Underwing inspection panels. Which ones need to be removed for annual?

[Eight8Victor]

Prepping my Mooney for the mechanic and I have misplaced my diagram of which underwing panels come off for the inspection. Does anyone have a diagram that they can share? TIA.

[DCarlton]

20 years and I’ve never had an answer to that.  Good luck.  I think it depends on your mechanic.  I’d like the F answer too.  

[Hank]

Many of mine are riveted in, so I remove all of the ones with screws. I keep one unpainted screw in each; it is loosened, the painted ones are removed, and the panel swivels out of the way. Then I can never mix them up during reinstall, and cuss because the screw holes are not all perfect matches. 

Seems like I remove about 4 panels per wing.

[PT20J]

A lot of those plates are not considered inspection panels -- they are there for access during manufacturing. That's why on later Mooney's some are pop riveted. The factory annual/100 hr checklist only says you need to lubricate the control system and inspect the interior of the wing in the area of the fuel tanks for leaks. Any additional openings are up to you and your IA.

[Ragsf15e]

Just don’t take out the fuel tank ones. It will be self critiquing.  They do look different, but it’s possible.  I remove them all like @Hanksaid.

[47U]

1 hour ago, Eight8Victor said:

Does anyone have a diagram that they can share? TIA.

[EricJ]

1 minute ago, 47U said:

Thanks for the diagram, that makes it a little easier.

12, and 13 if you need, to lube the rod ends for the aileron pushrods.   15 to check the end of the gear assist spring attachment and spar.   

Once in a while, or if leaks are evident,  the forward 16 to see if there is any staining inside or evidence of fuel travel along the leading edge.   Also whichever 14 is just off the end of the tank (which one depends on the tank configuration), likewise to check for any leaks, condition of the fuel sender gaskets, etc., if issues are evident. 

For a pre-purchase inspection, or once in a while in an area where corrosion is a concern, the rearward 16 gets you a look at the attachment point of the wing and steel cage and the rear spar caps.   This is a common area for corrosion.

Corrosion isn't an issue here, so my previous IA only ever wanted 12, 13, and 15 off.   I do the same now unless there's reason to do more, like fuel stains or something.   Looking in either or both 16s once in a while is not a bad idea, especially if corrossion is a concern.

[DCarlton]

1 hour ago, EricJ said:

Thanks for the diagram, that makes it a little easier.

12, and 13 if you need, to lube the rod ends for the aileron pushrods.   15 to check the end of the gear assist spring attachment and spar.   

Once in a while, or if leaks are evident,  the forward 16 to see if there is any staining inside or evidence of fuel travel along the leading edge.   Also whichever 14 is just off the end of the tank (which one depends on the tank configuration), likewise to check for any leaks, condition of the fuel sender gaskets, etc., if issues are evident. 

For a pre-purchase inspection, or once in a while in an area where corrosion is a concern, the rearward 16 gets you a look at the attachment point of the wing and steel cage and the rear spar caps.   This is a common area for corrosion.

Corrosion isn't an issue here, so my previous IA only ever wanted 12, 13, and 15 off.   I do the same now unless there's reason to do more, like fuel stains or something.   Looking in either or both 16s once in a while is not a bad idea, especially if corrossion is a concern.

Gonna take an out of cycle look at the rear 16s now just for grins.  Thanks.  Really want to buy some sort of inspection camera on a stick that I can view in real time from a laptop.  

[Eight8Victor]

6 hours ago, 47U said:

Perfect! Thank you!

[EricJ]

8 hours ago, DCarlton said:

Gonna take an out of cycle look at the rear 16s now just for grins.  Thanks.  Really want to buy some sort of inspection camera on a stick that I can view in real time from a laptop.  

Most borescopes or even the cheapie endoscopes that you can get online have USB interfaces, so will work on a laptop.   I use them that way sometimes, but usually on a phone or tablet.   Many also have a wireless interface available.

[RoundTwo]

My answer is “as many as you can” to make lubing the aileron pushrod guides easier. It’s also helpful to have someone with small hands and thin arms to get to some of the tight ones.

[TheAv8r]

It's in the Mooney Service Manual, they'll have a diagram of all of the inspection panels, numbered, and then in the "100hr" service manual, they refer back to those numbers and state what has to be open to perform what part of the service. Those are the ones you need to open up for an Annual. Your A&P IA from there can then ask to open up additional ones

[Yetti]

There is an SB M20-205B each 500hrw on the bell cranks for the airlons that my IA found.   So do those panels Number 12 on the diagram provided.

Edited April 19 by Yetti

[TheAv8r]

39 minutes ago, Yetti said:

There is an SB/AD 77-17-04 each 500hrw on the bell cranks for the airlons that my IA found.   So do those panels Number 12 on the diagram provided.

Pretty sure AD 77-17-04 is for the control yoke shafts and don't require you to open up any panels, but you do have to take the shaft's out from the panel

[Yetti]

17 minutes ago, TheAv8r said:

Pretty sure AD 77-17-04 is for the control yoke shafts and don't require you to open up any panels, but you do have to take the shaft's out from the panel

Ya that to.    Updated to SB M20-205B

[Shadrach]

15 hours ago, Ragsf15e said:

Just don’t take out the fuel tank ones. It will be self critiquing.  They do look different, but it’s possible.  I remove them all like @Hanksaid.

Non of mine are riveted. If I removed them all that would be >30 wing panels every year…NFW. 
We remove the panels needed to inspect and/or lubricate aileron control tubes, rub blocks and bell cranks.  I did a very extensive inspection of the wings in 2021 as we went into annual a month after the Victoria, MN crash.  It reaffirmed my confidence in the airframe. I won’t feel compelled to do anything that in-depth again anytime soon.

[Kelpro999]

15 hours ago, DCarlton said:

Really want to buy some sort of inspection camera on a stick that I can view in real time from a laptop.  

I have this one w/ 5” screen. Amazon ~$100

[EricJ]

57 minutes ago, Kelpro999 said:

I have this one w/ 5” screen. Amazon ~$100

They're getting so inexpensive now, even for good ones, that there's no reason not to have one if you want one.    I lost track of how many different ones that I have, including at least two (I think actually three) of the usual recommended Vividia scopes (rigid and semi-rigid), and one similar to what you linked here, which I linked below.   They keep improving them generationally and it seems like the cost either goes down or stays the same with improvements, so that's a nice trend.   I really like this one, it's more-or-less my go-to scope now unless I specifically need the rigid for something.

https://www.amazon.com/gp/product/B0B28HRSBP

 

 

[carusoam]

A good powered driver…

And a fist full of proper SS hardware…

A few screw driver bits, because they can wear and destroy screw heads…

 

The first time… replacing a lot of screws and other hardware can be expected…

Avoid opening the fuel tanks accidentally… this has lead to fires a few times…

 

the panels that are riveted on mine, conceal the mag compass for the HSI… the rivets are brass.

if you can plan with the layout drawing in advance… that helps a lot…

otherwise, taking all the panels out, gives a great view of everything….

 

The parts manual lists all of the screw types and sizes you need…

Find the sheet metal screws that aren’t the pointy ones.  

The machine screws come in different lengths and diameters…

Avoid using too long screws… they can cut into parts that move close by….

 

there are pics around here for all the things that can happen during and after an annual….   

 

Best regards,

-a-

[cliffy]

Use a good large diameter screwdriver handle (for leverage- mine is 2 1/2 inches in diameter) with a good sharp NEW Phillips bit (get several and good ones, not cheapos)) to do the first "break away" of the panel screws to loosen. 

DO NOT  THINK  you can just put a screw gun up to the screws and they will back out.

IF YOU DO THAT YOU WILL RUIN THE SCREW HEAD AS THE BIT TEARS OUT THE SLOTS WITHOUT LOOSENING THE SCREW!

You will have lots of screws to back out via Easyouts if you do that. 

Make sure the new bit is well seated and square in the head slots and then crack the screw loose.  

Mark my words on this.  CRACK EACH AND EVERY SCREW BY HAND FIRST OR HANG YOUR HEAD IN SHAME

WHEN YOU RETURN HERE  :-)

I learned the hard way many years ago!

[Fly Boomer]

1 hour ago, cliffy said:

Use a good large diameter screwdriver handle (for leverage- mine is 2 1/2 inches in diameter) with a good sharp NEW Phillips bit (get several and good ones, not cheapos)) to do the first "break away" of the panel screws to loosen. 

DO NOT  THINK  you can just put a screw gun up to the screws and they will back out.

IF YOU DO THAT YOU WILL RUIN THE SCREW HEAD AS THE BIT TEARS OUT THE SLOTS WITHOUT LOOSENING THE SCREW!

You will have lots of screws to back out via Easyouts if you do that. 

Make sure the new bit is well seated and square in the head slots and then crack the screw loose.  

Mark my words on this.  CRACK EACH AND EVERY SCREW BY HAND FIRST OR HANG YOUR HEAD IN SHAME

WHEN YOU RETURN HERE  :-)

I learned the hard way many years ago!

I have pretty good luck by tightening each screw just enough to break it loose, and then back it out.  Not sure why it works.  I use a drill/driver set for low torque for removal.