glidepath.
With the throttles set to idle, the landing flare was easily accomplished and resulted in a soft touchdown. Once on the runway, we deployed the spoilers in lift-dump mode, all three panels on each side extending. Although we did not use it, main gear anti-skid is standard on the Premier. Published landing distance over a 50ft obstacle for our conditions is 1,050m (3,450ft). Once slowed to a comfortable taxi speed, runway turn off and taxi to parking was uneventful.
Conclusions
Raytheon's Premier I has the look and feel of a much larger aircraft. Its composite fuselage provides the largest cabin in the entry-level class, while its light weight allows the aircraft to be certificated for single-pilot operations. Throughout our flight, we found the Premier to be both a responsive and a stable aircraft. The Pro Line 21 avionics, standard GPS, weather radar and full anti-ice equipment should help a wide range of pilots feel comfortable in adverse weather conditions.
Now that customer deliveries have finally begun, the company is working hard to meet pent-up demand for the aircraft, With 329 orders on the books, the next available delivery slot is not until 2006. But then if you have $5.2 million to spend and the desire to own a light business jet, the Premier I may just be worth the wait.
Source: Flight International
