zzaewon
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What is the MEL in terms of Commercial airliner?

Wed Feb 07, 2018 12:03 am

Hello,
I would like to know more about MEL and I know this is minimum equipment list. But it isn't clear enough to utilize how this effects to the maintenance (or operation) standpoint in the airline engineering. Would someone can explain please?

Thanks very much in advance!
 
Wacker1000
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Re: What is the MEL in terms of Commercial airliner?

Wed Feb 07, 2018 12:27 am

It allows something to be inoperative while still allowing the plane to be operated. There is usually some sort of additional requirement or action that goes along with it (IE: cockpit indication inoperative -> manually check quantity before departure.)
 
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AirKevin
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Re: What is the MEL in terms of Commercial airliner?

Wed Feb 07, 2018 1:09 am

This may or may not give you some idea, as it also goes into detail about the CDL and the NEF.

viewtopic.php?f=5&t=1381227
Captain Kevin
 
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Starlionblue
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Re: What is the MEL in terms of Commercial airliner?

Wed Feb 07, 2018 3:45 am

The MEL lists stuff that may be broken or missing (e.g. APU) and any conditions attached. The CDL lists stuff, typically aerodynamic, that may be damaged or missing (e.g. a flap seal), and how it affects the operation, e.g. increased burn.

The MEL is only binding prior to dispatch. Once pushed back, if something breaks and you didn't get a specific ECAM automatically, you'd refer to the QRH (330) or ECAM non-sensed procedures (350). Of course, the MEL might contain important information so it can be useful to have a read.

To use the MEL, either you know the MEL code or not. If you get an ECAM alert, you look that up in "MEL Entries". This will point you to the relevant "MEL Item" (or say "No dispatch"). Alternatively you get the MEL Item code in the dispatch documentation, e.g. if that piece of kit is inop from earlier flights. The MEL Item has a time period (max allowable until repair must be effected) and what the deviation affects (ETOPS, landing performance, etc.). It shows whether there is a maintenance procedure and/or an operational procedure. For example, if the APU is inop the ops procedure would tell you not to use the APU, and then point you to the external engine start procedure. Ops procedures are also in the MEL.

MEL items go from the significant to the trivial. "Eng 1 Manual start pusbutton inoperative" means the button doesn't work, but that button isn't used unless automatic start is inop, so the effect is normally "none". Still needs a little sticker to placard it though. :)


MEL items look like this:
Image

CDL items look like this:
Image

(Pictures are from a Google search.)
Last edited by Starlionblue on Wed Feb 07, 2018 4:06 am, edited 1 time in total.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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7BOEING7
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Re: What is the MEL in terms of Commercial airliner?

Wed Feb 07, 2018 4:03 am

On the Boeing side a DDPG Dispatch Deviations Procedures Guide would expand on the MEL explaining the Maintenance (M) or Operations (O) procedures needed to dispatch the airplane under the MEL.
 
Dalmd88
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Re: What is the MEL in terms of Commercial airliner?

Wed Feb 07, 2018 10:18 am

MEL items also come with a limit as to how long they can be inop. Some require the item be fixed within a short time span (can't recall the shortest) others can be on differed maintenance for 10 days. Reoccurring MEL items are not liked by the FAA.
 
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Starlionblue
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Re: What is the MEL in terms of Commercial airliner?

Wed Feb 07, 2018 12:08 pm

Dalmd88 wrote:
MEL items also come with a limit as to how long they can be inop. Some require the item be fixed within a short time span (can't recall the shortest) others can be on differed maintenance for 10 days. Reoccurring MEL items are not liked by the FAA.


Yep. That's the "repair interval" column in the Airbus MEL.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
Lpbri
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Re: What is the MEL in terms of Commercial airliner?

Wed Feb 07, 2018 2:25 pm

Usually if the same item faults three times in a given interval, it can't be placarded. Three strikes and its out.
 
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fr8mech
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Re: What is the MEL in terms of Commercial airliner?

Thu Feb 08, 2018 1:16 am

Lpbri wrote:
Usually if the same item faults three times in a given interval, it can't be placarded. Three strikes and its out.


I'll pretty much disagree with that. The MEL has no stipulation as to how many times an item may be placed on MEL. Your GMM, or equivalent, may tie your hands that way, but the MEL itself does not.

A good "repeating item" alert program should catch an item before it gets MEL'd 3 times, in a given time period. But, even then, the aircraft is not necessarily grounded. At my operator, the Technical Services group takes a look at it, and develops a plan to repair.

The FAA can take a dim view of repeating MEL's, but so long as the operator has a plan in place to address the item, and does so, in good faith, the FAA is tolerant. Trust me...been there, done that...answered the questions asked and the LOI's issued.
When seconds count...the police are minutes away.
 
CosmicCruiser
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Re: What is the MEL in terms of Commercial airliner?

Thu Feb 08, 2018 1:23 pm

I agree fr8mech. We had a problem that I was a little involved with that on a particular jet you would randomly get a lvl 2 alert for the fuel sys TNK 2 PMPS OFF. It would eventually go away but maybe 2 trips later come back That haunted maint for a while. I don't know what the fix ever was.
 
Adispatcher
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Re: What is the MEL in terms of Commercial airliner?

Sun Feb 11, 2018 12:15 am

Lpbri wrote:
Usually if the same item faults three times in a given interval, it can't be placarded. Three strikes and its out.


We don't have such a rule. There is a running history which will influence a decision to defer or fix based on the severity of the issue at my place of business.

Oftentimes we will MEL something with a history due to intermittent or partial faults as a precaution in case it fails again.
 
LAE320
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Re: What is the MEL in terms of Commercial airliner?

Sun Feb 11, 2018 3:02 am

fr8mech wrote:
Lpbri wrote:
Usually if the same item faults three times in a given interval, it can't be placarded. Three strikes and its out.


I'll pretty much disagree with that. The MEL has no stipulation as to how many times an item may be placed on MEL. Your GMM, or equivalent, may tie your hands that way, but the MEL itself does not.

A good "repeating item" alert program should catch an item before it gets MEL'd 3 times, in a given time period. But, even then, the aircraft is not necessarily grounded. At my operator, the Technical Services group takes a look at it, and develops a plan to repair.

The FAA can take a dim view of repeating MEL's, but so long as the operator has a plan in place to address the item, and does so, in good faith, the FAA is tolerant. Trust me...been there, done that...answered the questions asked and the LOI's issued.


I agree fr8mech. At my company, we've no specified number of times an item can be MEL'd. However, certain defects tech services will pick up on and attempt to formulate a plan, sometimes flight ops will get wind of the defect and say 'enough is enough', and other times engineers on the ground will deck the aeroplane due to defect history.

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