NBAA: Turboprop royalty: Beechcraft 350i King Air

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Introduced in 1964, the Beechcraft King Air series of turboprops may well the world's most popular business aircraft. The first King Air (Model 90) was basically a Queen Air fitted with Pratt & Whitney Canada PT6 turbines, and first flew in 1963. Versatility has been the cornerstone of the King Air's success. The King Air's basic attributes of a large cabin, simple durable systems, good field performance on unpaved runways and cruise speeds in excess of 300kt (555km/h) have endeared it to thousands of operators.

King Airs are used in a multitude of roles: executive transport, air ambulance, cargo and military special mission, to name a few. Since the Model 90, Hawker Beechcraft has continued to improve the King Air. The 350i, executive version, and 350c, cargo version, are the newest offerings in the prolific King Air line. While it may lack the cachet of a jet, more than 6,500 turboprop King Airs have been delivered to customers in 105 countries.

'i' for Improved Interior

The 350i was announced at the 2008 NBAA and certificated less than two years later in January this year. The 350i, a follow-on to the 350, sports four major improvements in the cabin. The first is the Rockwell Collins Venue cabin management system. Next, Hawker Beechcraft has worked hard to reduce the cabin noise levels. The level of cabin fitments has also been improved, on par with aircraft costing millions more, according to HBC. Finally, the cabin can be rapidly reconfigured, a benefit of the "FlexCabin" system. Flight Evening News was able to see these improvements first hand and fly with Royalty on a preview flight of the 350i in San Jose.

"Big" is the word that sprang to mind when I first encountered the 350i. The King Air was the first aircraft to earn a commuter category exemption from the Federal Aviation Administration, which limits take-off gross weight to 12,500lb (5,670kg). At 15,000lb, the 350i exceeds it by a wide margin. Adding to its gravitas are dual wheels on each of its two main landing gears. The large cabin entry door, 4.3 x 2.23ft (1.31 x 0.68m), allows entry into a spacious cabin. The 350i's cabin is 19.5ft long from the cockpit partition to the end of the 55.3ft3 (1.57m3) aft baggage stowage area. While its length is impressive, its squared oval cross-section is more noteworthy. The near rectangular cross-section gives more space at the foot and shoulder/head levels than a similar diameter circular fuselage. Compared with the Cessna CJ2, which has an identical 4ft 9in floor to ceiling height, the 350i is 11in wider (27.9cm) at the floor level and offers appreciably more lateral head room when seated. Total cabin volume for the 350i is 355ft3, markedly greater than the CJ2's 246ft3.

The standard cabin configuration of the $6.8 million 350i is a double club arrangement. Additionally, the aft chemical toilet is also belted, giving a total cabin seating capacity of nine. While there are numerous business jets that offer seating for eight, the lowest priced double-club configured jet is the $12.7 million Bombardier Learjet XR45. First- hand inspection of the 350i's cabin showed a level of refinement similar to midsized business jets I had flown. The Venue cabin management system gave total control of the cabin environment to any of the eight club seats. A 15.3in monitor swings out from an entertainment cabinet, aft of the cockpit partition. Optional displays can be placed at each seat, enhancing entertainment choices. The Venue system has preset "scenes" for the cabin, controlling the LED lighting and electrochromatic window darkeners. Selecting the movie scene, for instance, turns off all cabin lights except those over the aisle and darkens cabin windows to 75%.

Cabin noise is perhaps one of the biggest concerns of passengers when riding in a turboprop. Hawker Beechcraft had used active noise cancellation systems to tame the acoustic environment. For the 350i, it chose passive noise dampeners. Dynamic vibration absorbers are tuned for and mounted at several locations in the cabin and cockpit to reduce propeller noise and vibration. The 350i also has a propeller synchrophaser system that not only synchronizes RPM but ensures that propeller blades do not pass by the fuselage at the same time, eliminating an often annoying harmonic.

Fuselage vibration induced noise is reduced by the addition of skin mounted dampening panels. These, additional sound deadening materials and other features have served to reduce overall average cabin noise level to 78dBA, much lower than the 350's, of 82dBA. Finally, individual seats are provisioned for active noise canceling headsets.

While much attention is focused on the passenger compartment, the 350i's pilots will not feel left out. A Collins Pro Line 21 avionics suite is the centerpiece of the flightdeck. Three 8 x 10in displays - two primary and one multifunctional - cover nearly half of the forward instrument panel. Systems control panels and lighting switches are located along the bottom edge of the panel, and are arranged to enhance single pilot operations. The control panel for the Collins FGC-3000 automatic flight guidance system is mounted beneath the glare shield. Engine indications are presented on the centre multifunction display, but can also be displayed on the primary displays when in a reversionary mode. Cautions and warnings, however, are presented on an old-fashioned light panel located just forward of the throttle quadrant.

FLIGHTDECK FEATURES

An impressive list of standard features rounds out the 350i's flightdeck. Rockwell Collins electronic charts and an electronic checklist (ECL) give this venerable aircraft a true paperless cockpit. TCAS and TAWS are also standard, as well as an out-of-the-box RVSM capability. Our preview aircraft was equipped with a single flight management system and GPS navigation, but second units of each are available as an option. Finally, the cockpit is nicely sized, much larger than the Piaggio Avanti II's and even those of a number of light jets I had previously flown.

Casey Davis, the company's demonstration pilot, performed the pre-flight walk around inspection of our preview aircraft, N699HB. Several aerodynamic features stood out. First, the 350i has 1.96ft-high winglets, additions that doubtlessly improve cruise as well as field performance. The other stand-out is the two ventral strakes on the aft fuselage. Some earlier King Airs had a single ventral strake, but with an inoperative yaw damper, flight altitude was limited to 5,000ft. The 350i's dual strakes allowed for yaw damper inoperative operations up to an altitude of 18,000ft. While the 350i has ample baggage storage in the aft portion of the cabin, its wing lockers are in the aft section of each engine nacelle. These unheated compartments offer a total volume of 15.8ft3 and can hold 600lb of baggage. Davis pointed out the booted leading edge of the wing and horizontal stabilizer. The inlets for the 1,050shp (780kW) PT6A-60A engines are heated any time the engines are running. The inlets also have a particle separator for use on gravel strips and in icing conditions.

The four-way adjustable seat and two- position rudder pedals allowed me to find a comfortable seating position in the sizable cockpit. FMS initialization and pre-start checks were easily accomplished, Davis checking off items on the ECL. Both engines were started using a ground power cart, although the 350i is fully capable of a battery-only start. At 12% N1 the condition levers were moved to low idle, where they remained for the duration of the flight. Post-start checks were accomplished, again with reference to the ECL. During the taxi to Runway 30L for take-off, I found the manual nose wheel steering allowed me to accurately track taxiway center lines. The electrically actuated flaps were set to "approach" for take off. Computed indicated speeds for our 12,450lb aircraft, with four occupants and 1,760lb of fuel, were 96/102/106kt (V1/VR/V2). For our weight, published field length was 2,950ft, while at maximum take-off weight of 15,000lb, only 3,300ft is required. This is less than most light jets, but at sea level the CJ2 and CJ3 offer comparable take-off field performance.

TAKE-OFF ROLL

Other than the need for right rudder to counteract the p-factor induced yawing, the take-off roll was much like a light jet's. Yoke force needed to attain a lift off attitude of 10e_SDgr was a bit high. Once airborne, with the gear retracted, pitch trim easily countered the changing pitch forces as the King Air accelerated to an initial climb attitude of 18e_SDgr. Passing an indicated airspeed of 125kt, the flaps were retracted, with yaw damper engagement at 400ft AGL. I used flight director guidance to follow the departure ground track, a sweeping right-hand turn towards the south-east. In the climb I set the propeller RPM to 1,600, and advanced the throttles until the climb inter turbine temperature limit of 785e_SDgrC (1,390°F) was reached. Initial climb speed was 170kt, with the target speed decreasing 10kt every 5,000ft once above 10,000ft.

Air traffic control restrictions prevented a direct climb to FL330, and Davis suggested we assess the 350i's handling qualities at 15,000ft while waiting for the upper airspace to open up. At speeds from 120-170kt I found the 350i a joy to fly. Roll and pitch forces were well harmonized, with the effective yaw damper making maneuvering the large King Air a breeze. A landing configuration stall, gear and flaps fully extended was performed. Slowing at about 1kt per second, the stall horn sounded at 81kt. Noticeable airframe buffet was felt at 74kt, where a recovery to normal flight was initiated. Throughout the stall and recovery, control in all three axes was good. Adding power during the recovery however, did require right rudder to keep the King Air in coordinated flight.

While the stall and recovery were quite docile, the most instructive maneuver performed at medium altitude was a "surprise" engine failure. So as not to use the rudder, Davis had me place my feet on the floor and shut down the right engine. The 350i has a propeller auto-feather and rudder boost system. As the engine was shut down, the auto-feather system feathered the propeller. Sensing a large difference in engine torques, the rudder boost system put in a good amount of left rudder. With the right engine stopped at 150kt, I watched as the 350i flew along in nearly coordinated flight without my help. While this demonstration was performed at medium altitude, the rudder boost and propeller auto-feather systems should increase the odds for a happy outcome in the event of an engine failure on take-off.

After completing the medium altitude maneuvers, a climb to FL330 was resumed. During the climb I allowed the autopilot to fly the aircraft, while I adjusted the throttles to maintain maximum allowable ITT. While our flight profile prevented an accurate assessment of the 350i's climb performance, Hawker Beechcraft lists a time to altitude of about 18.5min at standard conditions, a realistic number based on our actual two-part climb to FL330.

Once level at FL330 I set a cruise RPM of 1,500 and a total fuel flow of 530lb/h, to approximate a maximum cruise power point. At 171kt, the 350i stopped accelerating, and at ISA +10e_SDgrC the resulting true airspeed was 294kt, just as the book predicted. With one pilot and four passengers (800lb payload), Hawker Beechcraft lists an NBAA IFR range of 1,535nm (2,843km) at maximum cruise power. With full fuel tanks, the 350i has an available payload of 1,489lb, while IFR range only decreases to 1,489nm. To approximate a maximum range condition, I retarded the throttles and set a total fuel flow of 390lb/h. The aircraft slowed to an indicated airspeed of 136kt with a test day true airspeed of 237kt. Slowing to maximum range speed will save fuel, but even at maximum power the 350i has over 5h of endurance and the range to accomplish most missions.

With four passengers, Hawker Beechcraft lists a flight time of 1h 2min for a 300nm flight. Total time increases approximately linearly with distance, a 1,000nm segment requiring 3h 27min. At the longer stage lengths, if payload capacity is not an issue, some operators will no doubt opt for the speed of a light jet such as the CJ2, which has a 100kt advantage at high-speed cruise.

Before leaving the cockpit to sample the cabin environment, I noted a cabin altitude of 9,600ft. The 350i's 6.6lb/in2 (differential pressure) pressurization system can provide a sea level cabin to 15,293ft, while the CJ2's 8.9lb/in2 system provides one up to 23,586ft.

The overall noise level in the cabin was fairly low as evidenced by my ability to carry on a conversation at normal voice levels with someone half a cabin away. Ambient noise levels were lowest in the middle four seats, just aft of the wing spar. Noise from the aft cabin entry door was low, and closing the aft cabin hard partition doors reduced it further. Based on my brief cabin experience I feel it is safe to say that compared with a typical light jet, King Air passengers may be happy to gain additional foot and shoulder room at the expense of a slightly louder cabin environment.

After completion of the high-altitude cruise conditions, ATC directed we hold at a fix while they sequenced us for arrival. I used the FMS to define the hold point and watched as the autopilot deftly flew and established the King Air in the holding pattern. After less than a full turn in holding, ATC allowed us to go direct to a fix on the GPS instrument approach procedure to Runway 30L. While different from the Boeing 737 I fly regularly, I found FMS operations in the Rockwell Collins system to be fairly intuitive. The autopilot accurately followed the approach's lateral and vertical profile. Our own ship position was displayed on the electronic approach procedure chart, greatly increasing situational awareness. Before reaching the final approach fix, I disengaged the autopilot and extended the landing gear.

Passing the final approach fix I extended flaps to approach. Three miles from the runway, about 1,000ft AGL, I selected flaps to down. About 30% torque was needed on both engines to hold a target indicated airspeed of 100kt. At 586ft MSL, minimums was called, and I transitioned to visual references. Passing about 30ft AGL I retarded the throttles to idle and flared shortly thereafter for a soft touchdown. I used moderate wheel braking and reverse thrust to slow to taxi speed. No effort was made to "max" perform, but the listed landing distance of 2,460ft for our test day conditions seemed readily attainable.

During the taxi back to the ramp, a break in arrival traffic provided an opening for a final visual circuit in the 350i. I jumped at the chance to double my take- off and landing experience in the King Air. Unencumbered by instrument flight restrictions, the final circuit was a joy to fly. On the downwind leg, the tower directed that we start an immediate turn to final. Although we were well above an instrument glide path, the 105in-diameter four-bladed Hartzell propeller allowed us to descend on speed. The final full stop landing and taxi back to parking were uneventful, a fitting conclusion to my first flight in a King Air.

Long Reign

Lyndon Johnson was the US president when the King Air first flew. That nearly 50 years later the King Air is still relevant is testimony to the strength of the design. Hawker Beechcraft's stewardship of this iconic aircraft has allowed it to field the highly capable 350i. With an updated cabin and cockpit that rival more expensive business jet offerings, the 350i can still operate out of grass and gravel strips. While not as fast as a light jet, its lower acquisition and operating costs as well as respectable high-speed cruise performance ensure that the King Air may never go out of fashion.