What did you think of the episode? Personally I'm a little disappointed they only used two of Johnny Cash's songs. It seems like you hear 'Sunday Morning Coming Down' every 30 seconds. Cash's performance was great of course, playing basically a worse version of himself. The murder plot with the parachute was solidly put together but having Columbo bait the villain into digging up the evidence just seemed like a repeat of Blueprint for Murder.
There's some Columbo background sprinkled throughout the episode. We learn that the Lieutenant served in Korea, and it's also mentioned (3 times I believe) that he's Italian.