Would my AI survive a roll?

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paramax55

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paramax55
I have a 1972 Arrow II with a Century II autopilot. It has the original AI which, I believe, would make it an Edo-Aire (due to the autopilot). I have some former fighter pilots and a former crop duster living in my neighborhood and a few of them have told me they would take me up and show me how to roll my airplane. One of them brought up a good point though - the AI crashing and becoming a $400.00 roll due to the cost of an AI rebuild. I asked one of the A&Ps in the neighborhood and he said that it might have stops to keep it from crashing and that I shouldn't be too worried. Then I read an article about a banner towing operation that quit fixing their AIs because it got to be a pricey operation - and that was just from steep banks (or was it pitching up after grabbing the banner...).

So... should my AI be OK? Should I be worried? Should I just do another roll in the other direction - just for safety, of course?
 
There's lots wrong here, and the AI is by far the least concerning thing about this deal. Suggest finding an experienced aerobatic instructor in an aerobatic airplane if you want to learn to do a basic roll.
 
Kind of like an F14 pilot taking me up in his Stearman 400? I'm not asking about an aerobatics course. I'm asking about my AI during a roll.
 
AI will be fine but when you jack up the roll because you didn’t pitch up enough, your wing won’t survive the 4 +G pull out.
 
That's why I won't be doing it by myself. It'll probably be the F14 pilot or the AG pilot in the right seat when I do it. I'm trying to get some time in the Stearman, but he doesn't pull that beast out but a few times a year.
 
Well if he’s a former F-14 pilot then I can’t see anything wrong other than the limitations section. Wouldn’t even bother with parachutes in that case.
 
paramax55 said:
It'll probably be the F14 pilot or the AG pilot in the right seat when I do it.
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Not to make judgments on any other type of experience these guys have, but FYI simply being an F-14 pilot or Ag pilot means squat when it comes to doing what you're talking about in an airplane like this.
 
Velocity173 said:
Well if he’s a former F-14 pilot then I can’t see anything wrong other than the limitations section. Wouldn’t even bother with parachutes in that case.
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I take helicopter pilots up so they can show me how to land the 182 vertically. Well, I would, but none of them ever seem to want to go... :)

Agreed it’s trolling. A former F-14 pilot wouldn’t be that effing stupid.
 
I did a barrel roll in a Cessna 177 once upon a time. While I got the nice 30 deg off and nose under the horizon just like the book sez, during the rolling pullup, the 177 had such low aileron authority (and correspondingly low roll rate), that the bird literally ran out of air speed approaching something close to wings level (inverted) with respect to the horizon. Running out of airspeed, the nose basically dropped through the horizon to nearly that of straight down. I briefly accelerated to and visited the redline area on the airspeed indicator but with care I got her nose back up without exceeding the g limits, to level flight. While I was solo, I eased out of that but would not want to try that again. On the other hand, it was easy to do in a Centurion. Only did it once. Centurion had much more roll authority. Having said all that, doubtful that I would try that in a Cherokee arrow, and yes I have time in the Arrow. I would also admit that it wasn't very wise of me to try a barrel roll in a Cardinal. Last, yes, I had been trained in acro.
 
If one is serious about acrobatics, then one can locate many acro instructor guys around the country with aircraft suitable for acro.. like Citabrias and up. Acro is great fun and doing it (correctly) on a regular basis is a neat way for honing one's flying skills.
 
So why would anyone want to take the risk of rolling an aircraft that never was designed to do so?
 
I spun a Cessna 150 and the AI tumbled. I doubt it did it any good, but it worked on the next flight. I wouldnt recommend it. Used to be the gyros had locks so they wouldnt do that.
 
Timbeck2 said:
So why would anyone want to take the risk of rolling an aircraft that never was designed to do so?
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Technically all aircraft are designed to roll. :) It’d be kinda hard to make coordinated turns if they weren’t. :)

(I know. Smart ass.)

What they’re not designed to do is high G loads or extended negative G loads and that’s what most non-aerobatic pilots will do to them inadvertently.

coloradobluesky said:
I spun a Cessna 150 and the AI tumbled. I doubt it did it any good, but it worked on the next flight. I wouldnt recommend it. Used to be the gyros had locks so they wouldnt do that.
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Back in the day, the club used to keep a Skyhawk with gyros that had been abused by spin training as a VFR airplane on the rental sheet only, and it was known as the “spin airplane”. Usually owned by the club itself and not a leaseback, since owners didn’t like replacing worn gyros all the time.

The poor AI in the “spin airplane” I spun a bejillion times was only ever upright on the way to the practice area and altitude and the pendulous vanes once in a while would right the poor thing on the way back to the airport. The DG fared better but watching a whirling DG was sometimes the result of an “over the top” spin entry.

It had a basic VFR panel and nobody was dumb enough to try to teach or be taught instrument flight in it.

We mostly just laughed at what the poor gyros would do on any particular flight. It was entertaining to do an XC in it too, since the DG precessed quite a bit. Made you pick good landmarks. ;)

“Check THAT out!” As the AI went bonkers.

I always wondered why the rental place didn’t buy gyros that would cage for it, so I asked... “They’re more expensive. It’s a VFR airplane and a VFR airplane it shall remain.”
 
P.S. Adding spins to a dual XC was fun back then.

Start a long climb on course to the destination, finally get to a safe altitude for a spin, spin it.

Brownie points if you could recover from the spin to something close to your original on course heading, climb for another ten minutes on course, make sure you’re on your course line, reach a safe altitude, spin again...

All the way to the XC destination.

Hahaha. There’s no way in hell anyone would ever do that today. But that’s how I got from Denver to Cheyenne one day.

We quit after a while figuring we’d never get there and it was coming up on lunchtime and need to fuel up. :)

During my run up to the initial CFI we noticed I didn’t have a spin endorsement and I laughed.

Okay now what? Instructor called up another instructor with access to a Citabria and we met, discussed spins and how many of them I had done in Skyhawks, wander out to the practice area in the Citabria, clear the area, “okay whichever direction you want...”

Did one to the right assuming it would be harder to enter and slower to go over, it was a little but the Citabria spins a lot quicker than a Skyhawk.

Ooh! This spins nice!

“Okay do one the other way...” Done.

“Anything else you want to work on? Might as well go do some landings, and get you started on your tailwheel endorsement.” Hahahaha.

Asked to do one a little more accelerated from a turn. Done.

Okay. Back to the airport... hahaha. Was a fun morning. I could have stayed out there spinning the Citabria for quite a while longer. Very fun.

I’m afraid to go do more Citabria time. I’d probably be hooked. :) My wallet would cry. Maybe later this year. :) :) :)
 
You need to buy one, Nate @denverpilot . Just so happens there's one parked in our hangar, keeping the Dakota's spot warm while she's at Meadowlark for paint. One of our club members decided he wanted to get a tailwheel endorsement before his 86th birthday, so he bought a Citabria, got his endorsement, and says he's going to sell it now. Don't know all the details, but he's grinning big after the check ride and says he loves the plane ...
 
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It's pretty hard to pull the wings off an Arrow. Unless they just fall off on their own...
Plus, an Arrow is pretty close to an F-14 in performance, so experience in the latter should carry over to the Piper with no problems at all.
And, we can be sure that this wouldn't be the first time someone rolled an Arrow - in fact, I even found some instructions on line (https://www.ntsb.gov/_layouts/ntsb....ev_id=20071119X01812&ntsbno=DFW08FA031&akey=1): "When the IIC asked the instructor to describe how this maneuver was done, he responded with the following: The airplane is nosed over until 140 knots is reached. The pilot then pitches up until about 10 to 15 degrees above the horizon. The pilot then applies left rudder and aileron." Note: The AI appears to have been damaged... :-(
 
I dunno. But video it so we can watch if the camera survives.
 
Capt. Geoffrey Thorpe said:
It's pretty hard to pull the wings off an Arrow. Unless they just fall off on their own...
Plus, an Arrow is pretty close to an F-14 in performance, so experience in the latter should carry over to the Piper with no problems at all.
And, we can be sure that this wouldn't be the first time someone rolled an Arrow - in fact, I even found some instructions on line (https://www.ntsb.gov/_layouts/ntsb....ev_id=20071119X01812&ntsbno=DFW08FA031&akey=1): "When the IIC asked the instructor to describe how this maneuver was done, he responded with the following: The airplane is nosed over until 140 knots is reached. The pilot then pitches up until about 10 to 15 degrees above the horizon. The pilot then applies left rudder and aileron." Note: The AI appears to have been damaged... :-(
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This is what makes me wonder about the recent ERAU in flight breakup. There always seems to be at least one of these fools, whether student or instructor, that decides they want to be a Blue Angel in a Cessna or Piper. Maybe they get away with it, maybe they don't. Maybe they just cause increased airframe fatigue that it bites someone days, months, or years later...
 
There's another whole thread going on ref a Pa-28 losing a wing due to stress fractures... How might they have gotten there...mmm I wonder...
 
midwestpa24 said:
This is what makes me wonder about the recent ERAU in flight breakup. There always seems to be at least one of these fools, whether student or instructor, that decides they want to be a Blue Angel in a Cessna or Piper. Maybe they get away with it, maybe they don't. Maybe they just cause increased airframe fatigue that it bites someone days, months, or years later...
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Fatigue takes thousands of cycles - if you overstress it enough to start a crack to create a starting point for a fatigue crack, you should have done enough plastic deformation that would, at least it would seem to me, to be obvious to the casual observer. Plus, using the above NTSB report as an example, the wing does not appear to fail at the root (the ERAU failure) when you pull too hard.

Back to our regularly scheduled program.
 
An instructor I would fly with from time to time would roll an Archer. More than once. Did a pretty decent job of it. If one had had their eyes closed, they would never have know he did it. Probably should have been a bit higher than 1500', but what the heck. And no damage to any panel instruments, and I didn't even spill my diet Coke.
 
Capt. Geoffrey Thorpe said:
Fatigue takes thousands of cycles - if you overstress it enough to start a crack to create a starting point for a fatigue crack, you should have done enough plastic deformation that would, at least it would seem to me, to be obvious to the casual observer. Plus, using the above NTSB report as an example, the wing does not appear to fail at the root (the ERAU failure) when you pull too hard.

Back to our regularly scheduled program.
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Fatigue failure *can* take thousands of cycles or it can take only a few, it all depends on the stress level and the environment. Even fairly low stresses can cause fatigue failure in a corrosive environment. Hydrogen is bad, sulfides are bad, high or low pH can be bad or good depending on material. Add stress risers to the picture and things can go south in a hurry.

Personally, I haven't seen a beam crack halfway through a flange and stop there without some substantial material change. I have seen cracks halfway through material where the crack released the stress in the material with plastic deformation in the adjacent material (which is the condition you specified). Repairing those things can be fun because all the structure has to be cut out and renewed. I have seen plastic deformation alone (no cracks) repaired by straightening then doubling everything. I have seen cracks through a portion of material in a saltwater environment and no plastic deformation in adjacent material.
 
A wise pilot I know once said "I'm not doing spins in an airplane I want to fly IFR." The extreme attitudes are pretty hard on the gyro instruments, even if they don't tumble *that* time.

I'd suspect a roll would be similar.
 
I'd suggest checking the aerobatic authorization in the POH, then call the FSDO when you're ready and let them know what you're up to so they can help you get into the correct airspace for your maneuver.

Or you can just crawl back under your bridge...

They're a pain, but they do keep things interesting.
 
denverpilot said:
P.S. Adding spins to a dual XC was fun back then.

Start a long climb on course to the destination, finally get to a safe altitude for a spin, spin it.

Brownie points if you could recover from the spin to something close to your original on course heading, climb for another ten minutes on course, make sure you’re on your course line, reach a safe altitude, spin again...

All the way to the XC destination.

Hahaha. There’s no way in hell anyone would ever do that today. But that’s how I got from Denver to Cheyenne one day.

We quit after a while figuring we’d never get there and it was coming up on lunchtime and need to fuel up. :)

During my run up to the initial CFI we noticed I didn’t have a spin endorsement and I laughed.

Okay now what? Instructor called up another instructor with access to a Citabria and we met, discussed spins and how many of them I had done in Skyhawks, wander out to the practice area in the Citabria, clear the area, “okay whichever direction you want...”

Did one to the right assuming it would be harder to enter and slower to go over, it was a little but the Citabria spins a lot quicker than a Skyhawk.

Ooh! This spins nice!

“Okay do one the other way...” Done.

“Anything else you want to work on? Might as well go do some landings, and get you started on your tailwheel endorsement.” Hahahaha.

Asked to do one a little more accelerated from a turn. Done.

Okay. Back to the airport... hahaha. Was a fun morning. I could have stayed out there spinning the Citabria for quite a while longer. Very fun.

I’m afraid to go do more Citabria time. I’d probably be hooked. :) My wallet would cry. Maybe later this year. :) :) :)
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Was that 53959? Fun airplane, but it had stiff pedals from the front seat when I flew it, especially the right pedal, which made takeoffs, uh, spirited for a low time tw pilot.
 
DeeG said:
An instructor I would fly with from time to time would roll an Archer. More than once. Did a pretty decent job of it. If one had had their eyes closed, they would never have know he did it. Probably should have been a bit higher than 1500', but what the heck. And no damage to any panel instruments, and I didn't even spill my diet Coke.
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You flew with Bob Hoover? ;)
 
Donno about roll, but the POH of my archer says bank more than 60 degrees approved under utility category. My CFI could believe it until I showed him that. I have never tried it though and I don’t know what they mean by greater than 60 degrees... 90 ... 180 ... 360? Who knows
 
Eric Gleason said:
A wise pilot I know once said "I'm not doing spins in an airplane I want to fly IFR." The extreme attitudes are pretty hard on the gyro instruments, even if they don't tumble *that* time.

I'd suspect a roll would be similar.
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We definitively break that rule in the USAF. We punch through an IMC deck, go rage in the MOA with over the top maneuvers, then shoot not just an approach, but a formation approach in the weather with a mechanical gyro as our only backup. Granted, they're the electric re-cageable kind, but still, those things are tiiired. Oh but for the grace of God go I... :eek:
 
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