The King of Versatility

Jets are sexier and more capable than propeller airplanes, right? Having flown the Beechcraft King Air 350i, I’m not so sure. Hawker Beechcraft Corporation (HBC) brought the newest and largest member of its successful King Air line to the Canadian Business Aviation Association (CBAA) convention in Toronto this past June, to show off its new and improved flagship turboprop. HBC was keen to demonstrate that it can stack up against the light jets. After flying the King Air 350i, I came to see that it does much of what a jet can do, and a whole lot more.

The King Air line of turboprop twin-engine airplanes needs no introduction. Beechcraft has sold over 7,000 of the solid, iconic King Airs since the original Model 90 was first introduced in 1964. King Airs have endured because they have proven themselves versatile and capable. They have carried charter passengers, served as military trainers, conducted aerial surveys and completed maritime patrols. A King Air has even carried the President of the United States as Air Force One.

The history of the King Air is a complex family tree that spans almost 50 years of development, but today’s reigning sovereign of the King Airs is certainly the model 350i.

AN AUDIENCE WITH THE KING

The King Air 350i has an impressive ramp presence, exhibiting the familiar family resemblance of the King Air dynasty, but seeming in every way more imposing and massive. I was privileged to fly the King Air 350i with HBC senior sales demonstration pilot, Mark Mohler. A hazy, hot summer afternoon full of thunderstorms was giving way to a crystal clear evening as we spent some time going over the 350i’s new interior amenities.

Hawker Beechcraft markets the 350i’s spacious interior as an attractive alternative to light jets. While most jets are indeed faster, HBC claims that the average business trip length is 300-600 nautical miles (nm), often making the 350i not only competitive for travel time, but preferable in terms of cabin space. There is no doubt that the 350i’s interior would be a comfortable place to travel. The cabin layout makes good use of space. Passengers enter via the aft cabin air stair, and can deposit their gear in the aft baggage compartment as they enter. That compartment is heated, pressurized and accessible in flight. Various seating arrangements are possible in what HBC calls its “FlexCabin,” but the nine-passenger interior seemed the most practical; eight passengers, that is, plus the side-facing belted potty. Configured in a double club arrangement, the demonstrator aircraft, N350BZ, included the Rockwell Collins Venue high definition cabin management system and an optional vanity in the aft cabin across from the air stair door. Each passenger seat is a reclining, articulating, oh-so-comfortable leather affair, and includes what Beechcraft calls a programmable switch panel. These control units allow access to all of the functions of the Venue system: audio or video feeds, lighting, optional seat warmers and the way-cool electrochromic window shades.

After sampling the comforts of the cabin, I slipped into the left seat; surroundings that would be immediately familiar to any of the thousands of pilots who have flown King Airs over the years, despite the inclusion of newfangled features such as the Rockwell Collins Pro Line 21 avionics suite. The King Air 350i is clearly an evolutionary design, mixing the old with the new. It retains the legacy layout common to all Kings Airs, such as the fuel panel on the left cockpit sidewall and the traditional large, solid Beechcraft yokes. Despite the Pro Line 21’s potential for systems integration, the lower instrument panel offers the traditional forest of toggle switches to interface with systems such as lights, pressurization and de-icing.

The 350i is certified for single-pilot operation, and although the cockpit was well laid out, secondary gauges such as vacuum and pneumatic pressure gauges were difficult to see where mounted outboard of the right yoke.

GOING FOR A QUIET RIDE

To flight test the 350i, we planned a route from Toronto Pearson airport toward the Wiarton navigation beacon (VOR), then descending to the Waterloo airport for some circuits before returning to Toronto. For our flight, the demonstrator aircraft had a basic operating weight of 10,224 pounds inclusive of two crew. There were 2,400 pounds of fuel onboard and 100 pounds of baggage, which brought our takeoff weight to 12,724, or 2,276 pounds below the maximum takeoff weight of 15,000 pounds. As a well-appointed demonstrator aircraft, N350BZ had an empty weight about 150 pounds higher than the advertised basic operating weight. Nevertheless, after uploading a full 3,611-pound fuel load, our aircraft had a payload of 1,165 pounds, enough for six passengers and a bit of luggage. With full fuel, HBC claims a range exceeding 1,500 nm at a high speed cruise power setting, including IFR reserves.

Start procedures in the paperless cockpit benefitted from the Pro Line 21’s integrated electronic charts and checklists, although my unfamiliar fingers fumbled a bit with the controls. In minutes, we had the flight management system (FMS) programmed with our routing and weights, and the integrated performance database proceeded to load our V-speeds onto the primary flight display (PFD). Configured for a flapless takeoff, our takeoff decision speed (V1) was 98 knots indicated airspeed (KIAS), our rotation speed (VR) was 104 KIAS, and the takeoff safety speed (V2) was 111 KIAS. The calculated takeoff field length was an impressive 3,550 feet.

Ground handling via pedal-operated nosewheel steering was solid and predictable. Speed control was easily managed with tiny throttle movements, although there was a noticeable small surge as the throttles were advanced from idle. The cockpit field of view was panoramic, allowing me to scan around to both wingtips while taxiing. We taxied from the Toronto Skyservice ramp and negotiated with air traffic control for a place where we could do our run-up checks. We checked the overspeed governors, the rudder boost, autofeather and pressurization systems. The procedures were straightforward, but are nevertheless a small additional complication that comes with flying a turboprop.

Mohler directed use of 80 per cent torque as a standard takeoff power setting, respecting the engine power limitation of 100 per cent by allowing for about a 10 to 15 per cent torque increase during the takeoff roll, due to ram air pressure rise into the inlets. Power on the King Air 350i’s 1,050 shaft horsepower Pratt & Whitney Canada PT6A-60A engines is manually regulated, and I found the throttles a touch sensitive. Just prior to brake release, Mohler offered the advice that I should be prepared to use some right rudder against torque. I take such casual guidance from demonstration pilots as a Big Fat Hint. I ran the power up, released the brakes, and watched my right foot rediscover propeller torque! The technique wasn’t difficult, but it was one more subtle reminder that this wasn’t a jet. The takeoff acceleration was very satisfying, and at rotation speed a pleasantly solid pull on the yoke was required to get us heading upstairs.

To my surprise, Toronto Centre cleared us to climb directly to flight level 220 (22,000 feet). Engine torques were initially set at 90 per cent, and we monitored power in the climb, adjusting the throttles as required as the engine power slowly became limited by the 785 degree Celsius interturbine temperature (ITT) limit. Mohler helped time our climb from 10,000 to 20,000 feet, which yielded an average climb rate of 2,048 feet per minute under conditions averaging 17 degrees above standard (ISA+17C). It was a very respectable performance.

In the climb, I took the opportunity to slip off my headset and sample the cockpit sound level. “Remarkable,” I muttered. “Isn’t it?” Mohler replied, in a soft but audible voice. With the props spinning at 1,600 RPM just outside our windows, the ease with which we could converse in the cockpit was surprising. Mohler emphasized that the sound level in the cabin is even lower. Although I never slipped out of the left seat to check, I believe him. HBC has invested a considerable amount into reducing cabin sound levels. In lieu of the previous active noise suppression system, the 350i uses a sophisticated passive acoustic suppression system. Mohler proudly described the four components of the system, which consisted of the following: “Scotchdamp” material bonded to the interior of the fuselage skins; 89 small “tuning fork” vibration dampers attached to the fuselage and tuned to the 1,500 RPM cruise propeller frequency; 862 honeycomb skin dampers bonded to the aluminum skins; and 151 tuned vibration absorbers attached to the skin dampers. Clearly, giving passengers a quiet ride is an important part of marketing a VIP turboprop.

DO YOU STILL WANT A JET?

We let the autopilot level off at flight level 220, at an outside air temperature 10 degrees Celsius above standard (ISA+10 C), and let the King Air 350i settle into cruise. The engine torques were set at 85 per cent, the maximum cruise power setting, with the propellers turning at the prescribed 1,500 RPM. The FMS indicated that our weight was 12,320 pounds. The airspeed stabilized at 217 knots indicated airspeed (KIAS), which equated to a true airspeed of 307 knots (KTAS). We were burning 380 pounds per hour, per engine. It was nice to see that the gauges agreed with the FMS performance predictions perfectly.

This was a very respectable speed for a turboprop airplane; but alas, it’s still a prop job, isn’t it? A jet would fly higher and faster, right? Well, that’s almost certainly true, but let’s look at a simple scenario to assess the performance trade-offs. Imagine a medium-range mission typical of a turboprop or a light jet, recalling HBC’s contention that most business trips are only 300-600 nm in length. Let’s link two national capitals by flying from my hometown of Ottawa, Ont., to Dulles Airport in Washington, DC. The straight line distance is 391 nm. We’ll further imagine that our light jet competitor (the latest development from a well-respected Wichita manufacturer…no points for guessing) cruises at 450 KTAS. Allowing for published climb performance, the King Air 350i would be overhead the destination only about 24 minutes after the jet. En route, the passengers would enjoy a comparably spacious cabin, but the King Air 350i would burn significantly less fuel. HBC quotes direct operating costs of US $1,090.98 per hour.

In that light, does the jet still retain such a strong advantage? HBC doesn’t think so. With its executive interior, cabin entertainment system and impressive attention to soundproofing, the King Air 350i clearly offers a viable alternative to a light jet. It’s real strength, however, is its diverse mission potential. Need to haul outsized cargo? Load stretchers? Operate from short or unprepared fields? The King Air 350i offers versatility that most jets cannot match.

Admittedly, time to destination is not the entire story. Although it’s certified to flight level 350 (35,000 feet), with a maximum cabin pressure differential of 6.6 pounds per square inch (psi), the passengers would be exposed to a cabin altitude of 10,000 feet; certainly a comfort factor. Furthermore, such comparisons to a jet presume that the King Air 350i cruises at altitudes in the mid-20’s where it achieves its best performance. Such altitudes don’t always clear the weather or offer the smoothest ride.

It was time to return to earth, and as if to demonstrate that the patriarch of the King Airs lacked nothing in modern capabilities, Mohler helped me set up the avionics for an autopilot-coupled GPS localizer performance, vertical guidance approach (LPV) to Runway 26 in Waterloo. We followed our progress on the georeferenced digital approach charts as the avionics capably took care of the steering. We weighed about 12,000 pounds on landing, which made our approach reference speed (VREF) 100 KIAS. The FMS specified a landing distance of 2,500 feet, which would have been easily achievable, except that we did a touch and go and proceeded back to Toronto.

En route to Pearson airport, I sat back to collect my impressions of the King Air 350i. It flies like a King Air, and I don’t expect that I can say anything new about an airplane as mature and familiar as that brand. The handling in every phase of flight was solid, stable, benign and predictable. It’s a good ol’ airplane, but in the case of the King Air 350i, equipped with very modern and capable systems. I don’t mind admitting that I enjoyed every minute in it.

LEADING TURBOPROP IN ITS CLASS

The King Air 350i certainly impressed me in terms of its handling, cabin comfort, and field performance, but the final analysis of any airplane is how it stacks up against the competition. This question lead to a surprising observation. What competes with a King Air 350i? Virtually nothing. Ideally, the competition would be comparable turboprop twins. But relatively few turboprop twins are currently in production, and none are directly comparable. Neither the Piaggio Avanti nor the new Viking Twin Otter serve quite the same market. As HBC’s emphasis upon the light jet market implies, the versatility of the King Air 350i allows it to nibble away at the market for a wide variety of airplanes. The single-engine Pilatus PC-12, for example, although a considerably smaller airplane, might vie for the same attention as the King Air 350i. At the other end of the food chain, as we’ve said, the King Air 350i is a sufficiently plush and capable people-mover that it could attract interest from bizjet operators. While many airplanes are capable “point designs” for a specific mission, the strength of the King Air 350i is the range of missions on which it would do a creditable job.

After 48 years of design evolution, the biggest and most capable of the King Airs still turns heads. Impressive versatility is the hallmark of this iconic design. With respectable turboprop cruise performance and a spacious, comfortable cabin with robust systems, the King Air 350i is ready, willing and able.

A graduate of the U.S. Naval Test Pilot School, Rob Erdos is an experimental test pilot licenced for fixed- and rotary-wing aircraft. In addition to being an engineering graduate from the Royal Military College, and holding a masters degree in aviation systems research, Rob is a former Canadian Air Force SAR pilot. An avid airplane builder, and a passionate flyer of historical aircraft for Vintage Wings of Canada, Rob flies such iconic planes as the Spitfire and Hurricane.