PHILADELPHIA INQUIRER DATE: FRIDAY October 16, 1987 PAGE: B16 EDITION: FINAL SECTION: NATIONAL LENGTH: MEDIUM MEMO: NATIONAL NEWS IN BRIEF STEALTH JET CRASH REPORTED United Press International WASHINGTON - A secret Stealth fighter plane crashed during exercises 100 miles north of Nellis Air Force Base in Nevada, killing the pilot, sources said yesterday. The F-19 plane, which the Pentagon has not officially confirmed exists, is crammed with top-secret technology designed to make it virtually invisible to enemy radar. The crash marked the fifth time in about 10 years that one of the fighters has crashed during tests. Sources knowledgeable about the Stealth fighter and bomber program told United Press International the fighter crashed Wednesday night 100 miles north of*Groom*Lake*on the base during exercises simulating combat in Europe. An Air Force spokesman said only that an ''Air Force aircraft went down.'' He would not confirm the type of plane. Nellis Air Force Base, which tests experimental aircraft, issued a statement last night saying that the pilot, who was not identified, was killed in the crash.