Electromagnetic Interference Control Within Aerospace Ground Equipment for the Mcdonnell Phantom II Aircraft

This paper describes the program conducted by McDonnell Aircraft Corporation to assure Electromagnetic Compatibility (EMC) within Aerospace Ground Equipment (AGE) for tile Phantom II Aircraft. The wide variety of sophisticated AGE utilized presents many unique EMC problems. AGE/Aircraft compatibility considerations at McDonnell are of prime concern. Consistent grounding philosophies within AGE and compatible with airborne equipment has been established. Grounding systems are classified as primary power, secondary AC power, DC power, signal and radio frequency. Each equipment ground is classified and controlled accordingly. A Weapon System concept that results in the extensive use of shielded cabling is an important part of the McDonnell Aircraft EMI control approach. Design and testing of shielded cables, connectors, and connector back-shells has been accomplished. New designs to reduce radiation from various front panel mounted switches, jacks, meters, and lights have been developed. These include the grounding of "Bat" handles and shafts of switches and using waveguide below cut-off devices for jacks. Testing complex AGE to determine compliance with Military Specifications can become very time consuming. Methods and procedures to reduce test time, yet maintain a valid test, have been formulated.