Some aircraft don’t merely carve a niche for themselves, they create a legacy. This comes about through the successful mating of a quality airframe and powerplant, through sound design philosophy and through longevity. The King Air range is very much one such aircraft with more than 7,300 of its many variants taking to the skies over more than 50 years.
The first King Air was introduced in 1964, back when Sir Robert Menzies was the Prime Minister and The Beatles were on tour in Australia. From its genesis as the smaller Model 65-90, the twin turboprop King Air has grown in both dimensions and reputation. Through the highly successful 200 series, which was originally known as the Super King Air, the aircraft was ultimately developed into the 350 and to date over 1,200 of the model have been built.
Sitting on the ramp outside Hawker Pacific’s FBO at Sydney Airport, Textron’s Beechcraft King Air 350i demonstrator is having a rare stationary moment on its extensive tour to the region. Appropriately registered N350KF, it cuts an impressive pose in its red, white and black scheme, highlighted by the towering T-tail rising to 4.37m and the winglets that rise at each end of the 17.65m wingspan.
The King Air has always had a proud stance, although the practical aspect behind the aesthetics is that standing tall on its tricycle undercarriage provides propeller and engine intake clearance on the unprepared runways that the versatile King Air may be called to operate from. Away from the ground, the aircraft has a maximum ceiling of 35,000ft and a maximum cruise speed of 312kt, although the latter is achieved at 26,000ft.
Not obvious to the eye are the performance figures that underpin the 350i. While certified for single-pilot operations, it is also certified under the Part 23, or ‘commuter category’, requirements. Firstly, this means that pilots require a specific type endorsement to fly it and secondly, it conforms to the rule set that calls for the aircraft to safely continue the take-off in the event of an engine failure within required performance margins and obstacle clearances. Like jet transport aircraft, the King Air 350i must have a nominated decision speed before which it can reject the takeoff with adequate runway to stop and from which it can continue a single-engined takeoff.
Breaking that down into basic numbers it means that the aircraft needs 1,006 metres to takeoff at maximum takeoff weight (MTOW) at sea level in ISA conditions and 820m to land and maximum landing weight (MLW). Furthermore, the MTOW and MLW are both 6,800kg meaning that an immediate return to land is not an issue for the King Air.
Possibly the most attractive aspect of the aeroplane’s performance is its ability to ‘gas up and go’. For so many aircraft, operations are a continual compromise between the uplift of fuel and the uplift of people and payload. The 350i has a range of over 1,500nm, yet when a single pilot seats eight passengers in the cabin, allowing 90kg for each person, the range is still greater than 1,400nm – that’s Sydney to Cairns.
The legs are even longer on the Extended Range (ER) version as it can carry an additional 717kg (1,580lb) of fuel in its nacelle tanks, which in turn increases the MTOW. Accordingly, the ER model has heavyweight landing gear to compensate, but in return there is 700nm of additional range which is particularly useful in search and rescue and special mission roles.
On paper the King Air 350i is impressive and it is no less so in the flesh.
Art meets science
Textron demonstrator pilot Karen DeMauro is already at the base of the air stair entrance when I arrive at the aircraft. However, before we climb aboard there is a great deal to see on the outside that speaks volumes about the aeroplane.
As we commence our walkaround Karen points out the nacelle lockers, which give way to fuel tanks on the ER version. With a 136kg capacity each side, the lockers are long and suitable for skis or golf clubs and one would suspect that the lockers generally bulk out before they reach their weight limit.
Along the trailing edge are the Fowler flaps with an initial extension speed of 202kt and a full extension speed of 158kt and the system has automatic flap asymmetry protection. Accordingly, if there is a difference in the degree of flap extension detected between the two wings, the system stops extension to prevent any unwanted roll moment that may occur. The combination of flap speeds and a landing gear extension speed of 182kt make it easy to appreciate that drag is very manageable and the aircraft is relatively straightforward to slow down when entering the terminal area.
The more demanding Part 23 certification requirements soon become apparent through the level of redundancy on the aircraft. Each landing gear has a pair of tyres, yet it can clear the runway and taxi if one tyre should deflate. Each flight control surface has dual pushrods, even though a single pushrod to the elevator, aileron or rudder can still actuate the control surface if needed. Each engine has a 300-amp electrical generator capable of supporting the entire system without shedding its load should a generator fail, and a dual bleed air system offers the same degree of redundancy for pressurisation and anti-icing.
The upturned, composite winglets are marked with the 350i name tag and tipped with static-wicks. In offering an effective increase in the wingspan of one metre, the winglets increase fuel efficiency while Karen emphasises that their major benefit lies in reducing the time taken to reach cruising altitude.
Within the wings are held a total of 1,635kg (3,600lb), distributed through pairs of main and auxiliary tanks, although the pilot’s interface with the system is that it is simply left wing and right wing, with no management required between the various tanks.
As the aircraft is approved for flight into known icing, the leading edges of the wing, like the tailplane, host pneumatic de-icing boots. There is also icing protection on the four-bladed, 2.67m Hartzell propellers and while not a major issue in Australia, there is ice protection on the brakes.
What can be significant in Australia is the use of the ice vanes located in the engine intakes, but not as you may think.
Designed to protect the engine from ice ingestion, the vanes deflect the ice down and out of the engine before it can enter the engine. Interestingly, the vanes can also be used to guard against foreign object damage from ingestion on runways and taxiways in exactly the same way.
Dominating the wings of the King Air are the equally revered Pratt & Whitney PT6 engines, which have a heritage parallel to the King Air’s. The 350i is fitted with the PT6A‑60A which is flat-rated to 1,050shp and features a time between overhauls (TBO) of 3,600 hours. The engine is even certified to operate for 150 hours between overhauls using AVGAS as a measure to avoid an aircraft being stranded in the absence of turbine fuel. That being said, AVGAS is becoming the rarer commodity these days.
The engine is also very well thought out with its accessories and hot section (1,800 hours HSI) located at the rear of the engine. Easily accessible, this reduces maintenance downtime and costs.
Each engine is also equipped with auto-ignition and in the event of an engine failure it will firstly attempt to relight the engine. If that is unsuccessful, it will then automatically feather the propeller to reduce drag.
At the other end of the aeroplane, the large rudder will also play its part automatically with rudder boost, offsetting the yaw created by the asymmetry of the failed engine.
From the pilot’s perspective, this reduces the workload significantly in an engine failure after takeoff (EFATO) and allows the focus to be centred on flying the aeroplane, retracting the landing gear and climbing away at the best single-engine rate of climb (Vyse) or ‘blue line’ – a speed of 125kt in the King Air 350i.
From the outside the King Air is immediately recognisable, but it is the closer inspection that reveals the functionality and redundancy contained within those clean lines. And it is a characteristic that extends within the King Air as well.
The commonsense approach of the King Air continues as you approach the air stair to enter the cabin. The stair itself has a hydraulic damper for ease of operation, while dual seals surround the door frame, supporting the pressurisation system and reducing noise in the cabin. On entry, the baggage compartment is to the right, towards the tail, allowing inflight access to luggage. Also in the aft cabin, a toilet seat is concealed within a fully functional sideways-facing seat with a harness. For privacy, the area can be isolated by a pair of solid, sliding doors.
Entering the main cabin, eight seats are arranged in a double-four, club seating arrangement while the ‘square oval’ cabin cross-section has a ceiling height of 1.45m. With a cabin differential of 6.5psi, drop-down oxygen masks and the ability to maintain a ‘sea level cabin’ to 16,000ft, the King Air is well suited to aeromedical operations, as history has shown, time and again. The air-conditioned cabin features the King Air’s distinctive large round windows, which can have their level of shading individually controlled. However, when the aircraft is unpowered on the ground, all the windows automatically become dark for both privacy and to keep the cabin cool.
The cabin fitout features a blend of leather and highly polished wood, reminiscent of any business jet with which the King Air may be compared. One impressive cabin feature that cannot be readily seen, in addition to standard Wi-Fi connectivity, is the 350i’s passive noise reduction system. Two types of dynamic cabin absorbers are fitted throughout the aircraft to reduce cabin noise and vibration levels. Airframe-mounted 100 Hz absorbers are set at the same frequency as the propellers, while 200 Hz skin-mounted absorbers are tuned into the same frequency as the skin’s harmonics. Unpowered and totally passive, the devices do not require ongoing maintenance.
The front of the cabin opens into the cockpit and immediately there is the familiar King Air feel, but with a very new edge. A new edge that goes by the name of Fusion.
The world of avionics evolves at an incredible pace and Rockwell Collins has long been a leader in the field. However, its latest offering in the form of the Pro Line Fusion suite is something to behold and even better to operate.
At first glance, the most striking elements are the three 14in widescreen LCDs that fill the flight instrument panel. Featuring synthetic vision, ADS-B Out, TCAS II and the ability to move various displays and their information about in a variety of formats, there is an additional element that is not so obvious – touchscreen functionality.
Everything from planning a weather diversion or setting the QNH, to accessing a checklist or selecting the flight director presentation can be done by touching the relevant LCD screen. Unlike most mobile devices where the screen is heat-sensitive, the Fusion screens are pressure-sensitive, requiring a positive force to make a selection, allowing the wearing of gloves and significantly reducing the possibility of an inadvertent selection by an unsteady hand in turbulence. Further indicating forethought, the edges of the three large screens have a roughened edge, allowing the rest of the hand to grip while the chosen finger makes the selection.
Between the two seats and aft of the throttle quadrant, the Proline keyboard and cursor control panel remains and offers an optional means of operating the system. It would seem that this is still the preferred method for a few of the tasks associated with the system, but the touchscreen philosophy has been well received for the majority of tasks.
Karen has already pre-programmed the route for our flight, so it is time to take our seats and see the King Air 350i and the Pro Line Fusion system in their element.
Seated in the left seat, the pressurisation panel to the left, the switches to the lower panel, the central throttle quadrant and even the control yoke will be familiar to any King Air pilot. Switching the battery switch to ‘ground’ powers up one primary flight display (PFD) and allows the aircraft to be readied for flight with the ammeter overhead showing barely an amp being drained from the battery.
Karen runs through the flightplan that she has loaded that will see a departure from the harbour city, south to the coastal township of Nowra before heading west and returning via one of the standard arrival routes.
Starting the PT6A engines is a simple process of spooling up and introducing fuel to ignition for the engine to quickly stabilise. With both engines running, both electrical generators are online, and each are checked independently for their output.
The Fusion display is impressive, and Karen has selected a format across the three screens, left to right, of primary flight display, a combination of engine instruments, Jeppesen chart and map display centrally and a condensed PFD and flightplan ahead of the right-hand seat. With airways and taxi clearance we move from the Hawker Pacific FBO with only a touch of power and when required moving the power levers aft through one detent to ground fine negates virtually any need for using the brakes when taxiing.
Accessing the checklists through the Fusion system and touchscreens introduces me to an immediate advantage – keeping one’s eyes outside the aircraft. The geometry of the system calls for only a partial lowering of the eyes to access any information that a pilot may require. On certain systems, even setting the QNH can be a challenge for the uninitiated.
To set Vspeeds on our way out to the runway, Karen simply asks me what would my intuition suggest I touch to set the speeds, to which I reply, “The airspeed tape on the PFD”. I was correct and touching the tape brings up a box and the speeds can be entered.
It is all extremely user-friendly and calls for minimal concentration or focus to be drawn from taxiing the aircraft.
Lining up at Sydney for a northerly departure, digital checklists are ticked off and we are cleared for takeoff. Advancing the power levers fully forward, the King Air accelerates quickly and smoothly with the Interstage Turbine Temperature (ITT) well below the 820-degree limit. Through V1, and rotating shortly afterwards, with the RPM set at 1,500rpm and the initial climb speed of 130kt, the aircraft is climbing away impressively, and I am reliably informed that at maximum weight it will climb on one engine at around 550ft/min.
The aircraft is an absolute joy to hand fly. The RPM is left at 1,500 RPM for the entire climb while the power levers are progressively inched up to their limit with increasing altitude and one eye on the ITT. Through all the turns, intermediate level-offs and climbs there is a really solid feel and sense of balance within the controls of the King Air. I reluctantly engage the autopilot to take in what else the King Air has to offer.
Setting an attitude of 5 degrees and still 1,500 RPM, the aircraft cruise climbs comfortably at 180kt. For pilots and passengers alike, the good news is that the noise-dampening devices obviously work as this is quite possibly the quietest twin-turboprop that you will ever fly in.
Along the way we amend our flight plan, change frequencies and pull up new charts through the touchscreens, and within a very limited timeframe Karen has me performing the tasks on my own. The Pro Line Fusion system is not only very capable, it is also extremely intuitive. Combined with the impressive synthetic vision and the map display, the product of these factors is a greatly enhanced situational awareness.
Levelling in the cruise at FL260, we modify the flightplan through a combination of the touchscreen and the cursor and keypad. Karen relates that pilots have their individual preferences for certain tasks and generally use a combination for their flight management.
To fully demonstrate the functionality, Karen draws a ‘weather diversion’ on the map display with her index finger. It not only creates waypoints in the flightplan, but automatically modifies the flight time and fuel remaining. Enhanced situational awareness once again.
Outside, the atmosphere is 10 degrees warmer than standard and I note the fuel flow as 310lb (140kg) per hour per engine and a true airspeed of 305kt. Checking the manual, the aircraft is performing virtually right on the book figures. In true pilot style, Karen has a rule of thumb, or in this case, her ‘Rule of Threes’. At FL300, 300lb/hour per engine and 300kt true airspeed. I like it.
With our return to Sydney via a standard arrival programmed into the system, the top of descent and descent speed and altitude restrictions are clearly displayed. As we head down, the synthetic vision portrays Sydney Airport in the distance as a white dome with an extended centreline for our programmed runway. It is long before we can visually acquire the airport, but once again offers a great sense of orientation.
Over the top of Sydney at 6,000ft and rolling into a right-hand circuit for runway 34 Right, one cannot help but be impressed by this aircraft. Conforming to air traffic control speed restrictions and slowing down for the approach could not be simpler. With the torque set at 25 per cent, the flaps and landing gear are extended in sequence with no need for a change in power and minimal adjustment of trim. Personally, it is in fact smoother to use the old-style trim wheel near the right knee rather than the electric trim switch on the yoke.
On approach and over the threshold, the King Air responds like a stable training aircraft rather than the high-performing twin that it is. It settles onto the runway nicely despite my efforts to the contrary and after only an hour we are back in Sydney.
A dominant force
An aircraft does not earn a reputation like the King Air’s easily. Pilots and engineers are a critical group, and yet I am still yet to find one who has not been impressed by the King Air.
Now equipped with the Collins Pro Line Fusion, an already formidable aircraft has enhanced the pilot and passenger experience even further. For the pilots there is simplicity and improved situational awareness, while the passengers benefit from a cabin boasting levels of quiet comfort normally found in business jets.
It might seem difficult to build further upon the King Air’s already revered reputation, but the 350i has done exactly that. One can only wonder what is next in store for this stylish stalwart of the skies.
This feature story first appeared in the January-February 2018 issue of Australian Aviation.