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Comment by John Montgomery on March 15, 2026 at 5:42pm

Perry made a very pertinent comment about how easy the blind rivets are to drill out. Build things like your stab but only use a few pulled rivets to stabilize the parts and close the top.  Saves cleos and MUCH easier to store the component.  THen, just drill those few rivets out bewore you inspector comes for the pre-cover.

In fact I have a friend who built an RV who  decided to just use pulled rivets instead of installing nutplates for a couple of cockpit inspection panels.  tHe odd time he wants to check his fuel fittings he just drills them out. And you know how anal RV builders can be!  ;)  {poke poke}

Comment by Klaus Gebert on March 15, 2026 at 3:54pm

Thank you Perry and John. I will folow your advise. I was wondering if i have to buy more clecos. Klaus.

Comment by Perry Delano on March 15, 2026 at 2:39pm

Hi Klaus,

Agree with all John has said. A tip I would provide is: If you are building a zenith with pulled rivets you will become a pro at taking them out. Sacrifice a few rivets (you don't need many) to hold the skin you will have to open for inspection rather than using clecos. Clecos make it hard to store parts, and over time with moving parts around catch on stuff and damage the cleco and more importantly the hole they are in. 

Re rivet removal:

Get a good Starrett automatic punch, hit the mandrel a couple of times to drive it away from the shop head, drill off the shop head using size for size bit and set the drill aside. Then hit the mandrel with the punch again it will likely fly clear first time unless the rivet is into a spar or something thicker, then you will have to hit it a few more times. Counter intuitively A5's are easier to remove than A4's as the punch can get a bit deeper in the A5 rivet. Unless something really goes sideways you should be able to avoid using the drill to knock off he shop head.

Comment by John Montgomery on March 12, 2026 at 4:50pm

Just for fun I used AI to dig up info on these questions for me just now.  Very useful for gathering and summarizing the info no obvious on the MDRA web pages.  I paste what it said here:

Core Rule: No Permanent Closure

The most critical guideline is that nothing enclosed should be permanently riveted or closed unless the internal areas remain visually accessible to the inspector. If you close a component (such as a wing or fuselage section) before the inspection, the inspector can legally require you to "unrivet" or remove skins to reveal the internal workmanship. 

Pre-Cover Inspection Guidelines

Guidelines on preparation are detailed in the MD-RA Construction Procedure and specifically within the C20E Inspection Procedures: 

• Materials & Samples: You must have samples of your work available for the inspector to test, including samples of glue, welding, composite layups, or riveted joints.
• Documentation: Before the inspection, you must have submitted a Letter of Intent (Form C01E) and received a "Reply to Letter of Intent" (Form C09E) from the MD-RA office.
• Progress Level: The project should be "as far advanced as possible" without closing any structures.
• Component Flexibility: You can choose to have a single pre-cover inspection for the whole aircraft or separate inspections for major components (fuselage, wings, etc.) as they are completed. 
  www.md-ra.com +1

Specific "Dos and Don'ts"

What You CAN Do	What You CANNOT Do
Assemble components using temporary fasteners (like Clecos).	Permanently close any area that will be inaccessible later.
Proceed with construction once you have received your C09E reply.	Apply fabric, paint, or final skins that hide internal structure.
Prepare all paperwork, including your builder's log and construction photos.	Skip the pre-cover and go straight to final inspection (this is prohibited for homebuilts).

----->

Will my MDRA inspector accept using something like an endoscope camera if I have riveted closed a component like my rudder?

In most cases, 

an MD-RA inspector will not accept an endoscope or borescope as a substitute for a physical pre-cover inspection of a closed component like a rudder. 

The MD-RA's primary mandate is to verify internal workmanship—specifically the "shop heads" of rivets, internal corrosion protection, and proper assembly—before they are hidden. 

Why an Endoscope is Likely to be Rejected

• Regulatory Policy: MD-RA guidance generally mandates that all internal areas must be visually accessible to the inspector's own eyes (often aided only by a mirror and flashlight).
• Detailed Verification: Inspectors check every single fastener for proper formation, "smoking" (signs of movement), or defects. An endoscope often lacks the resolution or field of view to allow an inspector to confidently sign off on the entire internal structure.
• Legal Standing: If a component is closed before inspection, the inspector has the legal authority to require you to "un-rivet" or remove skins to reveal the work. 

Exceptions and Nuance

• Specific Designs: Some components (like certain Van's RV rudders) have large enough lightening holes that an inspector can see everything through them with a mirror and light. In these cases, the component is technically "closed" but still "accessible".
• Inspector Discretion: While the official "song and dance" from the MD-RA office is that everything must be open, individual inspectors have some discretion. If you have already riveted the rudder, call your assigned inspector immediately to discuss the situation before doing anything else.
• Factory-Closed Parts: Only parts closed by the kit manufacturer (and noted on the kit's approved parts list) are exempt from pre-cover inspection. 

Recommended Course of Action

1. Do not rivet anything else closed. Use temporary fasteners like Clecos to hold everything together until the inspector arrives.
2. Contact your inspector. Explain the situation if required about a closed component.. They may ask for detailed high-resolution photos taken during construction, or they may tell you exactly which rivets need to be drilled out to provide a "peek" inside.
3. Prepare to drill. If the inspector cannot see the shop heads of critical internal rivets, expect to drill out enough rivets to at least partially open the skin for a visual check. 

Comment by Klaus Gebert on March 12, 2026 at 2:04pm

Thank you John. How did you handel the situation with the Ruder, Flaperons? In my case there are also the Slats. I hade the same thought about a endoscope with camera. I am living and building 30km. North of Prince George and the inspector is in Vancouver. So I realy like to get it right dhe first time. Klaus.

Comment by John Montgomery on March 12, 2026 at 11:02am

Good  topic!! When building our club 750 Cruzer components we just needed to provide access for inspection.  So for parts like the horizontal stab and wings we assembled everything and did not rivet stabilizer and wing top skins.  Top skins were drilled but only cleco'd until the pre-cover inspect was done.  Only then were they closed up and riveted.  It helped that our inspector was located near us so we did not have to pay for travel or try to get everything done in one go...  I'd love to see general planning and inspection preparation advice from  builders located in a more remote area.  I am really curious where using a modern endoscope inspection camera is ok.