RV7 Mosaic eligibility

[wirejock]

Here's another.
Not every aircraft has telemetry.
Some have older analog airspeed instruments. I don't know about all of them, but the ones I've flown tend to wander a bit and indications are a little vague.
When you perform the test, you document the stall speed. Did it say 58, 59 or 60.
Just sayin'. Seems a little gray

 

[cgeyman]

Not sure why so complicated- you can determine Vs1 on your own and update your POH, which should be acceptable as a owner of an E-AB, even if you were not the builder. A plane goes through mods and different w/b’s during its lifetime. I would expect an owner can determine Vs1 and update the logbook or POH.
Cal

 

[PhatRV]

Not only that, but because the rule is "since it's original certification", the documentation needs to exist since birth

From the EAA webinar, I thought this rule is applicable toward the standard certificated airplane with respect to the modification, like the C172. The EAB airplanes are not applicable to this rule which makes sense because EAB owners can always modify their own airplane.

 

[Roadjunkie1]

From the EAA webinar, I thought this rule is applicable toward the standard certificated airplane with respect to the modification, like the C172. The EAB airplanes are not applicable to this rule which makes sense because EAB owners can always modify their own airplane.

Also: stall speed is clean at gross weight in the 'most critical CG' configuration and KCAS. I asked what exactly defined that CG and that question was not answered. But nearly 3000 people were signed up and attended meaning there was not much time to answer submitted questions even though we were encouraged to ask.........

 

[PhatRV]

Also: stall speed is clean at gross weight in the 'most critical CG' configuration and KCAS.

Since our airplanes are EAB, we can set any reasonable gross weight we want and CG we want. I have not seen a RV builder test his airplane to the level where the CG spans the range of Vans design gross weight and CG. Some surely have but I haven't seen one. I haven't seen other non-RV experimental builders doing it either.

 

[TParker]

From the EAA webinar, I thought this rule is applicable toward the standard certificated airplane with respect to the modification, like the C172. The EAB airplanes are not applicable to this rule which makes sense because EAB owners can always modify their own airplane.

There's nothing in the rule or executive summary that I see that would exclude EAB aircraft from this requirement, so I would be curious as to that interpretation. If anything, I would think that the FAA would allow STC modification to certificated aircraft before they allow unchecked EAB modifications as that would be more consistent with the safety continuum philosophy. You can certainly modify an EAB aircraft, but that doesn't mean the modification makes it eligible for operation by a sport pilot. The new 61.316 doesn't include "except for aircraft certificated under 21.191(g)" or some similar exception.
The executive summary discussion:

Since FAA has already increased the originally proposed VS1 limitation and expanded eligible aircraft, FAA disagrees with additionally permitting airplane alterations after original certification that decrease the published VS1 CAS stalling speed. Allowing airplanes to meet the new 59 knots CAS VS1 requirement through the use of these modifications would inappropriately expand aircraft characteristics beyond those intended for sport pilot operations. These lift-enhancing devices would be considered major alterations because they may appreciably affect the weight, balance, structural strength, performance, flight characteristics, or other qualities affecting airworthiness that could affect the operation of the airplane. Therefore, FAA retains the § 61.316(a) rule text limitation that states ‘‘since its original certification.’’

and

To clarify, if an aircraft is certificated and then an aftermarket installation alters the Vs1 CAS airspeed from 61 to 59 knots, the airplane would not qualify for sport pilot use because the alteration affecting stalling speed was accomplished after the original certification of the aircraft. FAA maintains that based on the safety continuum concept, individuals operating airplanes with a VS1 CAS stalling speed greater than 59 knots must obtain at least a recreational pilot certificate or higher grade of pilot certificate. After consideration of the commenters’ recommendations, FAA maintains that the ‘‘since its original certification’’ language proposed in§ 61.316(a) does provide a necessary safeguard to indirectly limit the weight of aircraft sport pilots may operate by limiting modifications after its original certification.

In my opinion, they're focusing on things like slats and vortex generators and ignoring the easiest way to safely reduce the stall speed, which is to limit the gross weight; however the FAA has declined to provide an exception to allow reductions in gross weight in order to comply, and is specifying no modifications based on the text of the rule and the summary.

Also: stall speed is clean at gross weight in the 'most critical CG' configuration and KCAS. I asked what exactly defined that CG

AC 23-8C says, for 23.49 (stall speeds):

The stalling speed should be determined at all weight and c.g. positions defining the corners of the loading envelope to determine the critical condition.

In other words, the most critical CG location is the one that results in the highest stall speed, that way the pilot is adequately advised of the stall speed: in CG locations other than the most critical, the actual stall speed will be lower than published, resulting in a positive safety margin during operation. This is usually the most forward CG location permitted at maximum gross weight.

Being able to prove/show that you haven't made any aircraft modifications that would alter the VS1 stalling speed, and are just now documenting it, is probably reasonable but up to the FAA to decide whether that fits within the rigor of their wording and if they believe your documentation.

 

[lr172]

Something less obvious then: flying a 210 HP aircraft without a high performance endorsement. A lot of EABs don't fully document their engine model, much less how much power it makes and you can't tell from the outside what that RV-7's got under the cowl.

I think the legality is very clear. If the answer to the question "What's the VS1, in KCAS, of this aircraft?" is "dunno" rather than a number less than or equal to 59, then it can't be flown by a sport pilot; VS1=? is no different than VS1=60 KCAS. Not only that, but because the rule is "since it's original certification", the documentation needs to exist since birth that the aircraft didn't have a non-compliant stall speed and then was subsequently modified to lower it, or vice-versa.

At the end of the day, if a pilot's answer to the question "How do you know you can legally operate this aircraft?" is, effectively, "I didn't know that I couldn't" then they're probably not going to have a good time if/when the FAA decides to start asking questions.

Ok.

Eabs receive their certificates before flight testing, so there is never a documented Vs1 speed at certification and there is no requirement in the certification process or the related operating limitations requiring it later. Further, I suspect there are few eabs that test for and document vs1 in cas at max CG. I am sure there are a few, but doubt it is a significant number. So, what is the benefit of the expanded privileges if very few of the subject planes can be confirmed to fit the rules? Maybe the expanded rules are more geared to certificated planes where this data does exist.

Not challenging you here, but it does raise the question about how all this plays out and how sport pilots are going to deal with this in the eab world. I still believe that someone is going to ask the faa for a clarification surrounding this dilemma and the faa will likely reply with guidance for dealing with it.

 

[PhatRV]

If anything, I would think that the FAA would allow STC modification to certificated aircraft before they allow unchecked EAB modifications as that would be more consistent with the safety continuum philosophy.

Hmm, maybe I should rethink why anyone want to build an EAB with the understanding that the freedom to make changes to an EAB airplane doesn't exist.

 

[Roadjunkie1]

Another ruling that affects us in the Rocky Mountain States is: no flights above 10,000 feet or 2,000 AGL. Seems like a ridiculous ruling and one that, flying over the Rocky Mountains where, in Colorado, there are 58 peaks that top 14,000, might be difficult to comply with, unless they are going with an 'average' of 2,000 AGL. The mountainous terrain is so variable that it would be dangerous to comply with this ruling flying the roller coaster it would take to comply..........

 

[TParker]

So, what is the benefit of the expanded privileges if very few of the subject planes can be confirmed to fit the rules? Maybe the expanded rules are more geared to certificated planes where this data does exist.

I believe this was the focus, yes, allowing sport pilots to fly 172s, and more on new aircraft that might be designed and built under new Part 22, as opposed to existing EAB RVs.

Not challenging you here, but it does raise the question about how all this plays out and how sport pilots are going to deal with this in the eab world. I still believe that someone is going to ask the faa for a clarification surrounding this dilemma and the faa will likely reply with guidance for dealing with it.

Challenge away! I'm commenting based on my experience working within the certification system; we're figuring this out together.

One of the specific comments I made on the NPRM was that a lot of the language was consistent with type certificated aircraft and would make it confusing for experimental ones. That's clearly still the case with the final rule.

 

[gasman]

Ok.

Eabs receive their certificates before flight testing, so there is never a documented Vs1 speed at certification and there is no requirement in the certification process or the related operating limitations requiring it later. Further, I suspect there are few eabs that test for and document vs1 in cas at max CG. I am sure there are a few, but doubt it is a significant number. So, what is the benefit of the expanded privileges if very few of the subject planes can be confirmed to fit the rules? Maybe the expanded rules are more geared to certificated planes where this data does exist.

Not challenging you here, but it does raise the question about how all this plays out and how sport pilots are going to deal with this in the eab world. I still believe that someone is going to ask the faa for a clarification surrounding this dilemma and the faa will likely reply with guidance for dealing with it.

Maybe this should have been brought up during the comments period.

 

[lr172]

Maybe this should have been brought up during the comments period.

Possibly. Probably better they gave us what they di and let them figure it out later; that way the slate has been set. I remain confident that there is a way to make it work, we just need the faa’sinterpretation of what counts as vs1<59 in the eab realm.

 

[plehrke]

In other words, the most critical CG location is the one that results in the highest stall speed, that way the pilot is adequately advised of the stall speed: in CG locations other than the most critical, the actual stall speed will be lower than published, resulting in a positive safety margin during operation. This is usually the most forward CG location permitted at maximum gross weight.

I can’t even get anywhere close to being at max gross weight in most forward CG position in my -6A. The furthest forward CG I can get is full fuel and min pilot weight of 100 lbs. At that point I am 230 lbs under gross and still ~3” aft of most forward CG (as documented by Vans).

Discussion on mods that would affect Vs1. If I changed to a constant speed prop my most forward CG at max “attainable” weight (still below my max weight of 1650) would change my Vs1 ‘‘since its original certification’’. Of course that change I would (as well if you added vortex generators) would require me to go back into phase 1.

 

[Dugaru]

If I changed to a constant speed prop my most forward CG at max “attainable” weight (still below my max weight of 1650) would change my Vs1 ‘‘since its original certification’’.

I’m not sure you had a Vs1 at your “original certification” though. The rule just doesn’t map onto EABs very coherently.

 

[MacCool]

Eabs receive their certificates before flight testing, so there is never a documented Vs1 speed at certification and there is no requirement in the certification process or the related operating limitations requiring it later. Further, I suspect there are few eabs that test for and document vs1 in cas at max CG. I am sure there are a few, but doubt it is a significant number.

I'm a relative noob to the E-AB world, but I suspect that this is true. Van's lists Vs1 for the RV-9A at 56mph (48.6 knots) and CAFE says Vs1 for the RV-9A that they tested is 50.5 knots at gross. I have assumed that Vs1 of my airplane is 47 knots because that's what it says in the POH that came with it. I have no idea what methodology was used to determine that.....I can't find any test cards or other test info in the box of documentation that came with the airplane when I bought it. I have I have not formally tested any of my published V-numbers but I do have the set of EAA test cards that I bought with the vague intention of doing so at some point.

Based on my experience with my airplane, including a lot of time spent on stalls during transition training and calibrating my AoA several times, the 47 knot clean stall speed in my POH seems pretty accurate in a seat-of-the-pants kind of way, so I'm just going to wait for this VAF punch-out to finish, and for the FAA to weigh in on the issue with their customary clarity. I don't anticipate needing to fly under Sport Pilot rules any time soon.

 

[lr172]

I'm a relative noob to the E-AB world, but I suspect that this is true. Van's lists Vs1 for the RV-9A at 56mph (48.6 knots) and CAFE says Vs1 for the RV-9A that they tested is 50.5 knots at gross. I have assumed that Vs1 of my airplane is 47 knots because that's what it says in the POH that came with it. I have no idea what methodology was used to determine that.....I can't find any test cards or other test info in the box of documentation that came with the airplane when I bought it. I have I have not formally tested any of my published V-numbers but I do have the set of EAA test cards that I bought with the vague intention of doing so at some point.

Based on my experience with my airplane, including a lot of time spent on stalls during transition training and calibrating my AoA several times, the 47 knot clean stall speed in my POH seems pretty accurate in a seat-of-the-pants kind of way, so I'm just going to wait for this VAF punch-out to finish, and for the FAA to weigh in on the issue with their customary clarity. I don't anticipate needing to fly under Sport Pilot rules any time soon.

Most of us test for Vs0 and Vs1 during testing and document it somewhere. We stall the plane a few times and observe the IAS; Often done in several different weight configurations. The issue here is that it is an integrated number, meaning the plane will stall when that plane's indicated airspeed reads that number. Generally, this is all a pilot needs to fly safe. This approach, however, can have numerous errors built into it. So, these numbers may not be anywhere near the actual airspeed at stall. Unfortunately these new rules want the ACTUAL airspeed of a stall for eligibility and EAB builders rarely do that.

 

[lr172]

Most of us test for Vs0 and Vs1 during testing and document it somewhere. We stall the plane a few times and observe the IAS; Often done in several different weight configurations. The issue here is that it is an integrated number, meaning the plane will stall when that plane's indicated airspeed reads that number. Generally, this is all a pilot needs to fly safe. This approach, however, can have numerous errors built into it. So, these numbers may not be anywhere near the actual airspeed at stall. Unfortunately these new rules want the ACTUAL airspeed of a stall for eligibility and EAB builders rarely do that.

This raises an important point for non builders such as yourself. If you make changes to your aircraft, like fixing a static leak or replacing the wrong style static port with the correct one, etc., you need to repeat the stall testing to be sure you have a good reference.

 

[MacCool]

This raises an important point for non builders such as yourself. If you make changes to your aircraft, like fixing a static leak or replacing the wrong style static port with the correct one, etc., you need to repeat the stall testing to be sure you have a good reference.

If I ever have to fly under Sport Pilot rules and the FAA demands Vs1 documentation, I'll cross that bridge... I know a couple of guys that likely would do the testing for me as I'm not particularly interested in doing it myself. In the meantime, I'm going to rely on my AoA and published Vs1 and put that testing item on the "list-of-things-to-do-at-some-point".

 

[N8DAV8R]

I suspect that in order to be eligible to fly an eab under these new rules, the faa will require that a airframe log entry be made defining Vs1. They will likely also point to an faa doc, dictating how the test is to be performed. Pretty sure they have a procedure for determining cas stall speeds in a current eab testing guide.

Here you go, just like making up your own terms in other threads, you're making up imaginary rules out of thin air. This only adds to the confusion.

 

[Roadjunkie1]

 

[lr172]

Here you go, just like making up your own terms in other threads, you're making up imaginary rules out of thin air. This only adds to the confusion.

Not sure how you interpret terms like "suspect" and "likely" to be considered making up rules. I was simply speculating on what the FAA might do to address the ambiguity in the new rules. Point made though; I am done discussing the issue.

 

[Dugaru]

I'm a relative noob to the E-AB world, but I suspect that this is true. Van's lists Vs1 for the RV-9A at 56mph (48.6 knots) and CAFE says Vs1 for the RV-9A that they tested is 50.5 knots at gross. I have assumed that Vs1 of my airplane is 47 knots because that's what it says in the POH that came with it. I have no idea what methodology was used to determine that.....I can't find any test cards or other test info in the box of documentation that came with the airplane when I bought it. I have I have not formally tested any of my published V-numbers but I do have the set of EAA test cards that I bought with the vague intention of doing so at some point.

Based on my experience with my airplane, including a lot of time spent on stalls during transition training and calibrating my AoA several times, the 47 knot clean stall speed in my POH seems pretty accurate in a seat-of-the-pants kind of way, so I'm just going to wait for this VAF punch-out to finish, and for the FAA to weigh in on the issue with their customary clarity. I don't anticipate needing to fly under Sport Pilot rules any time soon.

My situation is exactly the same (right down to the unused cards ).