The PW-5 aileron story, and the post that mentioned distractions during glider preparation prompt me to offer my thoughts. Distractions are never a good thing, but they are also inevitable. Safety requires a scheme that ensures an airworthy glider even when a host of distractions interfere with assembly.
Thus we have the Critical Assembly Check (CAC). This is a separate check of each item that the manufacturer and the service history of the glider indicate are critical to flight safety. For every glider you fly you should have a list of these critical items, and you should check them prior to flight. It will help if you get in the habit of placing a mark on the wing root tape that indicates you have done the CAC.
The list should be as short as possible. It should not include "nice to have" items such as installing batteries and checking their voltage. Batteries are important and should indeed be checked prior to launch. Failure to do so might well be reason to land prematurely. But there should be no glider in which a battery is required for safe, controlled flight - so checking batteries should be part of your assembly checklist, but not your CAC.
On my Discus, the CAC includes three items:
- Main pin secured
- Tail pin fully seated
- Controls free
Note that the CAC is not the same as a positive control check (PCC). For an aircraft that has manual control hookups, the CAC might include a PCC (though direct inspection of the control hookups has in a number of cases been shown to be more reliable). And there are almost certainly other items in any CAC (such as checking that pins are secured).
*It should be noted that weight and balance sufficiently out of tolerance would provide another way to achieve an unairworthy Discus.
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