874
xkcd #2897: Light Leap Years
(imgs.xkcd.com)
Alt text:
When Pope Gregory XIII briefly shortened the light-year in 1582, it led to navigational chaos and the loss of several Papal starships.
I don't have an exact reference for you, but it sounds like a quote from Hawkeye (Alan Alda) from MASH.
Haha I wasn't looking for a quote, I was just making the "citation needed" joke that XKCD throws into a lot of stuff.