Are there any manoeuvres that would be considered unrecoverable in a General Aviation / Training Aircraft?

Question

I'll try to make this question a little more manageable by applying the following constraints, though of course all answers would be welcome:

By "General Aviation / Training" aircraft, I'm talking primarily about normal SEP's of the kind that we see daily and would require no more than a check-ride before hiring. No experimentals, warbirds, super rare aircraft etc - though MEP's and Complex Aircraft would count.
I'm ignoring low level maneuvers. We all know a stall at 100ft is going to be tricky, though on the other hand, if something is going to require 5000' at a minimum to recover from then that's going to be fatal in most cases.
Let's ignore mechanical and airframe failures that occur prior to the incident.
I'm assuming Weight & Balance are within the normal category of the POH (As opposed to utility or aerobatic).

Beyond that, the question is what it says on the tin. Is there anything stupid that I can do as a Pilot in a Single Engined Piston GA aircraft that I simply won't be able to recover from, even with a few thousand feet to do so?

What about the pilot? Are you including things like freezing up on the controls, trying maneuvers you haven't been trained for, knowingly exceeding the aircraft's limitations etc.? — Pondlife, Dec 10 '15 at 18:39
I would think anything beyond a second or two of inverted flight will cause "most" GA aircraft problems, although potentially not irrecoverable. — CGCampbell, Dec 10 '15 at 19:05
Autogyro - probably doesn't meet your requirement: Create negative g on rotor (eg climb then level out and descend rapidly so that rotor ends drop into unintended area and strike eg tail structure. (Happens :-(.) || Happens more in warbirds BUT perform takeoff in rotary engine craft (1st catch your rotary engined craft :-) ) and compensate for torque rotation in wrong direction! :-(. eg Merlin Spitfire and ?Sabre? engine had opposite rotation directions. A spitfire was destroyed here and pilot very severely injured due to this. (Torque is due to very large engine rotating mass). — Russell McMahon, Dec 11 '15 at 14:42
Specifics escape me (I am NOT a pilot!) please excuse really lame description (and any above :-) ). I understand that there is a known problem turning across a circuit with wind in a certain direction that traps newcomers. — Russell McMahon, Dec 11 '15 at 14:46
Some versions of entering turbulence behind larger aircraft - loss of US airliner (New York) some years ago attributed to this. || If wind-shear gets the professionals and ideally needs wind rRADAR surely it must affect amateurs too?. — Russell McMahon, Dec 11 '15 at 14:49

Peter Kämpf · Answer 1 · 2015-12-12T09:28:37.810

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Yes, easily. Just fly fast enough.

If you deflect a control surface fully at a speed above $v_A$, the risk of a structural failure is very real. After all, at $v_D$ only a third of the mechanically possible deflection is allowed (see §23.441 for the rudder and §23.455 for the ailerons). Even combining full deflections of more than one control surface at $v_A$ is not covered, as is a repeated deflection in sync with rigid body oscillations which can create excessive loads. For a definition of the design speeds, see §23.335.

The regulations require minimum control forces so the pilot feels when he/she overstresses the airframe, but they are still within the strength of a normal adult.

Also, if you fly too fast in gusty weather, you can overload the structure. This is rare because the 25ft/s gusts which must be tolerated up to $v_D$ are quite uncomfortable to fly through.

edited Dec 12 '15 at 09:28

answered Dec 10 '15 at 18:30

Peter Kämpf

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Naive question: By v_C and v_D do you mean "Design Cruise Speed" & "Design Driving Speed"? That's what Wikipedia tells me for this notation. https://en.wikipedia.org/wiki/V_speeds#cite_note-faacfr-7 – curious_cat Dec 12 '15 at 04:51
@curious_cat: Yes, exactly. – Peter Kämpf Dec 12 '15 at 09:01
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@curious_cat: Your question made me note that I confused v$_C$ with v$_A$. Silly me. – Peter Kämpf Dec 12 '15 at 09:29
There also has to be a steep descent, otherwise you could just reduce thrust. And even if there is a steep descent, it could be recoverable with 10% deflection, well above Vd. – Orbit Jan 07 '19 at 01:13

score 7 · Answer 2 · answered Dec 11 '15 at 04:04

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I'm pretty sure this is not the kind of "maneuver" you're looking for, but it is

something stupid that I can do as a Pilot in a Single Engined Piston GA aircraft that I simply won't be able to recover from.

CAPS deployment in an SR-20/22 is unrecoverable - once the chute is out, there's no putting it back in.

answered Dec 11 '15 at 04:04

Steve V.

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"Unrecoverable" is too ambiguous: ending in rapid unscheduled disassembly, unimproved field takeoff, knucle-busters and JB Weld, GPS ELT activation, hitchhiking or Uber. – dhchdhd Jan 05 '19 at 13:32

Dave · Answer 3 · 2015-12-10T18:48:15.513

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The two most common training aircraft out there are the Piper Cherokee (numerous variants) and the Cessna 172/152 (numerous variants as well). The cherokee is not spin certified and the 172 is only spin certified in the utility category so I would not try spinning either frankly. Technically you may be able to recover from a spin with enough altitude and depending on the situation but a pilot could get them selves into a nasty situation by spinning either plane. Even regular stalls put you at risk of entering a spin.

There are lots of maneuvers (aerobatic mainly) that would kill the engine on many common GA planes. Generally speaking the oil systems are not built for inverted maneuvers or anything that would starve the oil pump. The Cessna also has a gravity fed fuel system which would not do to well inverted. In regards to stalling the engine and recovering while you may be able to glide down to a field if an engine is lost this is more in reference to losing an engine during a maneuver and having insufficient thrust to recover properly from the maneuver.

I would think that you might also be able to get the plane into an aggressive dive that might be hard to recover from for an untrained pilot. At some point the recovery will exceed the load the wings can handle as well.

Here in the US the FAA requires knowledge of spin awareness and what may cause a plane to enter a spin but there is no requirement to demonstrate a spin for a basic private pilots license nor is there a requirement for them to be demonstrated to the student.

edited Dec 10 '15 at 18:48

answered Dec 10 '15 at 16:23

Dave

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I'm not sure I'd describe engine failure as unrecoverable, since it's still possible to glide to a handy field and make an emergency landing. It's something we're all trained for. – Dan Hulme Dec 10 '15 at 16:36
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Is it not thought essential to expose trainee pilots to spins? How about stall training (if the risk of a stall turning into a spin is high). – curious_cat Dec 10 '15 at 18:22
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@curious_cat See this question for information about stalls. Training requirements depend on the local regulations; the US requires spin training only for instructors, for example. It could be a good question if you want to ask it. – Pondlife Dec 10 '15 at 18:34
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172s are a pain to spin. you need an aggressive entry and they decay into steep spirals quickly. More danger in late recovery from the spiral dive over-stressing the airplane than the spin itself. @curious_cat private pilots just need to learn what an incipient spin feels/looks like, how not to get that far into one and how to recover from a spin, but they don't actually spin. Spin demonstrations aren't required until you get your CFI. (FAA) – casey Dec 10 '15 at 19:57
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@casey Yes, that's exactly what I had always thought. That 172's are a pain to spin. But I was confused on reading what wrote above. i.e. "Even regular stalls put you at risk of entering a spin" I always thought even if one wanted to foolhardily, putting a 172 into a spin needed some pretty bizzare antics? – curious_cat Dec 12 '15 at 04:53
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Yup. Most GA engines' fuel systems are gravity fed, whereas aerobatic planes can pump fuel from tanks, send it pressurized from nearly any orientation and G-loading and not have carbs hydrolock or suck air. Reminds me of the fuel restrictor plate hack on the Spitfire and Hurricane. (Miss Shilling's orifice... no joke.) – dhchdhd Jan 05 '19 at 13:14
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@Dave FYI, Cherokees are spin certified if the weight and balance falls into the Utility category. Mine even has a placard on the dash listing entry speeds for spins, lazy eights, and chandelles. – JScarry Jan 05 '19 at 17:48
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@JScarry interesting, all the ones i have flown have "Do Not Spin" placards but i guess its possible the flight schools put them in to prevent dangerous operations. – Dave Jan 05 '19 at 17:50
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@Dave Mine is an older one, so they may have changed it. Check out Page 23 https://touringmachine.com/Cherokee/PDFs/Cherokee%20140%20Owner's%20Handbook.pdf – JScarry Jan 05 '19 at 17:57
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@JScarry I did a lot of time in warriors which are ok for chandelles and lazy 8's but spins are not aloud in any category i guess its technically not a Cherokee but i always lumped it in as it is a PA-28 – Dave Jan 05 '19 at 18:31

score 4 · Answer 4 · answered Dec 11 '15 at 04:03

4

Yes indeed.

AD 69-24-04 PIPER increases the Vmc speed of the Twin Comanche by 9 knots because the aircraft was discovered to enter an unrecoverable flat spin when stalled near Vmc. Always a bummer when that happens.

answered Dec 11 '15 at 04:03

Steve V.

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score 2 · Answer 5 · answered Jan 05 '19 at 13:05

Some bad ones:

Stalling while turning too abruptly at low speed and low alt < 500', but above ground effect height, cartwheeling to your death. Ideally, a ballistic parachute system should optimize for this, but too much of a spin component may twist/collapse the chute of some designs from opening soon enough.

Losing power after takeoff but then trying an impossible 180° turn back when the safest plan is to dead-stick to anything remotely flat ahead.

Ripping wings off from too aggressive maneuvers plus repeated fatigue cycles of old/worn planes performing aerial firefighting without sufficiently-thorough metallurgical inspections (NDT). There was that Herc that sadly bought it on viceo.

Far exceeding Vd and causing structural failure from control surface, harmonic resonant and/or structural overload.

Mach tuck on the early P-38, Hawker P.1081 and other late, fast WW2 aircraft. Maybe they could sometimes recover with very careful dirty config and throttling back, but nosing over while transonic risks an unCFIT situation very quickly.

Are there any manoeuvres that would be considered unrecoverable in a General Aviation / Training Aircraft?

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