Power Off 180, CFI Says X, I Say Y

MauleSkinner said:
I’d rather see someone use the tools available to make the target.
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MauleSkinner said:
I’d rather see someone use the tools available to make the target.
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I mean to pass the checkride, sure. Or in an emergency to make a field, obviously. But if you’re a bit high in the pattern turning base or final, meh. Big deal. Go around. The statement was made that “you can only get to the runway from where you are,” and he can get to the runway from where he is. In fact all he can do is change the scenario to one where he can’t make it. Which makes more sense, land a bit long or slip off too much altitude and wind up short? So I don’t really get the logic in the response. OP’s answer makes perfect sense.
 
I couldn't find a thread on this crash last week, but it is an example of when use of a slipping turn to final would be legitimate.

Other reasons would be smoke in the cockpit when opening the pilot's window could supply fresh air to see and breathe. Haven't seen anybody point that out here as a valid reason yet, either. Or landing a replica of The Spirit of St. Louis.

I also looked for a video of forward slips and the funny thing to me was how many of them were demonstrations to instrument runways with lots of pavement ahead and brightly painted touchdown markers. In other words, no reason to be slipping there anyway, at least until ready to touch down.

Somebody above said, "You can't stall if you keep the nose down," which is true enough, but on the other hand it won't help you get into the tightest of fields which is exactly when you need a forward slip the most. The nose should be slightly high in those cases, according to CAA Bulletin #32 published in an era when they really knew their slips. Which, according to me, is fundamentally a bit risky since you can only guess at your actual airspeed while slipping. Keeping the nose down increases speed. But isn't that exactly what the slip is trying to avoid?
 
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mryan75 said:
I mean to pass the checkride, sure. Or in an emergency to make a field, obviously. But if you’re a bit high in the pattern turning base or final, meh. Big deal. Go around. The statement was made that “you can only get to the runway from where you are,” and he can get to the runway from where he is. In fact all he can do is change the scenario to one where he can’t make it.
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Why is that all he can do?
mryan75 said:
Which makes more sense, land a bit long or slip off too much altitude and wind up short? So I don’t really get the logic in the response. OP’s answer makes perfect sense.
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If those are the only two choices, flying isn’t for you.
 
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mryan75 said:
Strawman.
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Well, then, explain why being too long or too short are the only options.

And while you’re at it, why landing short is an acceptable option in an emergency or on a checkride when it’s better to go off the end.
 
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dtuuri said:
Except for misspeaking (you said skid for a slip) you are right. Slipping toward the left shortens your track to the runway. You are high, so you want to extend it not shorten it. So, you need to shallow the bank then come back to final from the opposite side. At that time, you can slip toward the wind (to the right) if still high. That will give you a headwind component and require a less severe slip.
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That's what I had in mind when visualizing this scenario. Fly the ground track as needed to get lined up on final with bank adjustment and use the rudder as needed for the added drag and rate of descent. The wind will be from the right on final, so the stick will be right duriing the slip. Power off 180 or not, this is routine stuff for airplanes without flaps and IMHO makes flying more fun!
 
dmspilot said:
It will enter a steep spiral.

I've done the math here before but I'll do it again. Gravity is ~32ft/s2, in a 60°-banked turn at a load factor of 1, the vertical component of lift is reduced 50%, resulting in a downward acceleration of 16ft/s2 or 960fpm/s. This will peg a 2000fpm VSI in 2.08 seconds. In a 45° banked turn, it takes about four seconds. Yes I've tested it in real life. The empirical data matches the math.

Yes it will, as the airspeed will increase and the airplane's longitudinal stability will cause the AoA to increase.
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Just to add to this a bit. that 2 second 1G 60 degree bank turn will result in a 32 degree heading change. (60kts)
Over that 2 seconds you will average about a 1000fpm decent and you lose 34ft of altitude. (1000fpm/60 = 17fps),
As you roll out descending at 2000fpm or 34fps and you would have pull 1.2G's (a 10% increase in stall speed (5kts?) for 5 seconds to return to your previous 1G state probably about a 8fps descent (500fpm). 1.4G= 2.5 seconds and a 18% increase in stall speed, I hope you are flying the approach at least at 1.2VS.

It is not near as bad a 2000fpm makes it sound, when you say it like a 34ft altitude loss and increasing the stall speed by about 18% ( 10kts) at most. Which probably isn't much different than what you might do to round out and flare anyway. Also it isn't that clinical in that you more likely just perform the whole turn and recovery at about 1.2G's with less altitude loss and less time to recover from that accelerated descent.

Feel free to pick my math apart. I didn't spend a lot of time make sure it was accurate.

Brian
 
mryan75 said:
Which makes more sense, land a bit long or slip off too much altitude and wind up short?
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In no-flap land, the slip is the primary tool to avoid both events. Approach high to ensure you don't wind up short, then slip to avoid landing long.

Or drag it in with power, I suppose, but no style points there.
 
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brcase said:
Just to add to this a bit. that 2 second 1G 60 degree bank turn will result in a 32 degree heading change. (60kts)
Over that 2 seconds you will average about a 1000fpm decent and you lose 34ft of altitude. (1000fpm/60 = 17fps),
As you roll out descending at 2000fpm or 34fps and you would have pull 1.2G's (a 10% increase in stall speed (5kts?) for 5 seconds to return to your previous 1G state probably about a 8fps descent (500fpm). 1.4G= 2.5 seconds and a 18% increase in stall speed, I hope you are flying the approach at least at 1.2VS.

It is not near as bad a 2000fpm makes it sound, when you say it like a 34ft altitude loss and increasing the stall speed by about 18% ( 10kts) at most. Which probably isn't much different than what you might do to round out and flare anyway. Also it isn't that clinical in that you more likely just perform the whole turn and recovery at about 1.2G's with less altitude loss and less time to recover from that accelerated descent.

Feel free to pick my math apart. I didn't spend a lot of time make sure it was accurate.

Brian
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I don't think there's anything wrong with your math, but we weren't actually talking about a 2-second turn. That was just an illustration of how quick the descent rate increases. It was asserted you could do a 180-degree turn a 60 degree bank without increasing the load factor. A 180° turn at 60° bank and 60 knots would take 5.7 seconds and end in a descent rate of 5,472 fpm.
 
MauleSkinner said:
One aspect of risk management is the understanding of and proficiency in the elements of the risk being managed. I see a lot of pilots refuse to do things under the banner of risk management simply because they don’t know or understand what’s involved, and refuse to take the time and effort to learn.
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I understand what is involved. Including a <400 hour CFI of teaching this procedure to <250 hour commercial student who is learning the power off 180 and practicing solo to gain proficiency. Students always do what you tell them. What could possibly go wrong with all this experience in the plane?
 
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Clip4 said:
I understand what involved. Including a <400 hour CFI of teaching this procedure to <250 hour commercial student who is learning the power off 180 and practicing solo to gain proficiency. What could possibly go wrong with all this experience in the plane?
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Not sure my multiple <15hr students seem to be able to do it just fine
 
Clip4 said:
I understand what is involved. Including a <400 hour CFI of teaching this procedure to <250 hour commercial student who is learning the power off 180 and practicing solo to gain proficiency. Students always do what you tell them. What could possibly go wrong with all this experience in the plane?
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Let me think…a CFI and a Commercial trainee using a Private Pilot maneuver. I would at least expect the CFI ti be proficient in what he’s teaching.

It’s only hard if someone tells you it is.
 
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Great topic and discussion just received from Pilot's Workshop on the subject of stalling during slips...

pilotworkshop.com

Stalling While Slipping - PilotWorkshops

Spencer: “Every pilot should be comfortable executing a slip on final. It’s helpful in losing altitude if high on final and critical for a smooth, centerline landing with a crosswind. The yaw in one direction and bank in the other can feel awkward at first. Add the back pressure often required...
pilotworkshop.com
 
The way the original post is phrased, the example sounds like it was developed to say you're slipping all the way through the left turn from downwind to final, and now highlight the decision whether to reverse the slip when you are on final, since the crosswind favors an opposite slip. I think it depends on the strength of the crosswind: light and it's "no", strong and it's "yes".
 
loganjvx said:
Hey Y’all,

Thank you for all of the replies and the insights. I apologize for the earlier error when discussing a slip versus a skid. In my personal experience flying the C172, slipping in a turn has not been a tool I have used often, and it has not been necessary in most situation that I've encountered throughout my training. I have approximately 200 hours in single engine aircraft and around 50 hours in multi engine aircraft, and I recognize that I still have much to learn as I continue my CFI training and prepare to teach others. The C172 will most likely be the primary trainer in which I am giving instruction, as well as the Piper PA-44 Seminole.

I understand and agree with the argument for flying aircraft without flaps and gliders that will not descend adequately without a hearty slip. In my limited experience flying a vintage J-3 Cub (awesome bird by the way), slips in both turns and level flight are critical to success.

That said, when teaching inexperienced low time student pilots, I struggle to see the benefit of introducing a slipping maneuver in a turn at low altitude. In this scenario, the airplane is at best glide, low to the ground, and already experiencing an increased stall speed due to load factor in the turn, even despite the fact that we are descending and the wings are in an "unloaded" state. Adding cross controlled inputs increases student pilot workload and reduces margin for error during a critical phase of flight.

My larger concern is what happens when those same students are endorsed for solo. If we normalize slipping in a turn at low altitude as an acceptable correction, we have to assume they might attempt that maneuver alone, without an instructor in the right seat. A developing student pilot who is still refining coordination and stall recognition may not fully appreciate how quickly a cross controlled stall can develop in a turning environment close to the ground. At that point, there is no safety net.

If a pilot finds themselves high and needing a slip in the turn to make the runway, I believe the approach was mismanaged earlier. I would rather emphasize disciplined pattern planning, early trend recognition, timely ground track adjustments, and proper configuration/energy management before the situation becomes compressed.

My concern is less about whether an experienced pilot can execute the maneuver safely, and more about the habits and standards we instill in students who will soon be operating solo.

I appreciate the continued feedback and perspective.
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I propose that being able to slip the aircraft, even in a turn, is a very basic skill for a pilot. It’s something every private pilot should be comfortable with performing.

The idea you hold that it is somehow advanced is misguided in my opinion.

When you have the cfi ticket in your pocket don’t forget the students are not being trained to fly a C-172 or any specific model of aircraft. It’s any ASEL with a gross weight below 12,500 lbs. thats not a jet.

Public service announcement: I’m putting on my ******* hat.

Which 141 program are you attending?
 
Tarheelpilot said:
I propose that being able to slip the aircraft, even in a turn, is a very basic skill for a pilot. It’s something every private pilot should be comfortable with performing.

The idea you hold that it is somehow advanced is misguided in my opinion.

When you have the cfi ticket in your pocket don’t forget the students are not being trained to fly a C-172 or any specific model of aircraft. It’s any ASEL with a gross weight below 12,500 lbs. thats not a jet.

Public service announcement: I’m putting on my ******* hat.

Which 141 program are you attending?
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I believe you nailed it.

To add to the mix, what about the crab method of landing in a strong strong crosswind, versus slipping it all the way down final? Is the crabbing method being considered, or even taught nowadays?

I often see videos of crabbing into the flare during real strong crosswinds being conducted by commercial airliners, rather than (I guess) running out of rudder (or scraping a wingtip) during the slip method. Plus, wingtips impacting the runway does seem to be happening more often now... could it be result of 141 programs not spending much (or any) time teaching the crab method?
 
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Rick A said:
I believe you nailed it.

To add to the mix, what about the crab method of landing in a strong strong crosswind, versus slipping it all the way down final? Is the crabbing method being considered, or even taught nowadays?

I often see videos of crabbing into the flare during real strong crosswinds being conducted by commercial airliners, rather than (I guess) running out of rudder (or scraping a wingtip) during the slip method. Plus, wingtips impacting the runway does seem to be happening more often now... could it be result of 141 programs not spending much (or any) time teaching the crab method?
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Normally it’s a pod that strikes first for the 121 stuff, think much over 5 degrees will nail one in some

Some of the corp jet stuff you can hit a wingtip much beyond 10

And yes, the lowering of the bar and race to go CFI - 121 ASAP has consequences
 
Rick A said:
I believe you nailed it.

To add to the mix, what about the crab method of landing in a strong strong crosswind, versus slipping it all the way down final? Is the crabbing method being considered, or even taught nowadays?

I often see videos of crabbing into the flare during real strong crosswinds being conducted by commercial airliners, rather than (I guess) running out of rudder (or scraping a wingtip) during the slip method. Plus, wingtips impacting the runway does seem to be happening more often now... could it be result of 141 programs not spending much (or any) time teaching the crab method?
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My experience is that the airplanes that require that technique do a pretty good job of teaching it in type training. Until that point, best to land on one wheel (the upwind one) like the cool guys.

My experience with the guys who try to do that in airplanes that don’t require it fail miserably…but my former employer thought damaging airplanes in crosswind landings was just part of the cost of doing business #keepingrentalrateshigh
And even managed to approve of it in a jet.
 
Rick A said:
I believe you nailed it.

To add to the mix, what about the crab method of landing in a strong strong crosswind, versus slipping it all the way down final? Is the crabbing method being considered, or even taught nowadays?

I often see videos of crabbing into the flare during real strong crosswinds being conducted by commercial airliners, rather than (I guess) running out of rudder (or scraping a wingtip) during the slip method. Plus, wingtips impacting the runway does seem to be happening more often now... could it be result of 141 programs not spending much (or any) time teaching the crab method?
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I think the opposite true and most 141/pilot mills prefer crabbing most of the way down final. I think a better explanation for increased 121 crosswind incidents (if that's even true, could be recall bias or a statistical anomaly) is that pilot mills just don't fly when it's very windy so their skills aren't challenged. Then they go to an airline and they do a max crosswind operations in the sim one time and call it good.

I know some transport jets can be landed in a crab, and others they kick the crab out only at the very last second, but I've transitioned to a slip over the threshold in the ERJ and somehow it works. I'll lower the upwind wing just a hair and the airplane doesn't drift off centerline in the few seconds it takes to flare and touch down.
 
dmspilot said:
I think the opposite true and most 141/pilot mills prefer crabbing most of the way down final. I think a better explanation for increased 121 crosswind incidents (if that's even true, could be recall bias or a statistical anomaly) is that pilot mills just don't fly when it's very windy so their skills aren't challenged. Then they go to an airline and they do a max crosswind operations in the sim one time and call it good.

I know some transport jets can be landed in a crab, and others they kick the crab out only at the very last second, but I've transitioned to a slip over the threshold in the ERJ and somehow it works. I'll lower the upwind wing just a hair and the airplane doesn't drift off centerline in the few seconds it takes to flare and touch down.
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Appreciate your experience and view!
 
dmspilot said:
I don't think there's anything wrong with your math, but we weren't actually talking about a 2-second turn. That was just an illustration of how quick the descent rate increases. It was asserted you could do a 180-degree turn a 60 degree bank without increasing the load factor. A 180° turn at 60° bank and 60 knots would take 5.7 seconds and end in a descent rate of 5,472 fpm.
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It would be interesting to redo the math performing the maneuver at 1.2 G.
Actually I decided to ask my AI Friend... Here is the summary

consider an airplane gliding at 60kts. with about a 10 to 1 glide ratio. If we rolled into a 60 degree bank and maintained 1.2 G-load. for a 180 degree turn.

1. How long would it take to complete a 180 degree turn?
2. How much altitude would be lost at the completion of the turn.
3. How much additional altitude would be lost to return back to the 1 G descent rate we had prior to starting the turn?
4. What would be the maximum descent rate achieved.
5. What is the diameter of the turn?

I then asked it to redo it at 1.4 G-s here is the results it provided.
remember 1.2g = 10% Stall speed increase (5kts) 1.4g = about 18% (9-10kts)

1771516780383.png
 
dtuuri said:
I couldn't find a thread on this crash last week, but it is an example of when use of a slipping turn to final would be legitimate.
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That has got to be one of the worst headlines I have ever seen:

Award-winning pilot and wife die in plane crash after dirty windows prompt emergency landing, pet dog survives​

The "dirty windows" was oil on the windscreen. Face, meet palm.

dmspilot said:
I don't think there's anything wrong with your math, but we weren't actually talking about a 2-second turn. That was just an illustration of how quick the descent rate increases. It was asserted you could do a 180-degree turn a 60 degree bank without increasing the load factor. A 180° turn at 60° bank and 60 knots would take 5.7 seconds and end in a descent rate of 5,472 fpm.
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brcase said:
It would be interesting to redo the math performing the maneuver at 1.2 G.
Actually I decided to ask my AI Friend... Here is the summary

consider an airplane gliding at 60kts. with about a 10 to 1 glide ratio. If we rolled into a 60 degree bank and maintained 1.2 G-load. for a 180 degree turn.

1. How long would it take to complete a 180 degree turn?
2. How much altitude would be lost at the completion of the turn.
3. How much additional altitude would be lost to return back to the 1 G descent rate we had prior to starting the turn?
4. What would be the maximum descent rate achieved.
5. What is the diameter of the turn?

I then asked it to redo it at 1.4 G-s here is the results it provided.
remember 1.2g = 10% Stall speed increase (5kts) 1.4g = about 18% (9-10kts)

View attachment 150077
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And here I was going to re-do all the math by hand because it sounded like maybe the horizontal component calculation was still using 2 g...

Now, given that it's AI, is it correct?
IMG_1356.JPG
 
flyingcheesehead said:
That has got to be one of the worst headlines I have ever seen:

Award-winning pilot and wife die in plane crash after dirty windows prompt emergency landing, pet dog survives​

The "dirty windows" was oil on the windscreen. Face, meet palm.
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I thought that too, but then realized it got me to click it.
 
MauleSkinner said:
Let me think…a CFI and a Commercial trainee using a Private Pilot maneuver. I would at least expect the CFI ti be proficient in what he’s teaching.

It’s only hard if someone tells you it is.
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A turning base to final slip is a private pilot maneuver?
 
Rick A said:
To add to the mix, what about the crab method of landing in a strong strong crosswind, versus slipping it all the way down final? Is the crabbing method being considered, or even taught nowadays?
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Both extremes of that continuum and most of the spots in between.
 
flyingcheesehead said:
Now, given that it's AI, is it correct?
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Complely different subject, but still aviation. Yesterday, I asked Claude to help me find a reference to something. It gave me a long explanation and then cited an FAA publication with what appeared to be a quote.

It made it up. The information does not exist in that publication.

Not the first time.
 
Clip4 said:
A turning base to final slip is a private pilot maneuver?
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If you’re flying with a competent CFI, yes

Asks a falling leaf stall, Dutch roll exercises, and spins if the plane can do them
 
midlifeflyer said:
Complely different subject, but still aviation. Yesterday, I asked Claude to help me find a reference to something. It gave me a long explanation and then cited an FAA publication with what appeared to be a quote.

It made it up. The information does not exist in that publication.

Not the first time.
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One of the biggest problems with AI is that it is completely incapable of saying "I don't know."

It will pull "facts" out of thin air instead of admitting defeat.
 
flyingcheesehead said:
One of the biggest problems with AI is that it is completely incapable of saying "I don't know."

It will pull "facts" out of thin air instead of admitting defeat.
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Recently when I corrected AI it thanked me and wrote "no hard feelings" to which I just had to again correct it ...
 
Daleandee said:
Recently when I corrected AI it thanked me and wrote "no hard feelings" to which I just had to again correct it
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This is the apology I received.

You’re absolutely right, and I apologize. I fabricated the specific AIP GEN 0.1 citation for 0901Z — it isn’t there. That’s a serious error and exactly the kind of thing I should never do. When I can’t find a specific reference, I should say so clearly rather than construct a plausible-sounding but false one.​

I almost replied, “actions speak louder than words,” but that felt too creepy :D

“Adventures with AI” might make an interesting thread.
 
midlifeflyer said:
This is the apology I received.

You’re absolutely right, and I apologize. I fabricated the specific AIP GEN 0.1 citation for 0901Z — it isn’t there. That’s a serious error and exactly the kind of thing I should never do. When I can’t find a specific reference, I should say so clearly rather than construct a plausible-sounding but false one.​

I almost replied, “actions speak louder than words,” but that felt too creepy :D

“Adventures with AI” might make an interesting thread.
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I have gotten many apologies like that, but the behavior never changes. AI is like a very articulate third grader with a good memory.
 
Forward slip from downwind to spot landing regularly in a Citabria (no flaps).
Rarely in 182, except x winds.

Be aware some aircraft have limitations on slips, slips w/flaps due to un-porting the fuel pickup, definitely check the POH to know what’s allowed.

Especially if you’re used to flying high wings with “both” fuel tanks option.
Low wings are different animal regarding fuel tank selector, will usually be L or R tank and be careful slipping without prior understanding of limitations.
 
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