glider aerobatics

[150flivver]

Question concerning aerobatics in glider category. We have 2 Grob 103s, a 103A Twin II and a 103C Twin III Acro. The Airworthiness Certificate for the first just says Standard Category Glider while the AC for the Twin III Acro says Standard Category glider, Aerobatic.

Now the question. The Twin II POH says loops are among the approved maneuvers. Are loops legal maneuvers in the eyes of the FAA, in a non-acro certified glider? Obviously, the Twin III Acro would be expected to be loop legal since loops are not specifically prohibited in its POH and are in fact listed as an approved maneuver. Are gliders that different from airplanes such that the POH can "approve" aerobatic maneuvers in "vanilla" Standard glider category aircraft? I was under the impression that the FAA considers anything over 60 degrees of bank or 30 degrees of pitch, (except for spins), as aerobatic and requiring an aerobatic airworthiness certificate unless it's a special AC such as experimental amateur built where limitations are listed separately in ops limits. The glider pilots I've talked to seem to think as long as the POH says they"re okay and there's no AD extant that prohibits them, then you can loop a standard category glider such as a 103A Twin II to your heart's content. What say you?

[Burt Compton - Marfa Gliders, west Texas]

I was under the impression that the FAA considers anything over 60 degrees of bank or 30 degrees of pitch, (except for spins), as aerobatic . . .

Well, perhaps.
Research through FAR 91.303 for a FAA definition of aerobatic flight (you might be surprised)
and FAR 91.307 for the parachute requirements. Glance at FAR 91.13 as well..

I'm just offering a clarification of the occasionally misunderstood FAA definition of acrobatic flight.
(Makes a good oral question on a checkride.)

When I imported my new Schleicher ASK-21 I had it certificated (by the factory) as Acrobatic, mainly for resale when (and if) I retire from my commercial glider operation.

I cannot answer your primary question of aircraft certification as I do not speculate without research.

Thread drift: The advice found on r.a.s. that may begin with "I heard" / "I think / "I recall" / "Someone told me" / "My impression was" may be speculation or hearsay. Not double-checking the facts with qualified sources may mix truth and fiction into a possible hazardous conclusion.

[150flivver]

On Sunday, July 30, 2017 at 6:36:40 PM UTC-5, Burt Compton - Marfa Gliders, west Texas wrote:
> I was under the impression that the FAA considers anything over 60 degrees of bank or 30 degrees of pitch, (except for spins), as aerobatic . . .
>
> Well, perhaps.
> Research through FAR 91.303 for a FAA definition of aerobatic flight (you might be surprised)
> and FAR 91.307 for the parachute requirements. Glance at FAR 91.13 as well.
>
> I'm just offering a clarification of the occasionally misunderstood FAA definition of acrobatic flight.
> (Makes a good oral question on a checkride.)
>
> When I imported my new Schleicher ASK-21 I had it certificated (by the factory) as Acrobatic, mainly for resale when (and if) I retire from my commercial glider operation.
>
> I cannot answer your primary question of aircraft certification as I do not speculate without research.
>
> Thread drift: The advice found on r.a.s. that may begin with "I heard" / "I think / "I recall" / "Someone told me" / "My impression was" may be speculation or hearsay. Not double-checking the facts with qualified sources may mix truth and fiction into a possible hazardous conclusion.

So tell me why you bothered to have the ASK certificated Acrobatic if it were true that any maneuver "approved" in the POH would be legal regardless of what the Airworthiness Certificate says. I've read all the regulations you cited and nothing jumps out as an answer to my original question.

[[email protected]]

The Twin-2 Acro is built stronger than the straight Twin -2 with an extra layer of uni-directional cloth over the spar, steel push-rods, rudder pedal loops, etc. Buyers of the Acro would most likely anticipate more than an occasional loop or spin. The G-103 Twin-2 Flight Manual authorized "loops", to show the ship is built strong enough to take the forces generated by a properly executed loop, but does not have the extra strength of the Acro. Most G-103's are over gross weight with 2 average sized pilots wearing parachutes and this has a direct effect on how many G's you can safely pull.
Hope this answers your question,
JJ

[Burt Compton - Marfa Gliders, west Texas]

On Sunday, July 30, 2017 at 7:06:35 PM UTC-5, 150flivver wrote:

> So tell me why you bothered to have the ASK certificated Acrobatic if it were true that any maneuver "approved" in the POH would be legal regardless of what the Airworthiness Certificate says. I've read all the regulations you cited and nothing jumps out as an answer to my original question.

I was not trying to answer to your original question. I just wanted to clarify the FAA definition in FAR 91.303 and 91.307.

The certification of my ASK-21 as aerobatic was no bother at all. I asked the Schleicher factory to certify it aerobatic in Germany. They simply added the static line red rings, crotch strap (only for inverted flight according the the British) and G-Meters front and back.

G-Meters marked with the red lines for positive and negative (for that glider) are essential for safe aerobatics! Consider adding (calibrated) G-Meters to any glider in which you will fly aerobatics.

Schedule instruction from a proficient glider acro instructor such as at Arizona Soaring, south of Phoenix.

An airplane is not always the best method to learn glider acro as it can use full power to round the loop at the top and mitigate "dish-out" from inverted flight.

The Germans take glider acro very seriously requiring a separate pilot license for acro after a structured course of ground and flight instruction.

Penny for my thoughts? There's my two cents!

[150flivver]

On Monday, July 31, 2017 at 10:32:26 AM UTC-5, Burt Compton - Marfa Gliders, west Texas wrote:
> On Sunday, July 30, 2017 at 7:06:35 PM UTC-5, 150flivver wrote:
>
> > So tell me why you bothered to have the ASK certificated Acrobatic if it were true that any maneuver "approved" in the POH would be legal regardless of what the Airworthiness Certificate says. I've read all the regulations you cited and nothing jumps out as an answer to my original question.
>
> I was not trying to answer to your original question. I just wanted to clarify the FAA definition in FAR 91.303 and 91.307.
>
> The certification of my ASK-21 as aerobatic was no bother at all. I asked the Schleicher factory to certify it aerobatic in Germany. They simply added the static line red rings, crotch strap (only for inverted flight according the the British) and G-Meters front and back.
>
> G-Meters marked with the red lines for positive and negative (for that glider) are essential for safe aerobatics! Consider adding (calibrated) G-Meters to any glider in which you will fly aerobatics.
>
> Schedule instruction from a proficient glider acro instructor such as at Arizona Soaring, south of Phoenix.
>
> An airplane is not always the best method to learn glider acro as it can use full power to round the loop at the top and mitigate "dish-out" from inverted flight.
>
> The Germans take glider acro very seriously requiring a separate pilot license for acro after a structured course of ground and flight instruction.
>
> Penny for my thoughts? There's my two cents!

Don't disagree with anything you or JJ have said. Neither of you have answered my question and that's okay if you don't know the answer. My question is: Is it legal to do loops in a Standard (not Acro) certificated glider? Not is it smart or what the difference is between two gliders, one with an Acro cert and one without. I'm asking whether a POH approved maneuver that would be Acrobatic in Airplane and require a Acrobatic Airworthiness certification, is legal in a non-acrobatic certificated glider.

[Frank Whiteley]

On Monday, July 31, 2017 at 9:47:34 AM UTC-6, 150flivver wrote:
> On Monday, July 31, 2017 at 10:32:26 AM UTC-5, Burt Compton - Marfa Gliders, west Texas wrote:
> > On Sunday, July 30, 2017 at 7:06:35 PM UTC-5, 150flivver wrote:
> >
> > > So tell me why you bothered to have the ASK certificated Acrobatic if it were true that any maneuver "approved" in the POH would be legal regardless of what the Airworthiness Certificate says. I've read all the regulations you cited and nothing jumps out as an answer to my original question.
> >
> > I was not trying to answer to your original question. I just wanted to clarify the FAA definition in FAR 91.303 and 91.307.
> >
> > The certification of my ASK-21 as aerobatic was no bother at all. I asked the Schleicher factory to certify it aerobatic in Germany. They simply added the static line red rings, crotch strap (only for inverted flight according the the British) and G-Meters front and back.
> >
> > G-Meters marked with the red lines for positive and negative (for that glider) are essential for safe aerobatics! Consider adding (calibrated) G-Meters to any glider in which you will fly aerobatics.
> >
> > Schedule instruction from a proficient glider acro instructor such as at Arizona Soaring, south of Phoenix.
> >
> > An airplane is not always the best method to learn glider acro as it can use full power to round the loop at the top and mitigate "dish-out" from inverted flight.
> >
> > The Germans take glider acro very seriously requiring a separate pilot license for acro after a structured course of ground and flight instruction..
> >
> > Penny for my thoughts? There's my two cents!
>
> Don't disagree with anything you or JJ have said. Neither of you have answered my question and that's okay if you don't know the answer. My question is: Is it legal to do loops in a Standard (not Acro) certificated glider? Not is it smart or what the difference is between two gliders, one with an Acro cert and one without. I'm asking whether a POH approved maneuver that would be Acrobatic in Airplane and require a Acrobatic Airworthiness certification, is legal in a non-acrobatic certificated glider.

Punching through the flight manuals for a Twin Astir and Twin II, simple aerobatics are spelled out as loops, spins, and stall turns. In the UK, this was called semi-aerobatic and stall turns were called chandelles. The flight manuals also describe what to do in the event a failed stall turn results in a tail slide.

AFAIK, the Acro models allow inverted flight, rolls, and whatever else is permitted. Not sure what resulted from the modifications to the Grob Acros resulted from the AD's of a few years ago.

Does that mean you should be teaching yourself aerobatics? Get instruction..

Frank Whiteley

[[email protected]]

On Monday, July 31, 2017 at 11:47:34 AM UTC-4, 150flivver wrote:
> On Monday, July 31, 2017 at 10:32:26 AM UTC-5, Burt Compton - Marfa Gliders, west Texas wrote:
> > On Sunday, July 30, 2017 at 7:06:35 PM UTC-5, 150flivver wrote:
> >
> > > So tell me why you bothered to have the ASK certificated Acrobatic if it were true that any maneuver "approved" in the POH would be legal regardless of what the Airworthiness Certificate says. I've read all the regulations you cited and nothing jumps out as an answer to my original question.
> >
> > I was not trying to answer to your original question. I just wanted to clarify the FAA definition in FAR 91.303 and 91.307.
> >
> > The certification of my ASK-21 as aerobatic was no bother at all. I asked the Schleicher factory to certify it aerobatic in Germany. They simply added the static line red rings, crotch strap (only for inverted flight according the the British) and G-Meters front and back.
> >
> > G-Meters marked with the red lines for positive and negative (for that glider) are essential for safe aerobatics! Consider adding (calibrated) G-Meters to any glider in which you will fly aerobatics.
> >
> > Schedule instruction from a proficient glider acro instructor such as at Arizona Soaring, south of Phoenix.
> >
> > An airplane is not always the best method to learn glider acro as it can use full power to round the loop at the top and mitigate "dish-out" from inverted flight.
> >
> > The Germans take glider acro very seriously requiring a separate pilot license for acro after a structured course of ground and flight instruction..
> >
> > Penny for my thoughts? There's my two cents!
>
> Don't disagree with anything you or JJ have said. Neither of you have answered my question and that's okay if you don't know the answer. My question is: Is it legal to do loops in a Standard (not Acro) certificated glider? Not is it smart or what the difference is between two gliders, one with an Acro cert and one without. I'm asking whether a POH approved maneuver that would be Acrobatic in Airplane and require a Acrobatic Airworthiness certification, is legal in a non-acrobatic certificated glider.

Read the flight manual for the glider in question. I will specify what is legal to do in the aircraft and under what limitations.
UH

[[email protected]]

According to the final outcome of the EASA AD situation the Twin II Acro is restricted to "Loop, Turn, Lazy Eight, Chandelle, Spin" unless the rear fuselage has been reinforced in accordance with OSB 351-66/1. Without the reinforcement the SB referenced by the AD states this and also states that the part of the flight manual "Flight handbook for acrobatics" is invalid and must be rmoved from the manual. Unless you've had the reinforcement work done to the glider it's only approved for the same simple aerobatics as the regular Twin II and earlier Twin Astir. The same thing seems to go for the Twin III Acro. My club is in Canada so I referred directly to the EASA AD's when we were dealing with this but I just read the FAA AD and it says the same thing. The SB's etc can be read here:

http://www.ltb-lindner.com/g-103-ad-sb.html

[150flivver]

On Monday, July 31, 2017 at 2:09:22 PM UTC-5, wrote:
> According to the final outcome of the EASA AD situation the Twin II Acro is restricted to "Loop, Turn, Lazy Eight, Chandelle, Spin" unless the rear fuselage has been reinforced in accordance with OSB 351-66/1. Without the reinforcement the SB referenced by the AD states this and also states that the part of the flight manual "Flight handbook for acrobatics" is invalid and must be rmoved from the manual. Unless you've had the reinforcement work done to the glider it's only approved for the same simple aerobatics as the regular Twin II and earlier Twin Astir. The same thing seems to go for the Twin III Acro. My club is in Canada so I referred directly to the EASA AD's when we were dealing with this but I just read the FAA AD and it says the same thing. The SB's etc can be read here:
>
> http://www.ltb-lindner.com/g-103-ad-sb.html

Thanks for the link. I guess my confusion rests with the prohibition of acrobatics in one section unless some structural modifications are done and yet "simple" acrobatics are approved for the ACRO designated airframes. Without any structural modifications, the Twin II Astir, with just a Standard Category Airworthiness Certification, is permitted simple acrobatics as per the POH. Thanks everyone.

[Bruce Hoult]

On Monday, July 31, 2017 at 7:39:26 PM UTC+3, Frank Whiteley wrote:
> On Monday, July 31, 2017 at 9:47:34 AM UTC-6, 150flivver wrote:
> > On Monday, July 31, 2017 at 10:32:26 AM UTC-5, Burt Compton - Marfa Gliders, west Texas wrote:
> > > On Sunday, July 30, 2017 at 7:06:35 PM UTC-5, 150flivver wrote:
> > >
> > > > So tell me why you bothered to have the ASK certificated Acrobatic if it were true that any maneuver "approved" in the POH would be legal regardless of what the Airworthiness Certificate says. I've read all the regulations you cited and nothing jumps out as an answer to my original question..
> > >
> > > I was not trying to answer to your original question. I just wanted to clarify the FAA definition in FAR 91.303 and 91.307.
> > >
> > > The certification of my ASK-21 as aerobatic was no bother at all. I asked the Schleicher factory to certify it aerobatic in Germany. They simply added the static line red rings, crotch strap (only for inverted flight according the the British) and G-Meters front and back.
> > >
> > > G-Meters marked with the red lines for positive and negative (for that glider) are essential for safe aerobatics! Consider adding (calibrated) G-Meters to any glider in which you will fly aerobatics.
> > >
> > > Schedule instruction from a proficient glider acro instructor such as at Arizona Soaring, south of Phoenix.
> > >
> > > An airplane is not always the best method to learn glider acro as it can use full power to round the loop at the top and mitigate "dish-out" from inverted flight.
> > >
> > > The Germans take glider acro very seriously requiring a separate pilot license for acro after a structured course of ground and flight instruction.
> > >
> > > Penny for my thoughts? There's my two cents!
> >
> > Don't disagree with anything you or JJ have said. Neither of you have answered my question and that's okay if you don't know the answer. My question is: Is it legal to do loops in a Standard (not Acro) certificated glider? Not is it smart or what the difference is between two gliders, one with an Acro cert and one without. I'm asking whether a POH approved maneuver that would be Acrobatic in Airplane and require a Acrobatic Airworthiness certification, is legal in a non-acrobatic certificated glider.
>
> Punching through the flight manuals for a Twin Astir and Twin II, simple aerobatics are spelled out as loops, spins, and stall turns. In the UK, this was called semi-aerobatic and stall turns were called chandelles. The flight manuals also describe what to do in the event a failed stall turn results in a tail slide.

There is no way in the world that a chandelle can result in a tail slide! If by "stall turn" you mean pointing the nose straight up and at speed X stomping on one rubber then that is not a chandelle. A chandelle maintains coordinated flight at all times. It is rather like the start of a barrel roll, from lower speed, followed by the end of a barrel roll, but joined by a low speed low but positive G bit in the middle with the fuselage horizontal and 90 degrees or a bit more of bank.

It's pretty much the same as the maneuver that ag pilots do every minute or two, all day, turning around from low level at the end of the field and going back the other way with a small sideways offset.