Zus Fasteners

[jpusser]

I was wandering if it was legal or possible to replace all the screws on the cowl of my 62 M20C with the zus fasteners.  I'm sure it would be a lot of work, but it would be worth it for me.  

[thinwing]

well the newer bravos use 1/4 turn camlocs,dzus fastners not as popular because they are harder to install.All and all ,Id say I doubt you could get a field approval..kpc

[jpusser]

I should have said quick fasteners instead of zus,  I wouldn't care what type.  I thought some of the later model vintage had them.

[N513ZM]

Quote: jpusser

I should have said quick fasteners instead of zus, 

[Vref]

Quote: N513ZM

they are DZUS fasteners - not zus.

just sayin.. :-)

[N33GG]

Quote: Vref

they are DZUS fasteners - not zus.

just sayin.. :-)

[Larrynoel]

Airplanes must meet what is on their type certificate to be considered airworthy.  There is no such thing in the FAA's eyes as better than new, (even if it is).  Your airplane was Type Certificated to be airworthy with a particular part number fastener installed in you cowl to secure it your airframe. Any deviation to this would be against your Type certificate.  Even if it was replaced with a stronger screw.  In the real would this happened's all the time.  Like changing an old rusty screw with a shiny stainless steel screw.  But change from one type fastener to another type of fastener...  That would be a sin in the FAA'S eyes!  It would literally take an engineer to prove to them that this modification would be safe.  I think it would be easier to keep it as it is.  Or go for it and make it an STC (supplemental type certificate).  This would give you the right to make the change to your airplane and sell rights to other people that want to do the same thing. 

[1964-M20E]

I'm not an A&P nor am I an aircraft engineer and Larry is more than likely correct to be 100% in compliance. 

However, any an all rules are subject to interpretation.  Food for thought, the parts manuals that I have do not list the type of screws to be used in attaching the cowling to the aircraft.  Were they listed on the type certificate?

My thoughts are if they are not specifically listed in the parts manual or on the type certificate then they can be changed by any accepted practices used to maintain an aircraft.  Things get replaced on airplanes all the time the more critical the part the more scrutiny.

Just my thoughts not intended to be followed by myself or anyone else and I do not want to stir up hornets nest either

[1970m20e]

My mechanic told me to use these for the battery access panel on the rear left side of the plane.

 

 

Studs

82-19-120-20

Wear washer

82-46-101-39

[MARZ]

Quote: 1970m20e

My mechanic told me to use these for the battery access panel on the rear left side of the plane.

 

 

Studs

82-19-120-20

Wear washer

82-46-101-39

[VAndersen]

Where did you find the Southco parts you've listed here? My plastic nylon cup washers are all worn out and/or missing. It looks like it would be easiest to replace all the parts (it would definitely look better), but I'm having a hard time finding them. Also the third belly panel on my E has a row of clip nuts that are coming off.....does anybody know the model or part number for those?

 

Vincent

N142EJ

 

[jetdriven]

I think changing cowl fasteners to Dzus would be a minor change, at most a 337 filed without field approval.  People do this with XeVision landing lights and AirGizmos panel docks.

[danb35]

If you're filing a 337, you're saying that you've performed a major alteration to the aircraft.  In that case, you must have some source of approved data for that change.  An STC is the most common source of approved data; a field approval is another.  A 337 sent in without any "approved data" to support the change should be rejected.

[MARZ]

Vincent - I found the fastners at Aircraft Spruce - LINK

[jetdriven]

OK how about basing it on another STC or kit for other aircraft such as a Cardinal RG or 182.  They use similar screws, likely the same size. 

[Hank]

Some people already have Dzus fastener on cowlings and ELT panels. Some one-piece belly panels have them, too. I have no idea about STCs, 337s, etc., just what I have personally observed. On the other hand, I'm not sure I've ever seen a Mooney cowling held on by actual screws . . . But I sure remove and replace an awful lot of them every annual.