The huge 355-cubic foot cabin is the 350's primary attraction, but until recently there wasn't enough cooling capacity to make the cabin comfortable on the ground and early in flight on very hot days. Beech solved that problem with a new environmental control system that increases cabin airflow by more than 250 percent. The system was developed by air conditioning experts at Keith Products and has now been incorporated into production airplanes. Included is an automated temperature control system that allows pilots to select the temperature for the cockpit and cabin individually. There are now seven outlets in the glareshield to cool pilots sitting in the hot sun, and the entire system weighs 35 pounds less than the manually controlled, less powerful system it replaces.
One of the best features of any King Air cabin is the big, round windows, and the 350 has seven of them on each side. The structure between the windows is so narrow I have the sensation of the whole cabin side being one big window. You can rotate a polarized inner window pane to reduce sun intensity. Several years ago Beech had problems with the polarization fading over time, but that seems to be resolved and every passenger can select their own level of light coming in the window.
Beech also has restyled the cabin chairs with recessed headrests, retractable armrests, and inboard and outboard tracking. The cabin overhead has indirect lighting that glows softly from a geometric pattern that surrounds cabin air outlets and reading lights. And cabin furniture has been upgraded with a large hot and cold beverage unit forward, plus pyramid-shaped cabinets between the seat backs. The entire cabin and exterior fit and finish, as well as materials, has returned to what most of us know as traditional Beech quality after a period where the company had failed to live up to its reputation.
Collins Pro Line 21 avionics, with dual flat-screen primary flight displays (PFD) and central multifunction display (MFD), are standard, along with the basic file server that allows the system to show weather and charts. The Pro Line 21 system includes a single flight management system (FMS) that can be used for all navigation, including the new GPS approaches with vertical guidance. You can dial com and nav frequencies using the FMS keyboard or the knobs on the single radio management unit in the panel. And I'm pleased to report that the automatic flight control mode selection panel is located on the glareshield instead of down in the pedestal where it resided out of sight for many years.
The 350's systems, as they must be to meet commuter category rules, have a high level of redundancy. The main electrical bus is fed by both generators and the battery, and this triple-fed bus can support essential equipment from any of the three sources, which are in turn isolated from each other. Nonessential loads are automatically shed if generators are lost. The fuel transfer system from tank to tank and to the engines is automatic with no pilot intervention required. And an all-electronic standby display in the middle of the panel shows attitude, heading, airspeed, altitude and nav guidance independently of the primary air data computers or attitude-heading reference systems.
With its up-to-date flat glass panel, but its traditional toggle switches and big throttles and propeller control levers, the 350 is an interesting mix of the old and new. In most respects, I generally forget that the airplane is a turboprop and not a jet, because the avionics and size of the airplane are so like a jet. And I think passengers don't think much about the propellers, either - except on the ground.
The 350 has automatic propeller feathering and rudder boost to immediately feather the prop if an engine fails on takeoff and to step on the proper rudder to overcome the asymmetric thrust. An engine failure in the 350 is virtually identical to the loss of an engine in a jet because the autofeather immediately eliminates the drag of the windmilling propeller on the failed engine. As you can imagine, autofeather and rudder boost are required items, and that means they need to be tested once each day. The test requires a ground run-up to high power to check each system, and that's when passengers are reminded the 350 is not a jet. Pilots who want to give their passengers the best possible experience will do the high power run-up before loading the people on the first flight of the day.