Brothers Kenneth and John Hunter had a plan for this trip: Break the world record for longest flight by staying in the air for more than 18 days. Midway through the journey, however, they realized the engine needed new spark plugs.
"Thousands of feet above the ground, it was necessary to crawl forward along a flimsy catwalk and risk being thrown off by an electric shock." Two other brothers, Walter and Albert, snapped this photo from the refueling plane as they cheered on their gutsy sibling.
The repair was a success, and the Hunter brothers set a new endurance flight record when they landed after 553 hours.
Read the full story in our September 1930 issue: New Spark Plugs Help Endurance Flight