Purpose of This Notice. This notice provides notification of a nonmandatory revision to
operations specification (OpSpec), management specification (MSpec), and letter of
authorization (LOA) C048/MC048, applicable to Title 14 of the Code of Federal Regulations
(14 CFR) parts 91, 91 subpart K (91K), 121, 125 (including part 125 Letter of Deviation
Authority (LODA) holders), 129, and 135, and provides revised guidance for the completion and
issuance of this authorization.

This advisory circular (AC) provides applicants with guidance for obtaining Federal
Aviation Administration (FAA) approval of compliance pursuant to title 14, Code of
Federal Regulations (14 CFR) 23.954, 27.954, and 29.954, Fuel system lightning
protection. This AC recommends how to protect an aircraft’s fuel system from lightning
strikes that may ignite fuel vapors.