MEL DDG CDL confusing!?
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Correct, and many companies have two sorts of sheets for deferring defects. MEL and CDL go to one kind (often labelled performance related items or DDG items), and others like AMM, SRM, ... go into the second kind (labelled non-performance or non-MEL related items).
Missing brake wear indicators happen and I have never grounded a ship for that.
Missing brake wear indicators happen and I have never grounded a ship for that.
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Its allowable iaw with the AMM, as yotty says it can be deferred nothing special needed.
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Intruder, I assume you have appropriately Licenced and Authorised Engineers that look after your aircraft. These people will sort it for you. 
Last edited by yotty; 26th Sep 2015 at 08:43.
That's why we can sign a CRS IAW AMM and raise a DD IAW the AMM, fortunately we have a delay code for flt crew querying DD's!
Last edited by TURIN; 27th Sep 2015 at 20:47.
CRS..Certificate of Release to Service. The signature sign off from the Eng/Mech to legally certify that all work performed was done so IAW the relevant Procedures and documentation using the correct parts and tooling etc.
DD..Deferred Defect. Often referred to as a Hold Item or ADD Acceptable Deferred Defect.
DD..Deferred Defect. Often referred to as a Hold Item or ADD Acceptable Deferred Defect.
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from the MEL:
For the sake of brevity, the MEL does not include all the obviously required items such as wings, rudders, flaps, engines, landing gear, etc. or any structural damage.
However, some of the obviously required items are included to remove any doubts regarding their importance of their being operative.
The MEL does not include items which do not affect the airworthiness if the aircraft such as galley equipment, entertainment systems, passenger convenience items, etc.
It is important to note that;
“ALL ITEMS WHICH ARE RELATED TO THE AIRWORTHINESS OF THE AIRCRAFT AND ARE NOT INCLUDED ON THE LIST ARE REQUIRED TO BE OPERATIVE AT ALL TIMES”.
Exceptions are items which have serviceability specifications contained in the manufacturer's Aircraft Maintenance Manual (AMM), Structural Repair Manual (SRM) or other approved manufacturer's manual/drawings. In this case Engineering will advise dispatchability of such items with the relevant extracts from AMM, SRM or other approved manufacturer's manual/drawings.
For the sake of brevity, the MEL does not include all the obviously required items such as wings, rudders, flaps, engines, landing gear, etc. or any structural damage.
However, some of the obviously required items are included to remove any doubts regarding their importance of their being operative.
The MEL does not include items which do not affect the airworthiness if the aircraft such as galley equipment, entertainment systems, passenger convenience items, etc.
It is important to note that;
“ALL ITEMS WHICH ARE RELATED TO THE AIRWORTHINESS OF THE AIRCRAFT AND ARE NOT INCLUDED ON THE LIST ARE REQUIRED TO BE OPERATIVE AT ALL TIMES”.
Exceptions are items which have serviceability specifications contained in the manufacturer's Aircraft Maintenance Manual (AMM), Structural Repair Manual (SRM) or other approved manufacturer's manual/drawings. In this case Engineering will advise dispatchability of such items with the relevant extracts from AMM, SRM or other approved manufacturer's manual/drawings.
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That statement does not appear in our DDG. Instead,
There IS a process to defer Nonessential Equipment and Furnishings (NEF) that do not appear in the MEL, CDL, or NEF list:
The end items on the checklist that apply are:
So (at least in FAA land), while a deferral per the AFM might be accomplished as you suggested, it must be done per the approved NEF listing procedure. It is NOT simply up to the mechanic/engineer on the scene.
I realize that procedures may differ in other jurisdictions.
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.
Controller will use the Maintenance Control Evaluation Process flow chart in conjunction with the Maintenance Controllers NEF Check list (T2091) to determine if the item can be deferred as an NEF item (see “Maintenance Control Evaluation Process” on page 4.00-01-00.4.) If the item meets the criteria to be deferred as an NEF item per the flow chart, then the Maintenance Controller will add the item to Form M2006 (see form sample, “Sample New NEF Item Record Form (M2006)” on page 4.00-01-00.6), and obtain the Maintenance Control Duty Managers approval. The item will then be deferred as an NEF item with a category as applicable.
Step 5
Can source (underlying cause) of the discrepancy affect equivalent levels of safety?
UNCERTAIN or NO
Step 6
If applicable, can source of the discrepancy be isolated from other systems with maintenance procedures?
YES or NOT APPLICABLE
Step 7
Defer the item in accordance with the approved NEF program and add item to NEF list
Can source (underlying cause) of the discrepancy affect equivalent levels of safety?
UNCERTAIN or NO
Step 6
If applicable, can source of the discrepancy be isolated from other systems with maintenance procedures?
YES or NOT APPLICABLE
Step 7
Defer the item in accordance with the approved NEF program and add item to NEF list
I realize that procedures may differ in other jurisdictions.
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We are not saying it is up to the mechanic/engineer on the scene. We interpret the various documentation and certify accordingly. You sound as if we make it up as we think fit! This is not the case. At least that how it happens in EASA land!
Last edited by yotty; 30th Sep 2015 at 21:28.
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We also have NEF's in our MEL/DDG, but no requirement to call MC. If it is outside the MEL/DDG/CDL/AMM/SRM then we would go to our MC and get a DOI/Concession if allowable otherwise it gets fixed.
The difference I guess between the FAA way and EASA way is we are allowed to think for ourselves and use the rules/regulations/processes and procedures without the need to call MC, once we've exhausted all avenues we would call and take it from there.
The difference I guess between the FAA way and EASA way is we are allowed to think for ourselves and use the rules/regulations/processes and procedures without the need to call MC, once we've exhausted all avenues we would call and take it from there.
fortunately we have a delay code for flt crew querying DD's!
I have worked as both Engineer and pilot, ( currently 737 skipper) and I really appreciate it when the Engineer understands me querying the resultant "fix" and takes time to explain his or her actions and point of view. We aren't privy to the same training and information and any non ATPL Engineer who thinks they understand the Captains role inside out is dreaming. ( and vice versa). Sometimes, before we elect to accept an aircraft and all that that entails we need to align information from the Engineer with knowledge we have ( eg fog forecast at destination, Lithium batteries in the hold, training taking place, notams regarding lighting/ Nav aids) and that may come across as pedantic to the Engineer sitting beside us in daylight with blue skies doing zero miles a minute.
Another element is that we may not know you. There are people ( Engineers & Pilots) who quite simply have sh1tty attitudes and only look ahead to the end of their shift rather than to the end of their career. Initially, we don't know if you are one of those ( it only takes a short conversation to determine if you are one of the true professionals, but determining if you're a drop kick can take a bit longer).
My point is, we are on the same side and any ' us v's them' attitudes are a waste of time and energy. It is easy to say
fortunately we have a delay code for flt crew
There is no point however. We just need to accomodate each others needs/ requirements while getting the job done.
Rant over. Time for another beer
Fair points framer. It was just a bit of banter.
To continue.. my own personal experience regarding the different regs are that with FAA registered aircraft any maintenance/pilot write up has to be reported to the Maint Control Centre (MCC) and it is they who determine what action should be taken. The Mechanics do as they are told. In the rest of the world (EASAland and others that use the same system) the Engineer/Technician has been authorised to use the full range of documentation to certify and release the aircraft. That includes SRM, AMM, MEL/CDL etc. Of course if it's something very unfamiliar and finding the correct reference document is proving difficult and time consuming then a courtesy call to MCC is in order as they can offer advice and between yourselves can isolate the correct documention to use. That is why ALL action taken has to be recorded with a reference. That enables anyone further down the line to refer to the same documentation if clarification is required by a pilot or eng/tech etc.
Anything that is outside the limits of SRM/AMM/MEL etc will require an EO or other dispensation from a suitably authorised source such as the manufacturer or national regulator. Or we get our toolbox out and fix it.
To continue.. my own personal experience regarding the different regs are that with FAA registered aircraft any maintenance/pilot write up has to be reported to the Maint Control Centre (MCC) and it is they who determine what action should be taken. The Mechanics do as they are told. In the rest of the world (EASAland and others that use the same system) the Engineer/Technician has been authorised to use the full range of documentation to certify and release the aircraft. That includes SRM, AMM, MEL/CDL etc. Of course if it's something very unfamiliar and finding the correct reference document is proving difficult and time consuming then a courtesy call to MCC is in order as they can offer advice and between yourselves can isolate the correct documention to use. That is why ALL action taken has to be recorded with a reference. That enables anyone further down the line to refer to the same documentation if clarification is required by a pilot or eng/tech etc.
Anything that is outside the limits of SRM/AMM/MEL etc will require an EO or other dispensation from a suitably authorised source such as the manufacturer or national regulator. Or we get our toolbox out and fix it.
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First of all, there are only two manuals for any airplane that approved by the state's authority.
- Master Minimum Equipment List (MMEL)
- Airplane Flight Manuel (AFM)
FAA publishes the MMEL on their FSIMS website.
Flight Standards Information System (FSIMS)
(FAA) Operators use the MMEL as a reference for creating their own Minimum Equipment List (MEL), which is provided to their flight crews, line maintenance personnel, and/or flight operations personnel.
An Operator’s MEL cannot be less restrictive than the MMEL.
Both the MMEL and the MEL are legal documents that are either approved by Airworthiness Authorities.
The Configuration Deviation List (CDL) is a reference document that enables the aircraft to be dispatched, even if some secondary airframes, or engine, parts are missing. These parts may be detected during maintenance checks, or pre-flight exterior inspections.
The CDL is included in the Airplane Flight Manual (AFM) an appendix, and is approved by Airworthiness Authorities.
The Dispatch Deviations Guide (DDG) is intended to assist airline operations and maintenance organizations in developing the procedures required to operate the airplane in the various nonstandard configurations allowed by the Federal Aviation Administration (FAA) Master Minimum Equipment List (MMEL) and the Airplane Flight Manual (AFM) Appendix Configuration Deviation List (CDL).
From Boeing's DDG:
"Background;
The FAA publishes an MMEL for each airplane model that is written in a brief format that does not include the detailed procedures necessary to properly prepare and operate the airplane. The AFM Appendix CDL does not include illustrations for positive identification of secondary airframe and engine parts that may be missing for dispatch. Historically, operators have found difficulty in developing procedures and identifying missing parts. They have often consulted Boeing for guidance in these areas and as a result, this document was prepared for reference."
- Master Minimum Equipment List (MMEL)
- Airplane Flight Manuel (AFM)
FAA publishes the MMEL on their FSIMS website.
Flight Standards Information System (FSIMS)
(FAA) Operators use the MMEL as a reference for creating their own Minimum Equipment List (MEL), which is provided to their flight crews, line maintenance personnel, and/or flight operations personnel.
An Operator’s MEL cannot be less restrictive than the MMEL.
Both the MMEL and the MEL are legal documents that are either approved by Airworthiness Authorities.
The Configuration Deviation List (CDL) is a reference document that enables the aircraft to be dispatched, even if some secondary airframes, or engine, parts are missing. These parts may be detected during maintenance checks, or pre-flight exterior inspections.
The CDL is included in the Airplane Flight Manual (AFM) an appendix, and is approved by Airworthiness Authorities.
The Dispatch Deviations Guide (DDG) is intended to assist airline operations and maintenance organizations in developing the procedures required to operate the airplane in the various nonstandard configurations allowed by the Federal Aviation Administration (FAA) Master Minimum Equipment List (MMEL) and the Airplane Flight Manual (AFM) Appendix Configuration Deviation List (CDL).
From Boeing's DDG:
"Background;
The FAA publishes an MMEL for each airplane model that is written in a brief format that does not include the detailed procedures necessary to properly prepare and operate the airplane. The AFM Appendix CDL does not include illustrations for positive identification of secondary airframe and engine parts that may be missing for dispatch. Historically, operators have found difficulty in developing procedures and identifying missing parts. They have often consulted Boeing for guidance in these areas and as a result, this document was prepared for reference."
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There is a fundamental difference between Engineers releasing an aircraft under the MEL and Pilots consulting the MEL.
The engineer signs a CRS in the tech log , the CRS is for an INSPECTION and that the defect complies with the MEL.
Its the inspection that is the most important part of the process , and its this part that is missing when the pilot / maint control are involved without an engineer present .
99% of pilot /MEL situations are without an inspection being done - This creates the largest problem when using the MEL
The engineer signs a CRS in the tech log , the CRS is for an INSPECTION and that the defect complies with the MEL.
Its the inspection that is the most important part of the process , and its this part that is missing when the pilot / maint control are involved without an engineer present .
99% of pilot /MEL situations are without an inspection being done - This creates the largest problem when using the MEL
