Federal Aviation Administration Kansas City Aircraft Evaluation Group DOT Building

Guidelines for (O) & (M) Procedures Guidelines for (O) & (M) Procedures

2 03/14/1985 ALL PAGES 3 03/16/1989 ALL PAGES 06/22/1989

                          11 09/11/2006 XI 11 09/11/2006 XII 11 09/11/2006 XII 11 09/11/2006 XIII 11 09/11/2006 XIV 11 09/11/2006 Preamble XV 2 06/14/1989 XVI 2 06/14/1989 XVII

                          7 01/25/2007 XX 7 01/25/2007 01/25/2007

System numbers are based on the Air Transport Association (ATA) Specification and items are numbered sequentially.

a.  "Item" (Column 1) means the equipment, system, component, or function listed in the "Item" column.

b.  "Number Installed" (Column 2) is the number (quantity) of items normally installed in the aircraft.  This number represents the aircraft configuration considered in developing this MMEL.  Should the number be a variable (e.g., passenger cabin items) a number is not required.

c.  "Number Required for Dispatch" (Column 3) is the minimum number (quantity) of items required for operation provided the conditions specified in Column 4 are met.

NOTE:  Where the MMEL shows a variable number required for dispatch, the MEL must reflect the actual number required for dispatch or an alternate means of configuration control approved by the Administrator.

d.  "Remarks or Exceptions" (Column 4) in this column includes a statement either prohibiting or permitting operation with a specific number of items inoperative, provisos (conditions and limitations) for such operation, and appropriate notes.

e.  A vertical bar (change bar) in the margin indicates a change, addition or deletion in the adjacent text for the current revision of that page only.  The change bar is dropped at the next revision of that page.

2.  "Airplane/Rotorcraft Flight Manual" (AFM/RFM) is the document required for type certification and approved by the responsible FAA Aircraft Certification Office.  The FAA approved AFM/RFM for the specific aircraft is listed on the applicable Type Certificate Data Sheet.

3.  "As required by FAR" means that the listed item is subject to certain provisions (restrictive or permissive) expressed in the Federal Aviation Regulations operating rules. The number of items required by the FAR must be operative.  When the listed item is not required by FAR it may be inoperative for the time specified by repair category.  The term “14 CFR” may be substituted for “FAR” in MMELs or operator MELs.

4.  Each inoperative item must be placarded to inform and remind the crewmembers and maintenance personnel of the equipment condition.

NOTE:  To the extent practical, placards should be located adjacent to the control or indicator for the item affected; however, unless otherwise specified, placard wording and location will be determined by the operator.

5.  "-" symbol in Column 2 and/or Column 3 indicates a variable number (quantity) of the item installed.

6.  "Deleted" in the remarks column after a sequence item indicates that the item was previously listed but is now required to be operative if installed in the aircraft.

7.  "ER" refers to extended range operations of a two-engine airplane (ETOPS) which has a type design approval for ER operations (ETOPS) and complies with the provisions of Advisory Circular 120-42A.

8.  "Federal Aviation Regulations" (FAR) means the applicable portions of the Federal Aviation Act and Federal Aviation Regulations.

9.  "Flight Day" means a 24 hour period (from midnight to midnight) either Universal Coordinated Time (UCT) or local time, as established by the operator, during which at least one flight is initiated for the affected aircraft.

10.  "Icing Conditions" means an atmospheric environment that may cause ice to form on the aircraft (structural) or in the engine(s) (induction).

11.  Alphabetical symbol in Column 4 indicates a proviso (condition or limitation) that must be complied with for operation with the listed item inoperative.

12.  ”Inoperative" means a system and/or component malfunction to the extent that it does not accomplish its intended purpose and/or is not consistently functioning normally within its approved operating limit(s) or tolerance(s).

13.  ”Notes:" in Column 4 provides additional information for crewmember or maintenance consideration.  Notes are used to identify applicable material which is intended to assist with compliance, but do not relieve the operator of the responsibility for compliance with all applicable requirements.  Notes are not a part of the provisos.

14.  Inoperative components of an inoperative system:  Inoperative items which are components of a system which is inoperative are usually considered components directly associated with and having no other function than to support that system. (Warning/caution systems associated with the inoperative system must be operative unless relief is specifically authorized per the MMEL).

15.  "(M)" symbol indicates a requirement for a specific maintenance procedure which must be accomplished prior to operation with the listed item inoperative.  Normally these procedures are accomplished by maintenance personnel; however, other personnel may be qualified and authorized to perform certain functions.  Procedures requiring specialized knowledge or skill, or requiring the use of tools or test equipment should be accomplished by maintenance personnel.  The satisfactory accomplishment of all maintenance procedures, regardless of who performs them, is the responsibility of the operator.  Appropriate procedures are required to be published as part of the operator's manual or MEL.

16.  "(O)" symbol indicates a requirement for a specific operations procedure which must be accomplished in planning for and/or operating with the listed item inoperative. Normally these procedures are accomplished by the flight crew however, other personnel may be qualified and authorized to perform certain functions.  The satisfactory accomplishment of all procedures, regardless of who performs them, is the responsibility of the operator.  Appropriate procedures are required to be published as a part of the operator's manual or MEL.

NOTE:  The (M) and (O) symbols are required in the operator's MEL unless otherwise authorized by the Administrator.

17.  "Deactivated" and "Secured" means that the specified component must be put into an acceptable condition for safe flight.  An acceptable method of securing or deactivating will be established by the operator.

18.  "Visual Flight Rules" (VFR) is as defined in FAR Part 91.  This precludes a pilot from filing an Instrument Flight Rules (IFR) flight plan.

19.  "Visual Meteorological Conditions" (VMC) means the atmospheric environment is such that would allow a flight to proceed under the visual flight rules applicable to the flight.  This does not preclude operating under Instrument Flight Rules.

20.  "Visible Moisture" means an atmospheric environment containing water in any form that can be seen in natural or artificial light; for example, clouds, fog, rain, sleet, hail, or snow.

21.  "Passenger Convenience Items" means those items related to passenger convenience, comfort or entertainment such as, but not limited to, galley equipment, movie equipment, ash trays, stereo equipment, overhead reading lamps, etc.

22.  Repair Intervals:  All users of an MEL approved under FAR 121, 125, 129 and 135 must effect repairs of inoperative systems or components, deferred in accordance with the MEL, at or prior to the repair times established by the following letter designators:

Category A.  Items in this category shall be repaired within the time interval specified in the remarks column of the operator's approved MEL.

Category B.  Items in this category shall be repaired within three (3) consecutive calendar days (72 hours), excluding the day the malfunction was recorded in the aircraft maintenance record/logbook.  For example, if it were recorded at 10 a.m. on January 26th, the three day interval would begin at midnight the 26th and end at midnight the 29th.

Category C. Items in this category shall be repaired within ten (10) consecutive calendar days (240 hours), excluding the day the malfunction was recorded in the aircraft maintenance record/logbook.  For example, if it were recorded at 10 a.m. on January 26th, the 10 day interval would begin at midnight the 26th and end at midnight February 5th.

Category D. Items in this category shall be repaired within one hundred and twenty (120) consecutive calendar days (2880 hours), excluding the day the malfunction was recorded in the aircraft maintenance log and/or record.

New generation aircraft display system fault indications to the flight crew by use of computerized display systems.  Each aircraft manufacturer has incorporated individual design philosophies in determining the data that would be represented.  The following are customized definitions (specific to each manufacturer) to help determine the level of messages affecting the aircraft's dispatch status.  When preparing the MEL document, operators are to select the proper Definition No. 23 for their aircraft, if appropriate.

Boeing airplanes equipped with Engine Indicating and Crew Alerting Systems (EICAS) provide different priority levels of system messages (WARNING, CAUTION, ADVISORY, STATUS and MAINTENANCE).  Any messages that affects airplane dispatch status will be displayed at a STATUS message level or higher.  The absence of an EICAS STATUS or higher level (WARNING, CAUTION, ADVISORY) indicates that the system/component is operating within its approved operating limits or tolerances.

System conditions that result only in a maintenance level message, i.e. no correlation with a higher level EICAS message, do not affect dispatch and do not require action other than as addressed within an operator’s standard maintenance program.

These aircraft are equipped with an alerting function which is a subsystem within the Electronic Instrument System (EIS).  The alerting function provides various levels of system condition alerts (WARNING, CAUTION, ADVISORY, MAINTENANCE and STATUS)

Alerts that affect aircraft dispatch will include WARNING, CAUTION, STATUS or MAINTENANCE level.  MAINTENANCE alerts are displayed on the status page of the EIS display panel under the maintenance heading.

A MAINTENANCE alert on the EIS indicates the presence of a system fault which can be identified by the Central Fault Display System (CFDS) interrogation.  The systems are designed to be fault tolerant, however, for any MAINTENANCE alert, the MEL must be verified for dispatch purposes.

Airbus aircraft equipped with Electronic Centralized Aircraft Monitoring (ECAM) provide different levels of system condition messages (WARNING, CAUTION, STATUS, and ADVISORY).  A-318/320/319/ 321, A-330, and A-340 also provide MAINTENANCE status messages.

Any message that affects airplane dispatchability will normally be at the WARNING, CAUTION or STATUS level.  MAINTENANCE messages (A-318/319/320/321, A-330, and A-340 only) are also indicated on ECAM Status Page below the white Maintenance label.

A MAINTENANCE status (Class II) message on ECAM indicates the presence of a system fault which can be identified by CFDS (A-318/319/320/321) or CMS (A-330/A- 340) interrogation.  The systems are designed to be fault tolerant.  For A- 318/319/320/321, MAINTENANCE STATUS (Class II) do not affect dispatch but are listed in the MMEL.  Dispatch is allowed without specific conditions except for:

Fokker aircraft are equipped with Multi Function Display System (MFDS) which provides electronic message referring to the different priority levels of system information (WARNING (red), CAUTION (amber), AWARENESS (cyan) AND STATUS (white).  Any messages that affects aircraft dispatch will be at the WARNING, CAUTION or AWARENESS level.  In these cases the MEL must be verified for dispatch capability and maintenance may be required.

System conditions that only require maintenance are not ¦presented on the flight deck. These maintenance indications/messages may be presented on the Maintenance & Test Panel (MAP) or the Centralized Fault Display Unit (CFDU) and by dedicated Built in Test Evaluation (BITE) of systems.

Canadair aircraft equipped with Engine Indication and Crew Alerting Systems (EICAAS) provide four classes of messages (WARNING, CAUTION, ADVISORY, and STATUS). Any message that affects aircraft dispatch will be at the WARNING, CAUTION, or STATUS level.

System conditions that only require maintenance are not visible to the flight crew.  These maintenance indications/messages are only activated by maintenance personnel using the Maintenance Diagnostics Computer.

The EMB-135/145 and ERJ-170/190 are equipped with an Engine Indicating and Crew Alerting System (EICAS) that provides three different message levels:  WARNING, CAUTION, and ADVISORY.  The ERJ-170/190 Series add STATUS messages.

Failures that effect dispatchability are presented to the flight crew at one of these levels. Other failures may be presented only to the maintenance personnel on the Multi Function Display (MFD) maintenance pages or through the download of the Central Maintenance Computer (CMC).  System conditions that result only in a maintenance level message, i.e. no correlation with a higher level EICAS message, do not affect dispatch and do not require action other than as addressed within an operator’s standard maintenance program.

Gulfstream airplanes equipped with EICAS provide different priority levels of system messages:  WARNING (red), CAUTION (amber), ADVISORY, STATUS and MAINTENANCE (cyan or blue).  Any WARNING or CAUTION message affects airplane dispatch status and requires that the Airplane Flight Manual or the MEL be used to determine dispatch capability.  STATUS messages which indicate a system failure (e.g., FMS-1 fail) require that the Airplane Flight Manual or the MEL be used to determine dispatch capability.  Maintenance messages do not affect airplane dispatch status.  They indicate the presence of a system fault which can be identified by Maintenance Data Acquisition Unit (MDAU on the G-V) interrogation, Central Maintenance Computer (CMC on the GV-SP/GIV-X) interrogation or by reference to the Airplane Flight Manual.

Series 400 aircraft are equipped with a Caution/Warning Panel that annunciates all cautions and warnings.  Advisory messages are displayed by the Electronic Indication System (EIS) or individual advisory lights supplied in the cockpit.

“Class 1 failures” are failures that prevent continued operation of a specific Line Replacement Unit or channel and are annunciated via advisory messages:  caution, warning or advisory lights in the flight compartment.  Dispatch with such posted failures are to be in accordance with the MMEL.

“Class 2 failures” are failures which do not prevent continued system function.  These faults will not be annunciated to the flight crew and the absence of the higher level alert (warning, caution, advisory) indicates that the system/component is operating within its approved operating limits or tolerances.  Such faults would be evident during maintenance interrogation performed during maintenance activities.  Class 2 faults do not affect dispatch and will be listed in the Fault Isolation Manual (FIM).  Class 2 faults will be left to the discretion of the operators when these faults are to be rectified.

24.  "Administrative control item" means an item listed by the operator in the MEL for tracking and informational purposes. It may be added to an operator's MEL by approval of the Principal Operations Inspector provided no relief is granted, or provided conditions and limitations are contained in an approved document (i.e. Structural Repair Manual, airworthiness directive, etc.).  If relief other than that granted by an approved document is sought for an administrative control item, a request must be submitted to the Administrator.  If the request results in review and approval by the FOEB, the item becomes an MMEL item rather than an administrative control item.

25.  "***" symbol in Column 1 indicates an item which is not required by regulation but which may have been installed on some models of aircraft covered by this MMEL.  This item may be included on the operator's MEL after the approving office has determined that the item has been installed on one or more of the operator's aircraft. The symbol, however, shall not be carried forward into the operator's MEL.  It should be noted that neither this policy nor the use of this symbol provide authority to install or remove an item from an aircraft.

26.  "Excess Items" means those items that have been installed that are redundant to the requirements of the FARs.

27.  "Day of Discovery" is the calendar day an equipment/instrument malfunction was recorded in the aircraft maintenance log and or record.  This day is excluded from the calendar days or flight days specified in the MMEL for the repair of an inoperative item of equipment.  This provision is applicable to all MMEL items, i.e., categories "A, B, C, and

28.  “Considered Inoperative”, as used in the provisos means that item must be treated for dispatch, taxi and flight purposes as though it were inoperative.  The item shall not be used or operated until the original deferred item is repaired.  Additional actions include: documenting the item on the dispatch release (if applicable), placarding, and complying with all remarks, exceptions, and related MMEL provisions, including any (M) and (O) procedures and observing the repair category.

29.  “Is not used” in the provisos, remarks or exceptions for an MMEL item may specify that another item relieved in the MMEL “is not used”.  In such cases, crewmembers should not activate, actuate, or otherwise utilize that component or system under normal operations.  It is not necessary for the operators to accomplish the (M) procedures associated with the item.  However, operational requirements must be complied with, and an additional placard must be affixed, to the extent practical, adjacent to the control or indicator for the item that is not used to inform crewmembers that a component or system is not to be used under normal operations.

30.  Nonessential equipment and furnishings (NEF) are those items installed on the aircraft as part of the original certification, supplemental type certificate, or engineering order that have no effect on the safe operation of flight and would not be required by the applicable certification rules or operational rules.  They are those items that if inoperative, damaged or missing have no effect on the aircraft’s ability to be operated safely under all operational conditions.  These nonessential items may be installed in areas including, but not limited to, the passenger compartment, flight deck area, service areas, cargo areas, crew rest areas, lavatories, and galley areas.  NEF items are not items already identified in the MEL or CDL of the applicable aircraft.  They do not include items that are functionally required to meet the certification rule or for compliance with any operational rule.  Operator’s NEF process shall not provide for deferral of items within serviceable limits identified in the manufacturer’s maintenance manual or operator’s approved maintenance program such as wear limits, fuel/hydraulic leak rates, oil consumption, etc.  Cosmetic items that are fully serviceable but worn or soiled may be deferred under an operator’s NEF process.

The following is applicable for authorized certificate holders operating under Federal Aviation Regulations (FAR) Parts 121, 125, 129, 135:  The FAR require that all equipment installed on an aircraft in compliance with the Airworthiness Standards and the Operating Rules must be operative.  However, the Rules also permit the publication of a Minimum Equipment List (MEL) where compliance with certain equipment requirements is not necessary in the interests of safety under all operating conditions. Experience has shown that with the various levels of redundancy designed into aircraft, operation of every system or installed component may not be necessary when the remaining operative equipment can provide an acceptable level of safety.  A Master Minimum Equipment List (MMEL) is developed by the FAA, with participation by the aviation industry, to improve aircraft utilization and thereby provide more convenient and economic air transportation for the public.  The FAA approved MMEL includes those items of equipment related to airworthiness and operating regulations and other items of equipment which the Administrator finds may be inoperative and yet maintain an acceptable level of safety by appropriate conditions and limitations; it does not contain obviously required items such as wings, flaps, and rudders.  The MMEL is the basis for development of individual operator MELs which take into consideration the operator's particular aircraft equipment configuration and operational conditions.  Operator MELs, for administrative control, may include items not contained in the MMEL; however, relief for administrative control items must be approved by the Administrator.  An operator's MEL may differ in format from the MMEL, but cannot be less restrictive than the MMEL. The individual operator's MEL, when approved and authorized, permits operation of the aircraft with inoperative equipment.

Equipment not required by the operation being conducted and equipment in excess of FAR requirements are included in the MEL with appropriate conditions and limitations. The MEL must not deviate from the Aircraft Flight Manual Limitations, Emergency Procedures or with Airworthiness Directives.  It is important to remember that all equipment related to the airworthiness and the operating regulations of the aircraft not listed on the MMEL must be operative.

Suitable conditions and limitations in the form of placards, maintenance procedures, crew operating procedures and other restrictions as necessary are specified in the MEL to ensure that an acceptable level of safety is maintained.

The MEL is intended to permit operation with inoperative items of equipment for a period of time until repairs can be accomplished.  It is important that repairs be accomplished at the earliest opportunity.  In order to maintain an acceptable level of safety and reliability the MMEL establishes limitations on the duration of and conditions for operation with inoperative equipment.

The MEL provides for release of the aircraft for flight with inoperative equipment.  When an item of equipment is discovered to be inoperative, it is reported by making an entry in the Aircraft Maintenance Record/Logbook as prescribed by FAR.  The item is then either repaired or may be deferred per the MEL or other approved means acceptable to the Administrator prior to further operation.  MEL conditions and limitations, do not relieve the operator from determining that the aircraft is in condition for safe operation with items of equipment inoperative.

When these requirements are met, an Airworthiness Release, Aircraft Maintenance Record/Logbook entry, or other approved documentation is issued as prescribed by FAR.  Such documentation is required prior to operation with any item of equipment inoperative.

Operators are responsible for exercising the necessary operational control to ensure that an acceptable level of safety is maintained.  When operating with multiple inoperative items, the interrelationships between those items and the effect on aircraft operation and crew workload will be considered.

Operators are to establish a controlled and sound repair program including the parts, personnel, facilities, procedures, and schedules to ensure timely repair.

WHEN USING THE MEL, COMPLIANCE WITH THE STATED INTENT OF THE PREAMBLE, DEFINITIONS, AND THE CONDITIONS AND LIMITATIONS SPECIFIED IN THE MEL IS REQUIRED.

The FOEB has identified a need for certain procedures to provide an adequate level of safety while providing relief for the following items. These procedures must be established by the operator. The following guidelines are to help establish these required procedures:

Maintenance procedure to ensure no fuel leak or mechanical/electrical fault exists and to deactivate the Heater.

Operations procedure to identify acceptable conditions to operate without affected heat in the aircraft.

Operations procedure to identify acceptable conditions to operate without affected heat in the aircraft.

Operations procedure to identify acceptable conditions to operate without affected heat in the aircraft.

Maintenance procedure to secure Air Conditioner to ensure fault will not affect other System.

Maintenance procedure to ensure Bleed Air shutoff Valve(s) are in the CLOSED position.

Maintenance procedure to ensure Bleed Air shutoff Valve(s) are in the CLOSED position.

Operations procedure to identify acceptable conditions to operate without heat in the aircraft.

Maintenance procedure to ensure no electrical or mechanical fault exists that will have an adverse affect on any flight control function.

Maintenance procedure to verify remaining Autopilot functions to maintain constant altitude and direction are available and placard for crew awareness.

Establish alternate procedures for Autopilot use with inoperative Autopilot functions.

Maintenance procedure to ensure no electrical or mechanical fault exists that will have an adverse affect on any flight control function.

Maintenance procedure to verify items on the now Single Fed Buss are operative.

Maintenance procedure to verify the External Power Solenoid is not powered.

Operations procedure for crew to verify correct external power is used and verify external power is disconnected and Receptacle Door is CLOSED prior to flight.

Operations procedure for crew awareness of inoperative baggage stowage area and alternate procedures for baggage.

Maintenance procedure to disconnect ELT Remote Switch and verify ELT is operative in the ARMED Mode.

Maintenance procedure to determine acceptable cargo loading limits with inoperative restraints.

Maintenance procedure to deactivate System and ensure Engine Fire Lights are extinguished prior to operation of the aircraft.

Operations procedure for crew to verify operation of Main and Standby Pitch Trim, Trim in Motion Warning, Out of Trim Warning, and to visually verify the Stabilizer Pitch Trim Position prior to each takeoff.

Operations procedure to ensure the quantity and balance of fuel on board meets the regulatory requirements for the intended flight.

Operations procedure to verify NO MTV FLOW Annunciator is operative and Nacelle fuel quantity is monitored.

Operations procedure to verify both the Primary and Secondary Fuel Boost Pumps are operative and both are operated for the entire flight.

Operations procedure to verify the NO MTV FLOW Annunciator and Standby Boost Pump are both operative prior to flight.

Operator must use procedure published by Raytheon Aircraft Company to verify the Landing Gear is down and locked with an inoperative Gear Indicator.

Operations procedure to prevent movement of aircraft when stopped or parked.

Operations procedure for crew awareness and procedure to manually release Gear Handle Downlock to retract Landing Gear.

Operations procedure for crew awareness of inoperative RA Mode and procedures to select and operate in TA Mode only.

Operations procedure to verify RA Mode is operative and procedures to select and operate in RA Mode only.

Operations procedure for crew awareness and flight planning for aircraft altitude, performance and terrain clearance.

Operations procedure to ensure alternatives are established and used for the appropriate inoperative mode(s).

Operations procedure to ensure alternatives are established for inoperative Advisory Callouts.

Operations procedure to ensure alternatives are established and used for windshear avoidance and recovery procedures.

Operations procedure for crew awareness and flight planning for terrain avoidance with inoperative FLTA/PDA.

Maintenance procedure to determine Bleed Air Shutoff Valve(s) are in the CLOSED position.

Operations procedure to brief the passengers to remain seated with the Seatbelt fastened for the entire duration of the flight and except for an emergency, only the crew will operate the Cabin Door.

Operations procedure to ensure Propeller Levers are FULL FORWARD prior to landing.

(O) May be inoperative provided: Operating conditions are acceptable without heat, and Both Environmental Bleed Air Valves remain ENVIR OFF.

Auxiliary Bleed Air Heat System (Except C-99)

(O) May be inoperative provided: Operating conditions are acceptable without heat, and Left Engine Bleed Air Shutoff Valve remains OFF and CLOSED.

Combustion Heater is not operated on the ground, Combustion Heater is turned OFF prior to landing,

May be inoperative provided one of the following is operative:

Annunciator Lights (Fails To Illuminate) (C-99 Only)

Affected side Environmental Bleed Air Valve remains ENVIR OFF, and

Affected side Environmental Bleed Air Valve is verified CLOSED.

13. Environmental Bleed Air Shutoff Valve(s) (C-99 Only)

(M) One may be inoperative provided: Affected Valve remains OFF, and

Both Valves remain OFF, Both Valves are verified CLOSED, and