Feul caps.

[danb35]

The AD requiring annual inspection and replacement of the OEM fuel cap o-rings is eliminated.

There is no AD requiring annual (or any other interval) inspection and replacement of fuel cap O-rings.  There's a Mooney "mandatory" service bulletin that purports to require this, but it, like all other service bulletins, is optional for Part 91 operators in the US.

 

There's also no reason that a set of flourosilicone O-rings should cost $100.  I bought two sets for my OEM caps (might as well have a spare) for under half that amount.

[DonMuncy]

There is no AD requiring annual (or any other interval) inspection and replacement of fuel cap O-rings.  There's a Mooney "mandatory" service bulletin that purports to require this, but it, like all other service bulletins, is optional for Part 91 operators in the US.

 

 

There is an AD (85-24-03) requiring the inspection per Mooney  S/B M20-229, The only question is whether it is a one time, or recurring AD.

[jetdriven]

They are not an MS number, but rather a specific part number to that fuel cap. Spruce has them, same price.  Good thing is they only need it every 20 years or so.

[danb35]

There is an AD (85-24-03) requiring the inspection per Mooney  S/B M20-229, The only question is whether it is a one time, or recurring AD.

...and there really isn't any question; the text of the AD is perfectly clear that it is a one-time AD.  That's not to say that periodic inspection isn't a good idea, only that there's no AD that mandates it.

[danb35]

The small one is a M25988/1-010; the large one is M25988/1-338.  More info, including other cross-references and sources, is at http://www.csobeech.com/o-Rings.html.

 

It should be noted that, while these are mil-spec parts, they do not conform to the same mil-spec as called for in the parts catalog.  Your A&P would need to agree that they're an acceptable replacement part.