A HAD is a Harness Assembly Drawing used to aid in the manufacturing of electrical wiring harnesses. HADs are used in the aerospace industry for all aircraft platforms including the AH-1F, AH-1Z, B-1B, B-52, C-130, EC-130, F-15, F-16, F-22, etc.
Before production of a harness, a HAD is printed in full scale (1:1) to ensure the exact dimensions are met. Each HAD has 4 principal parts:
1. The Title Block – This displays the title, drawing scale and standard tolerances.
2. The Revision Block – This is used to designate changes and revisions to the drawing.
3. The Part Illustration – This is the full scale drawing of the harness.
4. General Notes – This is used to eliminate repetitive local notes.
Once the HAD is created it is printed and placed on a table where the harness is assembled right on top of it. Depending on the customer, terminology for a HAD can differ. Lockheed Martin, Boeing, SES, and L-3 may use the term HAD while other companies such as Sikorsky, Northrop Grumman, and BAE may use terms like mylar, form board, T101 or T105. No matter what term is used, these are all manufacturing aids and are the exact same thing. At InterConnect Wiring, for our trunk electrical wiring harnesses, whether braided, double braided or string-tied, we use the term HAD.
If you need a quote for us to design a HAD for you, please touch here. Be sure to check out InterConnect’s other engineering design capabilities when you view that page.