Spinning a C172

[India Four Two]

In this thread:
http://www.pprune.org/private-flying...rformance.html

there was some drift towards the spinning characteristics of a C172. To avoid further thread drift, I have created this new thread.


My post in the performance thread:

Quote:
The more restrictive "Utility" C of G limits for intentional spinning, are for average pilot skill. At the "normal" C of G limits a safe spin recovery is still possible, but it will probably require skills beyond that of a new pilot.


ST,
Could you expand on that? It's a long time since I read a 172 POH, so I had a quick look at one for a 1978 172N. I saw a fairly standard spin-recovery technique for spins in Utility category but nothing else.

Step Turn's Reply:

Spencer, please forgive me, I'm going to drift your thread a bit, but we'll still discuss 172's

The 172 is approved to be spun in the utility category, which category has a more restrictive C of G range than normal category. That demonstration of spin recovery (up to six turns) was made with "average pilot skill". In essence, you're not allowed to have people in the back seat for intentional spins, which seems totally reasonable to me. For this configuration, there is a POH spin procedure. There is also the expectation that you could execute a less than perfect recovery, and there is enough "room" that you're not going to exceed a limitation. (The average pilot skill thing).

The 172 (like all "normal category" certified single engine aircraft (+- the Cirrus?)) has also demonstrated compliance with the requirement that it be recoverable from a one turn spin in not more than one more additional turn - at the full C of G range. Indeed, it probably is the spin recovery characteristics which define the aft C of G limit. However, that requirement does not require just average pilot skill - it can be demonstrated with some practiced effort. And, the recovery could take the plane alarmingly close to a limitation or two, as long as they are not exceeded.

I can say from first hand experience, that larger Cessnas can approach Vne, and at more than 2 G recovering from the dive resulting from a one turn spin. Not territory to be fooling around in without a G meter!

So, in that way, the 172 has two different limitations, based upon how it is to be flown.

In deference to Spencer's original question, (and respect of thread drift) was you question answered to your satisfaction?

ST,

Not quite.

I've done hundreds of spins in my career, mainly in Chipmunks, but also a fair number in Citabrias, C172s and various gliders. In the case of the 172, I've done them visually and also on instruments.

As I mentioned previously, it was a long time since I had looked at a 172 handbook and I wasn't aware (or couldn't remember) the exact wording, which is subtly different from the so-called "standard" spin recovery that I was taught on Chipmunks. However, in practice, all the spins I've done in 172s, admittedly at forward C of Gs, have been non events, with the spin terminating as soon as I started easing the control column forward.

In the 1978 C172N POH that I downloaded (http://www.tucsonaero.com/Documents/...-1978-172N.pdf), I saw the following (paraphrased and/or abbreviated):

SECTION 2: LIMITATIONS.
Normal Category (2300 lb AUW) ... Aerobatic maneuvers, including spins are not approved.

Utility Category (2000 lb AUW) ... Approved maneuvers - Chandelles, Lazy Eights, Steep Turns, Spins, Stalls (except Whip Stalls)

Looking at the load factors, Utility category allows slightly increased flaps-up G limits of +4.4, -1.76 versus +3.8, -1.52 for Normal category. Flaps down limits are the same in both cases +3.0 with no negative G allowed.

SECTION 3: EMERGENCY PROCEDURES
SPINS (inadvertant)
1. Throttle idle
2. Ailerons neutral
3. Full opposite rudder
4. Just after the rudder reaches the stop, move the control wheel briskly forward. Full down elevator may be required at aft CGs.
5. Hold the control inputs until the rotation stops.
6. As rotation stops, neutralize rudder and recover from the dive.

There is a note to say that if the pilot is disoriented, use the turn coordinator to determine the direction of rotation.

Also, there is a reference to additional information in Section 4: Normal Procedures.

This emergency spin recovery procedure, which clearly applies to both Normal and Utility category loadings, is a fairly standard spin recovery technique except that the word "briskly" is used. It is almost identical to the RAF Chipmunk Pilot's Notes spin recovery action, except for the following wording for the Chipmunk: After a brief pause move the control column firmly and progressively forward until the spin stops.


Section 4: Normal Procedures
Intentional spins are approved within certain restricted loadings. Spins with baggage or occupied rear seats are not allowed.

Following this, there is some discussion about appropriate altitudes, height loss and spin entry, but the specified recovery technique is identical to that in the Emergency Procedures section.

ST,

Can you expand upon your previous observations, particularly since I am not allowed to experiment with spins at aft CGs? The POH implies that the same technique is valid for all gross weights and CG positions.

[9 lives]

My reply, happily pasted here (thanks for the convenience of that I24) was perhaps a little too vague...

As the POH wording very clearly states, Intentional spins are not approved in the "normal" category for a 172. Indeed, for an aircraft (by type) to be spin approved, it must demonstrate six turn spin recoveries. For any other single engined aircraft to be certified, it still must demonstrate a one turn spin recovery, but that demonstration will not result in spin approval for the type, and therefore does not need to meet the mark of "average pilot skill".

I opine that Cessna "illuminated" spin recovery in the POH about the same time as it was no longer trained in the US. If I were Cessnas horribly over worked and abused legal team, I'd send a memo up to the ivory tower, saying: "if pilots are no longer being trained to recover from spins, we'd better write how to do it into the POH, just so no one can sue saying that they had never been told how to recover." Just my opinion....

An accident in Ontario in a 172 with four fatalities was widely thought to have been a deliberate spin entry, and failure to recover. No surprise there...

The aft C of G limit for a certified plane may well be determined by it's spin recovery characteristics, even though it is not spin approved. Do not ingor this! It is not a place you want to be in the sky (not you I24, those who are less familiar!).

Control wheel "briskly" forward.... Yup! I was spin testing a modified C 206, at GW and aft C of G. I was sloppy in my recovery, and just did the standard Cessna "let go". That did not work, and I really had to apply myself. Feeling foolish, I went again... Briskly forward did the trick! It was still quite a dive coming out.

My experience has been that airplanes will recover quite nicely from a forward C of G spin, but often end up in a wicked dive. Without a G meter, which you would use to actually pull the several G's you will need to recover below Vne, you're probably going to overspeed it. Particularly in dense, slinky types like a 182RG - they speed up fast, when pointed down.

On the other hand, a not so dense, draggy plane, like a Citabria on floats, pretty well has to be pointed straight down to recover, just to accelerate back to flying speed...

Aft C of G spins make me nervous. Too many times I've been holding the controls fully forward, and just waiting for the nose to go down. It always did, but it's a bit of a helpless feeling waiting.... So "briskly" helps, get some inertia helping...

For most types I have spun during testing, which were not spin approved airplanes (I get flight permits to allow this testing), I usually temporarily install a G meter. In one type, the forward C of G spin recovery resulted in dives, from which the pull out was around Vne, and 2.8G. Not much "room" in those numbers!

There are other types, Lake Amphibian comes to mind, which spin and recover beautifully. I opine that they are not spin approved, just because they have no operational need to be, so why would the manufacturer want to spin approve it anyway....

[India Four Two]

Step Turn,

Thanks for that very illuminating post. Much food for thought there.

I would like to re-emphasize what you said about the aft CG limit. It is a flight condition that pilots should treat with great respect, particularly since most pilots are probably not very familiar with it. I have many hours in four-seat Cessnas, but I have only had four passengers on two flights, so aft CG in Cessnas is not a condition that I have much experience with.

When I was learning to fly on RAF Chipmunks, weight and balance was not even discussed. The assumption was that no matter who was in the seats, you were within limits. I did multiple-turn spins both dual and solo, but unfortunately I was not sufficiently experienced in those days to notice if there was a difference in spin recovery between dual and solo flights.

However, when I became a glider instructor and did a lot of spin-training with students, I became very aware of the different spin characteristics, depending on the weight of the student and hence the CG location. Most of my spinning was done in Blaniks - a medium performance and relatively draggy glider. In the Blanik, like most two-seat gliders, the instructor is sitting quite close to the CG, so changes in weight in the rear cockpit do not have much of an impact on the CG locations. The weight of the student, being much further forward, has a profound effect on the CG location.

With heavy students and a forward CG location, the Blanik was often reluctant to spin and would often transition to a spiral dive, particularly if the student wasn't holding the stick right on the rear stop.

"Er, see the airspeed increasing! We are unstalled! This is a spiral dive! I HAVE CONTROL!"

On the other hand, with lightweight students, the spin entry was easy and the spin was very stable. Some years ago, my club had a "low mass" female CFI, so during our Spring Checkouts, she would sit in the front seat. The CG location was close to the rear limit and the aircraft flew very differently - much more "twitchy" and as I said, entered and recovered from spins very nicely.

This year, after a eight year absence, I am back in Canada and will be flying much more modern two-seaters this year - ASK-21, DG-1000 and DuoDiscus. I'm looking forward to seeing how they spin and more importantly, how they recover. Being very low-drag, they accelerate very quickly when pointed downward.

[Big Pistons Forever]

Originally Posted by India Four Two

I would like to re-emphasize what you said about the aft CG limit. It is a flight condition that pilots should treat with great respect, particularly since most pilots are probably not very familiar with it. I have many hours in four-seat Cessnas, but I have only had four passengers on two flights, so aft CG in Cessnas is not a condition that I have much experience with.

I will second the point about the dangers of a departure from controlled flight with an aft C of G.

However before your C 172 can spin it must first enter slow flight, then it must stall, then after it stalls it must yaw through more than 180 deg of turn.

Spins were removed from the PPL syllabus in most countries for 2 reasons.

1) There were more crashes in training than in real world inadvertent spins, and

2) The real world inadvertent spins generally occurred at such a low altitude, typically as a result of badly mis flown circuit, that recovery from the spin would be impossible.

I emphasized "from the spin" in point 2 because most of those "stall/spin"accidents were recoverable if the aircraft had recovered from the initial stall and not have been allowed to progress to a spin.

Transport Canada has licensed me to both teach aerobatics and teach instructors how to be aerobatics instructors.

However I don't teach spin recoveries in the PPL per se. Instead the emphasis on training is on stall recognition and recovery. If the aircraft doesn't stall it can't spin. If it does stall and a prompt recovery is made including controlling yaw it can't spin.

A deliberate spin is an aerobatic maneuver. A C172 is not intended as an aerobatic airplane and IMO deliberate spins should not be preformed in this aircraft.

I highly encourage new PPL to take at least a basic aerobatics course. Spins will be covered but also a lot of other maneuvers which will greatly increase your skill and confidence in all your flying.

By the way the majority of glider stall/spin accidents occur below 400 ft AGL.....

[RatherBeFlying]

Annual Glider Spin Check

By the way the majority of glider stall/spin accidents occur below 400 ft AGL.....

I do not understand why so many glider spin checkers are insistent on allowing the spin to go through a full turn before beginning recovery

It builds a bad muscle memory that will turn out very badly turning base or final

I'd far prefer an emphasis on recognition and prompt recovery from incipient spins.

The current annual spin check protocol has it bass ackwards in my book.

[S-Works]

My 172 is clearly placarded in the aircraft and in the POH as intentional spins prohibited.

[horizon flyer]

In training my instructor setup an approach situation with 1500rpm 30% flaps and told me to hold the aircraft level with the airspeed bleeding off. He did not tell me what would happen. It suddenly dropped the right wing, I dropped the nose and pushed with the left foot. Ended in a anti clock spin with flap & 1500rpm. By the time I had raised flaps throttle closed & sorted it out, we lost 1500ft. Or 1000ft under ground as classic stall spin turning on to approach, next try only lost 300ft. I believe this is better training than the classic clean stall spin training, real world setup and hard lesson.

DON'T DO THIS UNDER 4000FT AT LEAST.

[9 lives]

HF, it sounds like that instructor was not thinking far enough ahead of the plane. From what you describe, that should have been seen as an approach to a possible spin, which, in a 172 (other than BoseX's apparently) is permitted within limitations. But I recall one of those limitations being flaps up for spin entries.

Two reasons for this:

If you spin with flaps extended, it is very likely that you will exceed either or both of the flap limiting speed or G loading during the recovery, because you forget to retract, or the electric flaps won't retract fast enough.

Secondly, a spin entry is a sideslip. Most 172's are placarded to avoid slips with flaps extended. Not prohibited, just avoid... But, the avoid is because in some slipping conditions, the wake off the outboard corner of the flap will impinge on the H tail on that side, and render it less effective. If you're trying to recover a spin, you'd like the H tail to be effective.

BoseX, the placard against spins for your 172... is it original from Cessna? Or perhaps associated with an STC'd mod (engine change or STOL kit)?

[Big Pistons Forever]

I am totally with Step on this. A Cessna SEP should never be allowed to spin with the flaps down. The instructor should have initiated a recovery at the stall wing drop and initial yaw. Under no circumstances should he have let the spin entry progress to auto rotation.

[S-Works]

BoseX, the placard against spins for your 172... is it original from Cessna? Or perhaps associated with an STC'd mod (engine change or STOL kit)?

Yep its a Cessna original limitation. Its a 210HP Hawk XP, 6 cylinder and constant speed prop and is specifically prohibited from intentional spinning.

It would be very dangerous for us to sow the seed in peoples mind that all 172 are cleared for intentional spinning.

[9 lives]

It would be very dangerous for us to sow the seed in peoples mind that all 172 are cleared for intentional spinning.

Very true - understand the limitations, and fly planes within them!

I used to borrow a Hawk XP from a friend, it never occurred to me that I needed to spin it...

[India Four Two]

bose-x,

Thanks for that information about the XP. That prompted me to look up the 172SP, which is the most recent 172 I've flown and I see that is still approved for spins in the Utility category.

[westhawk]

When loaded within the utility category W&B limits, the 172 is so spin resistant as to be entirely useless for spin training. Getting it to enter a spin typically requires much more advanced technique than than recovering IF you can manage to get it to spin in the first place! Entering the maneuver as recommended with power off, and full rudder at the stall break will get it to yaw/roll through the inverted to an upright nose low banked attitude, but it will most often convert to a spiral dive before the first turn is completed.

The spin training required for the issuance of an initial airplane CFI certificate is the only required spin training for FAA certification. The 172 requires some learning and practice just to get it INTO a spin. Getting it out is something the airplane does itself, contrary to your best efforts. By my way of thinking, this is NOT the purpose of spin training! But if one can get a 172 loaded in the utility category to achieve a stabilized spin, then one has certainly demonstrated significant piloting skill!

But this is a kind of negative learning that has the potential to promote complacency regarding the spin resistance of the 172. As noted in an earlier post, the 172 spin characteristics are quite different with an aft CG or with flaps extended. I somehow let a student surprise me once while he was practicing slow flight with flaps. It's a bit of a different animal then. Timely recognition and a smooth recovery is required in order to avoid flap overspeed and/or excessive G loading.

After receiving my signoff for spin training in a 172, I considered it to have been a rather pointless exercise. My previous aerobatic training in the 8KCAB was far more valuable in recognizing and practicing the proper recovery from spins, the supposed purpose of spin training for instructors.

That said, Entering the maneuver a little more briskly and with some power on (>1,500 rpm) will result in a higher likelihood of attaining a stabilized spin in the 172. The adverse yaw added by opposite aileron also helps on the entry, as it's a pro-spin input. An hour's worth of trying to spin the 172 taught both myself and my instructor some lessons about instructing, so there's that. I do wonder how many hours of gyro life we used up that day.

Bottom line: The 172 is not the best choice of airplane type for the purpose of spin training. Stick with something in the aerobatic category.

westhawk

[9 lives]

In terms of spinning, there are three types of certified, single engined GA aircraft: All have demonstrated one turn in and one turn out, but maybe with considerable skill, and no reserve. A few are well designed to be spun and recovered = aerobatic types, and a small group of compromise aircraft which can be safely used for spin training, but are lackluster in handling - usually because their design errs to the safe side. The 172 is in this category. It is a massive compromise, but a compromise which has worked.

A 172/152/150 can be used for spin training, in it's basic form. A pilot competent in spinning those has spin recovery awareness, which is much better than none. I expect it's likely that pilot could spin another type, and with only modest skill, have to really work at getting out. But I opine that a pilot capable of recovering a spin at all, is better than one who cannot at all. They have a hope, if upended in a plane.

All of the formal spin training I received was in 150 and 150 Aerobat only. Does that training make me a well rounded "spinning" Pilot? I think not. If someone spun me up side down, in a quasi military or aerobatic training, I expect my skills could be exceeded - but I would attempt a recovery based upon the training I have - that's better than nothing. Although I have abused some spin recoveries, I have never deliberately explored abused spins. I'm a "one turn in then one turn out" pilot.

But I have practiced that lots, and demonstrated it on many types. My broad experience (not deep, broad) with many types tells me that a Cessna 100 series spin trained pilot, who practices, and applies themselves, can affect spin recoveries in other types, which are much less forgiving.

One of the nicest recovering types I have spun; Lake Amphibian. A couple of the least nice; Cessna 206, and 185 floatplane. Requiring the most precise recovery technique (to prevent exceeding limitations); Cessna Caravan - though it did recover well. Most viscous entry (unintended) DC-3. Non-event spins; C 182, and as amphibian, 150HP C 150 taildragger on wheel skis, Citabria on floats - and Ercoupe (but you can't hold it in )

In a competent training environment, spin training in a 172 (or 152/150) is much better than no training. It is incomplete, but better than nothing.

And... and aircraft which recovers a spin to a spiral dive on its own, does provide a valuable and different aspect of training - recognizing changes in condition of flight which may be uncommanded, and reacting accordinaly.

[tecman]

I agree that all competent spin training is good but I'm a bit surprised that you'd put the C150 and C172 in the same category. While there are many aircraft that will spin more satisfyingly than a C150, it does at least try, and the elements of classic entry and recovery technique can be demonstrated. Like Westhawk, I've found the C172s I've flown to be quite hard to spin, and they more or less sulk their way through the procedure. No doubt it's still a useful demonstration of the flight characteristics of a C172, though.

In terms of 'easy and fun' I'd also put in a vote for the Decathlon - guaranteed to leave you smiling!

[ChickenHouse]

Following the thread I tried to get my 172 to spin, after checking the POH which does allow it. I was surprised how hard it was even to start the spin and found that even with full tank I only had to let go controls to end the spin - no action necessary from my side. Do not rely on it! This is just my observation from this single try, though! Good training and nice to know now, but now comes my question: is there any 172 known to be lost by a spin?

[westhawk]

I'm a bit surprised that you'd put the C150 and C172 in the same category.

As am I. The mighty 150 and 152 are markedly different than the 172 (loaded in the utility category) in their spin characteristics. I agree with tecman that the 150 and 152 respond well to "classic" spin entry and recovery techniques. I don't consider myself any kind of spinmeister with fewer than 100 entries and recoveries to my credit, but the difference in spin characteristics between these Cessna types is considerable.

But I'd agree with Step Turn that there is definitely a learning opportunity in the 172 and that it's better than no spin awareness training at all. Particularly if that's a type you fly often. However I'll stick with my original assertion that the 172 is not an ideal choice of types for this type of training if a more suitable type is available. The 150/152 is pretty good. The Skyhawk may react entirely differently when loaded outside the utility category W&B envelope but we're not going to test that assertion intentionally.

I think someone mentioned earlier in this or perhaps another thread that it would benefit every pilot to do some upset recovery or perhaps more ideally, basic aerobatic training early in their flight career. I believe this to be true whether one is flying strictly for pleasure or has plans to turn pro. Partially for the skills gained and also for the value of having "been there before" and successfully recovered. It's much easier for one to "keep their cool" and react properly in the event of an actual upset. Those tend to come as somewhat of a surprise! Of course many of the bad things do don't they?

westhawk

[India Four Two]

I was surprised how hard it was even to start the spin

ChickenHouse,
It's a long time since I've spun a 172, but I don't remember it being particularly difficult to spin. What technique did you use to enter the spin?

I don't have any experience with spinning a 150/152 so I can't comment on the differences from a 172. I did spin a Tomahawk a few times. Now that was interesting!

westhawk,
I agree with you about experience of spinning being very useful. I was once teaching soaring to a young guy who was a 'natural pilot'. He learned very quickly and developed good skills and a good sense of airmanship.

One day, I was just relaxing in the back seat, while he was thermalling quite nicely, with half-flap about 5 kts above stalling speed (which is normal for most gliders), when suddenly we flicked inverted and started a spin entry. I took over and recovered. In retrospect, he must have got a little bit too slow and possibly applied too much rudder.

The interesting thing about this experience which has stuck with me over the years, was that my student, who had not yet done any spin training, was completely mystified by what had happened. He basically froze.

So, certainly in the case of gliders, I think spin training should be mandatory - not just incipient spins but three turn spins.

[nkt2000]

I am a student pilot so vastly under experienced compared to most of you guys. However, here is my two penneth; I did spin training in a C172SP with my instructor. Neither I nor he could get it to spin. He told me beforehand that this would be the case. On one flight he tried all sorts of techniques to get it to spin so I could at least experience a full blown spin. Not a chance.

[hollywood285]

spinning a 172 is quite a hard think to do, if you can mis handle it that badly as to get it into a spin in the first place, the chances are you will not be able to recover it, I did spinning in a 152, they proper flick into it and go round very quickly!