On Saturday, November 23, 2013 2:59:46 PM UTC-8, son_of_flubber wrote:
Let's say Joe Pilot installs a not-TSO'd six point harness in an experimental glider. He puts an entry in the log book. A month later he has the annual inspection done by an A&P. The A&P puts their "all good" sticker in the log book right under the entry for the new harness.



Has the A&P thus "signed off" on the new harness?

If the sailplane is a Experimental "Amateur Built" and was built by the current owner he can do anything he wants and he can sign off the condition inspection as long as he holds a repairmans certificate for his aircraft. If the sailplane is Experimental "Air Racing" the owner can still install seat belts under Part 91 and sign it in the log book but should consult his Mechanic if the belt attachments are changed. When the Mechanic comes and performs his "Condition Inspection" he should inspect the seat belt installation as he would on any Annual/condition inspection and at that time when he signs off the inspection he is stating that the aircraft is airworthy, and thus signing off on the installation of the seat belts. But it is the pilot who determines that the aircraft is in a airworthy condition before he flies.