It was used by the co-pilot to escape the cockpit of Comair 9151 following the post-crash fire. Despite extensive burns, he was able to extricate himself through the windshield using the axe. He would eventually return to the cockpit to fly another day. The use of the axe was something mentioned on a documentary I saw years ago.
https://en.m.wikipedia.org/wiki/Comair_Flight_5191