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From the end of issue #216 (June 1997) of Callback:

Another First Officer also learned too late the importance of consulting the MEL before take-off.

Inbound equipment arrived late. About 5 minutes before pushback time, I discovered that my right armrest was stuck in the UP position. I attempted to free it, but no luck. I contacted maintenance and asked them to bring something to lubricate the mechanism. A mechanic did so, but to no avail. We figured we could just go with it in the UP position. It did not occur to us to look it up in the MEL, as it did not seem to be a safety-of-flight item.

Upon our arrival, we were told that the armrest is a no-go item. The continuing flight was cancelled due to this fact, since no spare seat or replacement part was immediately available. The Captain and I were both amazed that something as simple and innocuous as an armrest would be considered a no-go item. In the future, I will check the MEL for any item, no matter how seemingly insignificant.

Why would a pilot's armrest stuck in the up position be a danger serious enough to require grounding the aircraft? One would think, like the aforequoted pilot did, that it would be, at worst, a minor inconvenience, and certainly not a safety-of-flight issue...

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    $\begingroup$ If say it was a FBW Airbus with side sticks, the side armrest may have been a critical item for dispatch, because the ability to rest your arm on it so you can control the stick with your wrist was important, and Airbus would be unable to get MEL relief. Does it say anywhere what the type was? $\endgroup$ – John K Jul 7 at 4:35
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    $\begingroup$ @JohnK I Googled "mel pilot armrest" and the first result shows " In addition, in turbulent conditions, the armrest stabilizes the pilot's...." $\endgroup$ – Terry Jul 7 at 5:41
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    $\begingroup$ This is ACN 314861, and it happened in a B757-200 in the year 1995. The report notes that "there are some crewpersons that use them for leverage when needed while other crewpersons never use the armrests." $\endgroup$ – Terran Swett Jul 7 at 12:27
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    $\begingroup$ When I was flying RJs I always used the arm rests because it permits fine control with your wrists. $\endgroup$ – John K Jul 8 at 1:09
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Perhaps it was just an oversight on the part of the creators of the minimum equipment list.

As I understand it, minimum equipment lists generally provide a list of those items which are permitted be inoperable. So if any piece of equipment is inoperable, and it's not on the list, that automatically means you're not allowed to fly.

(Going by the name, you'd probably expect a minimum equipment list to be, you know, a list of the minimum required equipment. But for one reason or another, it's not.)

So, in all likelihood, nobody thought to add armrests to the minimum equipment list. As a result, flying with an inoperable armrest was automatically prohibited.

However, things have since been adjusted: the FAA has added the armrest to the master minimum equipment list for the Boeing 757. So, it is now legal to fly your 757 with a stuck armrest, as long as it is stuck in the "up" position.

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  • $\begingroup$ Are you sure about your understanding of the MEL? See: aviation.stackexchange.com/a/12071/23223 $\endgroup$ – AEhere supports Monica Jul 7 at 23:18
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    $\begingroup$ Tanner has it correct. What is not covered under the MMEL grounds the airplane if broken. The OEM will continuously expand the MMEL over the life of the program because it's critical to getting the dispatch reliability to target, but starting out, there will be all sorts of items not covered. $\endgroup$ – John K Jul 8 at 1:16
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    $\begingroup$ Usually anything that impedes a rapid exit is not allowed. $\endgroup$ – Anilv Jul 8 at 1:27
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    $\begingroup$ @JohnK From the AOPA link in the answer I mentioned: "An MEL is a list of equipment that must be installed and operable for the aircraft to be considered airworthy" is what was confusing me. It does make more sense to default to no-go if an item is not explicitly allowed to be inop. Thanks for clarifying. $\endgroup$ – AEhere supports Monica Jul 8 at 9:11
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    $\begingroup$ You'll also notice that the vast majority of items covered in the MMEL are elements in redundant systems that allow continued function but without or degraded redundancy. It will be based on a risk analysis of the possible follow on effect of a subsequent failure, with a risk exposure window, within which the risk of bad news is acceptable. Typically 10 days, or for more criticality, 3 days. There is often a mitigation action that has to be done in concert, like a daily ops test of a system that is normally checked at A check (4-600 hrs), that was required to get an acceptable risk profile. $\endgroup$ – John K Jul 8 at 16:05

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