Unusual Attitudes
04-27-2009, 07:04 PM
#1
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Unusual Attitudes
I have been doing unusual attitude recoveries under the hood successfully for a long time but have always wondered why I've been instructed to add power before lowering the nose in a nose-high attitude. Isn't lowering the nose the only surefire way to prevent a stall? If you just add power, couldn't you still mush (nose-high) into a stall if you don't lower the nose quickly enough?
04-27-2009, 07:22 PM
#2
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You are correct if you just add power, you still can stall i.e. power-on stall. But if you don't add power the probability of stalling is significantly higher. I teach my students to simultaneously add power and pitch for straight and level. Being able to do mulitple things simulateously is why flying is done with just one hand on the yoke.
Ask your instructor why he/she has you do it that way too. There are a lot of things that instructors teach differently, often its not a difference of right and wrong. It has more to do with how each person's thought process occurss and what makes sense.
Ask your instructor why he/she has you do it that way too. There are a lot of things that instructors teach differently, often its not a difference of right and wrong. It has more to do with how each person's thought process occurss and what makes sense.
04-27-2009, 07:36 PM
#3
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Originally Posted by fjetter
You are correct if you just add power, you still can stall i.e. power-on stall. But if you don't add power the probability of stalling is significantly higher. I teach my students to simultaneously add power and pitch for straight and level. Being able to do mulitple things simulateously is why flying is done with just one hand on the yoke.
Ask your instructor why he/she has you do it that way too. There are a lot of things that instructors teach differently, often its not a difference of right and wrong. It has more to do with how each person's thought process occurss and what makes sense.
Ask your instructor why he/she has you do it that way too. There are a lot of things that instructors teach differently, often its not a difference of right and wrong. It has more to do with how each person's thought process occurss and what makes sense.
04-27-2009, 07:51 PM
#4
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Well, feds usually like to see you do the 3 things separately, power, pitch, level the wings. Its a lot more obvious in a nose down attitude.
1) Control airspeed (reduce power)
2) Reduce load factor (wings level)
3) Control pitch (pull up)
The perhaps more important part of the equation is doing the pitch and bank in the correct order. You dont want to unload (pitch down) the airplane after you have already taken the bank out.
You also do not want to increase load (pitch up) before you take the bank out because you dont want to increase G's and you also want the pitch up more effective...no horizontal component of lift.
1) Control airspeed (reduce power)
2) Reduce load factor (wings level)
3) Control pitch (pull up)
The perhaps more important part of the equation is doing the pitch and bank in the correct order. You dont want to unload (pitch down) the airplane after you have already taken the bank out.
You also do not want to increase load (pitch up) before you take the bank out because you dont want to increase G's and you also want the pitch up more effective...no horizontal component of lift.
04-28-2009, 03:15 PM
#5
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I think the reason why throttle first applied is that it generally controls rate of descent which may or not be critical in respect to altitude...but you are correct, if a real departure or accelerated stall occurs only pitch will recover...but an approach stall would be to add power first because it would equally reduce AoA and control altitude loss ...the real key to avoid a secondary stall would be to reduce back pressure...if it still stalls it's probably a CG issue
04-28-2009, 05:19 PM
#6
Flying Farmer
Joined APC: Jul 2006
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I always taught it as:
With a high Pitch: Pitch, power, level
Low Pitch: Power, level, pitch.
Now, the difference in timing between the first step and the last one shouldn't be more than 1 second IMO, that's how I know you know what you're doing, but that's just my style.
With a high Pitch: Pitch, power, level
Low Pitch: Power, level, pitch.
Now, the difference in timing between the first step and the last one shouldn't be more than 1 second IMO, that's how I know you know what you're doing, but that's just my style.
04-28-2009, 08:44 PM
#7
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We all know that an airfoil stalls at the critical AoA and not an airspeed, but adding power SHOULD reduce the AoA by supplying excess thrust and slightly changing the relative wind over the wing. That's how we can fly at 5 degrees pitch up with power but might stall at 5 degrees pitch up at power idle. Add power, which slightly changes the flight path (you will need the power anyway as airspeed bleeds off), then reduce pitch to the horizon.
Anybody?
Anybody?
Old UPT joke
04-28-2009, 09:52 PM
#9
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Originally Posted by atlmsl
We all know that an airfoil stalls at the critical AoA and not an airspeed, but adding power SHOULD reduce the AoA by supplying excess thrust and slightly changing the relative wind over the wing. That's how we can fly at 5 degrees pitch up with power but might stall at 5 degrees pitch up at power idle. Add power, which slightly changes the flight path (you will need the power anyway as airspeed bleeds off), then reduce pitch to the horizon.
Anybody?
Anybody?
tomgoodman - Haha I should use that on my instructor next time, but I'll probably have to mention different airplanes
04-29-2009, 03:16 AM
#10
Chief Jeppesen Updater
Joined APC: Oct 2005
Position: Executive Transport Driver
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Another reason that you're taught to add power first is that in some aircraft, such as those with geared or turbine engines, it can take a few seconds to start generating max power/thrust.
Although it may not be an issue in a 172, if you put a transport category aircraft in a nose high unusual attitude, you want to start generating thrust as soon as possible since you're going to be bleeding off airspeed and it might take a few seconds for the engines to spool up.
In addition, in a prop-driven GA aircraft, adding power first will provide additional airflow (wash) over the tail and wing, providing additional control effectiveness.
Although it may not be an issue in a 172, if you put a transport category aircraft in a nose high unusual attitude, you want to start generating thrust as soon as possible since you're going to be bleeding off airspeed and it might take a few seconds for the engines to spool up.
In addition, in a prop-driven GA aircraft, adding power first will provide additional airflow (wash) over the tail and wing, providing additional control effectiveness.
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