When the Modernization of Special Airworthiness Certification (MOSAIC) rule was first proposed, the big excitement was about old folks like me being able to sidestep the increasingly onerous medical toll that our golden years exact and keep flying the planes we’re used to flying as Light Sport pilots. There was much ado about the stall speed requirements and which aircraft would be captured by it.
With a few exceptions, most lower-end certified designs managed the 59/61 knot dirty and clean minimums and I’m sure we’ll see thousands of folks in my demographic reasonably squeezing a few more years out of a lifetime passion with reasonable limits and access.
As the wrangling over a few knots and a few more types grabbed the headlines, there was a steady drumbeat in the background about the opportunities for new technologies and modern designs to be introduced by the rule. Those of us who’ve been around for awhile have heard that siren song before and what sometimes results is the evaporation of billions in investor capital with little or nothing to show for it.
Fortunately, some people read the fine print of the rule, which will be finalized for the certification of aircraft on July 24 at AirVenture, and realized that there was actually something to this notion of bringing new tech to market under this new set of rules. The pilot and mechanics’ standards were set at last year’s AirVenture.
Last week we wrote about a Utah company that has based its entire business plan on that fine print, which includes elimination of the stifling maximum weight limit and restriction to internal combustion engines only. It also permits the use of MOSAIC aircraft for flight training. One of the first results of this wholesale change in small aircraft certification standards is Wasatch Aero’s SD3T, which is a perfect example of what the writers of the new rule intended for the “modernization” part of it.
It’s a sleek little two-place with a tiny turboprop from French company Turbo Tech that essentially matches the performance of an I0-360 and, most importantly, burns about the same amount of fuel, maybe a little less. It has a 3,000-hour TBO and simpler maintenance that reduces downtime, and the principals at Wasatch say that those factors balance out the up-front extra cost of about $100,000. It’s a lot, I know, but it’s not the $1 million extra that the smallest mainstream turbines run.
That’s important for flight schools, which rack up hours like crazy and amortize those engines quickly. Assuming everything else is equal, the decrease in downtime becomes a financial bonus. But, more importantly for schools that are creating our next generation of airline pilots, gaining turbine experience at the ab initio stage is a major advantage for students in that pathway. Of course, the panel in the SD3 is a row of screens so whatever awaits them in future training will likely be a comfortable fit.
Wasatch’s launch order will send up to 95 of the trainers to a big school that pumps out future right seaters. Students will learn on both the turbine and recip fleet and I’m betting they’ll have a significant leg up on those who learned to fly on legacy piston aircraft.
While training is the focus of the SD3, other models, including a four-place and an eVTOL, are planned. The Turbo Tech engine is scaleable and will come in 250- and 400-horsepower versions. While there’s always a lot of fretting about cost in new designs, OEMs that have managed to get to certification have found that individuals looking for a new airplane don’t want a bare-bones version. When Cirrus started, they couldn’t get rid of their value-priced aircraft. Almost all their customers wanted the latest and greatest. I think those customers will welcome a four-place turboprop that is a little more expensive than a typical high-performance piston single, especially considering the uncertain future of unleaded gasolines that can power it.
Watch for movement in electric aircraft to take advantage of new MOSAIC opportunities. Naysayers continue to write off electric aviation as not a serious thing, but technology marches on and their arguments that batteries will never reach the energy density of fossil fuels, while accurate, is misleading. They don’t have to. They just need to get a little closer.
Earlier this month, a Pipistrel Taurus flew using new solid-state batteries with 410 watt hours per kilogram of energy density. Gasoline’s is 12,000 to 13,000 watt hours per kilogram. Seems insurmountable, right? Well, when you factor in the weight of the engine and fuel system and consider it instead as capacity for more batteries, then factor in the 25% efficiency of a typical piston engine (electric motors are close to 100% efficient) the math starts to add up. It’s estimated that true viability for electric aviation comes when battery energy density hits between 500 and 1,000 watt hours per kilogram. I don’t think that’s far off.
While MOSAIC’s open door policy for new tech is important, there is another aspect that is far more significant. When I was interviewing the folks at Wasatch, I asked who their angel investor was. They don’t have one. The venture is financed solely by the principals of the company from the proceeds of their other businesses. They are not billionaires but they also don’t seem to need the bags of cash normally associated with aircraft certification to get their plane to market.
Granted, they’re benefitting from a lot of already-done R&D. The airframe is from the Czech manufacturer Spacek and there are about 300 aircraft flying with piston engines. The turboprop engine is being certified by its manufacturer. But it’s no small thing to do all the engineering to switch a piston powered plane to a turboprop. By contrast, I’m aware of another clean-sheet project for a single engine aircraft (albeit much larger) where the estimated certification cost is $50 million. MOSAIC seems to be making the Wasatch project go a lot more smoothly and at much, much lower cost.
Now, I didn’t pry into their financial affairs. Maybe they are billionaires but I doubt it. If my gut is correct, it seems their experience proves that ordinary people with ordinary amounts of capital can do extraordinary things under MOSAIC.
I’m sure there are issues with MOSAIC that will be discovered as it rolls out, but out of the gate it’s looking pretty useful. I’m sure the folks at Wasatch Aero are hoping it’s everything they’ve bet everything on.
Very well done article.
Maybe my initial skepticism o& MOSAIC was unfounded.
Came along about 6 years too late for me, when I finally pulled the plug. But I’m very happy for those who will benefit from this. And I sure can’t complain about the last 15 years for me when I just flew light sport with an Aeronca.
One “gotcha” of which anyone exercising Sport Pilot privileges should be aware is that under the new MOSAIC aircraft certification rules there will be LSA’s which Sport Pilots are not authorized to fly. It will be up to individual pilots in that group to be sure to compare the Sport Pilot privileges in 61.316 with the capabilities of those new LSA’s to be sure the aircraft is within those 61.316 limitations.
It is important to keep working on electric aircraft. But the problem, as I really see it, is that the platform is not ready for mass adoption.
Most current electric trainers have a total runtime of about an hour, which nets to roughly 30 minutes of useful time once you subtract the 30-minute FAR reserve. That’s fine for a 30-minute flight, but who really flies those? Most training flights run an hour or a little more.
The optimists will point to this month’s headline. The Helios Horizon, a modified Pipistrel Taurus motor glider, became the first crewed fixed-wing aircraft to fly on solid-state batteries, jumping from 260 to 410 watt-hours per kilogram. The usual rebuttal is that gasoline holds around 12,000 to 13,000 Wh/kg, so the gap is insurmountable. That rebuttal is wrong. A piston engine throws away about three-quarters of gasoline’s energy as heat, an electric motor delivers nearly all of it, and once you stop carrying the engine, the fuel system, and a tank of fuel that only gets lighter as you burn it, the honest gap on delivered energy is closer to 13 to 1 than 30 to 1. On the raw physics, the optimists have a point.
Here is where they lose me. That 410 number is a cell measurement taken on a solar-winged glider flying short validation hops, not a trainer flying an hour-long lesson. Pull those cells into a real pack with structure, cooling, and battery management and you are down around 250 to 300 Wh/kg installed. Put that pack in something with the drag of a 172 instead of a sailplane, strip off the solar panels and the regenerative windmilling that glider used to stretch its range, and the endurance picture changes completely. Even if energy density climbs into the 500 to 1,000 Wh/kg band that people call “viable,” and it may get there sooner than the skeptics expect, density was never the only wall.
The wall that actually matters for a trainer is cycles, not watt-hours. A flight school runs the same airframe through lesson after lesson, many deep charge and discharge cycles every single day. A cell that hits 500 Wh/kg but degrades after a few hundred cycles, or loses life every time you fast-charge it to turn the airplane around between students, is useless to them. Add the cost of manufacturing solid-state at scale and the years it takes to certify any of this for primary training, and the headline flight starts to look like what it is: an impressive research milestone, not a product.
So until then, the only answer many of the e-aircraft companies can offer is “just buy two,” one flying while the other charges. That isn’t necessarily economical, since a comparable piston aircraft costs about the same as the pair. Charge times do seem to be coming down thanks to the EV car fleet, and China is clearly eating our lunch on charging and range for cars. The open question is whether we get that here in the States.
Then there is the infrastructure. Most airports don’t have charging capability. For electric aircraft to go anywhere beyond their home field, we need a massive adoption rate, and most airports simply don’t have the funding to add charging. The one bright spot is that most of the charging adapters have standardized. In Colorado, much of the state’s airport funding comes from grants funded through fuel taxes. The airlines pay heavily into that through Jet A, so maybe that funding keeps flowing. But 100LL and unleaded avgas will slowly shrink as the fleet changes over, and we will have to figure out a new path for the funding.
A lot of people point to a hybrid scenario. I’m very skeptical of that. Now you have two different power plants to maintain, piston and electric, and you introduce far more complexity into the operation of what should be a simple aircraft.
There is no magic formula for batteries here. As long as I’ve been watching that market sector, at least a decade now, there have been many promises of “we found the magic bullet.” The Helios Horizon flight fits the pattern: a real result, a 60% jump worth taking seriously, paired with a founder’s claim of another 40% within two years and no published cell chemistry to back it up.
The other real issue is the news media. They latch onto “we flew an electric airplane” because it gets headlines. So the general public, seeing EVs on the road and one electric glider in Florida, assumes every new airplane is going electric.
So yes, absolutely, 100%, keep plugging away on development. It is necessary work. But we need to do a better job setting expectations about how close the future of electric aircraft actually is. And that is just for single-purpose training aircraft. We are a lot further out before we can expect a 1,000nm useful range from an electric aircraft.
Well said Flyboy.
It is not realistic to compare the worst of the piston engine (25% efficiency of a 1960s designed engine), with the hypothetical best of electric propulsion (near 100% efficiency of the motor alone).
The reality is: 250 mph at 30-40 mpg and 2000m range for a two seater is possible now with a modernized 0-360. And btw: mpg and range double at 1/2 the speed and 125mph is past the Vne of the single seat glider.
While I support R$D into future propulsion systems, I wish we would take more advantage of existing advanced combustion technology and aerodynamics available for GA.
Mosaic is making that easier.
I’d rather fly behind a Rotax than an O-360.
I agree that this is very positive development and could lead to a wonderful selection of new, high tech, high performance airplanes while allowing older pilots to continue flying their legacy airplanes with a drivers license. However, I don’t buy the touted advantage of MOSAIC easing the medical requirements. I would guess that most pilots my age (78) are already flying on Basic Med which works just fine and doesn’t involve any onerous demands – seeing your primary doctor once every five years is not a hardship! In the worst case, MOSAIC could allow older pilots who know they are not going to pass their next medical simply reverting to the drivers lic. – is that a safety enhancement? Re costs of new airplanes coming down to anything resembling affordable for an “average” person, i.e somebody earning less than 300k or so a year, I think that hope is a pipe dream. Most of us will be left nursing our aging airplanes along because the cost of moving up is just too much to bear as much as we would love a new set of wings – using myself as an example – sharing a 1965 150 with a fellow pilot. Our airplane is in great shape but we would only see about 45-50k for it at best. To move up, we would each have to come up with another 50k a piece at a minimum – it just isn’t in the cards for us and many others I suspect. Yes MOSAIC is great in many ways but it isn’t a panacea to kick start GA.
Perfect, what could be better…. From what I have learned these last five decades in the flying forum is to take a spoonful of digestives after reading all the glossy brochures. When small, light E.V.s have a range of 900 miles (1500 k.m.) I’ll begin to imagine electric powered aircraft have a niche in G.A. Oh, don’t worry, the future is just over the horizon…