1. Purpose of This Notice. This notice provides guidance to Flight
Standards Service aviation safety inspectors (ASI) for oversight of an approved
minimum equipment list (MEL) and MEL management program. This notice extends
the applicability of Notice N 8900.507, Operator Use of Engineering Change Authorizations
(EA), Engineering Change Orders (EO), and/or Other Acceptable Maintenance Methods
Applicable to Minimum Equipment List (MEL) Items, which expired on April 9, 2020.
2. Audience. The primary audience for this notice is Flight Standards
Service ASIs who have certificate management oversight responsibilities for
operators utilizing an MEL. The secondary audience includes Flight Standards divisions and branches and the Aircraft Evaluation Groups (AEG).
3. Where You Can Find This Notice. You can find this notice on the MyFAA employee website at
can access this notice through the Flight Standards Information Management Systems (FSIMS) at
can find this notice on the Federal Aviation Administration’s (FAA) website at
https://fsims.faa.gov. This notice is available to the public at
4. Background. Operators are required to accomplish Maintenance
(M) and Operations (O) procedures contained in their FAA-approved MEL prior
to dispatch and operation of the aircraft with inoperative equipment. Operators
commonly perform additional maintenance procedures to disable and/or troubleshoot
inoperative equipment or systems in accordance with Engineering Change Authorizations
(EA), Engineering Change Orders (EO), or other acceptable methods during the MEL deferral period.
a. Maintenance on Inoperative Instruments or Equipment. The presence
of an M or O procedure symbol indicates a specific M or O procedure is required
to be accomplished. The operator may perform additional maintenance for troubleshooting
or increased safety of the inoperative MEL item. The additional maintenance
may be more restrictive, but must not be less restrictive than the MEL. Such
maintenance may be performed in accordance with the operator’s MEL management
program, which may include the use of an operator-produced EA, EO, or other
methods acceptable to the Administrator. The procedures developed by the operator must include detailed instructions.
b. Components of MEL Items and Warning/Caution Systems. Defective
components of an MEL item (e.g., chafed or broken wiring, inoperative switch,
or worn electrical connector) that are directly associated with and have no
function other than supporting the MEL item, component, or system being deferred
per the MEL can be inoperative as part of the MEL action. Defective components
of an MEL item (e.g., engine or auxiliary power unit (APU) bleed duct systems
with chafed hole(s) or leaking) that are directly associated with and have function(s)
other than supporting the MEL item, component, or system cannot be deferred
per the MEL. However, warning or caution systems associated with the inoperative
system must be operative unless relief is specifically authorized in the Master Minimum Equipment List (MMEL).
c. Securing and Deactivating Inoperative MEL Items. The certificate
holder’s procedures should describe the methods for securing, labeling, identifying,
and deactivating an inoperative MEL item. Procedures for these methods should
be clearly documented in the certificate holder’s manual system. Such tasks
must be performed in accordance with instructions contained in the certificate
holder’s maintenance manuals. Such tasks include, but are not limited to:
• Disconnecting and securing an electrical connector;
• Draining and/or capping hydraulic, fuel, water, or pneumatic lines;
• Pulling and collaring circuit breakers; and
• Capping and stowing electrical wires (provided there is no effect
on another system or component).
d. Maintenance Instructions. An EA or EO produced in accordance
with the certificate holder’s MEL management program is an acceptable method
for supplementing current aircraft maintenance manual procedures for establishing,
clarifying, or adding to maintenance instructions for securing, labeling, identifying,
and deactivating a defective component or inoperative system, but cannot be less restrictive than the MMEL.
e. Approval or Acceptance of Maintenance Procedures. FAA certificate
management oversight Flight Standards District Office (FSDO)/certificate management
office (CMO) approval or acceptance of such procedures is only necessary at
the level of the certificate holder’s MEL management program and does not extend
to the review and acceptance of engineering documents. All MMEL M and O procedure
symbols are required to be included in the operator’s MEL. All such maintenance
must be documented in the aircraft records, such as the aircraft logbook. During
the deferral period, the operator may work/repair/diagnose/analyze the deferred
MEL item in accordance with the related manual requirements or engineering EAs
or EOs. The MEL repair category will remain as the control for the time limits in the MEL deferral process.
6. Action. Provide operators with guidance for additional maintenance
action(s) when disabling equipment and/or systems in conjunction with an MEL.
7. Disposition. We will incorporate the information in this notice
into FAA Order 8900.1 before this notice expires. Direct questions or comments
concerning the information in this notice to the Aircraft Maintenance Division, Air Carrier Maintenance Branch at 202-267-1675.
ORIGINAL SIGNED by
/s/ Robert C. Carty
Deputy Executive Director, Flight Standards Service