John Yamnicky was born on June 8, 1930, in Barren Run, Pennsylvania. He entered the U.S. Naval Academy in August 1948, and graduated with a commission as an Ensign in the U.S. Navy on June 6, 1952. Yamnicky served aboard the attack transport USS Calvert (APA-32), from June 1952 to September 1953, and then attended flight school at NAS Pensacola, Florida, where he was designated a Naval Aviator on January 26, 1955. His next assignment was with Utility Squadron 10 (VU-10) at Guantanamo Bay, Cuba, from January 1955 to April 1957, followed by service with Attack Squadron 46 (VA-46) flying the F9F-8 Cougar and A4D-2 Skyhawk at NAS Cecil Field, Florida, from April 1957 to December 1959. LT Yamnicky then served as a Replacement Air Group Instructor Pilot with VA-44 at NAS Jacksonville, Florida, from December 1959 to October 1960, during its transition from the AD-4 Skyraider to the A4D-2N Skyhawk. This was followed by Test Pilot School at NAS Patuxent River, Maryland, from October 1960 to June 1961, and then service as a Flight Test Project Officer from June 1961 to October 1963. LCDR Yamnicky served with VA-125, the Replacement Air Group at NAS Lemoore, California, flying A-4 Skyhawks from October 1963 to March 1964, and then joined VA-146, flying combat missions during two deployments to Southeast Asia between June 1964 and June 1966, aboard the aircraft carriers USS Constellation (CVA-64) and USS Ranger (CVA-61). CDR Yamnicky left VA-146 and entered the Naval War College in June 1966, graduating in June 1967. He was a replacement pilot with VA-44 at NAS Cecil Field from June to November 1967, and then served as Executive Officer of VA-172 from November 1967 to November 1968, followed by service as Commander of VA-172 from November 1968 to October 1969. During this time, CDR Yamnicky made two Mediterranean deployments aboard the aircraft carriers USS Franklin D. Roosevelt (CVA-42), and USS Shangri-La (CVA-38). Capt Yamnicky then served at NAS Patuxent River, taking over as Director of the Test Pilot School in May 1972. His final assignment was at Headquarters U.S. Navy in the Pentagon, where he retired on June 30, 1979. After retiring from the Navy, John worked as a defense contractor for Veridian Corporation, and was killed while flying as a passenger aboard American Airlines Flight 77 when terrorists crashed the plane into the Pentagon on September 11, 2001. He was buried at Arlington National Cemetery.