Mazda Fatality

Discussion in 'Mazda Rotary' started by TXFlyGuy, Nov 13, 2016.

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  1. Nov 15, 2016 #41

    TXFlyGuy

    TXFlyGuy

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    You would be correct. Anything that is man made, and mechanical, can and will fail. In my 25,000 plus hours of flying, never had an engine quit. I had a VW engine in my car that swallowed a valve...that was catastrophic. But it was my fault due to improper valve adjusting. Also, had another VW engine quit. It again was my fault due to lack of oil.

    In off field emergency landings, Titan recommends to "belly in", leaving the gear retracted. This plane has a strong tendency to flip over on it's back on rough fields. The crash photo below was non-fatal, and was the result of engine failure (Honda).

    dekalb-plane-crash-12111.jpg
     
  2. Nov 15, 2016 #42

    rv7charlie

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    Well, I just typed and then deleted a fairly long rant.

    Let's just say that the way you titled and opened this thread is both inappropriate, and when discussing safety issues, an obvious misdirection.

    Your last couple of posts just make it worse.

    Charlie
     
    Last edited: Nov 15, 2016
  3. Nov 15, 2016 #43

    Vigilant1

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    So, T-51s with piston and Wankel engines have crashed. We don't yet know that the Wankel engine was the cause of the apparent power loss (could have been a PSRU, ignition coil, etc). Is the last line quoted above trying to make the point that the Wankel engine was somehow responsible for the fact that this particular off-runway landing was a fatality? That the Wankel engine caused this poor guy's head to hit the instrument panel?
     
    Last edited: Nov 15, 2016
  4. Nov 15, 2016 #44

    TXFlyGuy

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    If the engine kept running would he be around today?
     
  5. Nov 15, 2016 #45

    rv7charlie

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    We're wading off into territory that is way past inappropriate, so I'm not going to answer that. But if you truly believe what you just wrote, you're a danger to yourself and anyone willing to listen.
     
  6. Nov 15, 2016 #46

    narfi

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    hehe this is like watching the unbiased reports from the ethical and unbiased american media........

    Prayers and condolences to the family.
     
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  7. Nov 15, 2016 #47

    TXFlyGuy

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    Yes, I honestly think that had the engine kept running, the pilot would be with us today.
    While the engine stoppage may not have been the sole factor, it certainly was a major contributing cause to the accident.
     
    Last edited: Nov 15, 2016
  8. Nov 15, 2016 #48

    Vigilant1

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    Does anyone know for sure why the seat (or at least its back) doesn't appear to be present in the pictures we've seen? Removed by the rescue crews in getting him out, or did it come loose during the forced landing? And, did anyone answer about whether the shoulder harness in the T-51 is attached to the seat or directly to a structural frame element? Did the CAA release information on whether the pilot was wearing his shoulder harness?
    In an accident, there's seldom a single cause. Lots of GA airplanes have forced landings, but in a plane that stalls at less than 50 MPH, flown by an experienced pilot, and which apparently landed under control on a flat surface and hit no rocks, trees, vehicles etc and in which the crew compartment appears to be largely intact-- well, a fatality is unexpected.
     
  9. Nov 15, 2016 #49

    BBerson

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    I think quite a large percentage of takeoff engine stoppage is from the fuel selector in off position.
    The reaction time must be rapid to avoid the stall pitch down from the nose high climb. Many pilots will delay or freeze.
     
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  10. Nov 15, 2016 #50

    bmcj

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    I don't understand why this hss become such a hot debate. The title may be a little misleading, but many titles are a little off the mark here and it's not until we read the subject matter that we understand what really happened. There are several things to look at and this one is the design and how it handles forced landings, another is the engine and possible failure modes. There simply is not enough information at the present to draw any conclusions, which makes this contentious discussion pointless. We should step back, take a breath, and talk about this like HBA brothers, not adversaries.
     
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  11. Nov 15, 2016 #51

    ScaleBirdsScott

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    The seat looks to still be there. In any case without more information it's hard to say what's going on.

    The Seat back is an integral part of the welded airframe. I'm not in any position to say for sure, but I doubt that is going anywhere either during or after a crash without some dedicated cutting tools.

    Copy-of-IMG_1235-103476_725x480.jpg
     
  12. Nov 15, 2016 #52

    wsimpso1

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    It takes more than an engine failure over good terrain to result in fatalities.

    Implying that the Mazda engine killed the man does nothing to help the rest of us avoid whatever both caused the engine cut and what caused the restraints to not keep his head out the panel. There are so many sources for an engine failure, that dumping it all on engine type displays an attitude of ignorance that helps no one.

    Doing a failure tree for both the engine failure and for the restraint system failure seems to be in order by someone, hopefully the CAA. A failure tree is a disciplined approach that results in a list all of the ways that the event can occur, starting with, in this case, abrupt engine failure. Then there is a branch for each major category, then each major category has all of its sub-categories. The accident review and teardown produces evidence and eventually allows you to say if each place on the tree did or did not make for the accident. As the work progresses, you can always add more branches and sub-branches.

    Another method is to methodically tear down the accident vehicle searching for anything that is out of place. This method relies upon knowledge and intuition - it can miss important stuff.

    Billski
     
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  13. Nov 15, 2016 #53

    TMann

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    Those who are familiar with rotary (Wankel) engines know that they have very few catastrophic failures. I know of a builder who had the impellor of a turbo fail and the blade fragments were ingested into the intake of a rotary. He flew it home.
    They don't burn valves, throw rods, blow jugs, quit from overheating, blow head gaskets ...... and on and on.

    They will stop suddenly if they do not have fuel. My "GUESS" would be that this is a fuel starvation failure not a engine failure. The typical post crash investigation for accidents similar to this usually begin with a engine start-up to determine if that was a factor.

    This could be as simple as forgetting to remove a fuel vent cover, a poorly designed/implemented fuel system or lack of fuel.
    We had a guy here that put his plane down in a bean field shortly after takeoff. When asked what happened he said he ran out of fuel. When asked if he checked his fuel level prior to takeoff he said "I knew I was low but I wanted to buy fuel at a nearby airport because it was cheaper there."

    Continental, Lycoming, P&W Turbines, V-8 and Rotaries will all quit producing power in the absence of fuel.
     
  14. Nov 15, 2016 #54

    max_burke

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    Apex seal failure?
     
  15. Nov 15, 2016 #55

    Vigilant1

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    Unlikely.
    1) If quality apex seals are used, they very seldom break anymore. If he was using the normal aviation Wankel setup (adding a small amount of two-stroke oil to the fuel rather than depending on a metering pump and crankcase oil), then lubrication is highly reliable and buildup of residue in the apex seal "slots" is reduced--both of these improve the already-good reliability of the apex seals.
    2) If a seal does fracture, the motor generally keeps running. Bits of the seal will likely tear up the rotor housing and require some work, but the engine keeps making power. Likewise, a conventionally-built Mazda Wankel will continue to run for quite awhile even if completely dry of water (especially with the modern high-temp side seals).

    I like piston engines and fly behind one, but the Wankel design itself has better inherent reliability, as long as it is getting fuel, air, and spark. In use, it's the "other stuff" (PSRU, fuel starvation, electrical problems, etc) that tends to be the more important cause for loss of power, just as in piston engine installations.

    It's a bit early to speculate on the reasons the engine stopped when don't even know that it did.
     
    Last edited: Nov 15, 2016
  16. Nov 15, 2016 #56

    Victor Bravo

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    I agree with one or two of the previous posts about figuring this out... I believe that the ONLY good thing that can come out of discussing it here is working together and figuring out how this tragedy can be avoided in the future.

    Let's put our egos and differing opinions aside for the moment. Focus on finding what caused this crash, and this fatality. They are quite probably two separate problems. But fixing either one of them would likely have saved a life, regardless of which direction the good fortune came from.

    The Mazda rotary clearly has good potential as an aircraft engine, precisely because it physically cannot "throw a rod" or "grenade" like conventional engines can do when they do finally break. The Apex seals can leave the building, but my understanding is that this will not cause a catastrophic failure.

    But the fact also remains that the typical airplane or car engine really doesn't throw rods or swallow valves anymore (unless you're spinning it at 10K on a drag strip). Even the O-200 Reno race engines will run at well over 4000 RPM without shedding parts.

    The "usual suspects" on the engine side are the systems providing the fuel and ignition.
    The "usual suspects" on the pilot injury side are the pilot restraints, seat, and "crush zone" aspects of the airframe.
     
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  17. Nov 15, 2016 #57

    Billrsv4

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    If they used Mazda apex seals the chance of their failure is near ZERO. Mazda cured apex seal failures in the early 1970's. If the engine started, the apex seals were fine unless they weren't standard. These engines keep running if you can start them. A full engine stopping failure requires a lack of fuel or complete ignition failure. Remember they have dual ignition. If the trailing plugs fail you lose about 10% power. If the leading plugs about 25%. The engine wouldn't have stopped in either case. I have seen race cars that had the radiator punctured and the engine continued to run until he returned to the pits. The engine never ran again, but kept running until shut off. This is something we want in an aircraft.

    T.O. Bill
     
  18. Nov 16, 2016 #58

    Winginit

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    There are a couple of things that seem reasonable when analyzing this scenario with out any substantiated facts. The most likely causes are going to be fuel or ignition loss. While it's not impossible for the engine to mechanically fail, since it was just starting a takeoff, it most likely had not reached any critical overheating scenario, and most any mechanical problem probably wouldn't have gone from the ability to lift off and into full seizure mode in just a few seconds. That leaves fuel and ignition as the two factors that could cause immediate stoppage. If the engine had backup ignition, then the culprit would seem to be fuel related as the thing that could cause immediate stoppage. (I know this kinda simplistic but seems plausible to me) One other factor is I believe I read that the pilot was in his mid 80s. It is possible that he had a health trauma issue and simply closed the throttle as a reaction. Nothing else really explains why he was unable to just land rather than crash.
     
  19. Nov 16, 2016 #59

    bmcj

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    Another possibility that has not been mentions is prop governor failure, though I think that is unlikely if there are eyewitness reports of engine failure.
     
  20. Mar 22, 2017 #60

    wsimpso1

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    If you tear up one apex seal, two out of six chambers will be way low on power, maybe zero power, the other four (One chamber out of three on that rotor plus all three on the other rotor) will run just fine, the engine will make partial power, and will run until you shut it off. History exists for exactly this scenario in road cars, race cars, etc. There is a well known case of a highly boosted drag racing RX7 that ingested something, tore up and blew all of the apex seals on one rotor, the car finished the pass down the quarter mile, and then was driven home before they pulled the engine and tore it down... Apex seals are highly unlikely to cause a total power loss.
     
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