Experience with On-board SHM System Testing on Small Commuter Aircraft

The general SHM idea which promises significant benefits for new designed vehicles, buildings and structures is simple and clear but its transition into reality brings many questions which needs to be answered. Monitoring of aircraft structures is one of specific SHM applications which puts several requirements on SHM system design like minimal impact on the aircraft design and manufacturing, low weight and small dimensions, system modularity and installation versatility, long-term and automated system operation, and integration with airframe and avionics. Stated requirements have been incorporated in the SHM system design described in this paper. This SHM system is an automated on-board system based on Ultrasonic Guided Waves (UGW) technology. It has been developed for the application on commuter aircraft. Specifically, this system has been installed on the flying prototype and on the full-scale fatigue test of the wing and central part of the fuselage of L 410 NG aircraft. The main intent of this paper is to present experiences gained during the SHM system operation on both the flying prototype and the full-scale testing. Installation and operation of the SHM system on the flying prototype have brought invaluable experiences related to integration, operational conditions and limits. Such experiences are important for future development of the HW part of the SHM system and for mitigation of environmental conditions influence on measured signals. On other hand, the SHM monitoring on the full-scale test proved capability of the system to cover all Principal Structural Elements (PSEs) prone to fatigue damage defined by OEM. This test is very important for evaluation of detection capabilities of the system and its comparison to common GVI and NDI methods as well. Additional experiences acquired from this SHM testing are related to measurement, collection, transfer and evaluation of huge amount of signals. This knowledge will be crucial during a SHM operational concept development and SHM technology implementation into service.