Has a NTSB Final been issued for N123SX?

[sonex1374]

Guys,

All engines fail, sooner or later. That is the hard truth, and if that frightens you, then aviation may not be your thing. To suggest that a failure is automatically evidence of a sub-standard design is preposterous. We can turn up any number of examples of engine failures in Lycomings, Rotax's, Merlin's, and even Atlas rocket engines, the most expensive ever developed. They've all failed. Every one. And to make matters worse, the history books are riddled with mysteries that were never solved as to why those engines failed.

We all want to make sense of this tragedy. Finding something to point at and label as the cause helps us get a sense of closure, and people desperately need this. But the reality in this case is that a cause, and closure, isn't likely coming.

Let's be clear, Sonex isn't hiding things from us. They're not covering up serious design flaws in the AeroVee. They have no incentive to do so, and in fact they have every reason in the world to uncover the cause. The fact that they can't does not mean they haven't tried, and in good faith. Accusing them of such is fear-mongering, and hurts us all.

[daleandee]

I was part of the fact-finding team, and had input into the factual report. (Some of which I do not specifically agree with, even after giving my input.) I was not part of the NTSB headquarters panel that took the factual report and issued probable cause determination. I am only reporting what I saw during the physical inspection of the wreckage. I do not make any claim to doing any analysis or cause determination.

It's OK for you to minimize your role in the work you have performed, but that doesn't change the fact that what you are saying and what the NTSB report says are not the same. So who are we to believe?

We did not find any physical evidence of a turbocharger failure, either partial or complete. I can not be any clearer than that. If you are not willing to accept my "eye witness" report of these facts, that's your problem, not mine.

I don't have a problem Joe. The problem is that the information being given by you and the NTSB does not agree. That is the problem.

Let's be clear. I said my bet would be that it's the turbo but admittedly that could be totally wrong. My point of contention was that the NTSB report clearly says, more than once, that the turbo would not turn yet you disagree with the report that says differently. On the 1st page of the final report and I quote:

The engine's turbocharger would not rotate

I can only report what I saw. I an not "responsible" for anything other than that.

Joe, I'm seriously not trying to be contentious but please try to see this issue from the bleachers where the rest of us are. It makes no sense for there to be no problem and yet there is this horrific tradgety. It cannot be that the entire NTSB team agrees that the turbo would not turn and state that in their report while you continue to claim otherwise. Did you as part of the "fact finding team" discusss your disagreement with the NTSB over your differences of the facts?

Dale
N319WF

[sonex1374]

Dale,

The damage to the turbo was caused by the crash impact forces, and only after the crash the turbo wouldn't rotate. The investigation notes and pictures of the turbo show that the damage to the housing was caused by the impeller wheel impacting it during the crash. The turbo would not rotate simply because it was damaged in the crash! The rest of the investigation showed no pre-impact turbo anomalies. The NTSB report could have been much better here, and Joe is trying to clear up any misunderstandings.

[MichaelFarley56]

For what it's worth, I would like to offer one small tidbit of information for the sake of this discussion.

This spring, my turbocharger was one of two customer examples that experienced the "coked turbo" issue which ultimately resulted in the issuance of the Service Bulletin. While that's a different story for a different thread (which we've all covered), I do feel this allows me to offer my insight on the performance of the airplane on takeoff with a seized turbo.

First, the good news is that the engine does in fact continue to run just fine if the turbo impellers aren't spinning. In fact, it runs so well that I didn't realize I had an issue until I applied takeoff power to start my takeoff roll. I do find this incredibly comforting on the hypothetical situation that, if someone were to loose their turbo in flight (which has never happened), the engine will still run fine and should offer sufficient power to reach an airport, or some improved location, for a precautionary landing.

On the other hand, I can tell you all from my own first hand experience (I had more than one aborted takeoff due to this issue) that, when attempting a takeoff with a seized turbo and the engine is swinging a 54" X 50" prop, you will only see around 26-28" manifold pressure and perhaps 2600-2700 rpm. Enough to land the airplane if you're up in cruise, but I'll be honest with you guys and gals...that's not nearly enough power to get a Sonex off the ground with any sort of climb rate. I operate out of a 4200' paved strip around the same density altitude as Oshkosh and, had I continued one of these takeoffs, I might have been able to barely get my airplane into ground effect, but that's only if I used nearly the entire runway. Even then I'd never be able to climb, and that's with just me in the airplane.

For a turbo AeroVee powered Sonex to depart an airport with two people on board (probably somewhat close to max takeoff weight) with 10 gallons of fuel on a 72F degree day and be able to even get off the ground, my personal feeling is that the turbo was working on the initial takeoff roll. Furthermore, I again speak from personal experience but having been in this situation, I can tell you that if the turbo isn't spinning, you know it as soon as the throttle is pushed in. Under normal circumstances, a turbo pilot may only push the throttle in 75-80% of the travel; with a failed turbo you will go to wide open throttle and not be getting any power or acceleration. Believe me on this...you know there's a problem well before you're off the ground!

Again this is just my two cents. I'm not trying to sway this conversation in any way; like all of you, I was really hoping the final report would offer more conclusive reasons as to what happened. I simply offer this information as my two cents....take it for what it's worth.

Thanks,
Mike

[daleandee]

Dale,

You just don't get it, do you.... The damage to the turbo was caused by the crash impact forces, and yes, after the crash the turbo wouldn't rotate. What's so difficult to comprehend about this? You seem dead-set on twisting the NTSB report around to insist that the Turbo wasn't rotating BECAUSE it was damaged. The investigation notes and pictures of the turbo clearly show damage to the housing by the impeller wheel impacting it.....as in impacting during the crash. You are confusing cause and effect here. The turbo would not rotate because it was damaged in the crash!

Instead of accusing Joe of incompetence or of covering up the truth why don't you show him some respect and listen to what he's saying. My money's on Joe, not an arm-chair mechanic.

No Jeff ... I don't get it and apparently you do not either as you are now twisiting what I have said. BTW ... what you said above is not correct'

the damage to the turbo was caused by the crash impact forces

because that is a direct contradiction to the report ... if you read it. From the report, and I quote:

It could not be determined whether the turbocharger would not rotate due to impact damage or whether it seized in flight resulting in a partial loss of engine power.

I'm not twisting anything Jeff. The report says clearly the turbo would not rotate while Joe says it would.

Then you ask me to show respect and you insult me by calling me an arm chair mechanic? I'm glad to see that it's OK for you to draw an in accurate conclusion as you did above when saying, " the turbo would not rotate because it was damaged in the crash!" and yet the NTSB report clearly says they don't know. Perhaps an apology is in order?

I have the greatest admiration and respect for you Jeff but please don't reply, insult me, and then state the facts wrong yourself. Go read the report again ... please.

Dale
N319WF

[lpaaruule]

Just an observation

I noticed in the picture of the mixture control, that right next to it is the button that activates the smoke system. I could imagine it getting bumped during a rush to grab the mixture control. It's in the off position in the picture though. It it were on for a second or so, maybe that's where the smoke came from?

Edit: I see that Joe stated in this thread a month ago that there was no smoke system in the plane.

[daleandee]

Dale,

The damage to the turbo was caused by the crash impact forces, and only after the crash the turbo wouldn't rotate. The investigation notes and pictures of the turbo show that the damage to the housing was caused by the impeller wheel impacting it during the crash. The turbo would not rotate simply because it was damaged in the crash! The rest of the investigation showed no pre-impact turbo anomalies. The NTSB report could have been much better here, and Joe is trying to clear up any misunderstandings.

I see you edited your original to make it nicer. I appreciate that.

For everyone concerned I'm gonna leave this alone as it's apparent that regardless of the facts of the NTSB report (trust me there are more concerning questions I have) there seems to be a great resistance to acually reading the NTSB report and speaking to what is there.

No doubt an answer won't be found but when the well known, long time members of this community start professing truths that are contrary to the stated facts of the report ... I'm done. I refuse to seek answers from those that aren't willing to search for them.

Dale
N319WF

[Direct C51]

So what's the plan here? keep selling engines that have an unknown flaw? Keep offering transition training in a fleet that has seen like a 25% failure rate? Forget about the B model, the jet, and any future projects. Shouldn't figuring out the flaw in your current product be absolutely paramount? It's not like this is a crank failure that has been identified and addressed. It's an unknown flaw and every Arrovee is possibly susceptible. Am I wrong in thinking this?

The Aerovee is a VW engine. VW engines have been modified for aviation use for going on 70 years or so. Lots of VW aviation engines have failed...with and without turbocharging.

Your suggestion seems to be to stop selling the Aerovee engine? What about alternatives? The Jabiru has had it's share of troubles and failures. The Corvair engine is noted for breaking crankshafts...at least they once were. Name an engine and someone has had a failure....Lycoming and Continental included.

Experimental aviation is a different breed of cat. You are the manufacturer and certify that the plane is airworthy. If you're not up to that then Cessna and Piper have some nice offerings.

Ok let's talk about the Corvair since you mentioned it. There was a history of crank failures. But you know what, the problem was found. It wasn't an unknown loss of the engine. It was a breakage of the crank. A fix was found. Add a 5th bearing and stop putting the starter on the back end of the engine. Show me one Corvair that stopped running for unknown reasons. Your argument is really moot here. The only similar instance I can think of is Zenith 601 wings folding. They couldn't find a cause yet they still issued a fix to resolve any problem they could foresee and there hasn't been a wing failure since. What has been done to fix the Aerovee issue?

Sure this is experimental aviation but it is the manufacturer of the engine that is in question. This isn't Joe Bob with his own modifications to the engine that are in question. It's the gold standard factory planes that have crashed. And not one but two.

[mike20sm]

Just an observation

I noticed in the picture of the mixture control, that right next to it is the button that activates the smoke system. I could imagine it getting bumped during a rush to grab the mixture control. It's in the off position in the picture though. It it were on for a second or so, maybe that's where the smoke came from?

I believe it was said that it didn't have a smoke system. I'm surmising that it was taken out when the turbo was installed and the switch was just left in the panel even though there wasn't a smoke system.

[WaiexN143NM]

Hi all,
Whew!! Ok everyone catch their breath. Lots of passion here. Passion for our planes, and community. Dale pls keep posting , all comments are good and gets peoples minds thinking. . Lets be nice , jeremy would not want discord.
Joe, can u please edit/correct your last post(page 7 6:08pm) all the highlighted comments are from dale, not from
Me.(WaiexN143NM) Just want to set it correct. I'll let dale take credit for his comments. Thanks.
Also joe, thanks for your input on the fuel state and valves. /compression. And the rest of the engine, was it dismantled further? Such as case halfs apart a look at the crank , camshaft, con rods , pistons wrist pins, pushrods, lifter bodies, gears, bearings?
WaiexN143NM
Michael