 Complete the following phrase:  In 1919, United States Marine Corps USMC pilot Lt. L. H. Sanderson mounted a rifle in front of the windshield of his Curtiss JN-4 a training aircraft as an improvised bomb sight, loaded a bomb in a canvas bag attached to the aircrafts underside, and made a solo attack in support of USMC troops trapped by Haitians during the United States occupation of Haiti. Sandersons bomb hit its target and the raids were repeated. During 1920, Sanderson familiarised aviators of USMC units on the Atlantic coast with dive bombing techniques. Dive bombing was also used during the 