Harry Ravenna was born near Houston, Texas and moved to
      San Antonio while still a youngster. He graduated from Thomas Jefferson High School in
      1955 and St. Mary's University in 1960. He enlisted in the Army, attending Officer
      Training School at Fort Sill, Oklahoma, and was assigned to duty in Vietnam in
      September 1966
      Ravenna was assigned to the 138th Aviation Company, 224th U. S. Army Security Agency
      Battalion (Aviation), U. S. Army Security Agency Group, Vietnam. All missions of this
      agency were highly classified during the war, and secret cover designations (Radio
      Research Units) were used instead of the actual unit designations on station lists and
      reports. The 138 was based at Da Nang. 
      On November 15, 1966, US Army Captain Harry M. Ravenna, pilot, and US Marine Corps Cpl.
      John C. Keiper, passenger, were flying a U6A aircraft (serial # 541723) on a routine
      flight from Dong Ha to Da Nang. Keiper was assigned to Helicopter Attack Maintenance
      Squadron 16, Marine Air Group 16. His role on this mission is unclear from public records.
      Ravenna filed a VFR (visual flight rules) flight plan, but ran into poor weather
      conditions. He radioed Dong Ha and request radar guidance. At 1430 hours he passed into Da
      Nang airfield radar control and radioed, "Lonely Ranger 723, heading 125, 3000 feet,
      estimating Da Nang at 40, request radar. Presently on instruments." Having trouble
      bringing him into radar screen, Da Nang instructed Ravenna to activate his transponder,
      but this did not improve radar contact, so they asked his location, which he gave as 45
      nautical miles from Dong Ha. Da Nang instructed him to tact Dong Ha (believing he was out
      of Da Nang range and still in that of Dong Ha). Ravenna acknowledged the transmission,
      radio contact was broken, and never resumed. Ravenn and Keiper were last believed to be in
      South Vietnam about halfway between Da Nang and the city of Hue. Later investigation
      concluded that on his present course, had it been followed, Ravenna's aircraft would have
      impacted with the side of a mountain in that vicinity. The hostile threat in the area
      prevented extensive search, and all efforts to discover the fate of Ravenna and Keiper
      have failed. 
      Keiper and Ravenna are among nearly 2500 Americans who did not return from the war in
      Vietnam. Today, thousands of reports have been received by the U. S. Government that
      indicate that men are still, held in captivity in Southeast Asia. Thus far, official
      policy is to state that "conclusive proof" is not yet available. Detractors
      state that proof is in hand, but the will to act on that proof does not exist. As long as
      even ONE American is alive, held against his will, we must do everything in our power to
      achieve his release.