Spiral dive from a spin attempt.

[Bruce Tuncks]

In a modern glider, a spin goes very nose-down very quickly. This means that the spin turns into a spiral dive and the speed can rapidly exceed VNE.

My fear of doing "spin Checks " in a glider is not from the spin entry, but from the overspeed which can result. There was a mate of mine who died in a Nimbus 4 glider in Nevada when it broke up in the air. I am pretty sure that this was the result of inadvertent overspeed.

[Jerry_Atrick]

I remember the first time I stalled a Blanik; the drop of the left wing was suddent and intense - straight into an incipient spin and had to be quick on the rudder. When they spiral dive, recovery also has to be quick (gradual, but quick)... Certainly a contrast to the benign PA28s..

[Bruce Tuncks]

Yep Jerry, there was an accident here in Australia when a Blanik bent its fuse on spin recovery. The bent fuse meant that the elevator pushrod no longer worked and they both died.

[SplitS]

Had an argument with my BFR instructor while doing a spin check. The aircraft would enter a spin but as soon as the rudder or stick pressure was relaxed it started flying again. He wanted a full spin recovery demonstration but as soon as the back pressure or rudder was centered the speed climed very quickly into the yellow arc I was on to this and would roll straight and get the nose up ASAP. He did not like the use of aileron which is true if it was still in a spin but not is a spiral dive with the speed getting away. Some people want to see the procedure rather than flying the plane hence the over speeds.

[APenNameAndThatA]

Had an argument with my BFR instructor while doing a spin check. The aircraft would enter a spin but as soon as the rudder or stick pressure was relaxed it started flying again. He wanted a full spin recovery demonstration but as soon as the back pressure or rudder was centered the speed climed very quickly into the yellow arc I was on to this and would roll straight and get the nose up ASAP. He did not like the use of aileron which is true if it was still in a spin but not is a spiral dive with the speed getting away. Some people want to see the procedure rather than flying the plane hence the over speeds.

[turboplanner]

Had an argument with my BFR instructor while doing a spin check. The aircraft would enter a spin but as soon as the rudder or stick pressure was relaxed it started flying again. He wanted a full spin recovery demonstration but as soon as the back pressure or rudder was centered the speed climed very quickly into the yellow arc I was on to this and would roll straight and get the nose up ASAP. He did not like the use of aileron which is true if it was still in a spin but not is a spiral dive with the speed getting away. Some people want to see the procedure rather than flying the plane hence the over speeds.

Hopefully you weren’t flying RA

[facthunter]

The deal is SPIN or SPIRAL? Two totally different things with totally different recovery techniques. 100 years ago it was the Graveyard SPIRAL that killed people.

How do you know which it is? In a spin the speed stays fairly low ( near normal stall) and "G" does not increase. The plane is not stressed in a spin. It does pull"G" when recovering from the dive if you are careful, and not running out of height, is 2.5 G or a bit more.

A Spiral is quite easy to get into especially in cloud. You still have a turn (yaw) but if the nose drops and the speed starts to increase and you apply back stick you are set up for a problem as the load on the airframe rapidly increases as airspeed increases and you are descending fast. You have to exit the TURN quickly and as the plane is not stalled this is done with aileron to get the wings LEVEL.

IF an instructor is so averse to using aileron. you could miss the chance to regain control quickly. That's why the question "identify" SPIN or SPIRAL be settled quickly and the clue is AIRSPEED and to a slight secondary consideration,"G" force felt. (by the seat of your pants, unless you have a "G" meter.) Nev

[pmccarthy]

I have often wondered whether you could recover if you lost control in a cloud and emerged in a vertical dive at cruise speed in a non-aerobatic plane, say a PA28 or C172. Could you pull back to straight and level without destroying the airframe by excessive G or by overspeed?

[Bruce Tuncks]

I know a guy who did just that in a glider pm. He was worried that he had overstressed the airframe and I was able to reassure him that since it was made of carbon it would either explode or be ok. Since it had not exploded, it was probably ok.

In a metal plane, I would advise the sort of inspection you do after a heavy landing. A careful look at the geometry ( no more dihedral than there should be etc ) and a careful look at the fittings.

[facthunter]

I know people who have fallen out of a cloud upside down or worse. One in a valley with cloud on all hills. Most become statistics. CFIT it's called but often it's NOT controlled. How long you last in a spiral depends on the planes characteristics. How draggy it is, how easy it spirals. how strong it is. In a spiral the tendency is to slow the plane and it's descent by back stick which often just tightens the spiral and pulls more 'G', then things start to come apart.

IF you came out of a cloud near vertical you would already be going perilously quick and probably well above Vne.. Any pull out not very carefully executed will probably pull the wings off, but the longer it's pointing straight down the faster it's going. You'd be much better off if you were spinning.. Spinning won't overstress the plane even if prolonged. The later part of the recovery (dive) is slower than a spiral will be in most cases. You just need enough height to do the pull out safely. Wrinkles in the upper skin or popped rivets underneath will tell but there's proper inspection procedures for various planes and it should be grounded until they are done if it's been seriously overstressed. Nev

[nomadpete]

A problem is identifying the speed, as many ASI gives invalid readings at unnatural attitudes.

I think I was taught to feel for the G's to help identify the difference between spiral and spin? It was quite a few years ago and those grey cells aren't current (not in RAA aircraft, so relax Turbs!)

[pmccarthy]

I did that unusual attitude training, under the hood too, when Gough Whitlam was PM so I can't add anything.

[kasper]

And for the entertainment if not a little enlightenment of the three axis drivers the wobble wing flyers have a different take on the spin/spiral recovery ... we can’t spin because we can’t hold any out of balance flight

 

but we can spiral dive like nobodies business so we always immediately go for spiral recovery

 

And we do mean immediately... speed build up to structural fail levels can happen very fast and in addition most wings will start to lock in and respond poorly in excess speed situations.

 

For example a p&m quantum15 will go from stall entry to vne in a spiral in under 2 turns and that’s in less than 10secs. If you have not pulled and pushed the bar within that time you are either a statistic or up for a wing strip and inspection.

 

The raven 912 eclipsr has a much higher vne and will try to roll itself out of the spiral but still you only have a few seconds before you are looking at a vertical dive at vne and accelerating.

 

At least exceeding vne in most of the European and UK wings does not have the outer wings folding under with spar failure in negative load through speed alone ...

[kgwilson]

I got sucked up into the bottom of a CU in my hang glider about 35 years ago. The vario was screaming & pegged at the maximum of 2000 fpm up & I was hooped over the bar & trying to spiral out of it but it wasn't working. Everything just went white & I thought I was flying sort of level but I got spat out the side of the cloud & the horizon was vertical. This all happened within a few seconds but it felt like an eternity. I reckon it took only 5-10 seconds for me to become completely spatially disoriented. I didn't fly for a while after that.

[facthunter]

The "Under the Hood" training covers it well and relies on a gyro turn needle as a prime instrument. Doing that sequence on limited panel, (learning it for the first time) is about as hard as anything you ever do in a plane. Spiral training is NOT permitted in RAAus aircraft. While that IS limiting of an opportunity, it's for a good reason. Recovery from a spiral must be quick and effective or you exceed the aircraft's limits easily. Nev

[Old Koreelah]

A problem is identifying the speed, as many ASI gives invalid readings at unnatural attitudes...

I made an "articulated" pitot tube in an effort to give a correct reading during all angles of attack and side slipping. Just a tiny little empenage hanging back from a flexible tube stuck in front of the pitot. It seemed to give accurate readings, but I never got around to doing proper testing before I accidentally broke the plurry thing.

[Flightrite]

I've always felt not enuf training is spent on unusual attitudes demonstration & recovery. A monkey can fly a plane when it's all going well that's the easy part it's getting 'unstuck' from where that demon lives out there in the sky!

[kgwilson]

The 5 hours under the hood was very valuable knowledge & experience. Why that isn't done in RA is crazy.

[Flightrite]

The 5 hours under the hood was very valuable knowledge & experience. Why that isn't done in RA is crazy.

I'd say it's not done as a lot of RA machines don't have any inst to ref in IMC where as a lot of cert GA did/have.

[ClintonB]

It’s noticeably more taxing under The hood, I always felt exhausted after doing it. I found out my artificial horizon is a little out, if I keep level with it I end up in a slight turn which needs correction every 5 minutes.

[kasper]

Hmmm. Core three asi, alt and magnetic compass was what I had to deal with under the hood. Then they gave back the vsi and it got a bit easier. Then the gyro instruments were uncovered.

 

worst was absolutely unusual attitude recovery under the hood- just as well it was aero allowed and the instructor rated to train in it - we had a few moments.

 

no raaus aircraft are certified for spins or aero so I’m very happy limiting instruction to incipient spin recovery - identify the coming sh$t storm and act early. ?

[Jase T]

The 5 hours under the hood was very valuable knowledge & experience. Why that isn't done in RA is crazy.

 

One could argue that “inadvertent IMC” is an important part of Nav training. Even if it just gets you thinking about a what if plan (which way am I going to go how high do I need to climb who am I going to call).

[Bruce Tuncks]

I looked up electronic artificial horizon instruments. The cheapest is still way over a thousand dollars, but you can buy model aircraft flight stabilization systems for about $30.

Of course the model setup still needs a display, but I wonder why an AH is still so costly?

[RossK]

My Instructor used the hood on me as part of my RAA nav endorsement. It's not required for the syllabus, but definately worthwhile doing.

One could argue that “inadvertent IMC” is an important part of Nav training. Even if it just gets you thinking about a what if plan (which way am I going to go how high do I need to climb who am I going to call).

[Flightrite]

I looked up electronic artificial horizon instruments. The cheapest is still way over a thousand dollars, but you can buy model aircraft flight stabilization systems for about $30.

Of course the model setup still needs a display, but I wonder why an AH is still so costly?

 

There a few EFIS system displays for yr Mob PH or tablet via the App Store, I have one on the Mob PH and Tablet just in case the zillion to one chance that the cockpits I was flying in went blank at night out over the Pacific! Obviously not to be used in anger but a free 'get-out-of-jail' card if you killed a Chinaman!