Mandatory TBO

[Towner]

I'm looking at buying a 2006 CTSW. Currently has 1500 hour and 12 year TBO. Because of the 12 year TBO, can it still be flown with a condition inspection? I saw prior posts regarding this topic, but I'm not sure I found an answer. 

Thanks, Jeff

[GrassStripFlyBoy]

Welcome to the group, and as an '06 owner for a bit over a year now I'll share it is a wonderful airplane.  The performance / endurance / fun factor / costs make the CT's hard to beat, I'm still wiping a grin off my face every time I fly it.

The question on TBO has two viewpoints, and you won't find a more divided topic around here, which is both strange and unfortunate as the forum intelligence more often can ferret out an answer fairly well established both in reason and fact.  I've watched these discussions over past posts, and can see both sides, my take is that one can legally proceed beyond the 15 year TBO.  I won't even begin to explain why I have that opinion - it's all based on the forum posts and documents that are attached.  In the end, it will largely depend on the view of the A&P you use for the CI.  Or, as I did, convert to E-LSA which is not difficult and then it's crystal clear.  If going E-LSA category is not appealing, understand you can still take it to A&P for the same CI, maintain it to the same level of S-LSA, and not do a thing different.  Not wanting to explain a whole lot on E-LSA, (there are many posts on that topic), I am a huge fan of what that affords one in these aircraft however you choose to maintain the airplane.  And if you're handy, take a 16 hour class and you're doing your own CI's.

On another note, the '06 you're looking at (only one & low time on market now), was listed on ebay about a year ago, time and time again without sale.  I've seen the price come down and this plane list on aviation sites from time to time.  I would not have major concern on the low time over the years, but as Dan just discovered in buying a similar low time CT, the service bulletins and such were a bit behind current.  Looks like a sweet CT, hope it works well for you.

[Roger Lee]

Read attached

TBO....willette-dodgecenteraviation - (2013) legal interpretation.pdf FAA and the TBO.pdf

[Towner]

I appreciate the quick response from both of you. After researching the topic until 3 am last night, I think I've made my opinion on the TBO topic. A lot was based on Roger's previous comments in prior discussions, so special thanks Roger!

Now some follow up for grassstripflyboy! If it is the same airplane, I reviewed the logs and a lot of the entries were of the "rubber stamp" style. It did not show a lot of the service bulletins entered. I have agreed to spilt the cost of an annual with verification of all service alerts and service bulletins complied with. If a major expense is found,, the annual is to stop until discussed with me. Should this resolve my problem? I'm in California and the plane is being sold from Ohio, so I'm limited on what I can do from here. Any suggestions would be appreciated! 

[Tom Baker]

I would think that should be sufficient as long as the airplane inspection is done by someone familiar with a Flight Design. I recently worked on an CT that had an inspection and major maintenance performed by a shop that didn't know what they were doing, and the shop made the airplane completely unsafe. When I started digging into issues the airplane was facing an imminent failure. 

[MEH]

Engines do quit.  Before AND after TBO.  If the engine were to quit, the FAA will investigate.  The guidance they give their Aviation Safety Inspector regarding beyond TBO ops on certificated aircraft is here:

https://fsims.faa.gov/wdocs/8900.1/v03 tech admin/chapter 64/03_064_002.htm

Thank you, Roger, for linking the FAA opinions regarding the official position on S-LSA "mandatory" TBO. The bottom line is that beyond TBO ops are allowed, BUT it will go well with you, should you have an incident, if you can show that you are going the "extra mile" to make sure your beyond TBO engine was healthy.  Namely, record your cylinder borescope findings in your annual logbook entry.  Submit oil for analysis at every change and keep a folder of the results. Record oil consumption, if only in your own records (the oil analysis provider I use records the oil analysis I tell them on their report).

By showing that you are going the "extra mile" you are not only doing everything you can to assure the engine health but you are demonstrating to those who care, that you made the effort.  Stuff happens anyway.

PS: For all of you who are not performing a borescope cylinder inspection, please read Mike Busch's book "Manifesto: A Revolutionary Approach to General Aviation Maintenance".

[Towner]

Thanks for this information. Thankfully, my mechanic does a thorough documentation and if I explain this to him, he'll make sure it's covered. Good information to know up front. 

[Roger Lee]

Hi MEH.

The FAA ask the insurance companies on their TBO stance. The insurance companies said they would go with whatever the FAA said.

Plus all mechanics should be using a checklist and you should keep it all signed off and annotated in the margins on everything they did. This is what protects you and the mechanic and shows due diligence. 

 

[Madhatter]

While exceeding TBO is not a legal issue there might be something else to consider. Aircraft engine companies will take their TBO's to the max reasonable limit they can get away with. I know this because I was one of the test cell engineers that did this testing. Some of the things I had to do give me a different perspective. There are reasons for a TBO. Not all engines will have failures but some will. Competition among engine companies is fierce. I personally do not exceed TBO on my engines. It always costs money to own and fly aircraft and engine integrity is primary to me especially for night operations.  Again just my opinion. 

[AGLyme]

About a solid perspective as we are all going to get.  Thank you.

[Jim Meade]

Fundamentally, TBO is based on a presumed condition after so much time, so many operations, such and such an environment, how much liability the company is willing to take, industry practices and existing regulations and such.  Material hardens, leaks, rusts, wears and so forth.  Let's cover it all with a date and quit arguing about it, the manufacturer will say.

I prefer to maintain my aircraft based on my inspection of actual conditions.  Age, number of operations, environment and such are considerations in my inspection which focuses on observable and demonstrable physical properties.  Borescope inspections.  Gaps.  Flexibility.  Leaks and seaps.  Minimum and maximum tolerances.

The manufacturer has no incentive to endorse my physical inspection in lieu of it's TBO.  I have only modest incentive to defer to a manufacturers TBO which is based on many issues in direct conflict with my objectives.

The military and airlines are using much more inspection by condition than is GA.   We're in the dark ages.

 

 

[Madhatter]

Everyone has their comfort zone. You can't see metal fatigue for the most part. You can't boroscope the 912 crank assy without engine disassembly. Yesterday I boroscoped a T28 engine with a very expensive boroscope because of a low fuel flow takeoff. Even with the large cylinders and extra lighting the inspection is inconclusive. I will have to remove at least the typical high egt cylinder to inspect for detonation. Sometimes you just can't see things. Turbine engines are much more setup for boroscopes. But that's just me.

[Madhatter]

I want to clarify one thing. As for calendar time I have no issues. The 912 is one of the least subject to corrosion that I have ever seen. No direct crankcase breather and extremely tight piston to cylinder wall clearance among other things. 

Also I am not criticizing anyone for their opinions and practices it's a free country (at least for now) but I am very anal about some things for myself. Some may do very well with their practices. I have been around a long time in aviation and have seen a lot of bad things happen, some who were friends that made the ultimate mistakes.

 

[FlyingMonkey]

I believe the Rotax 912 TBO numbers to be fairly conservative.  There are many out there flying well past TBO, and when Rotax had their contest to find the highest-time 912UL/ULS engine out there without an overhaul, the winner was a flight school (engine probably not babied) with over 6000hrs, 3x TBO.

None of the above means an engine won't spin a bearing or crack a rod at 500hrs, shit happens.  But it indicates reasonable safety right up to TBO in general; far greater IMO than the typical Ly/Con (Lie/Con?) engines that rarely make 1/2 TBO without needing at least one cylinder replaced.

My engine has 810hrs on it, and it still runs like new and shows no indications of premature wear.  Once my engine hits 1000hrs, I plan to do periodic oil analysis on it, maybe every other oil change.  If the numbers look good and continue to do so, and it acts the same as always, I'll run it until something changes.  I don't think I'd run it 4000 hours, but I have a long time to think about that...and by that time it might be time to hang up the headset anyway!  At the rate I've been accumulating hours, I have another 9 years to get to 2000 hours, and that will put me at 63 years old.  4000hrs will have me at 78 years old!  And that's if my flying doesn't slow down at all, which I'm sure it will.

 

[Jim Meade]

Remember that the cylinder replacement on L/C engines is often based on old standards that have been challenged as unrepresentative of actual conditions.  Compression checks are one case in point. 

[ct9000]

Andy when I was in my 30's 50 was old and at 50 70 was old. Now at 66 making 78 does not seem old at all. Why not make it an aim to reach 4000hrs. then plan to change the engine.

[GlennM]

@Madhatter

Which test cell?

[Madhatter]

Avco Lycoming,  Teledyne, and GE

[AGLyme]

2 hours ago, Madhatter said:

Avco Lycoming,  Teledyne, and GE

Very cool.  Quality Dept is at the heart of every excellent aero business plan, not the CFO’s office.  Reading you comments amount Rotax’s depenendibilty is good.  Lucky to have you here on the board.

[Madhatter]

At that time I was just a new engineer low on the totem pole. I got along better with the union guys and technicians on the floor than the management. I think I learned more from the  guys on the floor, they seemed to have more common sense and were easier to get along with. I don't do well with upper  management. GE was the worst company to work for but they had the best engine. It was a long  time ago.

[GlennM]

I worked for Pratt and Whitney testing primarily military engines like the F100, F119, and F135.  Now, I work for Siemens Energy testing gas turbines for power generation.

[GlennM]

My dad was a mechanic for Pratt and my grandfather was a sheet metal mechanic for Pratt, so I understand listening to the guys actually doing the work.