Mark I Demolition Bomb The Mark I 4,300-pound bomb, developed for the Mitchell bombing trials, was first tested on Sept. 29, 1921. Unfortunately, Mitchell never obtained permission to drop the bomb during the trials, and the largest bomb used weighed 2,000 pounds. Purportedly, the U.S. Army Air Service removed this bomb from service in the mid-1920s because its destructive force was greater than needed to destroy any man-made target. Also, with the grounding of its last, obsolete Handley-Page O/400 bomber from the World War I period, the Army Air Service no longer possessed an airplane that could carry a 4,300-pound bomb. Click here to return to the Early Years Gallery. Find Out More Related Fact Sheets Battleship Trials Note: The appearance of hyperlinks does not constitute endorsement by the National Museum of the USAF, the U.S. Air Force, or the Department of Defense, of the external website, or the information, products or services contained therein.