12 year mandatory overhaul

[Runtoeat]

I understand the need for a "legal" opinion is what we seek here and also am aware that this will probably not be realized.  I also understand there are probably as many non-legal opinions as there are FAA administrators.  Although I respect the expertise of Doug and Roger, and all others who have years of experience and training, my limited experience and lack of formal training servicing aircraft dictates that I use the best advice available to me in order that I am confident I am maintaining my CT properly.  I've serviced my carb float bowl and personally I'm confident that I can repeat this without any problem and so is my A&P who oversaw this.  So, where does this leave an owner, such as myself?  Although not binding, Mr. Stumpner's response indicates, to me at least, there is someone who, as far as I know, might be part of the FAA's "judge and jury" of me in the future, might I perform a service on my aircraft which could have bad results.  Perhaps the direction I need now is to see a response from Roger's FAA contact which supports this as being a preventative maintenance item?  At least this would provide me with a good argument if I might get "the call" someday from the FAA.

Roger and Doug, thank you for taking the time you've taken on this issue.  It is a great learning experience for me, and hopefully other non-technical persons.  Perhaps, it may even be a learning experience for the FAA too after the dust settles?

[Anticept]

My own opinion is this:

If you're in a field somewhere, you probably have bigger problems than just carb debris. But if you really need to get out of there, say you landed in a place where the nearest person is probably 300 miles away and it's either too cold or too hot to survive for long, then emergency owner maintenance is 100% fine. As Doug said though, document it and get someone to look at it at the first safe place to get it all kosher and legal again.

I recognize that regs are often inconvenient. They don't easily account for people's true abilities. There are pilots who can turn a wrench better than me, and mechanics that should never be allowed to touch a screwdriver in their life. But the vast majority of us sit somewhere in the middle. Statistically speaking, trained individuals are more capable than untrained. There are things that need to be done in the course of repairs that are not immediately obvious without training and experience, such as the need for a good eye to spot the real issue is vs what you think the issue is.

So what I am getting at, is err on the side of caution. Consider the fact that you lived through the failure. Carb debris had to get there somehow, and maybe that's a symptom of the REAL problem. Your next leg after your emergency field repairs might put you 6 feet under.

It's a pain in the ass, I get it, but if you ended up in a field, please call a professional if you yourself are not one. I do not recommend trying to save a buck or regain a bit of convenience. The knowledge you gain in Roger's video is great to have, I do not contest that, but I can tell you this: after carb debris causing an engine to stop, I'd be doing a lot more investigating than just cleaning a bowl to be sure.

[Roger Lee]

Van was out today and waiting to hear back from him. 

The other thing is no one said this video was for CT's, SLSA , mechanics or the tens of thousands of experimentals out there. Someone here thought it was only for  CT's or SLSA owners.

It's just an instructional help video just like you find on the Rotax Owner forum.  No one has said a word to them  for their self help videos and this video here was first posted there. You get to pick and choose what you do depending on your rating

Few have a good understanding about where carb debris comes from and or when it is likely. Carb debris from a hose change has not brought down any aircraft that I have seen in any documentation. The FAA agreed. I did talk to them today just not Van. Carb debris usually affects one carb at a time and not both at once.  Experience has shown that what happens is if the pilot is at 5200 rpm then the rpm just gets reduced to about 4K+. It hasn't shut down any CT's engine.  It just restricts some fuel flow, but not all of it. If you can show me any data that a hose change carb debris has brought down an aircraft I'm all ears. Not a single person can ever guarantee a 100% that this will NEVER happen. First it usually happens from someone doing a hose change that does not know how to be more sterile. Then it has filters along the way. The first filter for at least the CT is in the instrument panel and you can service this as a pilot. The second filter and sediment bow for debris and water is the gascolator. You can service this as a pilot. The third filter is in the fuel pump internal filter and isn't really serviceable. If you know how you could. The last sediment bowl and water basin is the Bing 64 carb bowl. It was designed with this very purpose in mind. The only hose that can get debris to the carb is the short 1/4" pressure hose off the bottom of the fuel pump that goes to the carb cross over tube assembly. All Rotax mechanical pumps have this internal filter. Experience has shown that rubber carb debris is usually limited to a piece or two and usually within 15 min. to 5 hours of run time at after the hose change and at high rpms to show up. Usually once the offending piece of rubber gets dumped most times that's it.  Mechanics that crush the end of the hose with a clamp over a barbed fitting cutting the inner liner can get more and those are easy to spot because the hose looks crushed under the clamp. (Must have been an A&P )

I had a CT owner today at the hangar. He just had a hose change and went out for a test flight today before heading home on a long cross country back home.  After the flight we popped the top cowl off to check for any carb debris and leaks.  I showed him how to do the carb like in the video and he did the other. No debris in his carbs. He said this is easy. I said it was because he wasn't an A&P.  Removing the cowl, disconnecting the light and or intake hoses is more complex.

If you know anything about a Bing 64 carb internal bowl design you know this was designed as the last water and sediment collection basin / filter. There's the deciding factor according to the FAA. The design makes this non complex and the fact that it is a sediment / water basin coupled with the ease of inspection with just a bale like the gascolator puts it in a different category. The key here is you change no settings and do not disassemble the carb, but  pull back the bowl bale which is acceptable.

 If you had to do any dismantling or carb calibration during this then it becomes another animal for the higher rating rule. Rules are rarely one size fits all. 

Hopefully I can get a hold of Van tomorrow. Once explained in full my bet is he'll be on the same page as others.

[Tom Baker]

Roger, I am aware of one CT that was brought down from hose debris. It was not in the float bowl, but rather in the fitting at the inlet to the carburetor. The engine doesn't run to well with just fuel in the 2/4 side carburetor. 

It was on a return flight from maintenance, but the maintenance that was performed could not have caused the debris. No fuel lines were replaced or opened during this maintenance event. It had been 2 years since the rubber replacement ( which I did not perform) and one year since the fuel pump was replaced.

The airplane landed on a road without incident. It was retrieved, inspected, the 1/4"line replaced and returned to service. There were no reports filed. I suspect that the 1/4" hose from the fuel pump to the splitter was some of the hose from CPS that was suspect in some of the other debris instances, but I don't know for sure.

[Doug Hereford]

Forum,

I never said that I thought that the video was aimed at any specific certificate of aircraft or airmen. It is obviously aimed at anyone who watches it and subsequently becomes "stranded" in a 912 equipped aircraft. Like I said before, I found out about this video through a customer of mine who saw it and said that he would use it if needed. He obviously thought it pertained to him. He is a non-mechanic, non-repairmen flight instructor and the aircraft is an SLSA. I did not even know who's video it was when I first saw it. Only after watching it a couple of times did I notice the name. I was just astonished by the context (not content) of it. I have watched numerous Rotax maintenance videos and find them to be very informative, but I cannot recall one that illustrates a maintenance procedure to facilitate someone "self rescuing" after  an off airport landing.

I had actually kind of forgotten about the whole carb debris thing until I saw this video too, but the more I hear, the more concerned I get. My guys drain/inspect carb bowls at every condition inspection, and at the mid time oil change also. I was beginning to think that that was over-kill, but have changed my mind. Hearing about suspected bad hose out there is really concerning too. I am unaware of any safety directive or SB on that subject, but I could have missed it. If there isn't one, it sure sounds like the might be a need for one, especially if all these A&P's can't figure out how to install hoses correctly (a little sarcasm).

Corey,

If the environment is actually too cold or too hot to survive, should you really be performing any kind of work on an aircraft at all?  What does that environment look like exactly?

I hate to think that our maintenance culture has moved so far that landing on a road is not an incident all by itself, and that a self rescue video for pilots is an ok thing. On top of that, we have apparently got 180 degree opposing FAA positions on the issue, and by this time tomorrow, Van will be shown the light and realize that he too was wrong.

I would be less suprised if I wake up in the morning with my head sewn to the carpet (Christmas Vacation ref.).

[Anticept]

Doug: it wasn't really something I would ever really expect to see or intended to elaborate. But to entertain your question: you landed in a desert with no phone service and you are pretty sure you don't have a way to reach anyone, and you have an old ELT, so you can't count on satellites. These days such a set of scenarios is next to impossible to have happen, but for all I know you decided an early morning trip over the Sahara was a good idea in your rush to get home... The sun is rising and you don't have a lot of water with you.

The above obviously is such a stretch in the first place, but it actually isn't that far from possible in the US. Being forced to land in the Badlands in the summer is not a place that you have time to stand around and wait, and your airplane, white or not, is going to turn into an oven REAL FAST in the summer. It is unbearably hot and if rescue isn't close, you're going to get heat stroke really fast. In the cold at least you can keep shelter in your plane, but if you ended up there on a -40 night, you're not going to survive the night if you don't have things to bundle up with. When I flew over the Badlands, I kept a high altitude and made sure I was within glide distance of a road at least.

I am aware that going out in such weather could and probably will only hasten your demise. That's something that you or whoever else gets stuck in such a position to decide if it's worth trying or not.  Certainly worth trying in the evening or morning if you didn't get the word out for help...

Anyways, always try 121.5 . I would not doubt that there are more listening stations for the emergency frequency than everything else combined.

[Doug Hereford]

Where is the Tylenol? (Another Christmas Vacation movie ref.).