During annual.

MelsML55 · #1 01-24-22, 05:55 PM

During annual for a new shop that has never worked on a 337, is it normal practice to not remove wing tips and wing root covers?

mshac · #2 01-24-22, 06:10 PM

I don't think those would normally be removed during an annual, unless there was an AD that required it for some reason, i.e. to inspect wing bolts or similar. Beechcraft has an AD to that effect on some models.

JAG · #3 01-26-22, 10:27 AM

I am not sure what's normal, but I can tell you that I remove the wing root panels. This allows me to inspect wing attach points, fuel selector valves (visual and lubricate) and general visual of wiring, cables and fuel lines for any issues.

I don't normally remove the wing tips - as I can inspect function of the fuel vent valves on my A model without removing. That is about the only thing under my wingtips that are worth looking at. That being said, I remove them every second annual so I can have a good visual look around for any mud daubers.

Jeff

mshac · #4 01-26-22, 11:54 AM

While certainly a good thorough annual inspection could go much farther, the "FAA Minimums" for an annual inspection don't require removal of either item. As was mentioned, there are other excellent reasons to remove them, but your shop may charge you extra because it isn't in the FAA requirements.

What are the FAA requirements? Well here they are: https://www.cessnaflyer.org/knowledg...checklist.html

JAG · #5 01-26-22, 12:44 PM

Part 43 Appendix D, subsection F says you SHALL inspect wing attachment; therefore, removal of the wing to body fairings (and cuffs on struts) would be required to inspect - or have I read this wrong?

Jeff

wslade2 · #6 01-27-22, 12:22 AM

JAG, what is your technique for checking the fuel vents? I have been wondering myself besides just probing the end for daubers.

Personal opinion here. I like to remove wing root covers on my high wing cessnas. Wing attachment bolts there. Besides bolts being pretty important, those covers aren’t the greatest at keeping rain/water out and bolts/wing attachments at risk for corrosion. Plus a stress point. Best to be eyeballed. I put some ACF-50 on them. A corrosion problem discovered late there could get pretty expensive.

JAG · #7 01-27-22, 04:17 PM

To check my fuel vent and vent valve, I have a 6ft piece of surgical tubing and a glass of water (or Costco bottle of water). I put the surgical tubing over the vent line on the trailing edge vent line at the wing tip. Next, I take a deep breath and blow into the other end of the tubing. If the air goes into the tanks (no resistance to my blowing), I know the vent is clear to the tank. Now, the next step I cheat a little...I take my compressor nozzle, and give a short shot into the tubing (simulating a real deep breath - I do this so I don't pass out), which slightly pressurizes your fuel tanks, then stick the end of the hose into the glass of water or bottle, and see if it bubbles. If it does, you know the vent valve weep hole is also doing its job of releasing pressure as well. if you have a fuel cap that does not seal well, your breath alone may not be enough to pressurize the tank (found that out the first time).

The main thing I am concerned with is the first part of the test - ensuring good flow of air into the tank. Small bugs can tend to block this line and that can cause issues with fuel flow or worse, collapsed tank.

Jeff