Rotax 100hr Maintenance Question

[FlyingMonkey]

Recalling what I know about "dissimilar metal corrosion"...

 

...best to point out that not just any washer will do!

 

Nylon or fiber washers should be good.  

[FlyingMonkey]

Roger,

What I am trying to say is that in my opinion, the wing inspection is part of the aircraft Condition inspection "procedure". Not pulling the wings and inspecting them at every Conditon inspection is (in my opinion) an incomplete aircraft inspection. This is how I keep coming back to the fact that SLSA aircraft only have ONE required inspection. We as inspectors, "have to make it count", so to speak. Whether any of us likes it or not, this is the system in the country. FD has not been made to understand this. They obviously think that pulling and inspecting the wings is important. That is why they included a requirement to do it. I also think it is very important. It is just that they (FD) have tried to specify WHEN it is done, and that is not their job.

 

 

 

Except it's not an incomplete inspection, because it's not a required maintenance item for every condition inspection, only every other one (or 600hrs).  To me this sounds like doing a prop overhaul with every condition inspection, because while the overhaul interval is clearly specified as every 1000hrs (for Neuform), "props are important."

 

There are lots of components that have service intervals other than annually, but you don't replace/repair/inspect them on every condition inspection.  To me, maintenance in excess of the manufacturer's recommendations is as detrimental as having intervals in excess of recommendations.  The chance of maintenance induced failure increases, and there should be no safety benefit.  There are exceptions of course, where experience shows that a manufacturer's recommended maintenance is inadequate.  But no CT I am aware of has crashed due to wing failure, so I don't think this is one of those.

 

IMO of course, and YMMV.

[Roger Lee]

Hi Doug H,

 

FD doesn't require it so I take it as a personal Inspection item?

Then why not pull the wings on every aircraft that comes in regardless of brand?

[Doug Hereford]

Roger,

Wing attachment features on the vast majority of GA aircraft have provisions for complete visual inspection without wing removal. For instance, the J3 cub attachments can be seen clearly 360 degrees around with a mirror and light. The King Air attachment fittings have access covers, and torque indicating washers that can easily be verified visually in situ. LearJet model 40/45, and Citation XLS+ wing bolts and fittings can easily be seen by removal of access panels. The Piper Cherokee line has a very similar attachment to the CT, however all structural components can be seen with a mirror and a light. Wing removal is not necessary on any of these aircraft to perform a complete visual inspection of wing attachment. Also, none of these aircraft have any manufacturer inspection recommendations that require wing removal.

 

That being said, the J3 cub and Piper Cherokee line both get Annual/100 hr. inspections. The King Air, Lear and Citation aircraft do not. Even so, J3 cub wing attachements have a recurring Airworthiness Directive that requires additional NDI inspections at specified intervals. King Air, LearJet and Citation have Airworthiness Directives and Airworthiness Limitations tied to wing attachment features. These additional inspection were put in place to insure no wriggle room with regard to the safe condition of the wings and their attachments.

 

So until FD issues a Safety Directive to mandate wing removal and inspection at some interval other than the current Condition inspection interval, the wings must come off. It is not a brand specific requirement. It is a design requirement.

 

Mr. Morden,

 

You said: "There are lots of components that have service intervals other than annually, but you don't replace/repair/inspect them on every condition inspection"

 

Neuform props, like ALL other parts of SLSA aircraft are required to be INSPECTED every 12 calendar months. As long as they pass this inspection, then no additional maintenance need be performed. Overhauls, or parts replacements are NOT inspections. Again, I will never advocate for arbitrary overhaul or parts replacement, but I will always insist on performing a complete required inspection. I am the one certifying the aircraft. As I have said, since the FAA will not clearly define Condition inspections, there is some level of discretion. For me, that discretion calls for wing removal for inspection at every Condition inspection on aircraft that have these attachment features.

 

Doug Hereford

[Roger Lee]

Hi Doug H,

 

I guess I'm missing this. Can you show me where you are reading that wings need to come off each annual?

[Doug Hereford]

Roger,

 

14 CFR part 91.327 ( (2) requires a Condition inspection each 12 calendar mo. (entire aircraft). It also requires this inspection be "performed" IAW inspection "procedures" developed by the mfg. This regulation has requirements of WHEN to perform the inspection, and HOW to perform the inspection.

 

Aircraft operating limitation 14 has the same requirement.

 

On the CTLS, these inspection "procedures" are found in chapter 3 of the Aircraft Maintenance and Inspection Procedures Manual (I am reading rev. 4 1/2/2009). Page 3-7 of chapter 3 is where the inspection procedures are found specific to the wing of the aircraft (sect. 3.6). The first item on the checklist contains inspection procedures for inspecting "Wing Attachment Area". I will cut and paste the "procedure" that instructs the inspector on HOW to inspect Wing Attachment Area.

 

Wing Attachment Area. Inspect wing spar and main bolt bushings 

for cracks and debonding. Check visible attaching hardware for loss 

of torque. Inspect aileron bellcranks for cracks and corrosion. Check 

root rib pins for debonding and cracks, and the forward one for fuel 

leak.

 

Now, I am aware that this procedure does not specifically instruct one to remove the wings, however without removing them, one cannot comply with the last portion of this procedure.

 

For reference and to be fair, I will now cut and paste the last sentence in this item:

 

Check each 600 hrs or at the next 100 hrs inspection after 

2 years, whichever occurs first.

 

This statement is not a part of the "Procedure". This is a requirement of WHEN. If you look over to the right side of the inspection procedures checklist, you will also see columns for "Annual", "100 hr." and Minimum levels of certification. These items are also examples of WHEN and WHO. They are not a part of a procedure, therefore not regulatory. In fact, if they are followed throughout the checklist as published, they are actually contrary to regulation.

 

So to summarize:

14 CFR part 91.327 tells the operator WHEN a condition inspection is to be performed. Every 12 calendar months (not 2 yrs. or 600 hrs.).

Operating limitation 14 echos this.

Manufacturer's procedure tells the inspector HOW to inspect the Wing attachment. In order to comply with this procedure, the wing must be pulled. Therefore it must be pulled every 12 calendar months.

 

There you go .

 

Doug Hereford

[Roger Lee]

Quote:

Wing Attachment Area. Inspect wing spar and main bolt bushings 

for cracks and debonding. Check visible attaching hardware for loss 

of torque. Inspect aileron bellcranks for cracks and corrosion. Check 

root rib pins for debonding and cracks, and the forward one for fuel 

leak.

 

Now, I am aware that this procedure does not specifically instruct one to remove the wings, however without removing them, one cannot comply with the last portion of this procedure.

 

For reference and to be fair, I will now cut and paste the last sentence in this item:

 

Check each 600 hrs or at the next 100 hrs inspection after 

2 years, whichever occurs first.

 

___________________________________________________________________________________________________________________________

 

This part could be worded more clearly, but it's intent is 2 years or 600 hrs. as per FD.  Being listed under the 100 hr or annual is just a place to initial, an N/A or some other notation for this particular inspection. Rotax has a few like this too. If you follow this analogy then all hoses (fuel and oil) in fire sleeve must be removed to be inspected every 12 months. You would have to remove the fuel hose in the wings to inspect them and inside the instrument panel. You would have to completely dismantle the front suspension to inspect the red polyurethane spacers and remove the tail counter balance mechanism to inspect it completely.

 

To me it becomes the spirit of the section or do you follow the letter of the section. Granted some wordings are poorly done, so there is some wiggle room for interpretation at times. These types of things should be written up and sent to an MFG for better wording.

[Doug Hereford]

Roger,

I don't see muchwrong with the wording for this inspection task procedure. And I see no analogy here. When we perform maintenance (Condition Inspections are a type of maintenance), we must, by law, use accepted methods, techniques, and practices (FAR part 43). The accepted method for performing an inspection of wing attachments on a CT involves removing the wings to gain access. The is no accepted method, technique or practice for inspecting hoses, or bob weights, or suspension components that require them to be disassembled. If there is, it will most likely be contained in some other document like an Airworthiness Directive, Airworthiness Limitation, or Safety Directive. CT does not require removing hoses, bob weights, etc...............when performing an inspection, but they do require removal of the wings. The issue is WHEN it has to be done. FD does not get to determine that as a part of a Condition Inspection.

 

I'd like to think that I am as spirited as the next guy, but I gotta pull those wings.

 

Doug Hereford

[Roger Lee]

You may be the only person that pulls wings every inspection. I haven't heard of anyone doing this.

[Doug Hereford]

Roger,

I believe that. Like I have said, Im not passing any judgement on other's positions related to this issue. It is a little gray to be sure. If you ask me, it is just more evidence that all of us in the field need to put in our 2 cents (or keep doing it) to the FAA that some claifications would be much appreciated.

 

Doug Hereford