Maintainability Concepts Used in the Design and Operation of Douglas Commercial Jet Aircraft

In the past few years, maintenance costs have risen only about half as fast as the other components of operating cost. The evolution of maintenance philosophy and maintainability concepts are prime factors which have permitted this degree of control of maintenance costs, in spite of rising wages and material prices.

This paper explains the maintenance philosophy at Douglas Aircraft and gives examples relating to the DC-8, DC-9, and DC-10. The three methods of maintenance control-Hard Time, On Condition, and Condition Monitoring-are described, and statistics of Delta Air Lines maintenance provided to illustrate their effectiveness.