Full flap slips okay in the 182T?

[simon]

I am trying to put this one to rest. I don't have either plane handy in front of me, but my recollection is that the old "avoid slips with flaps extended" was a placard in the 172, never the 182 or the current 182T. Can anyone confirm this?

My understanding is that this placard and a similar one "Slips with full flaps prohibited" appeared on a couple of light GA planes but never appeared on the 182.  So far, I found these kinds of placards on (Copied from a "Pilots of America: forum):

177 - The original Cardinal (not 177A or 177B models)
180 - The J model and most/all with floats or skis installed
185 - 185's prior to 18503683 with floats installed, or any 185 on skis
188 - Ag Wagon, serial numbers 1 through 293

The Cessna 170B owners manual states "avoid slips with full flaps deployed" or somesuch [sic]. However, this isn't a regulatory document and a placard is no longer required (if it ever was) as evidenced by TCDS A-799 rev. 54.

I remember it originated because of the 40 degree flaps on some models that would obscure airflow to the elevator. The old 182's have the 40 degree flaps. I am *fairly* sure the 182T's have something less than that, although all the POH says is 10/20/FULL. The POH does caution against slips for the following reasons:

Steep slips with flap settings greater than 20° can cause a slight tendency for the elevator to oscillate under certain combinations of airspeed, sideslip angle, and center of gravity loadings.

If flap settings greater than 20° are used in sideslips with full rudder deflection, some elevator oscillation may be felt at normal approach speeds. However, this does not affect control of the airplane.

When the fuel tanks are 1/4 tank or less, prolonged uncoordinated flight, such as slips or skids, can uncover the fuel tank outlets causing fuel starvation and engine stoppage. Therefore, if operating with one fuel tank dry or operating on either LEFT or RIGHT tank with 1/4 tank or less, do not allow the airplane to remain in uncoordinated flight for periods in excess of 30 seconds.

I have found that under the right conditions, power off, full flaps and a hard slip provides a great rate of descent and good visibility for the scanner / observer when flying down steep canyons. I will qualify that by saying it isn't something that needs to be done often and you need to ensure there's a good run off area towards the bottom of the canyon to allow plenty of time for flap retraction. But the observer and scanner get a great view down canyon gullys - places where planes can end up.

I still remember being warned about the full flap and slip thing when I was trained in the old 170's, but I don't see the placard anymore. Would any CAP check pilot (Or pilot rated passenger) take issue to this? When I was mountain training with a check pilot, he didn't seem to mind.

Aside from maintaining a safe airspeed, the only safety issue I can see is that if the flaps don't come up towards the bottom of the canyon, you're landing.

[jayleswo]

I am trying to put this one to rest. I don't have either plane handy in front of me, but my recollection is that the old "avoid slips with flaps extended" was a placard in the 172, never the 182 or the current 182T. Can anyone confirm this?

I took a look at the AFM for a 182Q and 182T and neither have this warning against slips with flaps down. The 172N and 172S AFM's I have mention that steep slips should be avoided due to oscillation of the horiz stab. It's in the Normal Operations section under Landing (section 4-20 and 4-27 if I remember).

-- John

[vento]

I've never seen the "Avoid slips with full flaps" placard on the C-182T, C-182R, C-182Q. Actually only seen the placard (or imprint) on the C-172s.

[simon]

Thanks for the confirmation.

[Mustang]

Just know that you *can* disrupt the airflow over the horizontal stabilizer when doing so; you'll feel the buffet through the yoke.

[simon]

Oh yeah, I can feel it. The pitch feels sloppy.

[Flying Pig]

DEFINITELY dont do it in a 206!  You throw the barn doors all the way out on that baby and your done flying.

[vento]

DEFINITELY dont do it in a 206!  You throw the barn doors all the way out on that baby and your done flying.

I forget about the 206's door design (only served once as a MO in it), did the right rear door only open with full flaps down or no flaps? I only remember receiving a more extensive briefing about evacuation in an emergency, something about climbing out of the aircraft thru the cargo door if riding in the back seat. Intriguing airplane.

[CadetProgramGuy]

I vaugely remember my flight training in a friends 182.  40 degrees of flaps can ruin your day if you are behind the power curve........

Also if I remember right on landing didn't you raise the flaps right away (not fully) in case of a go around?

[SarDragon]

The left hand (rear) section of the right side door will open with full flaps, but the right hand (forward) section only opens enough to allow rear section to open.

Our exit procedure practice in our newly assigned 206 was interesting. The small and/or skinny folks did OK, but the larger people had some issues.

[Jolt]

I vaugely remember my flight training in a friends 182.  40 degrees of flaps can ruin your day if you are behind the power curve........

Also if I remember right on landing didn't you raise the flaps right away (not fully) in case of a go around?

Virtually all of my flying has been in 172s.  Generally, the first 20 degrees of flaps is associated with additional lift.  If you keep adding flaps, you're mostly adding drag.  Go-around procedures call for flaps 20 immediately so that you get rid of that excess drag and it helps you climb out more quickly.  If you throw the flaps up immediately, you're going to get rid of all of that induced drag, but you're also going to lose a lot of the lift that was helping you climb for your go-around.

[Check Pilot/Tow Pilot]

I have found that under the right conditions, power off, full flaps and a hard slip provides a great rate of descent and good visibility for the scanner / observer when flying down steep canyons.

Ouch... something wrong with this sentence 

[simon]

I didn't pick it up.

[Check Pilot/Tow Pilot]

Just a suggestion to be extra-cautious when flying in or around canyons. 

Amy Hoover say's it well http://www.canyonflying.com/ "Fly in smooth air. When there is a lot of wind or turbulence in canyons, professional pilots are usually back at the hangar. Canyon winds can be unpredictable, and it is prudent to avoid flying in high winds or turbulence. Another, possibly not so intuitive, reason is that when flaps are lowered as suggested to slow and stabilize the airplane, the limit load factor of the wing may be drastically decreased. For example, an airplane that is normally certified for 3.8 positive G's may only be certificated for 2.4 G's with flaps down. Thus, slowing down and using flaps to maximize safety could compromise the structural integrity of the airframe in turbulence. "

For the 182Q, the design load limit s is 3.8g with flaps up but only 2.0g with flaps down.

[Flying Pig]

I have found that under the right conditions, power off, full flaps and a hard slip provides a great rate of descent and good visibility for the scanner / observer when flying down steep canyons.

Ouch... something wrong with this sentence 

  Did someone really teach you that as a technique?  I think the last thing you want to be doing in a mountain environment is to be flying uncoordinated with full flaps.  I think a better technique would be to make s-turns or just make 2 passes.  I am almost positive you cant do that in a 206. Ive done many canyon searches in a 206 and 182 looking for marijuana and on SAR, and a full flap, forward slip just never seemed like the thing to be doing.  Low, slow, uncoordinated, in the mountains with full flaps at high GW and high DA.....just doesnt seem like a good technique.

[NIN]

  Did someone really teach you that as a technique?  I think the last thing you want to be doing in a mountain environment is to be flying uncoordinated with full flaps.  I think a better technique would be to make s-turns or just make 2 passes.  I am almost positive you cant do that in a 206. Ive done many canyon searches in a 206 and 182 looking for marijuana and on SAR, and a full flap, forward slip just never seemed like the thing to be doing.  Low, slow, uncoordinated, in the mountains with full flaps at high GW and high DA.....just doesnt seem like a good technique.

And the power pulled off.

Yikes.  I mean, if you happen to be in a place where the wind is hitting the mountain and creating a gigantic updraft or something, that's one thing, but I should think that in a canyon is a place where you're not going to wanting to be sans power EVER.

[NIN]

I forget about the 206's door design (only served once as a MO in it), did the right rear door only open with full flaps down or no flaps? I only remember receiving a more extensive briefing about evacuation in an emergency, something about climbing out of the aircraft thru the cargo door if riding in the back seat. Intriguing airplane.

Yeah, 99.5% of all my C-206 flying was done in a plane that didn't have the rear doors on her at all.

We didn't worry too much about the position of the flaps except as they pertained to our ability to get to the wheel and strut.

[simon]

I don't want anybody to get the wrong impression here, so let's step back a little.

Mission Pilot, your point about mountain turbulence is well taken. I think anyone who's done a bit of flying around the mountains would agree with you. Having departed from high DA locations like Tahoe in the Summer, I am familiar with how this reduces one's margins in terms of lift and safety. Sometimes those very same potentially dangerous winds can be used to one's advantage (Orographic lift) or by thermaling to get up and out. I imagine you would know this from your own experience and I do want to point out that my original comment was not to suggest I would blindly fly down the lee side of a canyon when it is gusting 30 kts over the top. Everything within reason.

One aspect that I did not consider - one that I think so far is perhaps the best point made by anyone - is the change in load limit with the flaps down. In particular with the big barn doors on the Cessnas, I was surprised to read that the design load limit was 2g with full flaps. I am going to do some reading up on that part. 2g seems really low for a design load limit in a standard configuration. As far as a 206 goes, I've only flown one for a couple of hours - we've gotten ridden of ours out of the bay area, so my area of interest is really only the 182's.

Anyway, back to my original example, recently I was doing some mountain work with a check pilot and were working around this steep canyon. It had all the hallmarks of a good place to find a downed aircraft. It was on the way back into the bay area from the valley, it was in an area lower than the rest of the surrounding mountains that might be a place where a scud running pilot tried to sneak through and it was a long valley that went for a few miles, then turned a corner, then terminated in a box canyon. We were sort of looking at it thinking how it looked like a textbook example of somewhere that a pilot might fly along thinking it was going to open up into the bay area, they follow the river between the two valley sides, turn the corner then Bam! They are faced with nowhere to go. So anyway, we flew a contour search then discussed how we might be able to search the various gullys that ran down the canyon. Clearly the way to do it was to fly above and around the back of the canyon then fly down the canyon a couple of times in various areas, then following the escape route down and out to the open valley, then climbing back and doing it again. I found that a low power descent with more than the standard 10 degrees and some slips enabled us to follow the contour of the gullys down at a constant altitude AGL and give the right seat passengers good visibility. The canyons were so steep that if I just flew with the standard configuration, by the time we got near the bottom of the canyon, we'd be quite high AGL. If I pushed the nose over to stay at a reasonable distance for the scanner, of course the plane would take off and we'd be doing 120kts near the bottom - too fast to get a good POD.

So really, it was just a variation on a standard configuration that enabled me to give the scanner good coverage in a certain type of terrain.

BTW, Flying Pig, I don't get why you are so surprised at power off. I never said anything about gigantic updrafts. I think you have this image of some wild and gusty day up in the mountains. Clearly, if it isn't safe to be there in the first place then we aren't going. There is nothing wrong with power off, as with many things, in the appropriate situation.

I think it is worth pointing out that my original question was in relation to slips with full flaps in a 182, placarding, safety etc. So far nobody seems to be saying that it is a no-no, only that obviously the handling of the aircraft will be affected. Anytime terrain is in close proximity, of course one needs to be vigilant.

[Flying Pig]

BTW, Flying Pig, I don't get why you are so surprised at power off. I never said anything about gigantic updrafts. I think you have this image of some wild and gusty day up in the mountains. Clearly, if it isn't safe to be there in the first place then we aren't going. There is nothing wrong with power off, as with many things, in the appropriate situation.

Ive been flying through the Sierras on very calm days on SARs and rounded a bend and almost had my teeth knocked out by one single solitary gust that came out of nowhere.  Power off isnt an issue, at least you know you still have power.  Just seems like a full flap hard slip down a canyon could be a set up for bad things.  Again, never tried it though.

[simon]

Well, I will grant you that the mountains can be full of 'surprises'. I'm no expert. If they can get Sparky Imeson, they can get anyone.

(BTW, really enjoyed reading his 'Bible' and disappointed I had to pull out last minute from one of his talks last year)