Minimum Equipment List (MEL) for non-revenue flights

[ross_M]

I was reading about the Delta aircraft that made an emergency landing in Midway Atoll due to a cracked windshield. I suppose replacing the flt.deck window is not an "easy" job to do at a remote unequipped airfield.

Of course, this probably is not on the MEL. Question is, are there items not on the MEL that are ok to fly without if not doing a revenue flight. i.e. Are there some repairs for which it is ok for a maintenance crew to re-position the airplane to a better field. I suppose the regulations must be OK allowing a higher risk for non-passenger flights?

Curious if there is a similar non-revenue MEL.

[+TSRA]

An MEL is an "alleviating document", which allows an operator to defer the maintenance on an item where a risk analysis has already been taken into account for the loss of that item. In most cases they are applied in the air and for the vast majority, do not require an immediate turn to a maintenance base.

It varies between jurisdictions of what an operator may do if an item is not on the MEL, however here in Canada if its not on the MEL then the pilots (according to Transport Canada) do not have the appropriate information in which to make a decision on the status of the aircraft - which is evidenced by a recent event of a major airline grounding an aircraft because of an ashtray door being broken in the lavatory (it was not on the MEL and therefore the pilots had no choice but to ground the aircraft).

In the example of the windscreen, you are correct - this is not an MEL'able item and would potentially require a Ferry Permit to a maintenance base (if you could get one) which in itself does not allow for the carriage of passengers unless they are required for the purpose of the flight (i.e they are maintenance engineers)

There are situations where an MEL, as part of its conditions for use may indicate that "Passengers are not carried" or "the aircraft is configured for 'x' passengers or less" or it may have conditions that, if they cannot be met, passengers could not be carried (or example the Oxygen System on most aircraft have minimum time limits and distribution to a % of passengers, that if it cannot be met you cannot carry the passengers). However these are aircraft type specific requirements and what is OK for one type may not be OK for another type.

There are 4 cateogories to MEL, labelled "A", "B", "C" and "D" and determine how long an operator has to fix an item.

1. Cat "A" is generally determined by a number of flight hours, cycles or days/months by the manufacturer of the component - for example the MEL may state than an item must be fixed no later than 100 flight hours from the Day of Discovery (the day you found the defect) for some operators this may translate into a week while for others it may be a month or more.

2. Cat "B" MEL must be repaired within 3 calendar days following the Day of Discovery.

3. Cat "C" MEL must be repaired within 10 calendar days following the Day of Discovery.

4. Cat "D" MEL must be repaired within 120 calendar days following the Day of Discovery but to be considered CAT "D" the pilots must not rely on the component that has failed either during normal ops or emergency ops and it must not be a part of any routine.

Additionally, there are three procedural types of MEL on who may apply "fixes" in order to apply the MEL. These procedures determine what tools are required to make the fix, and as a result, whether the aircraft must divert to a maintenance base (which the long way around will answer whether you need to fly to one). These procedures are the immediate fix to apply the MEL, after which the times indicated above come into effect.

1. An (O) Procedure allows a trained person to perform basic procedures, like putting a sign on a door to indicate that it is no longer in service (this would be Flight Attendants, Ramp Agents, etc who would be given a formal briefing as part of their indoc.) This type of procedure can be completed without hassel on board the aircraft and in most cases you would not bother maintenance immediately because these are normally "passenger service items."

2. An (M) Procedure allows persons trained in Elementary Maintenance or Elementary Work (different terms for the same thing) to perform basic

maintenance tasks (note not procedures). This would be like resetting a circuit breaker or reconnecting an avionics cable to the rack, or changing out a light bulb. Elementary Maintenance training is normally given to Flight Crew and depending on the company, generally requires some call to maintenance especially if there is already an MEL applied on the aircraft.

3. An (M#) Procedure requires a trained Aircraft Mainteance Engineer (AME). If the aircraft is in flight, you may be told by the company to divert to the nearest suitable maintenance base or if you are on the ground, you are not going anywhere until Maintenance completes the procedure. An M# procedure may not be any more involved procedural wise than an (M) procedure, but there may be specific tools required which the pilots either do not have on board or are not trained to used.

I hope this answers your question the long way around as it were, but I hope that I've also answered some of the flow on questions that would result in a more simple answer.

[spannersatcx]

Of course, this probably is not on the MEL. Actually it is in the MEL. Depends on the window fitted as to what the dispatch limitations are.:ok: