Peter Henley/LUTON
By the time British Aerospace sold its corporate-jets business to Raytheon in 1993, the BAe 125 8-14 passenger twinjet had gained a formidable reputation. Since 1962, when the original de Havilland DH 125 was first flown, 850 customers from more than 40 countries had purchased various versions of it, and total worldwide sales of the 800 Series, introduced in 1984, stood at more than 160. The Wichita-based, US manufacturer had, arguably, pulled off a considerable coup by acquiring this charismatic gem.
Although the BAe 125 series had been stretched to include the 125/1000 version by 1993, Raytheon chose the successful 800 Series, incorporating improvements to the airframe for the longer-range 1000 variant, to be the flagship of its business-aircraft range. It has been complemented by the smaller Beech King Air twin-turboprop and the Beechjet 400A.
The resultant aircraft has been designated the Hawker 800XP (so reviving a famous name in UK aviation dating from 1920), and is proclaimed in the sales brochure as being "-a direct descendant of the most successful mid-size jet ever built".
By the time Raytheon brought an 800XP to the UK for the 1996 Farnborough Air Show, it had already sold 900 variants of it, of which the 800 Series was the best seller. Raytheon had already sold 30 800XPs and had been referring to it as its "first development since acquiring the Hawker line", and hinting at other future developments (see P54). Unusually, Flight International was set to sample the latest rendering of an aircraft which had first been flown 34 years earlier, and which is the culmination of a philosophy to "improve and develop", rather than "discard and design anew".
Pre-flight briefing
I was met at the 800XP's temporary base at Luton Airport by Pete Donnelly, the senior demonstration captain, and Clint Randolph, also a demonstration captain. Both men had an impressive enthusiasm for and technical knowledge of their aircraft, and wanted to focus particular attention on the XP's cabin.
The cabin is impressive - luxurious but business-like - and customers have a wide range of options from which to choose their requirements. Firstly, there are the "comfort" options. The usual number of passenger seats is eight and their configuration can be in the so-called "double club" layout , or in the more conventional format, where the front two face backwards and the remaining six face forwards.
The seats are versatile, having a 360í swivel range, plus fore, aft and lateral tracking and full recline. The galley can include a microwave oven, the lavatory at the rear is large and private enough to change in, and the baggage compartment is easily accessible in flight. Seats can be upholstered in leather, while tables, partitions and shelves are finished in lacquered wood.
The "productive-travel" options include Airshow flat-screen monitors, digital voice and facsimile telephones, video cassette players and lap-top computer compatibility. All this, says Raytheon, makes the 800XP a "conference room in the sky".
The cockpit is also impressive. The aircraft we were flying was equipped with Honeywell SRZ-8000 avionics, although Collins equipment can be specified by customers who want avionics compatible with their other fleet aircraft. The Honeywell equipment is almost universal among US operators, although some operators elsewhere have favoured Collins.
Production economics might eventually lead to a single standard supplier. Meanwhile, whichever system is chosen, the standard aircraft equipment includes a five-tube electronic flight-instrument system, global-positioning system and high-frequency communications - giving it a truly intercontinental capability to complement its long-legged performance (Raytheon cites non-stop potential for sectors such as San Francisco-Honolulu, New York-Bogota and London-Cairo).
Avionics options include a ground-proximity warning system and the TCAS II traffic-alert and collision-avoidance system. The primary-flying-display tubes are placed one above the other in front of each pilot, with attitude information above and horizontal situation below - although full switching capability between displays is provided to cope with tube failures. The fifth tube is at the top of the centre instrument panel between the two pilots and is used primarily for radar and TCAS displays.
The instrument panels are neither symmetrical nor neat. For example, there are six engine gauges (three for each engine) grouped to the right of centre at the top of the panel, while four more similar-looking gauges for fuel contents and fuel flow are grouped together, but to the left of centre and lower down on the panel.
There is an angle of attack indicator, the usual standby instruments for attitude, altitude and airspeed, and a radio management unit with colour cathode-ray-tube (CRT) display for each pilot. Remote radio tuning for navigation and transponder systems is provided by two alphanumeric keyboards and colour CRTs placed side-by-side between the forward end of the centre console and the lower portion of the central instrument panel. There is a master warning panel at the top right-hand corner of the central instrument panel.
Control of the aircraft systems is provided by a neat roof panel of switches, gauges and systems status indicators. The exceptions are the auxiliary power unit (APU) control and the refuelling and defuelling central panel. The APU is positioned, less than ideally, behind the captain's seat facing inward, enabling the co-pilot to operate it from his or her seat. The refuelling central is behind the cockpit, in the passenger cabin above the wardrobe. The APU is not designed for use in the air, except in an emergency, when it provides electrical power.
The pilots' seats, fitted with five-point harnesses and adjustment for fore and aft and vertical positioning, recline plus armrest angle, are easy to get into and out of. The rudder pedals can be moved fore and aft to suit after unlocking them by using a small lever on the lower edge of the instrument panel between the pilot's legs.
The field of view is good except that the top edge of the side windows cuts off sideways view at angles of bank greater than about 30í. Each pilot can see the wing tip on his or her side of the aircraft. The control columns have articulated "rams horn" grips, but they are shallow, like a racing motorcycle's handlebars. I found that the only way I could apply full aileron was by squeezing my knees against the column to avoid the grips hitting my thighs; one's legs cannot be spread because they are constrained by the centre and side consoles.
The 800XP is designed to be operated with the minimum of ground support, and for ease of turnaround. Refuelling is via a single point, the lavatory is serviced entirely from outside the aircraft and the cabin door, which incorporates steps, is light and easy to open and close.
The APU can be used to cool the cabin and power the avionics so that all the pre-departure preparations can be done while waiting for the passengers or late instructions. The engines can be started without affecting any of the avionics.
Start up and take-off
Starting the two AlliedSignal TFE 731-5BR, 21kN (4,720lb)-thrust turbofan engines was straightforward via a master switch, a starter switch and the relevant fuel cock. There is no full-authority digital engine-control, but there is the lesser-authority digital electronic engine-control (DEEC) incorporating a "thrust detent indicating system". In practice, this means that the thrust levers (throttles) can be moved to a detent indicated by the illumination of two green lights, after which the system will maintain and monitor relevant engine parameters.
The 800XP is fitted with only one nose-wheel steering control - on the captain's side - although this is light and positive. The toe-operated wheel brakes are powerful and progressive, but prone to judder. The parking brake is applied by a lever towards the right-hand side of the centre console with a thimble-shaped knob embracing a press-to-release button.
Luton Airport is at 520ft (160m) and we were to use runway 26, which is 2,100m long. The temperature at take-off was 15íC, surface wind was 10-12kt (18-22km/h) from the north, the runway was dry and the sky 8/8 overcast, base 3,500ft. The aircraft weighed 10,680kg (against a maximum permitted weight of 12,710kg) and had 3,178kg of fuel on board with the central tank empty. The reference speeds for take-off were V1 116kt, Vr120kt, V2129kt and a Vat of 127kt for an immediate emergency return. Checks were completed using a paper checklist, although fuel operator's electronic checklists can be programmed for display on the fifth CRT. Flap was set for take-off.
Donnelly, in the right-hand seat, re-capped on the take-off procedures. This was a full power take-off, so I moved the throttle levers to the forward limit; he checked the resultant N1 reading against "book" values. Acceleration was rapid and the 800XP was easy to keep straight (despite the crosswind from the right), using nose-wheel steering and a little rudder.
The recommended technique was followed, removing the left hand from the nose-wheel steering at 80kt and the right hand from the throttles at V1, so having both hands on the control column for the rotation. Once safely airborne, the gear was selected up. It travelled quickly with some noise and an end-of-travel clonk. The aircraft was climbed to flap-retraction height. Climb power was then easily selected by moving the throttles backwards a short distance into the detent, the correct selection of power being confirmed by the two associated green lights. Climb power would thereafter be maintained and monitored for fuel flow, over speed and over temperature by the DEEC.
Control forces on rotation and during the initial climb were moderate and well harmonised in pitch and roll. There was little pitch change discernible with gear or flap retraction, and the instrumentation had been easy to read and demand cues easy to follow. I did, however, notice that, after take-off and on subsequent flap retractions, Donnelly moved the flap lever slowly. It transpired that this was because flap travel speed was proportional to speed-of-selector lever movement, so rapid selections could provoke a more noticeable pitch change.
In the cruise
The 800XP does not have full automatic pressurisation, and because the take-off had been at full power, the bleeds were selected on after take-off, resulting in a smooth and quiet initiation of pressurisation without a discernible surge. Once established in the climb and flown manually, the aircraft settled down nicely at 250kt (M0.64), easing to 270kt (M0.70) at altitude. Contact was made with Eastern radar, which negotiated us through the overcast and into bright visual conditions above the cloud tops at 6,000ft.
General handling was undertaken between 15,000ft and 20,000ft over East Anglia. The yaw damper made little noticeable difference to handling; when it is switched off, a single rudder deflection exited a slight tail snake which washes out in about three oscillations. Rate two turns at 45í of bank and 280kt with turn reversals showed fairly high control forces from the manually operated ailerons and elevators, but they were well harmonised. At 200kt, the forces were much kinder and still well harmonised. The field of view during such a turn was limited by the tops of the side windows. Airbrake extension was directly proportional to the travel of the selector lever on the left side of the centre console. Moderate extension caused little pitch change or burble, but full extension provoked some nose-down pitch and noticeable burble. The airbrakes extend above and below the wing and cannot be used when flap is extended.
Both the gear and take-off flap have usefully high limiting speeds at 220kt. Selection of take- off flap at 200kt produced a slight nose-up pitch change, but this was easily trimmed out with the electric pitch trim. Selecting the gear down at 200kt resulted in no pitch change, but generated noise during extension with an end-of-travel clonk, then aerodynamic noise when extended.
Handling near the stall was the next exercise, speed being reduced to initiation of the stick shaker. The all-up weight of the aircraft was now just under 10,000kg and the relevant speeds at 17,000ft for a clean stall, power-off, were trim 134kt and stick-shake 118kt. With 25í flap and gear down, the speeds were 126kt and 110kt respectively. In both configurations the 800XP handled predictably with good aileron effectiveness. The application of full power at the onset of the stick shake was enough to fly the aircraft away, with little loss of altitude.
Because of the cloud tops at about 6,000ft, an engine cut and V2 climb could not be carried out as low as I would have liked. We settled for 9,000ft, full-power flap at the take-off setting and gear up when Donnelly shut down the starboard engine. The effect was singularly undramatic. The 800XP's bleed air-operated rudder bias system compensated convincingly by applying opposite rudder to maintain aircraft heading without foot force from the pilot and without any into-live-engine bank.
Airframe ice protection on the 800XP is provided by a TKS system using anti-icing fluid with a tank capacity large enough to last for about 2h. The engine nose cones have the integral bleed-air circulation.
Return to base
The Hawker 800XP has dual auto pilots, the performance of which was briefly evaluated in the descent and marshalling to the instrument-landing system for a coupled approach to Luton. In the modes used - altitude capture, height lock, heading, localiser and glide-slope capture - the aircraft performance was smooth and accurate, with good speed control, and easily manageable with manual power selections.
Upon discarding the auto pilot at 300ft, the landing was pleasant and easy to complete. The wheel brakes have anti-skid capability and their effectiveness is enhanced by the lift-dump feature, achieved by selecting air brakes immediately after touchdown and moving the lever beyond a detent to the lift-dump position. All the Hawker 800XPs have reverse thrust as a standard engine fit.
Conclusion
The 800XP exemplifies Raytheon's policy of marketing business jets which give boardroom comfort and airborne business tools. In the case of the "mid-size" XP, these qualities are well-blended with a useful range (under the US National Business Aircraft Association instrument flight rules, range is 4,650km, with six passengers in long-range cruise), and field performance. While ultimate speed is not a strength (it is probably limited to M0.80 by its relatively old basic design), it is no sluggard, and has the feel of being a fast aeroplane.
There are other features that doubtless stem from its history of continuous development, such as the mildly random instrument layout and off-the-flight deck APU and refuelling panels which deprive it of the clean-cut, neat, well-considered layout which can be achieved when starting with a clean sheet of paper. These are minor criticisms, however, when weighed against the overall competence of the 800XP.
The cabin and cockpit, despite minor reservations, is comfortable and user-friendly. The aircraft handles well, comforting passengers in turbulent weather, and this is reassuring for pilots flying in instrument conditions. It is equipped to operate with minimal ground support and to navigate the globe.
It is a pleasure to see the basic soundness of a proven and successful design being technically and commercially exploited in maintaining the breed and continuing that success.
It will be fascinating to see what Raytheon does to keep this classic aircraft as a market leader in the coming decades.
Source: Flight International
