DOT/FAA/CT-89/22 Aircraft Lightning Protection Handbook
The FAA Aircraft Lightning Protection Handbook by Andy Plumer and Frank Fisher of Lightning Technologies along with Rod Perala of EMA is a foundational document.
Completed in 1989, this volume contains in-depth information regarding the lightning protection of metal and composite aircraft, fuel systems, and electrical/electronic equipment. This handbook belongs on every lightning engineer's shelf.
You can download a copy here:
Aircraft Lightning Protection Handbook