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LSA and VLA (merged)

Peter wrote:

This is off topic for LSA but I cannot possibly believe that.

Well, I don’t believe in “believe”, I believe in facts I have posted this before also, but here is the report from NTSB who have done a large study on this particular topic. These were the key findings:

The pattern of study results identifies several safety-critical issues that, if addressed, could improve the E-AB aircraft accident record and better prepare pilots to operate E-AB aircraft. Study results indicate:

The largest proportion of E-AB aircraft accidents involved loss of control in flight and powerplant failures, and loss of control in flight has been the greatest contributor to fatal E-AB aircraft accidents.

More than one-half of the E-AB aircraft accidents investigated in 2011 were aircraft that had been purchased used, rather than built by the current owner.

A large proportion of accidents occurs early in the operating life of a new E-AB aircraft, or shortly after being purchased by a new owner.

During 2011, more E-AB aircraft accidents occurred during the first flight by a new owner of a used E-AB aircraft than during the first flight of a newly-built aircraft.

The most common accident occurrence for first flights of both newly-built and newly purchased aircraft was loss of control in flight.


As a group, the E-AB accident aircraft did not experience a large number of structural failures or problems related to the strength of a particular aircraft‘s structure. Rather, the occurrences of aircraft system and component malfunctions and failures were most often associated with non-structural systems and components and were typically unique to the accident aircraft.

Peter wrote:

I’ve read loads of pretty horrible and unusual homebuilt (in Europe, “experimental” is basically homebuilt) accident reports e.g. in-flight fires due to a fuel hose made of the wrong material. And this was from the UK, where some LAA inspector supposedly inspects and flight tests the plane every year. In most registrations nobody checks anything so you are relying totally on the builder (or whoever bought it from him) being technically savvy.

If this is true, and not some “believe”, this points to a major problem with the LAA. In most countries the experimental homebuilt aircraft “reports” directly to the CAA. I am not allowed to fly without the CAA doing an in person inspection of my aircraft. But, fuel related problems are also mentioned in the NTSB report. It is one of those things that are very easy to do wrong, but also very easy to fix and do right. It is not a major thing, just old fashioned sound engineering that any person with a minimum of technical knowledge or experience is able to do right the first time, from scratch. Problems arise when people with no technical experience try to reinvent the wheel themselves.

LeSving wrote:

If the above is wrong, and anyone can certify new stuff for the aircraft through EASA, then it is a different scenario of course.

Of course anyone holding a DOA or an ADOA can certify changes, just as on any other certified aircraft. And when the 912iS is certified in the Lightwing AC-4, you can reinstall another 912iS, complying to the AMM. Just the 912iS itself does not need to be certified and the certification of the 912iS in the AC4 doesn’t make it a certified engine, so it has to be certified again in combination with another airframe.

mh
Inside the sky.
EDXE, EDXF, Germany

LeSving wrote:

Well, I don’t believe in “believe”, I believe in facts

Well, if the biggest chunk of experimental aircraft fatalities are loss of control inflight and powerplant faliure, it suggests that peter is right. After all, flight characteristics that lead to an easy loss of control are a design or build flaw and cannot be subsumized easily under “pilot error”. Certification grants a controllability by a mediocre pilot in any certified flight condition. Experimental aircraft don’t. They may very well fly great, as with the RV designs or the Sonex, but those are vastly built and tested by the builder-pilots and their feedback go back into the the design updates for later kits. But this isn’t the case with all experimentals and, further more, as I said the pilot/operator/owner must be either tech savvy or have blind faith, because there is no independent unit checking the claims and whether the aircraft complies to the regulations.

Anyway, this isn’t part of the LSA discussion, perhaps Peter should move these posts?

mh
Inside the sky.
EDXE, EDXF, Germany

mh wrote:

Of course anyone holding a DOA or an ADOA can certify changes, just as on any other certified aircraft.

Then CS-LSA is indeed vastly better than the US-LSA. Now, if they only could allow aerobatics… One has to wonder though, what makes a Rotax 912 ULS “certified” in one airframe but not in another? Is it all to do with maintenance? What if I get an old, say 1000h used engine from a microlight and put it in a LSA? Will that engine suddenly become certified?

It’s not totally different from the way experimentals are handled (outside US). The aircraft gets a certificate of airworthiness, but a larger modification, like changing to a different type of engine requires new tests (by the pilot/owner) and new certification. There are no DOAs involved though. DOA = Design Organisation something?

mh wrote:

After all, flight characteristics that lead to an easy loss of control are a design or build flaw and cannot be subsumized easily under “pilot error”.

I disagree. If you are not able to fly the aircraft, the error is with the pilot. Easy loss of control is only easy if you don’t fly it right. A notion that everything should fly and behave like a C-172 is not very meaningful for an aircraft that is exclusively built for private use, mostly as a hobby or recreation. It’s equally meaningless as saying that a motorbike should be as safe as a car, or a fast regatta sail boat should be as easy to handle as a family motor sailer or something. It makes no sense to me.

LeSving wrote:

If you are not able to fly the aircraft, the error is with the pilot.

I agree. For example I’ve chosen the Europa Trigear over the Monowheel-variant because the latter is quite challenging in ground handling. I didn’t want that as the average-pilot I would count myself to. But there’s nothing wrong with the Monowheel in more capable hands.

EDLE

LeSving wrote:

If you are not able to fly the aircraft, the error is with the pilot.

Not necessarily. If you fly a proven design, yes, but if an aircraft leaves you in an uncontrollable situation, or one where you need too much workload to control the aircraft while tangling other problems, it might as well be a design flaw. Just claiming that loss of control is always just a pilot error is too lazy and might disguise deeper problems with the design. The Smaragd/Peregrine comes to mind…

LeSving wrote:

One has to wonder though, what makes a Rotax 912 ULS “certified” in one airframe but not in another?

The engine is still not certified, but it is certified to be used in the specific airframe.

Last Edited by mh at 26 Apr 11:12
mh
Inside the sky.
EDXE, EDXF, Germany

Peter wrote:

I’ve read loads of pretty horrible and unusual homebuilt (in Europe, “experimental” is basically homebuilt) accident reports e.g. in-flight fires due to a fuel hose made of the wrong material

Do you have any further details (registration, AAIB report etc.?) My search has so far brought up a lot of Boeings and Airbuses catching fire, but no homebuilts!

I note that LAS for instance sells some clear tubing as fuel pipe for permit aircraft (and that stuff won’t go anywhere near my aircraft!) – I’d be curious to see what material it was made from and what the fuel type was and how long the aircraft had been in use. I’ve had my own problems with avgas rotting flexible fuel lines from the inside out that were supposedly reinforced (although the fuel line in question – aft of the firewall – had probably been there for a while).

Last Edited by alioth at 26 Apr 13:55
Andreas IOM

One I recall had a rigid aluminium fuel pipe which cracked under vibration, came off, and the fuel caught fire. Maybe 5 years ago? Fatal.

I know about the clear tubing. That is evident in a variety of homebuilt kits. Lancairs use it for example (as of about a year ago) for brake hoses at least. A Kitfox I saw was full of it. The fittings are also really sh1tty. Given that even a Rotax 912 costs some five digits, I cannot understand why safety-critical stuff like this is so cheap and crappy. We did this here before quite a few times and RVs seemed to use the proper stuff.

Back to LSA, what would be the motivation behind Rotax wanting a VMC-only limitation? I do not believe product liability is anywhere near as big as is often claimed, but if you take out IFR you remove all kinds of other issues and not just flying into terrain. You make yourself un-suable for just about any loss of control incident.

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

One I recall had a rigid aluminium fuel pipe which cracked under vibration, came off, and the fuel caught fire

That’s interesting – quite a few certified aircraft have firewall-forward rigid alu fuel lines (my old Cessna 140 being one example). I don’t recall though if it was rigid all the way to the carburettor, but it does stick in my mind as we had an AD to comply with that involved this rigid fuel line (basically, installing a metal shield around the pipe).

Andreas IOM

Peter wrote:

what would be the motivation behind Rotax wanting a VMC-only limitation?

Where exactly is that stated?

EDLE
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