LSA Crashworthiness

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Life is full of moral dilemmas and compromises and here’s an interesting one: Does an airplane manufacturer-including an LSA manufacture–have a moral obligation to provide as crashworthy a design as technology and economics allow? The answer might be an easy yes, but then again, maybe not.I got pulled up short on this by Aviation Consumer reader John Valldejuli recently. Based on our favorable reviews of the Pipistrel Virus, including gushing a little about its fuel economy, Valldejuli checked out the airplane for himself. Here’s what he said: “Once I got into the pilot’s seat, I wondered who would buy this plane? To me, it is downright dangerous, as the main wing spar intrudes into the cockpit crossing just a little bit in front and above your head ( I am only 5 feet 9 inches tall). In a not-too-perfect forced landing, your head could easily be crushed by the impact with the main spar.” Between the lines, he was inquiring why I hadn’t noticed this in my review.The fact is, I did notice it, I just didn’t mention it. Why? It has to do with my peculiar background and experiences-flying and jumping out of airplanes, riding motorcycles and so on. Further, I tend to elevate things like speed and economy above safety and comfort, nearly to a fault. Because I think I understand the risks associated with these tradeoffs, I have a low expectation for crashworthiness in airplanes in general, but more so for LSAs. I think it’s all but inarguable that given the minimal structure in a 1320-pound airplane, it’s not reasonable expect it to be as crashworthy as a heavier Part 23 airplane. For me, crashworthiness in LSAs is not the same as for Part 23 aircraft. If you want an airplane as crashworthy as a Part 23 airplane, buy a Part 23 airplane.That’s probably an overbroad generalization because I suspect that some LSAs are more crashworthy than others. I just don’t have any meaningful data to rank these airplanes. But I think Valldejuli is correct. The Virus is compromised toward performance and safety, but that spar intrusion diminishes its crashworthiness in a way that other designs don’t. A basic principle of crashworthiness is generous flail space inside the cabin, so in a crash, your extremities don’t collide with something hard. Because of their cabin size, LSAs just don’t have the flail space of, say, a Diamond DA40 or a Cirrus SR22. In my view, the Pipistrel Virus may have even less because some of its speed comes from low drag and low frontal area. That translates to a small cabin whose crush and flail space is minimal.This is the very reason that Diamond declined to enter the LSA market. Diamond CEO Christian Dries is adamant that a manufacturer owes its customers the best crashworthiness possible and his airplanes have the unassailable record to prove that he’s not just talking the talk. Further, he thinks that with regard to safety in general, the regulators’ 1320-pound limit is artificial and sheer lunacy. I can’t argue the point. In a sense, Dries is on the same page as I am. LSAs and real crashworthiness may be mutually exclusive.By the way, Pipistrel doesn’t see it this way. The company’s Tine Tomazic told me he believes the Virus, with its beefed up A-pillars and spar cage and strong carbon fiber construction is actually more crashworthy than other designs. Pipistrel sees the spar intrusion as a net positive, protecting the occupants against a tree or other object slicing into the cabin. (I’d still pick the Virus as the LSA of year, by the way.)For me, the eureka realization in all of this is that I have to recuse my high-risk tolerance sensibilities and make a note to report such things as Valldejuli’s observation about the Virus spar intrusion. Doing so doesn’t condemn the airplane nor suggest that a buyer shouldn’t buy it. What it does do is illuminate a potential compromise that the reader can then evaluate guided by his or her own sensibilities.That’s about as direct a means as I can devise to say that it’s not just manufacturers who have moral responsibilities. So do journalists.Editorial addition 9/14/2012. What follows are the two texts mentioned above in their entirety. I did not include them originally because I try to get out of blogs in under 600 words. With these texts, it’s closer to 1700. These are routine editing decisions and not an attempt to smear anyone or suppress information.The context is this: I picked the Pipistrel Virus as the LSA of the Year. I picked the company as the Innovative Company of the Year. Nothing in the foregoing would make me reconsider that, but that’s not the same as companies and products being above criticism. Reader Valldejuli questioned my judgement, fairly I think, because his letter reminded me when I got into the Virus, I scuffed my head on the spar and when I got out, I did the same thing. Why didn’t I mention it in my report? Because it seemed minor to me and not worthy of comment. While I don’t share his view that it’s an unacceptable safety hazard, it is still my duty to make note of it. And that’s the point of this blog.Dear Aviation Consumer:I really enjoy your publication and find it well worth the money. However, I must disagree with you on a Gear of the Year choice.Flying a Piper Archer II, mostly by myself, I drooled over the gas mileage of your BEST LSA: PIPISTREL VIRUS. So I flew to the SLA showcase in early 2012 at Sebring, Fl airport to get a closer look at the Virus. Once I got into the pilots seat, I wondered who would buy this plane? To me it is downright dangerous as the main wing spar intrudes into the cockpit crossing just a little bit in front and above your head ( I am only 59). In a not-too-perfect forced landing, your head could easily be crushed by the impact with the main spar.I mentioned my extreme concern to the salesman who responded that, You lean forward in front of the spar just before impact… then I surmised the back of my head could be crushed as the indeterminate g forces toss my body – and head – around in milliseconds, seatbelts notwithstanding. I thought it a silly assumption that I could control where my head was in a uncontrolled crash with water or a fixed object like a tree. I surmised that not even a motorcycle helmet would save my life as my neck would be broken.In my opinion, this airplane would never comply with the safety portion of Part 23 certification, and it certainly does not meet the common sense certification. ( I can just hear fellow pilots at my funeral, Too bad his head got crushed, but he sure did get great gas mileage while he flew!)We as consumers must consider all of the possibilities – planes do crash land, both on land and in the water; and when they do, you may not be in control when you strike a stationary object or water as the g forces will be just too great. It is sort of the like the fool who does not wear his seat belt in a car because he thinks he can control how his body will react in accident. Anyone who has been in a bad accident knows the folly of that thinking – it is quick and with great force.New LSA airplanes are great and Viva la Innovation, but I have to thank Piper, the FAA, and Part 23 certification for really considering – and testing – the crashworthiness of my Archer II.John A. ValldejuliResponse from Pipistrel’s Tine TomazicWhile I am quite a bit taken aback by the tone of Mr Valldejuli, I am happy to comment on this.The cockpit design is made of Kevlar reinforced composites and the seat belts designed so that the head passes well below the main strut. I am 5 ft 9” myself and have never head an issue bumping into any structure. We have had serious crashes because of pilot error, and even there – none of the occupants bumped into the spar which Mr Valldejuli claims to be in front of his head. What everybody forgets is that your head is hinged to the body at the bottom of the neck – and not on the forehead. Hence in an impact, the head goes DOWN and not forward (you can see this in car crashes as well – this is why airbags are coming from the steering wheel, which is well BELOW the eye (forehead) level, and not from the windshieldsomewhere).Also, I am sure that there was a misunderstanding on what exactly the salesparson told this gentleman. It is common sense that you do not lean forward when the situation becomes an oh-shit moment! I do not know how the cockpit demonstration went for Mr Valldejuli, as I was not present, so I cannot directly comment on that. What is for fact is that leaning forward before impact is not our design principle behind cockpit safetyJFurther, because the spar is in the location of where it is, it makes the cockpit MORE safe, because an impact into e.g. a tree branch will be stopped by the spar and not fly freely through the cockpit into someone. You have flown the Virus, you saw where the spar is relative to oneself. When comparing the Archer II to the Virus – ever wandered what happens when the aeroplane rolls over on ground. It is one of the most typical crashes, e.g. nosewheel brakes off then the nose dips into the ground. Archer has no roll cage (like Virus, Panthera, even Taurus in our case), but the occupants heads would simply be squashed. Is that what makes an aeroplane so great?I am not saying our design is perfect, but there definitely was a lot of thought in its execution and keeping everybody safe. We have not had any deaths related to accident head trauma, and people were involved in ditching, even crashed into a mountainside in a white-out situation. In our view, we view our cockpit design safe, in fact, much safer than most aeroplanes. When strapped in, you are sorrounded by Kevlar reinforced element and energy absorbing zones from all sides, with the main spar protecting you from above (roll over), the A-pillars/spar cage (forward impact), undercarriage uni-element design (below) and collapsable fuselage ribs (behind).To put things into perspective: On thanking FAA and Piper for the crash tests – Crash test for small general aviation was imposed by the FAA with the The Dynamic Crashworthiness Requirements detailed in FAR23.562, first issued in August 1988 as part of the FAR-23 document. This was then further explored during the NASA/FAA AGATE program in mid-1990. My point here is that the Archer I (certified 8 July, 1975), which Mr Valledejuli references, was NOT even tested for Crashwortniess, despite his claims.Thank you and best regards,Tine.

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