A LOOK AT THE CONCEPT OF VIBRATION AND NOISE ENVIRONMENTAL TESTING

The reliability of airborne equipment is related to the thoroughness of the environmental test program. The importance of being able to rationalize the environmental tests in terms of the actual flight environment is stressed. Present environmental vibration test procedures, which are based for the most part on flight data obtained in propeller driven aircraft, are reviewed. It is shown that such procedures cannot be applied to turbojet aircraft. An environmental test procedure is proposed which utilizes the latest type laboratory shaker and control equipment to provide a vibration and noise analogue of an aircraft. The penalties of “over-testing” are pointed out. In conclusion, an environmental test specification is compared to an insurance policy, and it is urged that its implications be fully understood.