What are your suggestion to close this gap? I am tempted to get some
insulation
from the local hardware store and fix it, but my AP will frown on that.
Any suggestions?

If it's small, a dot (or line) of clear silicone caulk will do the trick.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"