Independent Safety Board Act Amendments of 1994 - Amends the Independent Safety Board Act of 1974 to authorize appropriations for FY 1994 through 1996 for the National Transportation Safety Board (NTSB). (Sec. 3) Amends the Federal Aviation Act of 1958 with respect to the applicability of Federal Aviation Administration (FAA) safety requirements to public aircraft (aircraft used exclusively in the service of any Federal, State, or local government, excluding government-owned aircraft engaged in carrying persons or property for commercial purposes). Revises the definition of "engaged in carrying persons" to include the provision of passenger transportation but not: (1) the carriage of crewmembers or of other required persons aboard such aircraft for a governmental function such as fire fighting, search and rescue, law enforcement, aeronautical research, or biological or geological resource management; or (2) the carriage of persons (other than for commercial purposes) aboard aircraft operated by the armed forces or a U.S. intelligence agency. Authorizes the Administrator of the FAA (Administrator) to exempt such aircraft from FAA safety requirements if it is in the public interest. Amends the Independent Safety Board Act of 1974 to grant the NTSB authority to investigate nonmilitary public aircraft accidents. (Sec. 4) Requires the Administrator to consider for approval the new generation, low cost, advanced landing system being developed by the Department of Defense.