PA-38 Tomahawk Spin Characteristics

[FlyTester]

I'm getting checked out as an instructor in a Piper Tomahawk. As I've flown the Beech Skipper at another school, I'm looking forward to seeing how the two compare. I have also flown and spun airplanes such as the T-37 that require timely and deliberate actions to recover from the spin. So...

I was not particularly daunted by the thought of stalling and spinning the aircraft intentionally during the checkout UNTIL I stumbled across several (less than detailed) references of Tomahawks with unrecoverable flat-spin tendancies.

Other than being loaded to an Aft CG, is there a particular means of entry of that results in a flatter spin [in the PA-38]?

Any personal experiences regarding the airplane's spin characteristics would be appreciated.

[BigEndBob]

The only time i thought i was going to die in an aeroplane was when i spun a Tomahawk and it didn't promptly recover but went into what is probably familiar to regular spinners of such aircraft as a very rapid rotation, low nose attitude, almost felt it was spinning about its longitudinal axis giving the rudder no lever arm to break the spin.
Got to admit probably a bit over weight as student was a big chap.
Most manuals have a page about spinnig in the flight manual, i think the Tomy as three. Read carefully.

[homeguard]

The Tomahawk pitches down very rapidly following recovery action and the rotation speed therefore increases, also rapidly, owing to the reduction in the rotational drag following the pitch down. In the early days, mainly in the USA, the increase in rotation was wrongly interpreted as a deepening of the spin although it is the first indication of the recovery.

Due to the increasing inertia from the rotations prior to recovery, for each full rotation undertaken, after a particular number of rotations (check the manual), it will take a further multiplying number off rotations to recover. So if you maintain the spin for anything more than, say, two spins you are going to wait a prolonged time for recovery and you will lose an awful lot of height.

Less important but quite dramatic is the crashing and banging emitted from the Fin and Tailplane during the spin. If you look back you will actually see the whole fin and Tailplane twisting and bending.

READ THE MANUAL CAREFULLY AND FOLLOW THE GUIDANCE. Although not mentioned in the manual is the crashing and banging.

[llanfairpg]

The Tomahawk pitches down very rapidly following recovery action and the rotation speed therefore increases, also rapidly, owing to the reduction in the rotational drag following the pitch down. In the early days, mainly in the USA, the increase in rotation was wrongly interpreted as a deepening of the spin although it is the first indication of the recovery.

Increased rotation after recovery action is a feature of one or two types and needs to pointed out when discussing standard spin recovery in the same way as moving the CC/stick fully forwards until rotation stops, even to the stops if necessary. It is also interesting(and obvious) to note that some aircraft with an aft C of G have completly different spin characteristics. Ensure when referring to POH they are the Piper/CAA approved handing notes/manual. I seem to remember the CAA issued a directive about these aircraft and spinning which should be in the Flight Manual but cant be sure.

[FlyTester]

Thankyou for your comments. I did another websearch today and found this very telling article buried in landings.com

"Landings: Opinions: RE: Tomahawk Article

By: Pat Finucane
E-mail Address: [email protected]
As a former flight instructor who taught all students spin recovery techniques in a Tomahawk and who has experienced flat spins in the aircraft I have some comments to make. I am also a Tomahawk owner so my comments may be considered somewhat biased. The flat spin is entered from an aggravated cross-control stall. Just hold the cross controls thru the first 1.5 turns and the nose will come up. It's about 30 degrees below the horizon, but the controls go 'dead' (i.e. no effect.) recovery is by deploying the flaps momentarily to get the nose to pitch down. Immediately retract the flaps when the nose pitches and then perform a normal spin recovery. Moving forward in the seats may not be possible due to forces in the pesudo flat spin. All spins in the Tomahawk that are unplanned or unexpected are the result of a stall at high angles of attack. The T-Tail gets into the prop slip stream and it is almost impossible to control the rolling or yaw moments. The Tomahawk stalls just like a C-150 when you limit the pitch angle of the nose to just slightly above the horizon. It exhibits normal characteristics, i.e. lost of buffeting, nose drop and smooth, progressive application of power with corresponding right rudder pressure, the airplane will fly out of the stall, in a hands off condition. This applies to all types of stall entries, power-off, power-on (limited to 2200 rpm), accelerated, take-off departure. By limiting the pitch attitude to the same as normal climb out, the stall characteristics are typical as in other aircraft. If you get the nose too high, so that the tail is being buffeted or affected by the propeller slip stream, the Tomahawk will begin to yaw and roll and will easily enter a spin. Recovery from knife edge flight is possible with full coordinated control input and smooth power application. Typical loss of altitude from the incipient spin entry is 400 ft. Hope these comments are helpful to understand this bird's characteristics ."

[fireflybob]

In the early days, mainly in the USA, the increase in rotation was wrongly interpreted as a deepening of the spin although it is the first indication of the recovery.


It's called Conservation of Angular Momentum - when the aircraft starts to spin in a smaller radius circle the rate of rotation will increase, normally a sign that the aircraft is in the process of recovering. (Think of ice skaters - when they spin round and bring their arms in they go faster and when they want to slow down they put their arms out)

My father was an instructor during WW2 on Miles Magisters. I remember only too well his stories of spin recovery on this type and when the PA38 came along he remarked that he had seen it all before, dear boy!

Seem to recall that one of the first ones in the UK spun in at Oxford.

[BoeingMEL]

yep.... those tail-feathers shaking all over the place can be a real shock - even if you're expecting it. Best not glance back over your shoulder - it's not a reassuring sight. Did it many years ago in the Daventry area and the words mortgage, kids and bl**dy hell flashed in front of my eyes..
Cheers anyway, bm

[mad_jock]

I see your from the states so i don't know what the rules are over there.

In the UK there have been several mods to the tail which need to have been done before you can spin it. All the G reg ones should have been done now.

Also in the Uk the aircraft needs to be fitted with 4 point harnesses.

Also there is c of g rear limits as well

And also a max fuel state up to the cross in the fuel tank did me as a max but everything was a whole lot easier with 1.5hours of fuel on board for a 50 min lesson. And make sure its balanced or things get a bit weird.

Your not allowed to flick it into a spin with a boot full of rudder acka c150. Your meant to bring it to the stall at 1knt per second then let a wing drop of its own accord.

If you play by the rules it behaves its self if you take the piss it can be a bit of a handfull.

There will be many a instructor who has stuck the boot in or had to much fuel who after loosing 4000ft and had 5-6 rotations in the space of >30secs and nearly pulled the wings off coming out of it, have vowed never to spin it again/ fly it again.

Which is a shame because its a bloody good training aircraft apart from its crappy trim system.

[llanfairpg]

It's called Conservation of Angular Momentum - when the aircraft starts to spin in a smaller radius circle the rate of rotation will increase, normally a sign that the aircraft is in the process of recovering.

You can do it on the C152/150 by entering the spin with full power, when you close the throttle in the recovery the rotational rate initially increases.

[B2N2]

Have been at least 12 fatal spin accidents in the "TraumaHawk".
mainly with very experienced pilots on board for CPL and Flight Instructor checkrides.
At least several because of the yoke getting stuck in the full aft position because of a worn out bushing/grommet in the instrument panel.

http://www.aopa.org/asf/asfarticles/sp9702.html
http://www.landings.com/_landings/reviews-opinions/tomahawk.html
http://www.landings.com/_landings/ganflyer/jul25-1997/New-Tomahawk-Tests.html

Here is the AD:

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/C0E57F03A05B1847862569A6005C9CF2?OpenDocument

[stevef]

'At least several [accidents] because of the yoke getting stuck in the full aft position because of a worn out bushing/grommet in the instrument panel.'

Are you sure about that? The AD related to the potential of being unable to move the control wheel from the fully aft position. In any case, that AD would have been complied with over twenty years ago (and it had to be implemented within 50 hours of the AD's release, which makes it more of a precautionary measure, as opposed to 'before further flight').

[B2N2]

Here is some very interesting reading from the NTSB,

Piper moved production of the PA-38-112 to the company's
Lock Haven, Pennsylvania, facility, where more than 2,400 PA-38-112 airplanes were built
between 1978 and 1982, when production ceased. The Safety Board has learned of reports of
significant differences in the stall characteristics between the certification-tested airplane and the
production airplanes

Full article:

http://www.ntsb.gov/Recs/letters/1997/A97_41_45.pdf

[CiFIcare]

Whenever I spin the Tomahawk (on the specific request of a student only), I always 'shadow' the controls when its their turn to have a go. Not actually manipulating, or touching the controls but my hands just below the column to prevent (un-intentional) application of aileron.

Stems from once in a left hand spin (as you'd expect, bit more rapid rotation rate than right in the PA38) when the student applied a handful of right aileron, in his attempt to rectify the situation. The nose rose and the rotation rate increased. Actually caused the engine to be starved of fuel as I suspect the float was lifted. Recovery was uneventful with my application of correct technique.

Am generally far less concerned in C150/2, where aileron in/and out of spin direction does affect the roation rate but has much less dramatic effects.

Overall, I do not believe the PA38 spin charecteristics deserve their dreaded reputation. I think it stems from the many out there who's only experience of spinning has been the PA38 and it's given them a shock!

Bit like the Bulldog who has now gained the same reputation in civilian hands after many thousands of hours military service where they were spun frequently with only a few 'incidents.'

Much of the talk in flying school bars is the same for the Firefly which like all the types mentioned here, I have found to be entirely predictable during spin training with correct control application.

[CiFIcare]

Forgot to mention, in the PA38, a nice way to demonstrate accidental incipient spin entry (ex. 11 anyone!?) rather than the usual full nose up and full rudder: (which most students find quite distressing on their first encounter)

Around 2000 rpm, 45 degrees AOB and a slight nose up attitude. Gently apply steady back pressure to the buffet and she'll autorotate very nicely and slowly out of the turn. Autorotation stops instantly with centralisation of the flying controls.

Works just the same in a descending turn (ask them if this could be a situation typical to a mis-flown final turn), of course this time the auto-rotation will be into the turn as the inside wing has the greater relative AoA.

[crumbo]

a bunch of sky before ;)

[V1... Ooops]

I have flown (and spun) both the Skipper and the Tomahawk. I don't think you have any reason to worry spinning the Tomahawk as long as you read and follow the directions in the AFM/POH. However - all the shaking and banging that comes from the back is not very reassuring, and for goodness sake, don't turn around and look at what the tail is doing (oscillating all over) or you might stain the seat.

[poss]

I enjoy spinning the Tomahawk, she always makes you work for your supper. I've only ever spun an MK2 though and from the state of some MK1's i've seen i'll only ever spin an MK2. There is some history of the tails on the MK1 falling off during training. I think it was actually mentioned at some point prior to my post about how they were modified. It's all about knowing the correct technique to pull her out of her spin and to keep a cool head when the spin speeds up.
:ok:

[joneden]

An old story: with hundreds of spins under my belt, the only one that scared me to death was in a PA38--I never spun one again nor would I. As others described, it initially increases the rate of rotation upon putting in recovery input--I don't need to see it again. I am not a test pilot.

The wing on the airplane is not the one that underwent certification, and engineers have complained that the increased flex in the modified wing is detrimental to the performance of this particular air foil.

The accidents from spins in this aircraft are said to be 3 to 5 x's that of the 150/152.

This past Aug (2012), a Montana State U student, and his flight instructor lost their lives in an accident which witnesses described as a spin into the ground. Clearly this is a dangerous airplane from the point of view of spin recovery. The death from this faulty aircraft continue to mount.

Wikipedia states that the NTSB recommended "re-certification" of the production airplane (given that it is a modified wing and not the one originally certified.)

I think spinning this airplane is like owning a pit bull--greatest airplane in the world until one day it isn't.

I am not a Tomahawk hater. I think it has a great visibility and a terrific cabin layout. I do though think its handling is not as sensitive as the 150/152--

[billiboing]

I am a licenced aircraft engineer and also a pilot. I also own and operate numerous Tomahawks. The instructors seem to like to spin them. The tail does flex in the spin, the same as most T tails do.

The reason I dont allow anyone apart from instructors to spin the Tomahawks ( numerous other leasing companies have also done the same) is simply COST. There are a stack of ADs on the tail brackets and the brackets are getting ever increasingly hard and costly to get hold of. Constant spinning wears out all the bracketry at the arse end and it costs money to replace!!! Excessive tail movement in the spin is down to poor maintainence.

This is the reason why some operators ask people NOT to spin Tomahawks, not cos of any other reason. So if you see a Tomy with SPINNING PROHIBITED marked on it, it may not be because the operator thinks it is dangerous, or cos that aircraft spins any worse than any other, but because they are trying to look after ever aging airframes!.

Fly safe guys.

[A and C]

A lot of good stuff above and only one traumahawk !

I think that the Root of the accidents is likely to be in the maintenance, as said above there are a lot of AD's that need to be done and the likelihood of the back end moving about after a poor AD instalation or when a well used aircraft is approaching the next inspection is high.

That having been said the aircraft exhibits a marked increase in the roll rate when the correct recovery action has been taken ( for reasons outlined in posts above) and I think this may well have panicked some pilots, I would think that the "Oxford" accident was most likely a student freezing on the controls.

That brings me to pre-flight breifing, with spinning it is vital that there is no doubt whatsoever in the students mind as to what is going to happen, one of the best instructional aids that I have used is an RAF film called Spinning modern aircraft. Made in the late 50's it is a wonderfully simple but effective way of making the subject clear to the student.

[Pilot DAR]

The wing on the airplane is not the one that underwent certification, and engineers have complained that the increased flex in the modified wing is detrimental to the performance of this particular air foil.


If the wing is legally installed on the plane, it underwent certification flight testing, and demonstated compliance with the requirement to be able to be recovered from a spin.

If the wing flex has been changed, a massively complex engineering and test exercise must have been undertaken, which would involved lots of spin testing. For the wing to be affecting the performance of of an airfoil, the wing torsional stiffness must have changed, which I very much doubt.

Everything on and aircraft is designed to flex a little when under load. Usually it's just not enough to be able to see. There's nothing wrong with some flexing, as long as it is under condtions which are within the manufacturer's intended limitations. Ever seen the upper skins of a 100 series Cessna wing, in a 3 G turn?

[goldeneaglepilot]

I do remember that in the early 80's the PA38 in the UK was only cleared for intentional spinning during either initial airtest for issue of a CofA or star annual. I also remember seeing a letter from the CAA strongly suggesting that a parachute should be worn during the airtest (no mention of nappy or rubber pants though)

Yes - the tailplane does flex the fueslage during the spin. Yes, it also clunks and bangs, but it does recover predictably. It just takes time (and height)

The mechanics face is fun to see though, if he's flying on the airtest as an observer

[Pilot DAR]

CAA strongly suggesting that a parachute should be worn during the airtest

For flying those few (any?) Tomahawks with jettisonable doors? Or, did the author simply think that the whole fuselage would split open to allow you to exit in flight?

[Genghis the Engineer]

For flying those few (any?) Tomahawks with jettisonable doors? Or, did the author simply think that the whole fuselage would split open to allow you to exit in flight?

You could extend that argument to spinning in many aircraft types. Given that even the most benign spinning aeroplane can hit that one in a million set of conditions and lock in (Bulldog, T67....), is it appropriate to ever deliberately spin anything without a get-out-of-gaol-card: a parachute and canopy/door jettison being the most obvious route out for most aeroplanes.

G

[18greens]

Has anyone tried the application of full power after full opposite rudder to help the airflow over the rudder correct the spin?

[goldeneaglepilot]

I suspect that the man at the CAA who sent the advisory note about the flight testing of PA38's at the time, who might have been or was related to the designer of the door catch mechanism. It was never the best in the PA38.

I never questioned the wisdom of the advisory note - after all the CAA always knows best....

Might be worth reading: http://www.aaib.gov.uk/cms_resources.cfm?file=/11-1981%20G-BGGH.pdf