Just curious are you allowed to use nylock nuts in the engine compartment in the USA? And 1/4 in fuel line from wing tanks to carbs.I think both Canada and USA have different Regulations according to my inspector.( my oversight)

Have almost tore the plane I purchased in the USA apart ...opening wings , stab,elevator,flaperons, rudder and any part that was closed...  (a ch701 with 912s) and have found may things that were overlooked or missed which is on the original builder and not to do with the regs. But that is another story as to why when the plane has a N number, 400hrs in the air and the next inspection is 6 mos away  its not to be trusted until thoroughly inspected top to bottom. 

I think there may be builders who do things differently then others.But I guess I unwittingly accepted that most ch701s are build the same or very close to the plans?...Nuts and Bolts included?

I wasn't a builder at all and didn t want to be but guess Im now in the same boat or plane as the other builders never seen so many rivets to drill out and replace, nuts to replace,fuel lines and fittings  and all that goes with the building process and Im working on an already previously flying CH-701. Just had a pre-closing inspection which went well other then a few minor things and now moving on to other parts to replace and hope to fly before winter with no probs with engine?

Views: 404

Reply to This

Replies to This Discussion

Just curious are you allowed to use nylock nuts in the engine compartment in the USA?

A nylock nut firewall-forward "might" get by a careless DAR or FAA inspector in the US, but normally, metal locknuts (AN363) are required.



The reason I asked was I bought a plane ch701 which had 400 hrs on it and every nut in the engine area including the engine mount bolts were nylock ...all are being replaced here in canada. As well as the 1/4 in fuel lines? It was still in service with an N number....

My recollection is that nyloc nuts are permitted for use where the temperatures do not exceed 250 F, or on rotating machinery or control surfaces.  Also, while not necessarily a good practice, if the nuts cannot be tightened by hand then the nuts may be reused.  In my navy days, there was a documented running torque.   We use nylocs on non-critical items in our engine space such as adel clamps, but nowhere near high temp components such as exhaust.  By the way, if it ever gets hot enough to damage nylon in a nyloc nut, then what about your engine mounts and nylon firewall penetrations?

Your inspector may require castle nuts FWF but they're not required. Some DARs apply the same standards as certified and I guess if you want him to sign it off you have to do what he says. Yes, I think the AC (or wherever it's written I forget) recommends castle nuts but doesn't require it. If you can put a Briggs and Stratton motor and lawn mower wheels/tires on it it makes sense that you can put any hardware you want to on it. Our pop rivets that hold out airframes together aren't certified rivets and they sign that off. What's the difference...purely DAR preference with AFAIK, no supporting reg.

You guys correct me with a link if I'm wrong.

Have fun

The FAA handbook provides guidance and the Airworthiness Standards states when and where a self-locking nut may be used.  I do not see where it's up to a DARs discretion.  He may not just arbitrarily decide based on subjective whims.  A DAR must substantiate or reference his determination and recommendations. 

Title 14: Aeronautics and Space 
Subpart D—Design and Construction

§23.607   Fasteners.

(a) Each removable fastener must incorporate two retaining devices if the loss of such fastener would preclude continued safe flight and landing.

(b) Fasteners and their locking devices must not be adversely affected by the environmental conditions associated with the particular installation.

(c) No self-locking nut may be used on any bolt subject to rotation in operation unless a non-friction locking device is used in addition to the self-locking device.

[Doc. No. 27805, 61 FR 5148, Feb. 9, 1996]

Hi LOren

I looked at your link briefly, specifically the Applicability section and according to that section it doesn't apply to Experimental(Special a/w certificate). Maybe I missed it somewhere.

I got an original design here that I designed and built over the last few years. It's got a small Continental based experimental motor in it, built up from parts; no data plate. My DAR said I had to do the AD search...I asked him what motor did he want me to search. He didn't have an answer. Then I asked him if it was a Briggs and Stratton or a VW would he require an AD search on those experimental motors also? Course not...he dropped it. Those guys make up their own rules lotsa times. Well, around here they're hard to find so we're kinda stuck with whatever they say unless we can reason with them as in the case stated above.

I'm still open to a link that shows a reg that states we gotta do certain hardware an an EAB FWF or anywhere else for that matter



I realize that it's not applicable to experimental, but I do not see how a DAR can justify requiring more than this.  

Sorry fellas been a bit busy but have noted all the comments. In Canada registered as an Amateur build have to change all bolts under cowl to metal lock nuts ..no nylock. change fuel lines from 1/4 to 3/8 except from pump to carbs.Replaced all moving parts petals etc. because no washers and replaced nylocks with castlenuts and cotter pins.Wanted re-run most wiring over engine further from exhaust. Drill drain holes ....and safety wire oil filter...and who knows what else on final inspection but got the go ahead for pre closing..So we will see what the future holds....fuel flow , climb test, w&b....We will get there ....guess still better then a full build:)...This is the last GUY I want to %$@# off...


New from Zenith:

Zenith Planes For Sale 

Classified listing for buying or selling your Zenith building or flying related stuff...

Custom Instrument Panels
for your Zenith

Custom instrument panels are now available directly from Zenith Aircraft Company exclusively for Zenith builders and owners. Pre-cut panel, Dynon and Garmin avionics, and more.

Custom Upholstery Kits for your Zenith Aircraft:

Zenith Vinyl Upholstery Kits

Zenith Apparel from EAA:

Zenair Floats

Flying On Your Own Wings:
A Complete Guide to Understanding Light Airplane Design, by Chris Heintz

Builder & Pilot Supplies:

How to videos from HomebuiltHELP.com

Developed specifically for Zenith builders (by a builder) these videos on DVD are a great help in building your own kit plane by providing practical hands-on construction information. Visit HomebuiltHelp.com for the latest DVD titles.

Aircraft Insurance:


West Coast USA:

Pro Builder Assistance:


Transition training:

Golden Eagle Aviation

Pianosa Flying Farm

Aircraft Spruce & Specialty for all your building and pilot supplies!

© 2021   Created by Zenith.Aero.   Powered by

Badges  |  Report an Issue  |  Terms of Service