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View Full Version : Region of command. Confused


diego5614
12-24-2018, 03:26 PM
Personally, I feel that the way the instrument flying handbook explains the two regions of command is a little confusing for me. From MY understanding, in the region of normal command, a pilot can pitch for altitude and use throttle for airspeed. However, in the region of reverse command, the pilot uses pitch for airspeed and throttle for altitude.

Don't get me wrong, I understand that in slow flight pitch is for speed and throttle is for altitude control. My only question is...is this what being "behind the power curve" means? is this what the region of reverse command is all about? What about the region of normal command?

If someone could clarify this for me, I would really appreciate it!
Thanks guys and merry xmas!


galaxy flyer
12-24-2018, 05:10 PM
Yes, you’re conclusion is correct, however, “being behind the power curve” can imply that recovery is only possible by trading altitude for airspeed while “reverse command” implies there’s sufficient thrust/power to maintain level flight. The Concorde flew final in “reverse command” as did a number of fighters.

GF

ToastAir
12-24-2018, 05:54 PM
Any further decrease in airspeed requires an increase in power to maintain alttitude (or constant decent rate) in the area of reverse command. In the normal area, a decrease of airspeed requires a decrease of power to keep from climbing (or slowing decent rate)


PerfInit
12-25-2018, 06:25 PM
Region of reverse command - It takes more power to fly slower. Its where induced drag increases exponentially until you get to the critical (stalling) Angle of Attack.

rickair7777
12-26-2018, 07:29 AM
Most "normal" airplanes are not routinely operated on the back side of the power curve... if speed bleeds off a little bit, you get more drag, which bleeds more speed, causing even more drag and you keep slowing and can stall if you're not paying attention. A certain large regional had multiple high altitude stalls because they were assigning cruise speeds which were right on top of the power curve... if anything happened to reduce speed or increase drag, the speed would slowly fall off the back of the power curve.

If you're on the front of the power curve and you lose some speed, drag will also drop and the airspeed drop will stabilize at a slightly lower value. Basically the front of the power curve acts as a backstop.

sourdough44
12-27-2018, 03:48 AM
I’ve seen longer discussions about what controls what when it comes to pitch or power. Depending on what you want to do you could use either.

One could stay at idle, dump the nose, and speed up.

One could also stay level, add a bunch of power, and speed up, while trimming for level flight. Then we have a combination of the two.

Keeping it simple ‘power plus attitude, equals performance’.

Behind the ship pitch controls AOA, power controls rate of descent. No need for absolutes, I like ‘whatever it takes’.

I’ve really never spent time on reddit, from what I hear they go on & on about such things.