What is important MEL for safe flight?


Hello, this is Korosuke, who is wondering what the government will do with the increase in the number of people infected with Corona.

I think that there are many people who feel uncomfortable with the current situation where there are many infected people despite the strict corona regulations, but what will happen in the future is a matter of life and death for those in the aviation industry.

Well, this time, I would like to explain “MEL”, which can be said to be essential knowledge for ensuring the safety of airplanes.

What is MEL?

First of all, let’s confirm what “MEL” is.

MEL: Minimum Equipment List

Maintenance work is one of the most important aspects of flying an airplane safely.
However, at overseas airports where maintenance work is not possible, if there is a problem with the aircraft, it would be a problem for both the company and the customer to have to cancel the flight and call a mechanic from Japan.

It is MEL that plays an active part in such a case.

Airplanes have multiple lines of defense in order to fly safely, and there are many equipments that can actually fly normally even if one of them is minor and does not work.

Similarly, the safety factor is set based on the concept of providing a margin up to the actual limit value.

In some cases, such as when maintenance work cannot be performed, the aircraft is operated using MEL.


In addition to the MEL I wrote earlier, MMEL is a higher level rule.

MMEL: Master Minimum Equipment List

MMEL is an aircraft manufacturer (such as Boeing) that receives approval from the design country’s supervisory authority when an aircraft acquires a type.

Now let me explain what is different from MEL.

Airplanes have different equipment and company policies for each airline, so the scope of MMEL will change accordingly.

In other words, MEL is within the scope of MMEL, and it is a regulation with a different scope for each airline.

MEL contents

Now let me explain what is actually written in MEL.

  1. Applicable items/malfunctions

The name of the item to which MEL can be applied and the malfunction phenomenon are written.
Example: Beacon Light INOP

  1. Number of implementations

Originally, it is the number of the equipment in question.

  1. Minimum working equipment

It is the minimum number of equipment that can be activated for the equipment in question, in other words, the number of equipment that can actually be used.

  1. Deadline for repair

Of course, MEL cannot be applied forever, so it is decided that repairs must be done within a few days after the date of application.
However, the repair period differs depending on the item to be repaired, and there is no fixed number of days.

  1. action required

Depending on the type of MEL, there are some that restrict the operation of some pilots and cabin crew, and it is necessary to put a placard that cannot be used.

MEL application flow

Now, I will explain the flow of actual MEL application.

By the way, MEL does not apply during flight (spot-out to spot-in), and divert, GTB, etc. are performed at the discretion of the captain.
By the way, it is effective to use MEL for the judgment at that time.

  1. Start preparing for the next flight
  2. A cabin attendant discovered a problem during a safety inspection that “the reclining of the passenger seat does not return”
  3. The captain visually confirms and contacts the mechanic at home base.

4.Because it is impossible to maintain for various reasons, it is asked to apply MEL

  1. The captain also has room in the number of seats and reservations, so he approves the application of MEL.
  2. Tell the dispatcher that MEL is applied and change the flight plan

Please note that when applying MEL in this way, it is necessary to have a tripartite consultation between the person in charge of the maintenance department, the dispatcher, and the captain.

Note that if you apply the wrong MEL here, you will need to report it to the Civil Aviation Bureau at a later date.

Summary of MEL

What did you think.

The concept of MEL is unfamiliar during basic training, and I think that it will become a field that you will become more familiar with after joining an airline company, but the concept is very simple, so if you know it, you will have less trouble later on. , I think it’s good to keep it in a corner of your head.

I also write other aviation-related articles, so if you have any questions, please read them.

Documents Absolutely Necessary for Flight (Aviation Law)

東レ トレビーノ 浄水器 カセッティ交換用カートリッジ トリハロメタン除去 MKCT2J-Z(3個入)【イチオシ】【d2rec】【トレビーノ】

(2023/1/25 19:03時点)