In recent months many light aviation enthusiasts have been asking about progress on FAA’s proposed rewrite of the Light-Sport Aircraft regulations. Following a lengthy teleconference in 2019, the Light Aircraft Manufacturers Association is pleased to provide a further update for the agency’s work on MOSAIC, or Modernization of Special Airworthiness Certification. Here is our earlier article on this subject.
This update is one of a continuing series. As time passes and FAA progresses toward its goal — of issuing a NPRM, Notice of Proposed Rule Making — LAMA requests a teleconference or in-person visit to learn the rule writers’ latest concepts and language decisions.
This progress reports identifies new discoveries and clarifies previous statements that may now be better understood.
Some Key Messages
FAA is moving forward on the rulemaking project yet everything remains in progress while the agency gathers internal assessments. What follows is as accurate as possible at this time but changes will occur.
Nor can FAA personnel guarantee that current proposals, as discussed in this progress report, will appear the NPRM.
LAMA will continue asking FAA for greater clarification until the agency enters “ex parte,” a quiet period when they can no longer discuss the project. That period remains in the future at this time.
Common Question — When?
Almost everyone wants to know when this is coming, especially after an early (incorrect) statement that the change was coming by a date now well in the past. MOSAIC is not coming soon. Even though rule writers are progressing, this will take many more months.
FAA generally agreed with our back-calendar estimate that the NPRM may be forthcoming in late 2021 or early 2022. This was based on the perceived amount of work remaining.
The NPRM must be released about that time to allow FAA to have a finished regulation by the end of 2023. The 2023 date is a deadline set by the U.S. Congress as part of approving FAA’s budget — called the FAA Reauthorization Act of 2018.
While changes in wording are inevitable, it is the big changes on which we will focus here. Please remember, MOSAIC encompasses more than LSA, but LAMA’s focus remains entirely on matters of interest to the LSA producer community, to other businesses that serve that market, and to the recreational pilot community.
FAA functions under the Department of Transportation. DOT approved this project for rulemaking under its Fall 2019 Unified Rulemaking Agenda. FAA advised that interested parties can go to this link and enter the following code in the field labeled “RIN” — 2120-AL50
This action by the Department of Transportation does not mean an NPRM will follow soon.
FAA Proposals Under Consideration
What LAMA Originally Requested:
• SLSA (fully built, not kit) Gyroplanes
• Aerial Work / Commercial Use
• Electric Propulsion
• Single Lever Control (in-flight adjustable prop)
More Changes Under Consideration (to present-day LSA):
• Increased weight (see below)
• Four seats
• Retractable gear
• Maximum stall speed
• Capped horsepower
• Increased airspeed
• Hybrid propulsion
Questions raised since LAMA’s last progress report:
• Will Sport Pilot-certificate holders be allowed to fly four seaters?
• Can Sport Pilots do aerial work or commercial use flying?
• What changes will be made to LSA mechanics, specifically LSR-M?
• What about turbine powerplants?
FAA’s Goals Remain the Same:
• “LSA of the future should remain “safe, simple, and easy to fly.”
• “We want to be less prescriptive …to leave more for industry to decide.”
• “LSA has been a successful development” (LSA experience was key in the rewrite of Part 23).
• FAA sees “opportunities to safely expand this sector of aviation while decreasing burden on the industry” and seeks to “make this a positive for industry.”
More on Weight Increase
— Power Index —
Perhaps the greatest amount of interest focuses on proposed weight changes.
Repeating, FAA will not specify a particular aircraft weight (as it does not do so for Part 23 certified aircraft of today). Instead, FAA may employ something called the Power Index (basically a formula) to determine the size of an aircraft. Nonetheless, aircraft weight will increase, perhaps rather dramatically. Indeed, weight may rise to 3,000 pounds (1,360 kilograms).
If FAA will not set a specific weight, how do we know weight will increase and what can provide wise limits?
FAA may use “Power Index.” (Words like “may” are frequently used because this regulation is only a proposal at this time, however, FAA personnel have seen what we are reporting here and offered clarifying suggestions to our language.) For those more technically oriented, at the bottom of this post is an engineering analysis by Powered Sport Flying publisher — and engineer, plus LAMA board of directors member — Roy Beisswenger.
A number of pilots and aircraft developers, surprised by the large potential increase in weight, have wondered what will keep these aircraft from becoming very large. If FAA will not specify a weight, what will prevent LSA 2023 from becoming heavier aircraft beyond the scope of LSA and the Sport Pilot certificate?
In addition to the Power Index concept, here are methods to describe and constrain unlimited weight as learned in LAMA’s last conference with FAA:
- 200 horsepower hard point — As with other parts, this is not fully determined yet but 200 horsepower may be a cap
- 50 knot stall — presumably with lift devices; such as flaps or leading edge devices deployed
- 1.2 Power Index (still being devised; please do not assume this is a final value FAA will accept for rule making) — See “TECH TALK” at the end of this article
- Thus, aircraft that fit the criteria will likely weigh less than 3,000 pounds (≈1365 kilograms)
More Questions Answered
Airspeeds — Referring to maximum horizontal and never-to-exceed speeds (Vh and Vne), FAA said, “These may be higher than in the current rule, but will still be limited.”
At present, FAA has given no specifics on speed, but reading between the lines, LAMA expects maximum flight speeds could be 140-150 knots.
Pilot & Mechanic Certificates — Related to FAA’s ultimate decisions about what a Sport Pilot is allowed to fly and for what flight missions, what about mechanics? Specifically, what changes are coming?
FAA is examining what type of mechanics (LSR-M or A&P) can do what kind of work on specific systems of aircraft.
As an example, will a LSR-M be allowed to work on an in-flight adjustable prop, retractable landing gear, or electric/hybrid propulsion systems?
These questions are still being evaluated, but FAA acknowledges that the issue may work itself out through the industry consensus standards process as it has for similar maintenance issues.
FAA General Comments on
Sport Pilot and Mechanic Questions
Most of LAMA’s work has been with the Aircraft Certification division of the rule writing staff. That focus is of keenest interest to those designing and manufacturing aircraft.
However, matters regarding operation of LSA falls under Flight Standards, the people who manage Part 61 (airmen certification) and Part 65 (mechanics).
Because MOSAIC is such a wide-ranging rule, various other FAA departments will address areas of their expertise. Note that this is a central reason why the regulation will take all of the next two years to fully develop.
FAA is evaluating what type of mechanics (LSR-M or A&P) can do what kind of work on specific systems of aircraft but maintain their focus on the consensus standards process to sort out maintenance issues.
This report is current and was reviewed in March 2020. It is as accurate as we can make it at this time, but it bears repeating one more time: this is a regulation still in process. Many changes may occur. Despite that caveat, the report shows where FAA is generally headed with MOSAIC. Keep your seat belts fastened!
T E C H T A L K
“Power Index Explored More Deeply”
by Roy Beisswenger
The FAA is loath to have prescriptive weight limits in MOSAIC. Instead, they are working with other kinds of formulae to describe limits without specifically calling out the actual weight of the aircraft.
One idea floated within the FAA was to use a calculation called a Power Index or Ip. It is described by the formula:
Ip = {(W/S)/(W/P)}1/3, where:
W = maximum takeoff weight (MTOW) in pounds,
S = wing area in square feet,
P = maximum rated power in horsepower at sea level and standard temperature.
If the Ip value worked out to be less than 1.2, it was proposed at one point that the aircraft would fit within the definition of a Light Sport Aircraft. This formula would only work for airplanes, not applying to rotorcraft, powered parachutes and weight shift control trikes.
Earlier, an Excel spreadsheet escaped from the FAA that allowed a user to plug in different values for maximum gross weight, wing area, and maximum horsepower and it would instantly calculate the Power Index value.
Industry people played around with the spreadsheet, putting in different values. Soon they found that no matter what value they put in for the weight of an aircraft, it never changed the Ip. This became a topic of vigorous discussion.
However, there is a very simple explanation for the lack of sensitivity of the formula to weight. And in fact, the explanation comes from algebraically simplifying the equation itself. When you do that, you find that even though weight appears in the original equation, it quickly drops out since it is in both the numerator and the denominator.
So let’s start with the original equation:
Ip = {(W/S)/(W/P)}1/3
If you divide by a fraction, that means that you are multiplying by the inverse of that fraction. (The inverse meaning that you switch the numerator and denominator.) Doing that, you get this:
Ip = {(W/S) * (P/W)}1/3
That means that the weight is being divided by the weight, which works out to 1. The equation then solves to:
Ip = {P/S}1/3
That means that weight has no influence on the Power Index. Instead, the power index is essentially a ratio between the power of the engine in horsepower and the size of the wing.
Now that the equation is simplified, we can do something else interesting. Let’s solve for Max Power:
Ip = {P/S}1/3
Ip³ = P/S
Ip³ * S = P
In other words, the larger the wing, the more power you can use. That certainly makes sense from a safety point of view.
Solving for Max Wing Size:
S = P/Ip³
That says the same thing. The more power you have, the larger your wings need to be. Let’s see what that looks like with some real world numbers. If you have a 100-hp motor (for example, the very common 100-hp Rotax 912ULS) then for an Ip of 1.2, your smallest possible wing size is:
S = 100/1.4³ = 57.87 square feet
As an example, the wing area of a Flight Design CTSW is 107.0 square feet indicating that it is considerably larger than the minimum 57.87 square feet defined by an Ip of 1.2.
This probably means that an Ip of 1.2 is unlikely to be the only way that a light sport airplane will be defined with MOSAIC. Perhaps a smaller number will be used or perhaps it is only going to be one way of defining a light sport airplane (see above constraints). Perhaps a minimum stall speed (above) may also be included. That way a maximum gross weight won’t be cooked directly into the regulations, but will still end up being a consideration for airplane designers.
Really, why not just a weight increase that would include 150/152, Tomahawk, Skipper and other certified aircraft to be included in the FAA’s list of approved LSA? They are no more complex and arguably safer than the presently allowed LSA choices. Seems like a no-brainer without all the mess of a power index.
The problem I see is that some pilots want the LSA class to be opened up so they can fly pretty much anything 200 horsepower and under (Mooneys, Arrows, SR20s, etc.) and use them as traveling machines. Light-Sport aircraft were meant to enjoy the pleasures of flight for SPORT, not mimic the capabilities of a 180 horsepower Mooney.
Having said that, I can see the simple answer to be allowing a weight increase to include 2-seat certified aircraft that are affordable to those that can’t afford a $100k-$200k manufactured LSA. Why does everything have to be so complicated?
It is not inconceivable that it would work out as you describe in your first paragraph, except that those GA aircraft will retain their standard airworthiness certificate and not become LSA. However, it may be that you could fly some of those with a Sport Pilot certificate after the new regulation is issued.
I agree these aircraft are for recreation even if they may be used successfully for some transport.
I also hear you loud and clear about less complication… and the good news that came out of this week’s activity is that complexity is being reduced.
I’m a little confused. Based on the formula a Cessna 170B with a gross weight of 2200lbs, wing surface area of 174 Square feet and horsepower of 145 has an PI of 2.5. Is my math off? Or am I just not understanding the formula?
I asked for an engineer to weigh in on this but have no reply yet. However, I would not expend too much time on these calculations yet as FAA has not yet firmly said Power Index will be their final suggestion in the NPRM they may issue next year.
Kenneth hasn’t taken notice of the feedback I left about the display error and is applying the formula as still displayed in your post ( 145hp / 174 wing area) 1 / 3 = 2.5. If you alter the method to use as I outline, you get a result of 0.94 instead.
Setup for Excel spreadsheet:
Cell A1 = Wing Area
Cell B1 = HP
Cell C1 = “=(B1/A1)^(1/3)” {to find Ip result, don’t enter quotes as part of cell}
(corrected)
You may want to update your article display to remove this confusion for those who don’t also read through the feedback.
145/(174×3)=0.277=power index
According to the equation alone nearly anything under 200hp…
Took me a while to figure out the error in display on this formula.
Ip = {P/S}1/3 should have been presented as Ip = {P/S}^(1/3)
Otherwise it’s simplified to 3 * Ip = P/S instead of Ip^3 = P/S
Hope this helps others trying to figure this algorithm out.
I asked engineer Roy Beisswenger — also the author of our “Tech Talk” article — to comment. (To read “Tech Talk” follow this link and scroll down.)
Roy wrote, “Yes, [Leonard] has accurately presented it for the way typesetting works on a website. When it was laid out originally, the 1/3 was a superscript. This was literally lost in translation.”
I add that despite the potential for math expressions (superscripts and such) by use of special software, this is too specialized for general use and most readers are unlikely to grasp the difference.
Dan, with all this talk of weights, speeds and passengers, has there been any discussion on IFR flight into IMC? I would hope that if a pilot is IFR rated and has an airplane that is properly equipped, you would be able to fly in IMC. I live in a foggy area and I can file a flight plan in my Cessna 150 to fly in and out of the fog layer to fly up the coast. It’s time to replace it with an RV-12 but the limit on IMC flight is a real problem.
Thanks
Van
IFR flight into IMC is again being discussed in ASTM. The effort broke down once but the new regulation appears to have reenergized work. FAA never specifically disallowed IFR in LSA, much as the agency does not prohibit IFR in any suitably-equipped EAB aircraft (referring to a minimum-equipment list that is fairly easy to meet).
Officials wanted a standard and encouraged the ASTM committee to create such a standard while discouraging such activity until a standard was ready. The original effort may have failed because it attempted to define “IMC-Light,” which proved difficult.
It is unwise to predict the outcome of the committee’s work but agreement on other challenging standards has been found so some proponents are optimistic IFR could emerge with the new reg.
Read several articles (or watch videos) about IFR on LSA on ByDanJohnson.com.
I don’t know who wrote that equation or tried to explain it, but that was a disaster. Here, try this:
The limit Power Index is set by this ratio: 1.728 = Horsepower divided by Wing Area
So, you can’t have more horsepower than 1.728 times your wing area.
By the way, the 1.728 is just 1.2 x 1.2 x 1.2. The cube root of 1.728 is 1.2.
For an example: going by this 1.728, I have 180 horsepower and a 125 square foot wing area, and a 1,500 pounds gross weight, what would be my PI ratio? Appreciate the help.
Interested in your thoughts on the Jabiru J230-D. Fits into LSA now but it’s based on the J430 in Australia and has higher weight and total of 4 passengers buts it’s the exact same airplane. Do you think these types of airplanes would easily become LPA’s?
I don’t know if “easily” is the right word, but, yes, the J-430 is one of several existing airplanes that could become LPA *IF* they declare (and can defend) that model’s compliance with industry consensus standards that FAA has accepted. My guess is that we could fairly quickly have several models of LPA available soon after the regulation becomes active. Whether that applies to Jabiru will depend on the Australian factory pursuing the opportunity.
Interesting. An RV-14A with a wing area of 126.1 sq. ft. and a 215 HP engine has a Power Index of approx. 1.195. Stalls at 54 mph = approx. 47 knots. You could put a 200 HP engine in it, but at KPRC, a 215 HP engine will only develop about 85% power, or approx. 183 HP anyway, so no thank you.
I’m not following the nomenclature in the Power Index equation. I’m an engineer and I’ve never seen the {} symbols used that way. You’re saying {P/S}1/3 is not P/S times one third but rather the cube root of P/S? Do I have that right?
I checked with Roy Beisswenger, also an engineer, who said, “Yes, cube root of P/S.”
The “{ }” was probably used to show the double brackets were deliberately used and not a typo.
You DO NOT need to touch Part 103 to achieve an increase in weight, fuel, airspeed, etc. All you need to do is add a line to the sport pilot regulations that reads something like the following:
“The holder of a Sport Pilot certificate is granted the additional privilege of 500 pounds maximum weight, 12 gallons of gas, and an overall 15% increase in stall and maximum speeds to a vehicle defined in Part 103 providing that vehicle retains a single seat.”
That type of regulation would create a much needed “stepping stone” between Part 103 and Sport Pilot. Anyone flying under 103 could fly a heaver UL by simply obtaining a Sport Pilot certificate. In my case, I fly weight shift. Since it is basically impossible to obtain and remain current in Sport Pilot weight shift without considerable expense and travel, I could opt for a three-axis Sport Pilot Certificate, that I could obtain locally. Then I could fly both weight shift and three-axis.
Everybody wins…
Many people blur the line between pilot certificates (Sport, Private, etc.) and aircraft certification (Standard Category as used by Cessna, Cirrus, et al. — or Special Category as used for LSA and Experimental). However, FAA does not blur this line; two distinct divisions of FAA deal with pilot licensure and operation on one side while another deals with aircraft approvals using various mechanisms. This is why no such “stepping stone” can exist between Part 103 (aircraft) and Sport Pilot (a certificate). One is about pilots; one is about aircraft.
OK, now to your main point, I believe.
If I understand your desire — and it is a rather common wish — you’d like to fly a Part 103-type aircraft but have a few more permitted pounds so you can have more fuel, and more payload, along with a little more speed. To have that under the Part 103 regulation would require a change in regulation.
Yet so long as a greater-than-254-pound Part 103 ultralight stays within LSA parameters, such an Experimental (not Part 103) aircraft can be flown with a Sport Pilot certificate today. No change is needed. As long as your favorite aircraft gets an Experimental certificate and weighs less than LSA can weigh, you can fly it now with a Sport Pilot certificate using a drivers license in lieu of an aviation medical. Contrarily, to fly with zero pilot certificate, zero medical requirement (even drivers license), and zero N-number registration, a Part 103 ultralight vehicle must stay less than 254 pounds other than for exceptions made in AC-103-7.
I hope that added clarification.
Come on Dan, Mark Taylor was asking for relief with a change of Light Sport not a change of FAR 103. Since Light-Sport is up for change now anyway, why not change it?
My request was the same as Mark, but Mark stated it better. Please put the request to the FAA.
Alternatively, the FAA could issue exemptions for Sport Pilots without changing FAR 103. I know the FAA said they don’t want to rule by exemptions… but my god, do something.
In fact, the FAA does continue to give exemptions to Icon and Terafugia and others.
Why should a licensed pilot flying solo be restricted to the same FAR 103 as a non-pilot? The step-up in hassle from FAR 103 to Light-Sport is too great (biannual flight review, DAR cost, local state fees, 51%-rule limit on kits and on and on).
Thanks for listening.
Hi Mark,
It could be a simple addition to FAR 61.315 (privileges and limitations of my Sport Pilot certificate).
This proposed modification to the Sport Pilot rule COULD be interpreted to allow you to get into an existing “ultralight” type aircraft and take off with 300-500 more pounds of weight, on an airframe that was already marginal at 500 or 550 pounds MGTOW.
If a more common sense interpretation is used, of course it could allow someone to design and build a new “ultralight style” vehicle that is strong enough to take off at 900 or 1000 pounds gross.
But without that discrepancy addressed clearly in the new rules, disaster could easily happen with some UL vehicle owner who shouts “Hooray, now I can add a bunch more gas and weight to my old Weedhopper and fly away without a second thought!”
When are they going to fix the ultralight problem of under weight and unsafe? I am a sport pilot and ultralight pilot. We all flew what is called fat ultralights. They need to fix that also to make it safe!!! …say 400 to 500 pounds. Thanks
This subject comes up regularly. The also-regular response is that any move to change a single word in Part 103 will cause the entire regulation to be re-examined and the result is sure to be more rules, possibly with a pilot license requirement, perhaps medical certificates, and N-number registration, plus other rules that few want. Be careful what you ask for.
Stay your course, Dan, you know better than anybody else that Part 103 is truly a blessing and it’s probably far better to leave it as-is than risk “new age” rules and re-examination. There are lighter and more reliable engines available now, which allow several more “vehicles” to make 103 weight than they could have before. There are better materials, CAD design, and many other things that make it easier to achieve a 103 vehicle than it ever was before. Several older designs that were not capable of making 103 weight can now squeak through using the Polini and Simonini engines. The Kolb Firefly, the Aerolite, the MiniMax, Airbike, and others are well-proven, usable 103 vehicles. Let the FAA spend all of its rulemaking and examination for adjusting Light Sport and the Part 23 updates.
You make several excellent points and I am in full agreement. Thanks!
I say they do the Trump Version:
EXECUTIVE ORDER Jan .13, 2017
Sec. 2. Regulatory Cap for Fiscal Year 2017. (a) Unless prohibited by law, whenever an executive department or agency (agency) publicly proposes for notice and comment or otherwise promulgates a new regulation, it shall identify at least two existing regulations to be repealed.
My + 1 minus 2 cents.
2023 for implementation of the new rules..goodness gracious, no wonder the industry is dying a slow death since the pilot numbers peaked around 1980. The regulators are too slow at implementing improvements.
What is the primary need of the industry? pilots.
More people flying leads to everything else, more manufacturers, more airports, etc. Without people flying the rest don’t matter. Many 2 seat certificated planes are over the 1320lbs (600kg) but functionally not much different than their slightly lighter cousins. Allowing 4 seat aircraft will make acquiring a sport plane more attractive to prospective pilots and will grow the industry. Every single independent or flight school in the US could train SPL’s. Access is important to encourage more people to learn to fly.
Another thing that needs to be done is to remove the TSA requirement and Student Visa Requirement for Private Pilot Applicants. There is no “security” risk…19 years later that’s definitely proven- it’s 9-11 politics. Private Pilots aren’t going to be engaging in commercial work why do you need a student visa? I fly commercially in Asia and many Asian students are going to Canada and other places without visa requirements to obtain their PPL. For them they treat it like a diving license, sailing license etc…just for fun.
Its too bad a lot of LSA manufacturers will have to compete with 2nd hand certificated airplanes which often are a lot cheaper…buyers will make their choice of a new 2 seat LSA or a 4 seat 2nd hand either way if the aggregate flying hours increases the industry wins.
This is an obvious observation, but I can’t image what this slow beaurcratic process is doing to the current and future LSA manufacturers. I really feel sorry for Texas Aviation’s Colt LSA aircraft. I assume the design was started well before these (up to 3,500 pound) rumors started. The company must have been so far along, so much money invested, that they could not turn back and stop development. So, they have a nice LSA (i.e., Sport Pilot license only required) that, if the LSA definition turns into a 4 place, ~140 – 150 knot airplane with a MTOGW of ~2600 pounds, there will be no market for their Colt as it exists today.
The tying of the Sport Pilot License to the final LSA definition is the key. Again, if you can fly a C-172/C-182 class aircraft with a Sport Pilot license (no medical), the whole traditional LSA market just evaporated. Used LSA prices will fall through the floor. I suspect many new LSA start-up are in limbo and have been since the first rumors about weight stated. It seems to me, poor memory and all, that those rumors stated around late 2016.
Dan, your thoughts on this impact to traditional LSA sales would be greatly appreciated.
Regards,
Joe T.
I doubt the market for a 1,320-pound SLSA will disappear. Any 2,600 model will be considerably more costly meaning many folks will continue looking at the more affordable lighter models with two seats. Light-Sport Aircraft clearly did not negatively impact Part 103 ultralight sales (which are strong the last few years), and I believe 1,320-pound LSA will continue to have good value even after FAA allows some heavier aircraft after 2023.
Dan,
Thank you very much for your reply.
I have tremendous respect for you and your ‘mission.’ You are a tremendous help to those of us interested in an LSA. But, I must say I do not agree with your conclusion above.
The paragraph below is from AVweb. I am sure you have read it. It states that most new LSAs cost between $150K and $175K with an average selling price, including used aircraft, of $117K. $117K will buy a pretty dang good C-172.
“The typical price of a well-equipped LSA—and few buyers skimp on options—is north of $150,000. For our survey group of a dozen owners, the average price was $117,000, but some of the owners bought used airframes. The high price was $175,000.”
So, if I can use my Sport Pilot license on a used, good condition, C-172 (or similar), then the choice between a new 1320#, 2 seat LSA @~$165K, and a good condition, used 4 seat fixed gear VFR airplane, it is an easy choice.
As an example:
https://www.controller.com/listing/for-sale/197881449/1993-piper-dakota-piston-single-aircraft
A $199K 1993 Piper Dakota with 2,374 TT and 362 SFOH with 362 since prop overhaul. The useful load of this Dakota is almost as much as the LSA MTOW!
Again, I don’t mean to be argumentative, but I truly believe the value of existing LSAs, new and used, will be hit very hard if the FAA decides to let a ~2,500 – 3,500 pound (no one knows yet) aircraft with four seats and fixed gear and a max speed of 148 kts with a maximum horsepower of 235 (again, no one knows yet) be flown by SPORT PILOTS.
The point I am trying to make is that the FAA has created a monstrous time void in the revised LSA design regulations. NO ONE KNOWS where the final design point(s) will be. It has been, what, 5 or 6 years since these LSA change rumors started? And still, nothing definitive? Nada??? Why??
I believe this has significantly hurt the LSA movement. I believe it has stopped any new design efforts that were not almost completed years ago. That is a shame – – – There is a lot more innovation out there.
Oh, WAIT!!! The more I look at it, that 1993 Piper Dakota, in that link above, with 2,374TT and 362 FHOH and prop OH, looks pretty dang good. Dan, ya’ want to go partners on this bird??? (that’s a joke, but that particular aircraft really does looks interesting. And, it only took me about 10 minutes to find it.)
Regards,
Joe Thompson
Wichita, KS
Thanks for your kind words. I’m pleased to provide a useful service.
We don’t know yet if a Cessna 172 or Piper Dakota will be permitted into the LSA2023 or new LPA categories and we don’t know if they will permit someone with a Sport Pilot certificate (or using the privileges thereof with a higher certificate) to fly these larger, heavier, faster airplanes with more seats, especially if it is also retractable. Neither has the medical question been resolved regarding the L-H-F airplanes.
Also, while many LSA are indeed in the $150,000 to $200,000 range, choices below $100,000 exist and if you can accept something that does not look like a legacy airplane, the prices can be much lower.
The beauty of LSA and the other lightweight categories is not only that some are capable substitutes for legacy airplanes, but that buyers have many choices in multiple configurations at multiple price points.
Curious if you have flown modern LSAs? If you had, an argument for flying an old 172 would be void. Feels like an old school bus in comparison… but if ya want four seats, suppose a valid option still.
Yes, I have. A Piper Sport. I have abut 50 hours in it. I’ll take a C172 over that aircraft any day. As you know, one of the biggest concerns, at least for those of us who live in the Great Plain (not PLANES 😁) is the low wing loading. “Bouncy” doesn’t quite cover it…
Joe T.
Still looking to fly my club’s C-172 with my PPL and a driver’s license… will I live long enough?
You quote “Airspeeds — Referring to maximum horizontal and never-to-exceed speeds (Vh and Vne), FAA said, “These may be higher than in the current rule, but will still be limited.””
Why in the would would they want to limit Vne?? Would that mean an aircraft with a very high safety margin but that’s otherwise not very fast need to be structurally weakened to be legal in our hypothetical LSA 2023?
Hi: Agency rule writers are stating that all top speeds will not be unlimited. That’s not the same as “artificially” lowering never-to-exceed speed.
My mind must be going. I only now realized that it clearly meant the published Vne and that the Vne can be lower than whatever will actually damage the airframe.
One of the things I have noticed about some LSA is that they have been artificially restricted to the 600kg / 1320 lbs weight limit in order to meet our U.S. LSA standards, even though they have been engineered to support more weight (Jabiru J230, etc). Are you aware of any discussions with the FAA regarding a process in the future that would let manufacturers apply for a higher weight limit for existing LSAs? Not only would this allow current owners to realize an increase in useful load if their plane was engineered for it, but it would also increase the value of existing LSAs once the “new and improved” limits are finalized.
That is a valid question and while it seems such an idea could work, FAA remains in planning on this regulation.
Great information and thanks for staying on top of this, and other things.
I currently own and fly a 172 with 180HP constant speed prop STC.
Should I assume the CS Prop will kill any chance of it being allowed under these current proposals?
Bill, I suspect a conventional constant speed prop would not qualify under the “safe, simple, and easy to fly” mantra that guides FAA. Single lever control, yes possibly; but constant speed, I doubt. However, I was surprised that retractable gear (which LAMA did not request) is on the possibilities list so perhaps…
Does the Sling TSi with the Rotax 915iS have the ability to use single level control? It may count as an LSA when the new rules are finalized, I would think.
That answer depends on a decision by The Airplane Factory, which I cannot predict (though I find it likely if the SLC system is available). However, Sling TSI can presently use the fixed pitch version as does Bristell. Sling TSI appears to qualify for what FAA is proposing for LSA 2023 but we will see when the regulation is published for public comment (in a year and a half or so).
Is something SLC according to the new MOSAIC if it the prop pitch can be manually selected via a number of discrete settings (e.g. “takeoff”, “climb”, “cruise”) instead of a blue knob with variable positions? I.e. something like https://www.kitplanes.com/wp-content/uploads/2019/05/sling-tsi_05.jpg which is the Sling TSi with the constant speed prop. I know that it CAN use the fixed pitch version but a lot of people will probably adjust it on ground for maximum cruise speed which means sacrificing some safety by not having ideal climb speed.
The reduced safety by having worse takeoff performance sounds greater than the supposedly reduced safety of having one more switch that you select takeoff/climb/cruise with. I hope the FAA will take that into consideration.
FAA has not yet determine if they will allow SLC (Single Lever Control) or how such a system is to be defined. We believe they will go forward with this as we made the safety argument you presented and FAA top executives responded favorably, but the detail rule writers still have much ground to cover. We hope they might accept the system you mentioned, but only time will tell. However, LAMA plans to keep making the request as we seek addition updates.
Retractable gear on SEL airplanes should be permitted. They are already permitted with amphibious LSA.
Hi JB: FAA did not agree with you in 2004, when they first stated their “safe, simple, easy to fly” mantra, but retractable will come with LSA 2023 (we believe).
Dan,
Very informative article, and the first to give any sort of inkling as to how the power index might be calculated. Thank you! I did notice a typo in the following:
“That says the same thing. The more power you have, the larger your wings need to be. Let’s see what that looks like with some real world numbers. If you have a 100-hp motor (for example, the very common 100-hp Rotax 912ULS) then for an Ip of 1.2, your smallest possible wing size is:
S = 100/1.4³ = 57.87 square feet”
In the equation on the last line, the 1.4 cubed should be 1.2 cubed (don’t know how to do a superscript numeral on my iPad) to agree with the text that precedes it. The numbers didn’t quite work with 1.4. Sorry to pick a nit – occupational hazard of being a financial analyst…
Keep us posted!
Mahalo and Aloha
Thanks. I’ll go fix the error. I appreciate your nit picking. I want this website to present accurate information.
Dan
One item I didn’t see was the issue of LOA [Letter of Authorization] on Light-Sport from the manufacturer. Point in case, ADS-B it wasn’t until 18 months before the deadline when we finally got the LOA. Built overseas, some are interested in U S rules. If it’s good enough for standard aircraft why not LSA?
Dan,
Could you please comment on my requests for LAMA representation to remove the wording from the definition of an LSA relating to reciprocating engines, in order to allow the use of electric, turbine, or any other type of engine? I see that there is a push to allow electric engines, but not turbines, which are way simpler and more reliable than the reciprocating engines currently installed in LSA.
Thanks.
Hi Dave: My direct reply evidently did not reach you (I’ll investigate; it could be “operator error”) so I will respond here first.
LAMA most definitely has spoken to the FAA about not omitting turbine. As you note they made this mistake with calling for reciprocating engines only, effectively knocking out electric. They’ll fix that with the new regulation but some among the rule-writing staff are still resistant to turbine, believing they are too complex. Upon learning this, LAMA specifically asked that they not eliminate turbine as FAA cannot know what the future holds. Most turbine operators to whom I’ve spoken agree with you that these engines are simple to operate (though maintenance may be another matter). LAMA will not give up the fight!
Hi Dan,
When LAMA goes into the fight, they need to be armed with the best weaponry. The weapons in this case are the technical and safety cases that will allow LAMA to clearly refute and rebutt any assertion by the FAA that a turbine engine is more complex or less safe than a reciprocating engine. I have offered to provide this information to LAMA as part of my request for LAMA to make representation to the FAA for the use of turbine powerplants in LSAs.
If we take the gearbox off a Rotax 912 and also off our turboprop engine, we end up with a piston engine that has a much higher parts count, significantly more moving parts/assemblies (there are two moving assemblies in our turboprop; the gas generator rotating assembly and the power turbine rotating assembly), significantly more failure modes, higher mechanical stresses (the pistons pounding back and forth versus a constantly rotating shaft) etc.
Winning a war is also about choosing your battles. To date, even with our offer to support a LAMA initiative to seek approval for the use of turbines in LSAs, we are not aware of any pro-active initiatives that have been undertaken, nor any tangible discussion with the FAA about this topic.
With several turbine offerings that are suitable for LSA class aircraft currently being available, and with a few highly suitable turbine engine options in the development pipeline, it could be argued that the proven reliability and safety record of turbine engines is better demonstrated than that of electric powerplants in aircraft.
Not everyone wants to do an hour of flying then have to land to recharge the batteries. There are also some who will prefer the reliability of turbines and who find that JetA or diesel is more available to them than Avgas or regular fuel. Those that want to fly for a longer endurance than electric aircraft can provide, or who want the reliability of a turbine when flying over tiger country should have the option of turbine power and this could be achieved by having LAMA support an initiative to proactively lobby the FAA to allow the use of turbine powerplants in LSAs.
I disagree that turbine engines have better reliability than electric engines or even that it could be argued as such. The forces in any engine using hydrocarbon combustion are so great that they result in significantly more wear, even if turbines are more resilient to that than a reciprocating piston engine. Although electric aircraft are few and far between, the reliability of the electric motor (if brushless), the power source (assuming Li-ion or LiFePO4), and the power distribution and regulation (a solid-state array of switching FETs for PWM) is proven.
That’s not to say that electric propulsion systems have a future beyond environmentally-conscious flight schools doing 1 or 2 hours sessions, though. The energy density of even the most powerful batteries is still underwhelming when compared to even the least efficient traditional engine. Electric powerplants will occupy a smaller niche than turbine powerplants for light aircraft.
Personally, I’m not too interested in turbines simply because of how inefficient they are at the altitudes and speeds typical of the missions for light aircraft, but I can see why some people would prefer them if jet or diesel fuel is cheap where they are or when reliability and endurance are a must.
I agree with you that LAMA should lobby the FAA to allow the use of turbines in LSA, simply because it gives us and the manufacturers more options to choose from. I just had to nitpick any poke at the reliability of electric motors!
Dan, the FAA’s primary motive is and must continue to be safety. The entire concept of “dumbing down” flight training, and allowing pilots to be flying around with significantly lower levels of basic airmanship skills (20 hours of training with no spins, no real stalls, and not enough emergency procedure training) is not a recipe for safety. If the MOSAIC initiative allows a new low time pilot to be moving faster, with more people on board, and with a more complex airplane (CS prop, retractable gear) may not be a wise choice. I’m ALL FOR a weight increase, but I’m not excited about minimally trained pilots scud-running in a 180 HP Mooney or an RV-8. We are living in an age where every fatal incident is an opportunity for the evening news and come ambitious congressman to take private aviation further away from the average Joe.
Hil Bill: You make good points but we don’t know what will be required for a Sport Pilot certificate holder to fly a larger, faster aircraft with more complex equipment. However, it will surely NOT be a 20-hour pilot set loose in such a machine.
The existing LSA rules already utilize a concept of add-on endorsements for skills not required for the initial certificate. Flight into B, C and D airspace is an example (see FAR §61.325). This sort of graduated licensing makes sense and I hope it would be further incorporated in the expanded LSA rules to cover things like bigger aircraft, faster aircraft, etc.
Hi Dale (and Bill): I completely agree and that is what LAMA has consistently said to FAA.
No spins? Does any pilot certificate other than CFI require spins?
If I was planning on buying a plane before MOSAIC is completed, how would I find which LSA could simply be given a higher MTOW without being redesigned when the time comes?
The 1320-pound limit is pretty arbitrary and many sport aircraft could easily carry a higher load very safely but just can’t for legal reasons. Two LSA today might be physically capable of taking off safely with 1,400 pounds and 1,800 pounds respectively, but both of them would still be limited to an MTOW of 1,320 pounds until MOSAIC is finalized despite one theoretically having a much higher limit. I would hate to buy the former and only discover that when I end up taking off and staying within the new legal weight limit (but contrary to the PoH) and crashing because it’s too heavy.
The Jabiru J250 LSA has the exact same fuselage and engine as their four-seater non-LSA version so it could easily carry a big guy like me (but not with any of my equally big would-be passengers), and once the new rules are approved, it may simply get a larger MTOW and I’d be able to carry a passenger without having to buy an entire new “MOSAIC LSA” plane. The problem is not all planes advertise what their “real” useful load would be so I might end up buying a plane whose MTOW wouldn’t really go up all that much after the rule changes.
If I could wave a magic wand, I would just lobby the FAA to remove the 3rd class medical requirement for the Recreational Pilot certificate.
FAR 61.101 already has most of the things in it that LSA advocates are looking for.
No more than one passenger
No more than four seats
180 max horsepower
No retractable gear.
Recreational pilots CAN fly over 50 miles from their home airport with an instructor’s endorsement and they CAN get an endorsement for flight into Class B,C and D airspace just like a Sport pilot can.
They are restricted to the same 10,000 foot ceiling, 3 miles visibility and maintain visual with the surface as Sport pilots.
This would open up so many more aircraft to pilots on a drivers licence medical while still maintaining a reasonable level of restrictions that the FAA likes to have on pilots without a medical. It would require a checkride for a Sport Pilot to earn the Recreational pilot certificate but all those processes are already in place so it would be an easy transition.
In my opinion this could have been done much faster than re-writing the LSA regs with a somewhat complicated formula.
P.S. I work for the agency (in Air Traffic, not the regulatory part) so these are my views as a Sport pilot and not necessarily those of the FAA, but from my experience, the simplest solution offered to the agency and the fewer agency divisions that have to get involved, the quicker a rule change is made. 😉
These calculations were made after Friday night drinks, but…
The formula means that P/S P/1.728. If we set P=200, S > 115.7 sqft. For a 50 kt stall speed, wing loading needs to be under 14 lb/sqft. Since people like to go fast, we’ll assume 14 lb/sqft. So, W/S = 14, and thus W = 14 x S and S > 115.7 sqft, so W > 1,620 lb, and cruise speed is about 155 kt (if it’s any higher, the ride gets very rough at the relatively low wing loading).
So, the gross weight could be as high as you wanted, as long as the wing area was big enough. But, as a practical matter, you don’t want W/P to be bigger than 15, i.e., W=3,000 lb, otherwise climb performance suffers. So, for a 200 hp motor, the gross weight would have to be between 1,600 and 3,000 lb. For 100 hp, between 800 and 1,500 lb. We know that the current 1,320 lb MTOW for LSA is about as low as we want to go. So, we’re looking at the MOSAIC rule expanding the LSA rule up to roughly 3,000 lb. A C172 is 2,450 lb, and would fit. A Cirrus SR-20 would fit, at 200 hp / 3,050 lb (so, a hair above my 15 lb/sqft rule, but okay under the P/S rule, at P/S = 1.45). An SR-22 has over 300 hp – outside the assumed 200 hp limit.
So, roughly speaking, the MOSAIC rule would allow a 2 x LSA: double the power, double the seats, double the gross weight. But, only about 28% more usable speed (the airplane may be capable of more, but your passengers would hate you).
I’m curious if a Pitts S2E would qualify. 180 HP, GTOW: 1500 lbs, wing sq ft: 125, stall: 50 mph, cruise is 140 mph with a vNE of 203 mph. I think the S2E would be the only Pitts that would come close to qualifying since the S1’s are way too fast on stall and the S2 B, C, & S are 260 HP
A Pitts S2E will retain its original airworthiness certificate and will not change. It is possible that FAA may allow a Sport Pilot to fly such an aircraft but with the larger engine and speed north of 150 knots, I think it highly unlikely. Regardless, we won’t know with certainty until the NPRM and the final resulting rule.
It’s airworthiness certificate says experimental. This is a kit offered from Pitts based off the S2A but has a fixed pitch prop. Stall states 50 knots in the POH so it qualifies there at the proposal stall speed. Also It’s under 200 HP at 180 so it qualifies there. Also it states 137 knots max level cruise by POH. Proposed is 140-150. Only thing that would knock it out is a PI of 1.2. Why could you not change an airworthiness cert? It would be great since I’m already a LSRIA. Love your research and insight btw Dan. I’m always learning something
FAA rarely, almost never, changes an airworthiness once assigned to an aircraft. An EAB would therefore likely remain such, but if FAA allows a Sport Pilot to fly such an aircraft, being an EAB would not matter. We simply will not know for a while what FAA intends regarding the pilot licensure side of the equation.
Thanks for you kind words!
Very informative, thank you!
Dan,
I think the 50 knot stall speed will limit more aircraft than the 200 horsepower. Example, Beech Sierra and Muskuteer can both have 200 horsepower engines but stall at 51-54 knots.
Considering how these aircraft normally cruise about 20 knots above stall speed, seems like they should be given an exemption.
Thanks for the update, Dan. A point from my perspective: Rather than “asking” the FAA to clarify whether Sport Pilots will be allowed to fly the proposed larger LSAs, I’d like to see all interested parties take a firm, non-negotiable stance that LSA = Sport Pilot eligible. From the beginning, Sport Pilot airman certificate and Light Sport Aircraft airworthiness certification have been all but inseverable. It would be a mess if we get into a situation where Sport Pilots are allowed to fly some LSAs, but are excluded from other LSAs. As a community, we should insist that any-and-all changes to LSA criteria remain Sport Pilot eligible.
Hello: While I love your spirit, the fact is that Sport Pilots have all-along been asked to demonstrate skills for a higher performing aircraft. The base level, 20-hour Sport Pilot training leads to the chance to fly sub-87 knot aircraft outside of Class B & C airspace. Flying a faster aircraft into busier airspace has always required further training (or prior experience, as exhibited by a pilot using a Private or better to exercise SP privileges) plus a logbook endorsement. This did not involve a new check ride. Something similar for a pilot of a LSA 2023.
Logbook endorsements are totally reasonable, no disagreement there. I’d just hate to see a situation arise where some hypothetical larger LSAs are totally off-limits to Sport Pilots, with no avenue for access (short of getting a 3rd class medical and moving up to Private Pilot). My apologies for being unclear in my previous post.
Why do you say sub-87 knot? Aren’t LSAs limited to 120 knots, not 87 knots, even without additional endorsements? I haven’t received any “extra” training but my CFI will let me use a SP certificate to rent and fly his Evektor SportStar which can reach over 100 knots true.
I know that I’d need an endorsement to fly in controlled airspace or to use a taildragger, but never heard anything about needing that to exceed 87 knots.
Achieving a Sport Pilot certificate in the minimum 20 hours suggests an easier, more docile, lower-speed LSA. The sub-87 knot (100 mph) designs demand less of the pilot. You can always train — as you evidently did — in a faster machine and are then OK to fly that without endorsement. However, if you learned in, let’s say, a Quicksilver SLSA, then you might not be adequately prepared for an Evektor. In such a case, after a few more hours of transition training, you get a logbook endorsement and off you go. Likewise, if you trained outside of Class B/C airspace, you’ll need extra training to enter such space, but only after you get a logbook endorsement. Since so much LSA training happens in over-87 knot aircraft, that number may not become known to the student. However, those pilots likely accumulated more than 20 hours getting a Sport Pilot certificate.
Everything the FAA does and likely will do in the future is “prescriptive.”
Hi Bill: I assume you mean despite FAA’s statement that they want to be less prescriptive. You may be right, but they have let the LSA industry find its own course more than many of us once expected …so anything is possible, I suppose.
Although the weight is not directly limited (as far as we know), the horsepower cap will become an effective weight cap. Say that the max horsepower allowed in the new LSA regs is 200 horsepower, as the article estimates. The question then becomes: What is the heaviest airplane that can be powered by 200 horsepower? In other words: What is a reasonable range of power-to-weight ratios?
Various aerobatic airplanes (Pitts Special, Zivko Edge, Harmon Rocket) weigh about 1,600 lbs and have IO-540s making 260 horsepower to 310 horsepower. For an airplane with that kind of performance, 200 horsepower would mean an aerobatic weight of 1,230 pounds (which probably would barely be able to carry a pilot and enough fuel for reserve requirements). At the other extreme, the Rutan Voyager only had 235 horsepower but took off at about 9,700 pounds, which means that (with such a low-drag shape, narrow CG range, and the 15,000-foot runway at Edwards) 200 horsepower could theoretically power as much as 8,200 pounds.
For practical purposes: Some early Cessna 205s and Cherokee Sixes have 260-horsepower engines. Their max weights are 3,300 to 3,400 pounds. They’re considered to be somewhat underpowered, but apparently they are certifiable. With better aerodynamics and structures (think: analogous to a Cirrus or Diamond) and sacrificing some fuel capacity and passenger comfort, would it be possible to make a 200-horsepower six-seater? That’s interesting to think about. I’m guessing: Probably, but it would be really marginal, like a Beech 19 Sport: Fill all the seats and you can only carry enough fuel for an hour of flying plus reserves. At max gross, you’ll need over 3,000 feet of runway, climb anemically, and cruise at maybe 100 knots. But the landing performance will be just fine, due to the wing area. Would people want such an underpowered airplane? I’m guessing probably not, but I can imagine folks who can’t get a medical and who would really like a six-seater. Who knows. We’ll see!
Hi Bernardo: I enjoyed your viewpoint. The only thing I would remind readers about is that FAA is not talking about six seat LSA. Four seats, yes, but that’s the most I’ve heard.
How about an S2E Pitts that has a fixed pitch prop, 180 HP, GTOW of 1500 lbs, stall speed of 50 mph, vNE of 203. It’s going to be close
I (like so many) am a bit old and desirous of Sport Pilot (although I hold a PP license) operation of club C-172 – WHEN???
Hi James: I understand the timing is important. I doubt you will see this as a final regulation before the end of 2023, though miracles do happen. Now, whether FAA will allow operation of a C-172 with a Sport Pilot certificate may be a different question than if they will allow a SP holder to fly an aircraft the size and weight of a 172. What’s the difference? It is that a 172 is presently a type certified, Standard Category aircraft (where LSA are Special Category) and a 172’s designation will not change. So, while it appears possible that FAA may allow the operation for which you hope, it is not definite at this time.
Will I live long enough?
Dan is on the money.
For example, right now a J3 Cub falls under the description of a Light Sport Aircraft by it’s design – gross weight, stall, VNe, etc., but it is not an LSA aircraft. It is a Certified Aircraft that falls within the parameters set forth for LSA restrictions.
So a Sport Pilot can legally pilot a J3 Cub.
The same will happen under the new rules. A C172 may fall under the category of LSA by it’s design and performance under the new criteria, but it won’t be an LSA.
It might seem like a distinction without a difference, but it actually matters, and something a Sport Pilot has to be aware of.
Yet another example: A 7AC Champ is LSA compliant right now. But a 7EC Champ isn’t, as it’s gross weight is 1,450 pounds – over the 1,320 allowed. One might say they are functionally the same aircraft, but in the eyes of the FAA, the 7EC is just too darned heavy for a Sport Pilot to handle. 😉
If you have a PPL (Private Pilot certificate) and a current drivers license, will you be able to fly a Cessna 182 and 210 under this change?
Hi Steve: If you follow all the points in the current understanding (repeating again, that this is all proposed, not final), then the answer is surely, “No.” While a 182 can stall around 50 knots with flaps deployed, both 182 and 206 have more than 200 horsepower so neither would appear to meet that parameter and this is before applying the Power Index formula. The C-172 might qualify.
Nice analysis of Mosaic and the insensitivity of the P/S. Hope this proceeds quickly. I’m 79 and trying to stay in the game long enough to fly some of the aircraft I instructed in.