Landing Gear Structural Health Prognostic/Diagnostic System

Landing gear systems are one of the more problematic subsystems on Naval aircraft. Landing gear failure can be caused by hard landings due to actual severe high sink rate with high enough GW to exceed the design strength, but are extremely rare. More common are fatigue and environmentally caused failures. Aircraft managers address this issue by making estimations of operational loads, and doing detailed fatigue analysis as appropriate to ensure safe landing gear operation. These estimations are conservative by nature, and frequently necessitate assumptions about landing, ground or braking conditions that may be different in actual operational service. The ability to measure, record, and possibly process the operational loads data for each aircrafts"landing gear would give Aircraft Program Offices the ability to make more intelligent management decisions about operational limits, inspection intervals, and removal & depot overhaul cycle values. Additionally, landing gear failures can be caused by mis-servicing of the landing gear, resulting in much higher loads (even for a"normal"landing events or cause excessive fatigue damage than originally assumed). This phenomena is present and problematic for multiple aircraft platforms. The proposed SHM system would address this issue at two levels - detecting and prevent mis-servicing gears hence eliminating higher peak load failures, and also minimize/avoid unnecessary inspections due to perceived"hard landings". ES3 proposes to address all these issues through the use of on-aircraft miniaturized data acquisition systems, with sufficient data storage and processing capabilities to utilize multiple sensor inputs. Additionally, some data acquisition systems have the ability to process captured data, and use the programmed logic to send a signal to a separate fault display unit that will alert the operator to a problematic landing gear (low fluid level, hard landing, overheated brake, maximum fatigue cycles etc). In this Phase I SBIR effort, ES3 will evaluate several of these systems, and numerous applicable sensors for their suitability in a SHM system. During optional activities, prototype hardware will be laboratory tested for various SHM functionality. This Phase I effort will prepare for Phase II activities that will focus on design, qualification and implementation planning efforts.