Main Avionics Rack
 
 
Key Issues
 
Company McDonnell Douglas
Product Main Avionics Rack for the MD-11
Objectives Reduce product cost
Simplify build and installation to the aircraft
Shorten construction lead times
Reduce the weight
Simplify the maintenance tasks
Approach Concurrent engineering team using Design for Manufacture and Assembly tools.

Original Design

The main avionics rack was a complex structure consisting of six miles of wire crammed into five shelving units. Because it was built as a single assembly, only two employees could work on it at the same time, requiring 55 days of build time including repeated wiring integrity tests. Once built it took six people to load it into the nose of the plane prior to the nose-to-fuselage join. Once installed it was difficult to change or maintain.
 
 

New Design

Adopting a modular construction of pressed parts, enabled concurrent wiring and testing of shelf units reducing span time. Each shelf unit can be loaded to the aircraft through the avionics compartment access hatch after nose-to-fuselage join. Subsequent maintenance and retrofitting is much simpler and more cost effective.
 
Benefits
  • Modular construction enabling multi tasking and easier installation
  • 80% part reduction
  • 31% fewer build days
  • 19% fewer labour hours
  • 47% reduction in structure weight
  • 1 mile of wire less
  • total saving of $54,000 per aircraft
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