At the end of the 90's, the Israeli Air Force (IAF) decided to expand its activities regarding aircraft Total Health-Usage Monitoring Systems (THUMS) for rotary wing platforms. This action began in order to increase the safety of dynamical components in certain IAF platforms and the desire to improve the helicopter fleet availability by developing new technologies based on individual component maintenance and by reviewing and implementing worldwide researches in the field of aircraft health monitoring. The IAF is known to operate its aircraft in very demanding operational environments; this further emphasizes the need to install an onboard health monitoring systems which will increase flight safety, mission readiness and potentially reduce maintenance cost. This paper describes the scope of activities the IAF took in order to develop advanced maintenance methods by installing onboard health monitoring systems in the IAF's AH-64A APACHE helicopters fleet. In addition, this article will try to describe the lessons learned during the development and in the process of adapting the THUMS to fulfill the requirements of the IAF's AH-64A fleet.