12 Year Structural Inspection

[Davestation]

Just to stir the pot a little:

Those of you that said you only have to maintain your plane in accordance with the manual that was in existence at the time the plane was built are correct. Now go have fun changing your rudder cables and fuel hoses...

P.S. Many mechanics will tell you that this is not true. In fact, several FAA will tell you this is not true. It's a VERY common misconception.

Having said that, I don't think anyone has brought up the SB on the matter yet -

As an additional benefit the reinforcement is the basis for the Major Structural Inspection interval increase to 6000 hrs since new and every 4000 hrs thereafter.

I read that as DAI telling you that the MSI in its entirety is pointless to perform at a mere 2000 hours, because the only issues they've found whatsoever are rectified by this minor reinforcement. Diamond does not give a calendar limit on the new MSI, nor do they specify calendar compliance since the last one. What's purely bizarre is that in their AMM they they actually differentiate between a 2000hr inspection (which is actually 2000 hours or 12 years) and a MSI (which is also 2000 hours or 12 years, only with a shorter grace period), but I digress.

Per their AMM Addendum:

If MÄM 40-394 or MÄM 40-398 is installed:
 at 6000 hours since new and every 4000 hours intervals or 12 years, whichever comes first.
Maximum tolerance is ± 2.5%

The language is pretty ambiguous, but I don't see the calendar time being relevant one way or another because the fatigue will be brought on by cycles, not just sitting there. It's a moot point though because as others have pointed out this is not FAA approved anyway.

I'd just like to meet the guy that decided on "114 months after August 27, 2014". Diamond asks that you please do it by 12/31/2022 by the way.

[Rick]

We went back to our shop and showed them https://publicsafetyaviation.org/images ... 142018.pdf, which states:

Installation or compliance with these FAA approved design changes is not retroactively mandatory for in-service aircraft, unless mandated by an AD or some other rulemaking action

We also showed them the airworthiness certificate transfer documentation, which references the older version of document 6.02.01 where the MSI is not mandatory.

The shop went back to their FAA inspector for clarification and we're still waiting to hear back.

Is there any update from the FAA on this topic? Specifically, is the MSI now an airworthiness requirement for Part 91 operators in the US or still just a recommendation?

[mhoran]

Is there any update from the FAA on this topic? Specifically, is the MSI now an airworthiness requirement for Part 91 operators in the US or still just a recommendation?

I don't believe the shop ever got a definitive answer from the FAA. They signed off on the annual without performing the inspection. We brought the plane to another shop this year (the shop we'd used for all years prior) and they didn't even bring it up.

[Rick]

I notice that the 2017 addendum from Diamond has the following (poorly-worded) statement in it:

“This addendum to the DA 40 Series AMM 6.02.01 must be inserted into the front of the manual and carried in the aircraft at all time.”

Since when are we required to carry the AMM in the aircraft? At least that statement is in the preamble and not contained within the amended text of Chapter 4!

[yl472401]

FYI, had a discussion with a Diamond shop last Friday. Per the shop, the MSI for 2k hours is not mandatory, it is manufacture recommendation, it doesn't affect the certification and legality of my aircraft. I'll provide update once my aircraft is finished with annual inspection.

[mhoran]

I brought our plane down to SouthTec to have the MSI performed along with a few other things. The MSI is really no big deal. The previous estimate I received for the MSI (over $7000) was ridiculous. If I had done my annual at SouthTec (which I will do next year), the MSI would only have been an additional $850. Unfortunately I already had my annual this year, so I essentially paid for another annual. Lessons learned!

No major items came up as a result of the inspection. All the items that came up were already on the list, and none were airworthiness items. For reference, the previous estimate I received would have included unnecessary replacement of parts. Glenn had no interest in wasting my money.

Both SouthTec two other Diamond shops in the NY metro believe the MSI is mandatory. I know we've talked that point to death in this thread, but I'd just recommend getting it done. It really shouldn't be a big deal. There are not many more items in the MSI than what is looked at during a standard inspection. A shop that quotes more than $1000 to add the MSI on to an annual is doing something wrong (replacing unnecessary parts, wasting time, etc.)

[Davestation]

The fact that it isn’t mandatory is an important for this conversation because it means that not all shops may be doing the same thing - they could very well be picking and choosing which parts they think are important. Some things need defining before we assume shops are doing something “wrong” (might be subjective):

unnecessary parts: what parts are unnecessary? What parts are necessary? Are the unnecessary parts completely arbitrary to the MSI or are they listed but just not replaced?

wasting time: since the entire thing is optional, the argument could be made that all of it is a waste of time. Which aspects aren’t a waste of time?

What did the $7000 shop quote that southtec didn’t do in their $850 version? Or was it all the same inspections, just done much quicker/more efficiently?

[mhoran]

I trust that SouthTec completed the MSI in full. However, Glenn at SouthTec did inform me that they would not take certain steps if not absolutely necessary -- for example, removing the wings to replace perfectly functional fuel interconnect hoses.

We've discussed in this thread that many items in the MSI are already covered during an annual inspection. Some additional items are a coin tap test and inspection requiring removal of the horizontal stabilizer. The tail skid is also removed, which in my case uncovered some slight fuselage damage that otherwise would have never been detected.

I do believe that SouthTec is also more efficient. The shop that estimated $7000 for the MSI had only performed one MSI previously, and estimated the work at 70 hours. SouthTec performed the inspection in 30 hours.

I agree that the fact that there exists an argument as to optionality of this inspection complicates the matter since shops haven't had to optimize their process. I'd argue this is exactly why the FAA requires an AD process for such changes, which would include the estimated costs of the inspection and extra guidance for the average shop. Unfortunately that is not the route that Diamond chose to take with the type certificate transfer and subsequent AMM amendment.

FWIW we never received a definitive answer from the FSDO regarding optionality of the MSI. We've been to two shops that didn't even know about it, and three others that believe it is mandatory. Diamond definitely wants you to get it done, and since it's not a big deal, I'd recommend it. Just be sure to get an estimate before hand and ideally find a shop that has done it before.

[Davestation]

30 hours including the Annual I assume? Otherwise $850 is a steal!

That’s exactly what I mean about the number of hours though, it isn’t a matter of efficiency or price if one shop is charging 30 hours to do 30 hours worth of work and another is charging 70 hours for 70 hours worth of work. I think much of the issue is that people are conflating MSI with 2000hr inspection, as the MSI used to coincide with it (and is now 6000hrs with the completion of the wing spar AD). So it sounds like the $7000 shop quoted both an MSI (basically a coin tap) and a 2000hr (basically the fuel hoses) combined.

The debate on whether either inspection is mandatory is news to me though, and I’m stunned that there’s any debate on this at all - it seems pretty black and white to me. What evidence do they provide in saying it’s airworthy?? Sorry, I’m probably beating a dead horse here. Tell you what, we’ll get the oldest, highest time DA40 in existence that has never had it done, we’ll sign off a fresh Annual, and we’ll march to oak city and ask them how they like those apples. If it’s not explicitly forbidden, it’s implicitly allowed.

[mhoran]

$850 would have been if we did the MSI along with an annual. 30 hours was for the MSI alone. If we look back earlier in the thread this seems to line up with the additional time for the MSI items over a typical annual, so it makes sense.

I do think you're on to something with the 2000 hour inspection being conflated with the MSI. The book is clear as mud in this regard, but I think that is what was happening with the $7000 estimate. This even confused me at first.

The FAA doesn't seem to want to answer anyone definitively as to whether the MSI is mandatory. Diamond claims that when they had the type certificate transferred to Canada, their amendment making the MSI a chapter 4 item was binding for US registered airplanes. Some shops follow their word, others either don't know about the amendment or refute it.

The actual type certificate itself references the January 9, 2003 version of the AMM and states that "The FAA accepts such documents and considers them FAA-approved unless one of the following condition exists: The documents change the limitations". That condition is the sticking point as to whether this inspection can really be made mandatory without an AD.

Regardless, I just wanted to let everyone know that it's not a huge deal, could uncover some hidden damage, and will help ensure your airplane lives a long life.