Cost for SB 208B inspection and repairs

[rbmaze]

I have read some old discussions about SB 208 and I am looking to add this to my prebuy inspection. Is anyone familiar with the amount of labor required to open the interior and inspect the tubes? If insulation needs to be replaced (say all of it) how much additional cost might this add?

Are there other ways of inspecting for airframe corrosion or would any good Mooney shop agree that following the SB inspection steps is the best course of action to understand what one is purchasing?

Thanks!

[Vance Harral]

If you want to "cheap out", you can remove a single interior panel and/or use a borescope to look for rust on "some" of the tubes, and assume the rest are comparable.  This is what we did when we bought our Mooney, a couple of decades ago, and it only takes about an hour.  But I wouldn't really recommend that approach.

If you're actually going to perform the SB, the first step is to remove all the interior panels.  This is not sophisticated work, at least not in my vintage of Mooney - it's just a bunch of small, non-structural screws.  Figure 1-2 hours of labor to remove, and 1-2 hours to re-install.  Note that the owner can do this work (not that you're the owner yet, but this becomes relevant later).  You're also supposed to pull up the duct tape that provides a seal between the floor panels and the roll cage structure.  This is easily replaced, but requires supplies and time.

If, after removing the interior panels, you find that the airplane still has the old fiberglass insulation, deduct the cost of the new insulation kit, plus a few hours of labor, from your offer.  See https://lasar.com/misc-supplies/insulation-kit-170018-901.  After you buy the airplane, you can pay someone to do the work, or you can save a few bucks and do it yourself (R&R of interior panels is owner/operator work, and you can get your own A&P to "supervise" the installation of the closed cell foam insulation).  Installing the new installation is not a complicated job, just tedious.  Figure 4+ hours of labor if you don't do it yourself.

Once you've got the panels off and noted what kind of insulation it has, you can visually inspect all the roll cage tubes, which is the main focus of the SB.  But, visual inspection isn't the full extent of it.  If you're really doing it right, you should perform all of "Part B" of the SB.  This requires removing the tension bolts that attach the roll cage structure to the spar, and running a magnet inside the most critical of the tubes, to see if it pulls out any rust.  Hopefully there's nothing significant, and then you get a chance to spray LPS or similar corrosion inhibitor inside that set of tubes.  This work is not particularly difficult, but it does involve R&R'ing some very important structural bolts, and it's possible the seller may balk at allowing this to be done by your pre-buy mechanic.  If the tubes look in good shape after removing the interior panels, the SB permits skipping this higher level of disassembly, but up to you and the seller whether to do so.

The good news is that the procedure for doing all this stuff is well-documented in the SB, so it's not like you're proposing something out of left field to check for corrosion.  In my opinion, any reasonable seller would (a) already know all about SB-208 and be able to tell you when/if it was last performed; and (b) allow the SB to be part of a pre-buy if it hasn't been recently performed.

 

[PT20J]

Sometime in the mid-1980s Mooney switched to foam insulation, epoxy primed tubes and sealing the rivets that attach the window frames to the tubes. On those airframes, it it often a simple matter of checking that the pilot's storm window doesn't leak and removing the belly panels and checking for corrosion in the bottom tubes.  A complete by-the-book inspection removing the belly, side panels, rear seat and tension bolts and putting everything back together is probably $1000 at a shop.  @jetdriven would know.

I might contact Frank Crawford at Mooney with the model and serial number and he should be able to look up the build records and tell if it has the updated insulation and primer.

I bought bulk foam insulation that Mooney uses from a MSC for $475 and installed it myself. It took me maybe 4 hours to remove the old insulation and cut and install the new.

[rbmaze]

2 hours ago, Vance Harral said:

If you want to "cheap out", you can remove a single interior panel and/or use a borescope to look for rust on "some" of the tubes, and assume the rest are comparable.  This is what we did when we bought our Mooney, a couple of decades ago, and it only takes about an hour.  But I wouldn't really recommend that approach.

If you're actually going to perform the SB, the first step is to remove all the interior panels.  This is not sophisticated work, at least not in my vintage of Mooney - it's just a bunch of small, non-structural screws.  Figure 1-2 hours of labor to remove, and 1-2 hours to re-install.  Note that the owner can do this work (not that you're the owner yet, but this becomes relevant later).  You're also supposed to pull up the duct tape that provides a seal between the floor panels and the roll cage structure.  This is easily replaced, but requires supplies and time.

If, after removing the interior panels, you find that the airplane still has the old fiberglass insulation, deduct the cost of the new insulation kit, plus a few hours of labor, from your offer.  See https://lasar.com/misc-supplies/insulation-kit-170018-901.  After you buy the airplane, you can pay someone to do the work, or you can save a few bucks and do it yourself (R&R of interior panels is owner/operator work, and you can get your own A&P to "supervise" the installation of the closed cell foam insulation).  Installing the new installation is not a complicated job, just tedious.  Figure 4+ hours of labor if you don't do it yourself.

Once you've got the panels off and noted what kind of insulation it has, you can visually inspect all the roll cage tubes, which is the main focus of the SB.  But, visual inspection isn't the full extent of it.  If you're really doing it right, you should perform all of "Part B" of the SB.  This requires removing the tension bolts that attach the roll cage structure to the spar, and running a magnet inside the most critical of the tubes, to see if it pulls out any rust.  Hopefully there's nothing significant, and then you get a chance to spray LPS or similar corrosion inhibitor inside that set of tubes.  This work is not particularly difficult, but it does involve R&R'ing some very important structural bolts, and it's possible the seller may balk at allowing this to be done by your pre-buy mechanic.  If the tubes look in good shape after removing the interior panels, the SB permits skipping this higher level of disassembly, but up to you and the seller whether to do so.

The good news is that the procedure for doing all this stuff is well-documented in the SB, so it's not like you're proposing something out of left field to check for corrosion.  In my opinion, any reasonable seller would (a) already know all about SB-208 and be able to tell you when/if it was last performed; and (b) allow the SB to be part of a pre-buy if it hasn't been recently performed.

 

Thanks for the reply. This is extremely helpful.

I have reviewed the SB document itself and have seen mention of running a magnet; I didn't understand it would be inside the tube, so it all makes sense now.

I was quoted 10-12 hours of labor to perform "Part A" of the SB. This is higher than I anticipated based on my review of the procedure, but I am completely unfamiliar with removing the interior panels and I note it calls for removal of all four seats. This is for a late 60s E.

After reviewing the airframe logs myself, I can confirm SB-208 has never been logged which is why I want it done as part of my prebuy.

Thanks also for the link to the insulation kit.

Cheers!

[rbmaze]

2 hours ago, PT20J said:

Sometime in the mid-1980s Mooney switched to foam insulation, epoxy primed tubes and sealing the rivets that attach the window frames to the tubes. On those airframes, it it often a simple matter of checking that the pilot's storm window doesn't leak and removing the belly panels and checking for corrosion in the bottom tubes.  A complete by-the-book inspection removing the belly, side panels, rear seat and tension bolts and putting everything back together is probably $1000 at a shop.  @jetdriven would know.

I might contact Frank Crawford at Mooney with the model and serial number and he should be able to look up the build records and tell if it has the updated insulation and primer.

I bought bulk foam insulation that Mooney uses from a MSC for $475 and installed it myself. It took me maybe 4 hours to remove the old insulation and cut and install the new.

Thanks for the details. Sounds like a good change they made in the 80s and I have read a bit about it. I'm looking at an older M20E, so unfortunately the updates will not help me here.

I was quoted about $2000 for the inspection with no repairs. This is for 10-12 hours of labor in an expensive part of California. This may be a reasonable estimate then. Thank you!

[1980Mooney]

11 hours ago, rbmaze said:

Thanks for the details. Sounds like a good change they made in the 80s and I have read a bit about it. I'm looking at an older M20E, so unfortunately the updates will not help me here.

I was quoted about $2000 for the inspection with no repairs. This is for 10-12 hours of labor in an expensive part of California. This may be a reasonable estimate then. Thank you!

This is an extreme example. 

 

[A64Pilot]

On old rag and tube airplanes I use an ultrasonic thickness gauge to inspect for interior corrosion on the tubes, they aren’t expensive and work well, if there is a mechanic that works on Supercubs etc around they may have one you could use.

The old school way was to use an ice pick, if it didn’t make a hole, the tube is good.

[MikeOH]

@rbmaze

You otherwise best be certain about any particular plane you have inspected in FULL compliance with SB208 as you will be out $2000 per your own research.  Shopping is going to get pretty expensive if you do this on every pre-buy!

[1980Mooney]

17 minutes ago, MikeOH said:

You otherwise best be certain about any particular plane you have inspected in FULL compliance with SB208 as you will be out $2000 per your own research.  Shopping is going to get pretty expensive if you do this on every pre-buy!

Why do you think that he would be inclined to do this on every pre-buy?  He clearly stated above that on this particular plane “After reviewing the airframe logs myself, I can confirm SB-208 has never been logged which is why I want it done as part of my prebuy.”

[MikeOH]

1 minute ago, 1980Mooney said:

Why do you think that he would be inclined to do this on every pre-buy?  He clearly stated above that on this particular plane “After reviewing the airframe logs myself, I can confirm SB-208 has never been logged which is why I want it done as part of my prebuy.”

Because I suspect there are plenty of planes where SB208 has NEVER been logged as it is NOT an AD.  While corrosion concern is a normal worry when buying Mooneys (among others) I have noted prospective buyers are interested in some kind of inspection for corrosion but this is the first time I've seen a prospective buyer somewhat INSISTING on compliance with SB208.  Also, per SB208 it is supposed to be performed annually!  What are the odds that EVER happens?!  When you bought your Mooney did its logs show SB208? And, if so, how far back? Did you pay for 10 hours of labor to comply with SB208, or just had them (or yourself) 'inspect' for corrosion? Finally, if he is 'inclined' to do so on this aircraft, why do YOU think he would not on others?  I didn't think it unreasonable to post my caution.

Why do you find it necessary to even comment on my caution to him?

[47U]

16 hours ago, rbmaze said:

This is for 10-12 hours of labor in an expensive part of California.

 

5 hours ago, 1980Mooney said:

This is an extreme example.

A picture the tube in the video before it was cut out of the aircraft.  The video estimates 10 amu for the repair.  That was a few years ago, probably more now.

Hangtown Aviation in Placerville did the repair.  When it was finished, you could not tell that any work had been done, paint included.

[rbmaze]

5 hours ago, 1980Mooney said:

This is an extreme example. 

 

This is a fantastic video! Thanks for sharing.

[rbmaze]

I appreciate all the discussion and differing points of view.

With regards to getting this done on all Pre Buys I may be doing, I am not necessarily insistent on getting SB 208 performed and it may help if I explain I do not know what I don't know. This is my first aircraft purchase. I asked a shop if they advise performing this inspection and they said yes. Of course, the shop is a business and does not necessarily have my best interests in mind.

It seems prudent to know as much as I can before purchasing the aircraft and if spending $2000 is what it takes to discover significant corrosion, it seems like it would be money well spent. If corrosion can be detected other ways, I could consider forgoing this inspection.

The person in the video linked above suggests SB 208 could become an AD in the future.

[EricJ]

28 minutes ago, rbmaze said:

I appreciate all the discussion and differing points of view.

With regards to getting this done on all Pre Buys I may be doing, I am not necessarily insistent on getting SB 208 performed and it may help if I explain I do not know what I don't know. This is my first aircraft purchase. I asked a shop if they advise performing this inspection and they said yes. Of course, the shop is a business and does not necessarily have my best interests in mind.

It seems prudent to know as much as I can before purchasing the aircraft and if spending $2000 is what it takes to discover significant corrosion, it seems like it would be money well spent. If corrosion can be detected other ways, I could consider forgoing this inspection.

The person in the video linked above suggests SB 208 could become an AD in the future.

I think if it was going to become an AD it would have by now.    Given the traffic on mooneyspace, this isn't something that comes up very often, and a lot of people check it during prebuys, so if it was a common issue it would probably be known as such.   As it is, it seems pretty rare to really be an issue.

As can be seen in the pic, if there's surface corrosion it may be evident on top of the tubes.    An easy thing to do without spending hardly any time or money, is to loosen up the top of the interior side panel by removing the top screws, and just sending a cheapie endoscope or a borescope camera down the side of the airplane.   You can see a lot more than you might think, and it'll be very evident both what type of insulation is present as well as whether there is surface rust on the tubes.    If the insulation has been changed, then the tubes were likely inspected when the old insulation was removed.   If the new type of insulation is present, it'll still be evident whether there is any water damage on that.

So you don't have to spend much to get a reasonable first-order visual inspection to at least see if there's an avoidable disaster happening.

[MikeOH]

38 minutes ago, rbmaze said:

I appreciate all the discussion and differing points of view.

With regards to getting this done on all Pre Buys I may be doing, I am not necessarily insistent on getting SB 208 performed and it may help if I explain I do not know what I don't know. This is my first aircraft purchase. I asked a shop if they advise performing this inspection and they said yes. Of course, the shop is a business and does not necessarily have my best interests in mind.

It seems prudent to know as much as I can before purchasing the aircraft and if spending $2000 is what it takes to discover significant corrosion, it seems like it would be money well spent. If corrosion can be detected other ways, I could consider forgoing this inspection.

The person in the video linked above suggests SB 208 could become an AD in the future.

You are definitely going about the purchase process as a first time buyer the right way!  You've gone to the work to come here and ask questions on type specific forum; good on you!

@EricJ has done a very good job of outlining the pragmatic nature of this issue.  And, to reiterate what he said, SB208 has been around since 1989 so the odds of it becoming an AD, absent a sudden rash of crashes caused by the failure of the tube structure due to corrosion, seems pretty unlikely.

I looked at an embarrassingly large number of Mooneys before buying mine.  The reality is that there are many signs of corrosion in other areas that will tip you off to whether the plane has had exposure to less than ideal environments.  For example, after decowling the engine look at the engine mount, other steel parts, bolts, etc.  Similarly, is there excessive 'white' corrosion inside the wings?  Pull the tail access panel and look inside at the control rods.  Even steel parts in the interior; I remember one plane where the control shafts we seriously rusted along with the levers of the throttle/prop/mixture controls!

For myself, I think only one set of logbooks out of all the planes I considered even had a written record of SB208...and it was many year back.  The plane I ended up with did NOT have any record of SB208 but everything was clean, the previous owner had it hangared for his 13 years of ownership, and it looked it!  I was MUCH more concerned with recent and consistent use; that was my number one concern with any plane.  And, nearly all of the planes that I first considered had NOT had recent use; that seemed typical, unfortunately.  I suspect the owners parked the planes, figure they'd fly again 'soon' and years later decided it was finally time to sell....those were a hard "NO" for me.

[Shadrach]

No need to complete the SB. Just pull the side panels and inspect the tubing. Tube under the pilot window and the lower aft tubes that connect to the spar are especially prone to corrosion.  Once you’ve verified the cage is good, you can proceed with purchase. You can do the complete SB on your own time and money. When I did mine we did the complete SB which included new insulation and a repaint of the tubes with two part zinc-chromate epoxy. I would expect to pay a lot more than $1000 to pay someone to do what I did. That was 15 years ago. I pull the interior about every third annual. The status of the structure has not changed since we performed the SB.

[1980Mooney]

19 hours ago, MikeOH said:

Because I suspect there are plenty of planes where SB208 has NEVER been logged as it is NOT an AD.  While corrosion concern is a normal worry when buying Mooneys (among others) I have noted prospective buyers are interested in some kind of inspection for corrosion but this is the first time I've seen a prospective buyer somewhat INSISTING on compliance with SB208. ... When you bought your Mooney did its logs show SB208? And, if so, how far back? Finally, if he is 'inclined' to do so on this aircraft, why do YOU think he would not on others?  I didn't think it unreasonable to post my caution.

Why do you find it necessary to even comment on my caution to him?

This is a hot button issue with any prospective Mooney buyer. A quick search of the MooneySpace site using Google shows that SB208 (either spelled SB208, SB-208 or Service Bulletin 208) is a subject of discussion in over 200 different topics.

I have never seen a late 1970's - 1990 Mooney that did not have SB208A done and logged - granted I never looked at anything but J models.  I saw some really poor looking welding repair of frame corrosion of one particular J that was in Louisiana. I passed on that plane.  Yes my logs showed that SB208A had been complied with before purchase.  And the fiberglass had been removed and replaced with foam insulation.  It had been done about 8 years prior to my purchase.

You have never seen a Mooney buyer that insisted on SB-208?    Searching MS topics/discussions on "pre-buy, you will find over 60 separate discussions that specifically highlight the need for SB208 to be completed on the aircraft.  Many say it is at the top of their list and to read the logs first.  And many say "SB208 will need to be done" and to walk away if it has not been done and logged.  

 

 

 

 

Edited August 31 by 1980Mooney