Minimum maneuvering speed?

Will Kumley

Will Kumley

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As flying has been reduced thanks to our stay at home order I've been watching videos, reading articles, etc.. to get a better understanding of the certificate I just earned. After watching this video though I was slightly confused.

According to the video, min maneuvering speed is 1.404 times the clean stall speed of an aircraft. Sounds like a reasonable thing and I've seen/heard this reference in other videos. However, that sets the minimum maneuvering speed of the Cessna 172 I rent at approximately 83 mph.

I question this as the CFI instructed me to fly it like I fly the Cherokee in the pattern. 85 on downwind, 80 on base, and 75 on final. While I think 75 on final is a bit fast and causes a heck of a float I guess I don't have a fear of being too slow. But this means my base to final turn is below the calculated speed according to the math.

Now, I also add 2 seconds of flaps on the downwind, 2 seconds of flaps on base, and full flaps on final. I know lift increases with flaps and stall speed decreases but this video doesn't really discuss the addition of flaps. Are they not applying flaps until final? Are they saying even with flaps I shouldn't maneuver the aircraft below 83 mph? I've never even had the stall horn hint at anything with my current pattern. Also, now that I think about it best glide in the 172 is 80mph, also below this speed.

Things that make me go hmmm....
 
Will Kumley said:

As flying has been reduced thanks to our stay at home order I've been watching videos, reading articles, etc.. to get a better understanding of the certificate I just earned. After watching this video though I was slightly confused.

According to the video, min maneuvering speed is 1.404 times the clean stall speed of an aircraft. Sounds like a reasonable thing and I've seen/heard this reference in other videos. However, that sets the minimum maneuvering speed of the Cessna 172 I rent at approximately 83 mph.

I question this as the CFI instructed me to fly it like I fly the Cherokee in the pattern. 85 on downwind, 80 on base, and 75 on final. While I think 75 on final is a bit fast and causes a heck of a float I guess I don't have a fear of being too slow. But this means my base to final turn is below the calculated speed according to the math.

Now, I also add 2 seconds of flaps on the downwind, 2 seconds of flaps on base, and full flaps on final. I know lift increases with flaps and stall speed decreases but this video doesn't really discuss the addition of flaps. Are they not applying flaps until final? Are they saying even with flaps I shouldn't maneuver the aircraft below 83 mph? I've never even had the stall horn hint at anything with my current pattern. Also, now that I think about it best glide in the 172 is 80mph, also below this speed.

Things that make me go hmmm....
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I’ve never heard of minimum maneuvering speed before. Maneuvering speed, yes, and that’s a maximum. Anyway, good ol’ 1.3 of Vs over the fence works pretty good for me in 172’s.
 
Stall speed changes with bank angle and load. There is no set "floor" for minimum maneuvering speed. Flying thinking there is a set V-speed for minimum maneuvering speed seems dangerous.

Of course good CFI's practice operating at minimum speeds at 3500 or 5500 AGL to allow for a successful recovery to learn the danger signs of stalling and preventing spins.
 
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The “minimum maneuvering speed” is predicated on your configuration, so it will be slower as you add flaps. make sure you’re doing the math using calibrated airspeeds and then converting back to indicated. ;)

I forget exactly what the math is (hopefully they talk about it in the video), but the 1.404 is 1.3xstall speed when you add in the load factor of a normal turn. Basically, that’s what your 85/80/75 should be built on, so there’s really no need to come up with another set of numbers using the formula. It’s more for figuring out what those numbers are for a new airplane.
luvflyin said:
I’ve never heard of minimum maneuvering speed before. Maneuvering speed, yes, and that’s a maximum.
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That’s an entirely different maneuvering speed...unfortunately the video I saw that talked about seemed to be intended to show that the instructor knew more than you, rather than making a clear differentiation between the two “maneuvering speeds”.
 
VSO x 1.1 works great assuming you know what your doing and are aware of the wind. VSO x 1.5 won't keep a bad pilot from spinning in. Don't get hung up on absolute speed values. Learn the variables. Pilot skill, airplane performance, weather, weight, CG, etc all play into it.
 
Morgan3820 said:
The following is an excellent discussion and video of minimum maneuvering airspeed. A very important concept in larger aircraft flight.
https://www.flyingmag.com/flight-chops-ga-four-big-failures/
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Yeah, that’s the video...The article author falls into the same trap...
Their first task is to question random airline pilots at the airport on a seemingly simple question: Is maneuvering speed a maximum or a minimum? Airline pilots say minimum, and it's a speed they have calculated in advance of each flight based on conditions, but general aviation pilots quizzed later have routinely been taught VA as a maximum—and they tend to spout out one number with only a minor adjustment for weight.
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Neither the article nor the video mention that the airline guys and the GA guys are talking about two different “maneuvering speeds”. Fortunately most GA pilots don’t find themselves in situations requiring them to stay below Va, so the video and article probably won’t be cause for fatal accidents, but it’s very poorly done, IMO.
 
MauleSkinner said:
The “minimum maneuvering speed” is predicated on your configuration, so it will be slower as you add flaps. make sure you’re doing the math using calibrated airspeeds and then converting back to indicated. ;)

I forget exactly what the math is (hopefully they talk about it in the video), but the 1.404 is 1.3xstall speed when you add in the load factor of a normal turn. Basically, that’s what your 85/80/75 should be built on, so there’s really no need to come up with another set of numbers using the formula. It’s more for figuring out what those numbers are for a new airplane.

That’s an entirely different maneuvering speed...unfortunately the video I saw that talked about seemed to be intended to show that the instructor knew more than you, rather than making a clear differentiation between the two “maneuvering speeds”.
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Yeah. I’ve never heard of the 1.3 thing being referenced to flying the pattern. It’s a landing speed. It doesn’t come into play until the turns to downwind, base and final are over with. Even then it’s an ‘over the fence’ thing.
 
luvflyin said:
Yeah. I’ve never heard of the 1.3 thing being referenced to flying the pattern. It’s a landing speed. It doesn’t come into play until the turns to downwind, base and final are over with. Even then it’s an ‘over the fence’ thing.
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“The 1.3 thing” is the normal final approach speed...the 1.404 that the OP & videos discuss is what “comes into play” before that.
 
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I, too, struggle with the terminology. In the Flight Chops video where Dan Gryder talks to private pilots and airline pilots and asks them whether maneuvering speed is a minimum or a maximum, he mixes up two completely different and unrelated things and presents that mixed up mess as the magic solution to preventing slow flight accidents. I am all for doing things to prevent accidents, and I applaud them for trying to help with this video, but I feel we could do more good with more regular slow flight training. At some point before touch down, one HAS to slow down, so this concept of "minimum maneuvering speed" merely gives pilots a little more margin before bad things happen.

- Martin
 
During my private pilot exam (at FDK) the examiner told me to enter slow flight with the stall horn sounding and then had me do turns and climbs and descents and told me if the horn stopped sounding I would fail. We were at full flaps in a 172. At the end of that she told me to raise the flaps but keep the horn sounding. I had never done anything like that in training but learned the 172 really can go slow and maneuver and not fall out of the sky.
 
I agree with the previous comments. Stall speed changes with banks angle/load and there is a difference in what the ga/airline pilots are talking about. I also agree that all the videos I've found that reference it give the impression of I know more than you and I want to show you how smart I am. However, I won't discredit what could be a valid opinion on that alone. I believe all the videos I have found have the same guy pushing the idea, I don't know him and he could be a great instructor, but he can be a bit of a turnoff with the persona he exudes.

My initial concern was the lack of considering a/c configuration when calculating these speeds. Adding flaps effectively decreases angle of attack thus allowing a slower flight if angle of attack is kept constant. This means as flaps are added pitch increases to maintain the same AOA. After all, its AOA that causes the stall, not speed. In my brain, we just use speed to help determine AOA as most GA aircraft don't have an AOA indicator.
 
Will Kumley said:
we just use speed to help determine AOA as most GA aircraft don't have an AOA indicator.
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most dont even understand the concept of AOA let alone flying it. i agree without AOA indicator the next option is airspeed, but calculating that airspeed for that given flight under that specific load factor, DA etc could potentially take up 100% CPU .... some vendors are now offering AOA under NORSEE, which is a great thing...now to find a CFI who actually understands and train it is a different discussion altogether.

my CFI, 9000 hrs flying all sorts of planes, still thought its just a gizmo and wont let me land using it, until i showed him a 50 degree bank on the blue dot and no stall at altitude... he still wasnt convinced... sigh
 
Martin Pauly said:
At some point before touch down, one HAS to slow down, so this concept of "minimum maneuvering speed" merely gives pilots a little more margin before bad things happen.
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As the OP noted, we’ve been teaching the proper way to slow down for years...this is merely a different way of stating the same old thing. While I understand that saying the same thing a different way may get something to “finally click” with some people, it should really be presented as “just another way of stating it” rather than “something new that’s going to save lives”.
 
Huh...I thought the flight chops video was pretty great. Who cares if the instructor is a turnoff? When I want to get turned on, I...never mind...
 
Will Kumley said:
I agree with the previous comments. Stall speed changes with banks angle/load and there is a difference in what the ga/airline pilots are talking about. I also agree that all the videos I've found that reference it give the impression of I know more than you and I want to show you how smart I am. However, I won't discredit what could be a valid opinion on that alone. I believe all the videos I have found have the same guy pushing the idea, I don't know him and he could be a great instructor, but he can be a bit of a turnoff with the persona he exudes.

My initial concern was the lack of considering a/c configuration when calculating these speeds. Adding flaps effectively decreases angle of attack thus allowing a slower flight if angle of attack is kept constant. This means as flaps are added pitch increases to maintain the same AOA. After all, its AOA that causes the stall, not speed. In my brain, we just use speed to help determine AOA as most GA aircraft don't have an AOA indicator.
Click to expand...

That slow flight should be shown to every student. Now the ACS went even further to not get that close to MCA, but CFIs should still be having students fly the plane that way. It takes a lot of the fear of the unknown away.
 
I thought the 1.3 x Vs target was meant to take into account load factors during normal turns. Otherwise why not approach at 1.2 Vs or some other number...

Never even heard of minimum maneuvering speed at my airline. Our maneuvering speed (Va) has the same definition as the GA one.
 
WannFly said:
most dont even understand the concept of AOA let alone flying it. i agree without AOA indicator the next option is airspeed, but calculating that airspeed for that given flight under that specific load factor, DA etc could potentially take up 100% CPU .... some vendors are now offering AOA under NORSEE, which is a great thing...now to find a CFI who actually understands and train it is a different discussion altogether.

my CFI, 9000 hrs flying all sorts of planes, still thought its just a gizmo and wont let me land using it, until i showed him a 50 degree bank on the blue dot and no stall at altitude... he still wasnt convinced... sigh
Click to expand...

A lot of GA aircraft have an AOA indicator, it's called a stall horn/buzzer... ;-)
 
TommyG said:
That slow flight should be shown to every student. Now the ACS went even further to not get that close to MCA, but CFIs should still be having students fly the plane that way. It takes a lot of the fear of the unknown away.
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Yeah, the cfi’s at my school taught slow flight to just above the warning. The Cherokee published Vso was 55 I think. I consistently flew down in the upper 40’s dancing at the brink of the light which usually came on with a few mph to spare before the buffet. On my checkride the examiner asked for slow flight and I held it right at something like 48. Got the light to flash for a half second then kept it just above that.
 
My last recurrent the check airman asked me if we had an AOA indicator on the CRJ. I said, “is this a trick question?” He said think about it. After thinking about it, I couldn’t give him an answer and he said “what about the shaker?”
 
MauleSkinner said:
The stall horn indicates whether you are above (horn on) or below (horn off) a specific AOA. That is an AOA indicator.
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in that case the buffet is also AOA indicator. none of them indicates minimum sink/ max glide operation range (and in case i wasnt clear.. thats what i was referring to when i mentioned AOA indicator)
 
WannFly said:
in that case the buffet is also AOA indicator. none of them indicates minimum sink/ max glide operation range (and in case i wasnt clear.. thats what i was referring to when i mentioned AOA indicator)
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Yes, the buffet is also an AOA indicator.

Yes, you were unclear enough to be incorrect.
 
Well I guess I was wrong. Small GA aircraft do have AOA indicators. Light/horn is just in the yellow, buffet it heavy in the yellow, and stall is in the red. Do I have it right? This dynamic means the stall is also an AOA indicator, just that you've gone too far...
 
Will Kumley said:
Well I guess I was wrong. Small GA aircraft do have AOA indicators. Light/horn is just in the yellow, buffet it heavy in the yellow, and stall is in the red. Do I have it right? This dynamic means the stall is also an AOA indicator, just that you've gone too far...
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no, you missed the white knuckle of the pilot ... sigh
 
WannFly said:
thats not even close to AOA :)
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Agree to disagree... No, it's not a fancy AOA, but if it is properly calibrated and working it provides the information that's important...
 
Bottom line is no matter how much or how little equipment is in the airplane (including a piece of tape at 1.404Vs) it’ll be plenty for some and not nearly enough for others.
 
idahoflier said:
Agree to disagree... No, it's not a fancy AOA, but if it is properly calibrated and working it provides the information that's important...
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yes we have already established that everything including soiled underwear is AOA indicator
 
MauleSkinner said:
No, we have established that indicators based on AOA are AOA indicators. You have determined to be wrong.
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i am wrong, you are right. happy?

for everyone else who wants to understand AOA indicator that can actually provide maximum lift / min sink.. there are lot of informative articles over the interwebz
 
WannFly said:
yes we have already established that everything including soiled underwear is AOA indicator
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Well... I guess?

OP: I think far too many pilots are scared of stalls or flying at MCA. If in doubt take your favorite instructor for a ride and fly patterns at altitude. With your instructor fly maneuvers at MCA. Do this until you are comfortable flying around with the stall horn/buzzer.
 
WannFly said:
i am wrong, you are right. happy?

for everyone else who wants to understand AOA indicator that can actually provide maximum lift / min sink.. there are lot of informative articles over the interwebz
Click to expand...
Sure...might even be an appropriate comment in a thread that was remotely related to max lift/min sink.
 
Will Kumley said:
I agree with the previous comments. Stall speed changes with banks angle/load and there is a difference in what the ga/airline pilots are talking about. I also agree that all the videos I've found that reference it give the impression of I know more than you and I want to show you how smart I am. However, I won't discredit what could be a valid opinion on that alone. I believe all the videos I have found have the same guy pushing the idea, I don't know him and he could be a great instructor, but he can be a bit of a turnoff with the persona he exudes.

My initial concern was the lack of considering a/c configuration when calculating these speeds. Adding flaps effectively decreases angle of attack thus allowing a slower flight if angle of attack is kept constant. This means as flaps are added pitch increases to maintain the same AOA. After all, its AOA that causes the stall, not speed. In my brain, we just use speed to help determine AOA as most GA aircraft don't have an AOA indicator.
Click to expand...

Did you watch the whole video? The lower stall speed with flaps is part of the point. They talk about the flaps and how you must gain airspeed prior to taking them out for a go around...which is objectively true... The case in point referred to the cirrus going down when flaps were retracted at low speed. The mark is a good idea for some, as an easy visual check if they’re under stress
 
GrummanBear said:
Did you watch the whole video? The lower stall speed with flaps is part of the point. They talk about the flaps and how you must gain airspeed prior to taking them out for a go around...which is objectively true... The case in point referred to the cirrus going down when flaps were retracted at low speed. The mark is a good idea for some, as an easy visual check if they’re under stress
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I really didn't correlate the discussion on go- arounds to the discussion on DMMS. When talking about the Cirrus he stated that in that plane the speed needs to be above a certain speed before flaps can be retracted. The way he said it and/or the way I hear it is as per the POH or a checklist item. Speed above x-check, flaps going up-check. When I was training I was always taught on a go around to verify positive rate of climb, airspeed above Vx then I can retract the flaps. Vx is well below the DMMS. I do like the idea of a simple mark on the Airspeed indicator but think he could have done a better job of explaining it as it causes confusion in my brain when considering my base to final speed.
 
Will Kumley said:
I really didn't correlate the discussion on go- arounds to the discussion on DMMS. When talking about the Cirrus he stated that in that plane the speed needs to be above a certain speed before flaps can be retracted. The way he said it and/or the way I hear it is as per the POH or a checklist item. Speed above x-check, flaps going up-check. When I was training I was always taught on a go around to verify positive rate of climb, airspeed above Vx then I can retract the flaps. Vx is well below the DMMS. I do like the idea of a simple mark on the Airspeed indicator but think he could have done a better job of explaining it as it causes confusion in my brain when considering my base to final speed.
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If you don't retract the flaps you may not get a positive rate of climb. Waiting for positive rate is not part of the procedure.
 
dmspilot said:
Never even heard of minimum maneuvering speed at my airline.
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But I’m sure you had procedural speeds...x airspeed, flaps 1, slow to y airspeed, intercept the final approach course, gear down at a dot below glide slope, landing flaps at glide slope intercept, slow to Vref. PM calls out if you’re z knots below target. Just another way of doing the same thing.
 
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