Hi Nasser As Larry says - you must avoid any sealed compartments anywhere in the airplane - so that atmospheric pressure can always equalize.
The above is particularly important for the spars, where individual "compartments" are formed by the pillars between the spar caps. All of these cavities must be able to "vent" to the outside of the spar. I recall that you made some super strong spars with CF between cap laminations as well as ply /CF webs front and back. If you did not know this at the time, you may have created a sealed spar. If so Nasser - consider drilling a small hole (1 to 2 mm) through the web (front or back) into each compartment. From the plans you should know exactly where each full depth spar pillar is. Maybe glue an eyelet into the hole or pull a blind rivet to seal the exposed wood and keep the opening neat and clear. These holes can be very small - pin holes would be Ok, just ensure that nothing (paint /dirt /attachment) blocks them. Take care Steve J
