When the 850 is operating at any typical cruise power setting all the way up to the 31,000-foot ceiling, the new bleed air system taps a lower pressure section of the engine compressor, which robs less power from the engine. If the pilot wants to make a rapid descent from high altitude and reduces power to at or near idle, a system of valves move and tap bleed air from a higher pressure section of the engine compressor and the cabin stays pumped up and nobody's ears pop. TBM pilots can select to use the high-pressure bleed air continuously and give up the extra power, but the automatic mode is the norm, and will be used except in abnormal conditions. As I said, this is a typical pressurization bleed system in many jets, but is a new level of sophistication in this class of airplane, and for the price of some additional plumbing and valves, increases high-altitude cruise for almost no more fuel burn.
Since the design objective for the 850 was to increase high-altitude cruise speed, and everybody was pretty happy with the TBM's takeoff and initial climb performance, the decision was made to keep takeoff and initial climb power at 700 shp. The 850 weighs the same as the 700, which can use runways of 3,000 feet, so the decision makes sense. The 850 also retains the 700's torque limiting system during takeoff and normal airport maneuvering, which protects the engine and reduces pilot workload.
The flap selector in the 850 has a new, fourth position. It retains the flaps up, takeoff, approach and landing positions of the 700, but when you move the selector to the new detent beyond flaps up, the torque limiting system is disengaged and the full power of the new engine is available for climb and cruise. In this mode the pilot must observe torque limits by restricting power lever movements, but this mode is the normal mode in nearly all other PT6-powered airplanes.
I had a chance to fly the first TBM 850 off the production line at the company's U.S. headquarters in North Hollywood, Florida. No matter how closely I looked, I couldn't spot an external difference between the 850 and 700s that were parked nearby. The reason is that there aren't any, except for the most subtle reshape of the exhaust stacks on the new engine. When you open the cowling you can see the second shiny bleed air pipe for the dual tap system, but that's about it for external differences. The 850 weighs about 20 pounds more empty than the 700C2 that it supersedes, and most of that weight is accounted for by the pipes and valves of the new bleed air system.
The new TBM 850, like the 700, is a very complete airplane as standard. The dual Garmin GNS 530 GPS/flight management systems are standard, as is the electronic flight instrument system (EFIS) from Bendix/King. Pilots can choose XM Weather or the Bendix/King system to deliver weather to the cockpit. Everything else you need, including the equipment for reduced vertical separation minimums (RVSM) to fly above 28,000 feet, is available. The one major airframe option is a crew door that allows the pilots to enter ahead of the wing after passengers have been loaded and the huge main cabin door closed. This has become a popular option, though if it were my airplane, I would leave it off. The TBM cabin is large enough to climb into the pilot seats from the main cabin without unusual gymnastic ability. The cockpit space and room to maneuver is certainly on par with existing light jets.
The TBM cockpit has a big airplane feel about it, as you would expect from a company whose parent is part of the group that builds the Airbus. The systems are of modern design, which means they have a high level of automation. There is little to system management in flight, except to make sure you have the necessary fuel onboard. The fuel selector is also automated and a big knob rotates from one tank to the other on its own, to maintain fuel balance. The TBM is, obviously, a single-engine airplane and that means it must stall at 61 knots or less at maximum weight, and has demonstrated that after one turn with pro spin controls applied, the airplane recovers in less than an additional turn even at extremes of weight and CG location.