We report the use of a fiber optic distributed sensing system to monitor structural fatigue on an aircraft undergoing a full scale fatigue test. This technique involves using optical frequency domain reflectometry to demodulate the reflected signals from multiplexed bragg gratings that have been photoetched in the core of an optical fiber. The optical fibers, containing a high density of bragg gratings, were applied along the surface of a Lockheed Martin P-3C Orion fatigue test article to assess the suitability of this technique for long term structural damage detection and monitoring. The ability of this technology to accurately map strains with a high spatial resolution on the structure was assessed for both static and dynamic loading conditions. Preliminary results indicate good agreement with quasicollocated foil strain gages and demonstrate great potential for supplementing or providing an alternative to conventional nondestructive testing techniques.