Editor's Note: This is the second part of Ron Wanttaja's survey of LSA safety (here's the first). This time, he takes a close look at how modern LSAs compare with legacy trainers as epitomized by Cessna's 152, both in terms of accident rates and the kinds of mayhem they succumb to. Let's dive in!

In the previous safety review, we looked various forms of LSA—SLSA, ELSA and Experimental/Amateur-Built. For this article, we’ll look only at SLSA airplanes. We’re not addressing powered parachutes, weight shift or other SLSA classes—just traditional flying machines with wings and a motor. Call them “SLSA-A,” or “SLSA-As” for plural. We’ll address their accidents from 2005 through 2021.

To identify the SLSA-A accidents, I cross-referenced the NTSB accident database with FAA registrations, including both active and inactive aircraft.

What to compare them to? Let’s pick the near-ubiquitous Cessna 152. It’s close to the general definition of Light Sport, other than exceeding the LSA gross weight requirement. Cessna made almost 7600 of them in the 1977–1985 time frame, though only about a quarter of them remain on the U.S. registry. On the average over the 2005–2021 time period, there’s roughly the same number of SLSAs as Cessna 152s.

I also have a good database of Cessna 172 accidents. They’re often used for training, like the SLSA-As and Cessna 152s. The time period of the accidents is different (1998 through 2016), but it should be a valid comparison.

Pilot Error

I divide Pilot Error into two basic categories: Pilot Miscontrol and Pilot Judgment.

Pilot Miscontrol refers to basic stick-and-rudder errors. Undershoots, overshoots, stalls, loss of control on landing or takeoff and so forth.

Pilot Judgment addresses accidents due to faulty decision making: running out of fuel, attempting VFR flight in IMC conditions, etc.

Figure 1 compares the rates for the SLSA-As, 152s and 172s. Note that the percentage of accidents due to Pilot Judgment issues is almost identical for all three aircraft. This is perfectly logical; the type of airplane strapped to the pilot’s rump is not likely to affect whether they go scud running or buzz the girlfriend’s house.

The Pilot Miscontrol rate varies between the types, but not really by much. The SLSA-A rate is slightly higher than the two Cessnas, but about 10% of its accidents involve tailwheel aircraft. On the other hand, the SLSA-A accidents involve fewer pilots with just Student certificates. Yet, when one combines Student with Sport Pilot certificates, the total for SLSA-A accidents is about the same as for Cessna 152s (which, of course, cannot legally be flown by Sport Pilots).

Figure 1 also includes the fatality rate for each type; that’s the percentage of accidents that result in at least one fatality. The fatality rate for SLSA-As is about 50% higher than the Cessna 152, but only two percentage points more than the 172. But as I discussed in “Homebuilt Accidents: Fatal Factors” in the October 2019 issue, this appears related to the configuration of the aircraft. High-wing aircraft protect the occupants better. The Cessnas are all high wing, but the SLSA world includes a mix of low and high wings. For that matter, the Cessna 150 has a higher  fatality rate than the SLSA-As.

So, taking everything into account, which type of plane is better? In my opinion, it’s pretty much the same.

Wind Issues?

One of the usual warnings about Light Sport Aircraft is their sensitivity to wind. A Cessna Skycatcher weighs 1320 pounds versus a 152’s 1670 pounds. The wind should affect the lighter aircraft more, leading to more wind-involved accidents. Somehow, our grandfathers managed to make it through flight training with airplanes just as light—and taildraggers to boot. Oh, and a Cessna Skycatcher actually has higher wing loading than a 152.

Yet, looking at Figure 2, we see some basis for this concern. There are almost twice as many SLSA-A accidents due to the wind’s effects than Cessna 152 accidents.

But look at the results for Cessna 172s: almost identical to Light Sport Aircraft.

Take Figure 2 and cover up the legend—the part that tells which color represents which aircraft type. Could you honestly be certain which bars were SLSA-A accidents?

What about the bounces/hard landings? The greater percentage of loss of directional control? Would you be sure the SLSA-As were neither of those? Again, overall, there’s nothing that stands out.

Mechanical Issues

At last, the LSA bashers have something that can let them rub their hands with glee: As Figure 3 shows, SLSA-As have a higher rate of non-engine-related mechanical failure: more than twice that of the Cessna 152 or 172.

Part of the problem here is that the SLSA-A statistics cover a wide variety of aircraft types. The 417 SLSA-A accidents from 2005 to 2021 include nearly 60 different aircraft manufacturers. Spotting specific issues is difficult.

The statistics show a greater rate of fuel-system related accidents. Sound familiar? If you’ve read my series on Experimental/Amateur-Built aircraft accidents, you’ll remember that fuel systems had an elevated rate there, too—and higher rates for other mechanical issues as well.

New airplanes are going to have problems, and fuel system issues can rapidly bring aircraft down. There are undoubtedly some bugs being cleaned up in the Light Sport world. Remember, Cessna has had about 40 years to get problems with the 152 fixed. That includes 21 airworthiness directives for various reasons. With time, fuel system problems in Special Light Sport airplanes will be solved as well. The newest 152 rolled off the Cessna line more than 30 years prior to the start of the time period used for this analysis. Good bet that the little issues had been cleared up long ago.

One factor is likely to be the unfamiliarity of the types in the U.S. aircraft inventory. While the rate of maintenance error is about the same, one might expect that maintainers are far more familiar with the traditional Cessna products.

Engine Non-Issues

Did you notice the other major result in Figure 3? SLSA-As have about half the rate of engine mechanical failure than the Cessna 152. The SLSA-As are only a little higher than the Cessna 172s.

The probable reason? More than 70% of the SLSA fleet uses one of the Rotax four-stroke engines. As discussed in “Homebuilt Accidents: Passing the Engine Baton” in the February 2023 issue, the Rotax 912 has one of the best safety records in the Experimental/ Amateur-Built fleet. This good reliability is obviously being passed on to the Light Sport world. The Continental O-200, used in the Cessna 150 as well as the Cessna Skycatcher, has a failure rate about the same as the Rotax.

Fleet Accident Rate

My usual way to compare types is using the fleet accident rate: the number of airplanes per year that suffer an accident versus the total number of that type in the registry.

The yearly fleet accident rates are depicted in Figure 4. It shows the SLSA airplanes at a higher rate, tapering down over the years as the fleet size increases. It’s fairly close to that of the Cessna 152s as the years pass.

However, there’s another factor here: The fleet accident rate doesn’t reflect how much the aircraft are flown, nor does it take into account the number of aircraft still in the registry that are inactive.

It gets rather interesting when those factors are included. The annual FAA General Aviation Survey includes flight-hour estimates and the estimated percentage of the fleet still active. Unfortunately, while it includes estimates for Special Light Sport Aircraft, it does not break the numbers down to the SLSA airplanes. Similarly, while it includes estimates for all reciprocating-engine aircraft, no estimates for specific aircraft types are included.

However, if one uses the “generic” estimates for comparison, SLSAs fly 25% more hours per year than 152s, and 33% more of the SLSAs are active aircraft.

So, it’s likely the accident rate for the SLSA airplanes is close to that of the 152s.

Conclusions

When performing analyses like these, the analyst usually hopes the data produces an unequivocal outcome. Good or bad, we want a definitive answer.

No such luck here. Comparing SLSA airplanes to the Cessna 152? Practically a wash. Yes, the SLSA-As see more wind-related accidents (like everyone expected) but do better in other categories. And the wind-related rates are close to that of the ubiquitous Cessna 172.

The higher rate of mechanical failure for the SLSA-As does seem significant. Even more so when you consider the Cessna 152s involved in accidents had an average total time of 10,300 hours…vs. just 350 hours for the SLSA-As.

On the other hand, the engines for the SLSA-As are more reliable, with the Lycoming O-235 having a failure rate almost twice that of the Light Sport fleet. When all the causes of engine failure are tallied (both mechanical issues and pilot issues, such as running out of fuel), the SLSA-As come out significantly better. Twenty-seven percent of Cessna 152 accidents stem from a loss of engine power, versus 19% for the SLSA-As. Cessna 172s are even lower, about 15%.

So, what’s the final call?

Pilot error rates are about the same as those of the Cessna 152s and 172s. The higher rate of mechanical-failure-related accidents are somewhat offset by the use of more reliable engines.

Personally, I’d call it even. While there are obviously things to watch for, I don’t believe the Special Light Sport airplanes have an accident rate significantly different from the traditional fleet.

Editor's Note: This two-part short series is the handiwork of Ron Wanttaja, who has been tracking accident and registration data for Experimental aircraft for decades. Here, he looks at both the fleet size and accident rates among the various LSA categories. Looking ahead, the next installment will dig deep into how LSAs fare against more common certified trainers. It’s been almost 20 years since the FAA implemented the Light Sport Aircraft category. While the planes might appear similar to traditional Experimental/Amateur-Built (E/A-B) aircraft, there are significant differences in how they are designed, constructed, maintained and operated. Light Sports have had a major impact on flying in the U.S., even if their numbers are still relatively few. Without Light Sport (and the accompanying Sport Pilot program), the FAA would have lacked data to justify the simplification of pilot medicals known as BasicMed. Light Sport’s proven safety led to the MOSAIC program, featuring a major relaxation of the limits of what can be flown without an FAA medical.

The Light Sport Aircraft

The structure of Light Sport is very complex. It was the definition of a new type of aircraft. The Light Sport Aircraft (LSA), as defined in 14 CFR Part 1, was restricted in weight and airspeeds, could only carry two occupants and did not include complex elements such as retractable gear or constant-speed propellers. Fundamental to the program was the FAA decreeing that any aircraft, regardless of its certification category, meeting this definition could be flown by individuals without an FAA medical. The Sport Pilot program removed one layer of bureaucracy in gaining a license and allowed those with less-than-stellar medical histories to continue to fly. Any aircraft meeting the Light Sport definition could be flown by a Sport Pilot—Standard category, homebuilts, etc.  At the same time, the FAA created two new certification categories: Special Light Sport Aircraft (SLSA) and Experimental Light Sport Aircraft (ELSA). These featured simplified certification processes using consensus standards developed in conjunction with the American Society for Testing and Materials (ASTM). SLSAs could be sold ready to fly, and the ELSA category was established in part to allow “fat ultralights” and other previously non-certified airplanes to be formally licensed. ELSA would also allow the sales of kit aircraft (with no 51% rule limitation) and allow owners of SLSAs produced by defunct companies to continue to operate their aircraft.

Getting Wonky

Unfortunately, the Light Sport certification structure is far, far, too complex. Standard category, which contains the Cessnas and Pipers we’re familiar with, has five aircraft categories—Normal, Utility, Aerobatic, Transport and Commuter. These include well over 200,000 aircraft. In contrast, Light Sports have eight separate categories (including both SLSA and ELSA), encompassing fewer than 9000 aircraft. This makes it complicated when you want to look at accident statistics. Take the RV-12, for instance. Of those eight Light Sport certification categories, RV-12s are registered in four of them—all with different requirements for original certification as well as maintenance and inspection. Plus, the RV-12 can be licensed as Experimental/Amateur-Built, as well. That’s five different certification categories for approximately 800 nearly identical aircraft. So…which type of RV-12 should we assess? The ready-to-fly models produced by the factory and maintained by an A&P or someone with a Light Sport maintenance repairman certificate? The models built from a kit, maintained by whoever owns it regardless of qualifications? Those built by the 51% rule for E/A-B aircraft? Ideally, it might let us compare the safety differences between the five different certification categories. Unfortunately, so many categories result in small sample sets that don’t provide trustworthy results. Figure 1 illustrates the thorny nature of Light Sport certifications. It lists the eight Light Sport certification categories, with the number of these aircraft on the U.S. registry as of January 2023. Also included is the fleet size for Experimental/Amateur-Built as well—more than three times the entire Light Sport fleet. 

That Frisky Grampaw

One of the ELSA categories in Figure 1 is listed as “Grandfathered.” The actual term for these aircraft is “Registered Prior to 01/31/08.” That’s a mouthful, so I use Grandfathered as a shortcut. These have a curious history. One of the goals for the FAA during the transition to Light Sport was to get the fat ultralights and two-seat ultralight trainers into the N-numbered registry. To accomplish this, the FAA allowed these aircraft to be formally given Experimental Light Sport certificates, as long as they met the Sport Pilot criteria. The owners just had to apply by the end of January 2008. There was an interesting loophole. The FAA allowed any aircraft meeting the Sport Pilot eligibility requirements to get ELSA certification, as long as it had not been previously registered. There was no ASTM Consensus Standard involved—just the DAR’s willingness to believe the subject aircraft met the Light Sport rules. Grandfathered ELSA rolls include traditional homebuilts like Kitfoxes, RANS Coyotes and Zenair CH-601s, added long before any of them were formally established as Special or Experimental Light Sport.  There are even two RV-10s listed as being licensed as Experimental Light Sport under the Grandfather provision. Now, I’m guessing these reflect typos, and that the certificates in the airplane rightly identify them as Experimental/Amateur-Built. But I can’t help grinning, thinking about builders ripping out the rear seats, removing the spinner and wheel pants, filling the fuel tanks and interior with helium, and smiling blithely at the DAR as they request approval. Why were people so interested in getting traditional homebuilts licensed as Grandfathered ELSAs? For ELSAs, anyone can take a 16-hour Light Sport Repairman-Inspection course and perform the condition inspection on the plane they own, while only the original builder of an E/A-B can receive a repairman certificate. ELSA certification was perceived as enhancing the resale value of the airplane, as later purchasers would be able to get a repairman certificate and perform their own condition inspections. Anyway, a lot of people took advantage of this policy.  A lot. Grandfathered ELSAs comprise almost half of the total number of Light Sport Aircraft. Until about 2019, they actually were in the majority—51.8% in 2018. In 2022, their portion of the fleet had dropped to 44%, but they still comprised over 70% of the ELSAs. Why is this significant? Because the Grandfathered planes hadn’t been required to comply with the ASTM consensus standard. For that matter, they weren’t required to comply with the E/A-B “51% rule,” either. Grandfathered ELSAs came into existence with the least possible regulatory interference. Any guess on how that affected the fleet accident rate of “Light Sport Aircraft”?  You might be surprised.

Tallying the Accidents

We’re almost there. The last step is to identify the accidents that involved aircraft licensed as Light Sport. It’s “semi-easy” for E/A-B aircraft. The NTSB database includes a flag for Amateur-Built. It’s actually not that accurate; every year, I eliminate about 15% of the Amateur-Built-flagged accidents as they occurred to aircraft that were not licensed as E/A-B. In the same sense, I add about 5% to the  tally due to aircraft that didn’t have the Amateur-Built flag set, but were obviously E/A-B. The problem is, there isn’t any such flag for Light Sport Aircraft. One solution is to search for the term “Light sport” in the NTSB accident narratives. I found about 250 accidents from 2005–2021 using that phrase. The problem is, that method isn’t reliable, either. I found a number of cases where the airplane was stated to be a Light Sport but a check of the registration showed it as an Experimental/Amateur-Built aircraft. Remember, the NTSB investigator wasn’t wrong. The aircraft did meet the Part 1 definition of Light Sport; it just wasn’t licensed as a Light Sport. The only way to find the accidents was to cross-reference the NTSB accident database with the FAA registry of aircraft licensed as SLSA or ELSA. I found about 950 total accidents involving aircraft licensed as Light Sport.

Results

Figure 3 summarizes the annual fleet accident rate for Special Light Sports, Experimental Light Sports and Experimental Amateur-Built aircraft. ELSAs come out the best. Kind of surprising, isn’t it? And remember, almost three-quarters of the ELSAs are minimally regulated Grandfathered ELSAs. Why is the rate for ELSAs so low? A couple of things come to mind. First, the majority of the airplanes licensed as ELSA prior to 2008 had already been flying as ultralights. First-flight accidents occur to about one in 150 homebuilts, but these preexisting fat and two-seat ultralights had already been through their infant mortality period. They had less of a chance of mechanical failure. The pilots already had experience in them, too—fewer chance for bumbling the first flight. Second, most of these airplanes were glorified ultralights, even if they exceeded the Part 103 limitations. They weren’t flying all that fast, and ultralight pilots are probably a bit more accustomed to fixing bent tubing without making it a (literal) federal case. Unless injuries are involved, many Experimental pilots have proven reluctant to report their accidents to the NTSB. Third, the certification of new Grandfathered ELSAs ended over 15 years ago. Beyond 2009 or so, there were no Grandfathered ELSAs making their first flights or undergoing the Phase I test period. In comparison, almost 13% of all E/A-B accidents occur during the first flight or the test period. Finally, realize that Figure 3 shows the number of accidents divided by the number of registered aircraft in a given year. It does not reflect the flying time of the aircraft involved. The 2021 FAA General Aviation Activity Survey says that Special Light Sport Aircraft fly, on the average, more than twice as many hours as Experimental Light Sport Aircraft. After all, the whole intent was to produce a new series of trainer and rental aircraft. When you account for the fact that the SLSAs are flying twice as much as the ELSAs, it appears that on a per-hour basis, the accident rate for the two are very similar. It’s still a good reflection on ELSAs that the per-hour accident rate isn’t much different than the LSAs sold ready to fly.