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.

This advisory circular (AC) provides guidance for showing compliance with the airworthiness
regulations for transport category airplanes regarding lightning protection of fuel tanks and
systems. These lightning protection requirements apply to normal conditions and possible
failures of fuel tank structure and systems that could lead to fuel tank explosions. This AC also
provides guidance for developing critical design configuration control limitations (CDCCLs) and
Airworthiness Limitations required to be included in the Instructions for Continued
Airworthiness (ICA) related to lightning protection features of the airplane fuel system.
If you have suggestions for improving this AC, you may use the Advisory Circular Feedback
form at the end of this AC.

This advisory circular (AC) provides guidance for showing compliance with title 14, Code of
Federal Regulations (14 CFR) 25.981, Fuel tank explosion prevention, which provides the
certification requirements for the prevention of ignition sources, other than lightning, within the
fuel tanks of transport category airplanes. AC 25.954-1, Transport Airplane Fuel System
Lightning Protection, now addresses ignition sources due to lightning. The guidance in this AC
is applicable to transport category airplanes for which a new, amended, or supplemental type
certificate is requested.
Revisions to this AC include: (1) removing the lightning-related aspects because they are now in
AC 25.954-1, developed specifically to address compliance with § 25.954, Fuel system lightning
protection; and (2) describing means of compliance for prevention of failure conditions created
from ignition sources, other than lightning, using circuit protective devices—such as an arc fault
circuit breaker or ground fault interrupter—to provide fail-safe features.
If you have any suggestions for improving this AC, you may the Advisory Circular Feedback
form at the end of this AC.

This revision provides guidance to operators when developing, implementing, and revising standard operating procedures (SOP) and training programs regarding crew communication and coordination. We intend this advisory circular (AC) for those operators governed by Title 14 of the Code of Federal Regulations (14 CFR) and 14 CFR part 119 certificate holders conducting operations that include both flight crewmembers and flight attendants. The AC provides research and discussion topics, followed by communication and coordination issues between crewmember findings in National Transportation Safety Board (NTSB) reports.