In the design of the S-65-200 Commercial Compound Aircraft - a 230 knot, 86 passenger transport - maximum consideration was given to meeting a high dispatch reliability goal and to ease of performing maintenance. This paper describes how maintenance and reliability of this compound helicopter is enhanced by use of new and improved technology.Use of built-in test equipment reduces electronic component maintenance by approximately 43%. An airborne integrated data system reduces line level maintenance by approximately 16% and provides trend information for detection of incipient malfunctions. A newly developed rotor head bifilar vibration absorber reduced aircraft vibration levels, thereby reducing airframe and structure maintenance by almost 15%. A modularized engine allows for minimum disassembly at intermediate levels of maintenance. New and high grade materials, such as composites and vacuum-melt steels, improve life characteristics of structure and dynamic components. The ability to inspect subsystems is increased, and all components are readily removable. Almost 95% of all maintenance actions are performed from outside the aircraft.The cumulative result of these features of the S-65-200 Commercial Compound Aircraft is a predicted 0.98 dispatch reliability. Direct maintenance is estimated at 9.3 maintenance manhours per flight hour for all levels of aircraft maintenance.