Minimum Equipment Lists: Keeping Planes Flying With Inoperative Parts 

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The APU is more of an inconvenience than a safety issue. So long as the airports that are being being serviced by that aircraft have GPUs (and external air conditioning depending upon climate) otherwise one aircraft engine, typically one of the RHS engines, must remain running during the turn around creating issues for servicing and refuelling. Reverse thrust systems are essential on shorter runways or when contaminated with rain, snow or slushy ice etc. Having them U/S or INOP (unserviceable or inoperative) is less of an issue providing the airports that are being serviced by that aircraft have long enough runways in use to meet the minimum requirements of that aircraft type. An aircraft with reverse thrust system/s that are U/S have additional considerations with regards to takeoff decision speeds, V1. Certainly high speed rejected takeoffs are of greater concern in the absence of serviceable thrust reverse systems. Naturally a number of contributing factors such as total weight, meteorological conditions, runway length, airfield elevation etc are all considered when calculating, or the FMC is calculating the takeoff decision speed. VR (rotation) and V2 speeds are required unaffected. Generally speaking though, the aircraft’s brakes are efficient enough. Reverse thrust for a period of time was a little out of favour and often not used in favour of auto braking, this caused enormous wear on the brake discs/pads so a combination is now typically preferred. Airbus were so confident with their A380 auto brake technology they only fitted reverse thrust systems to two of the four engines, which has proven to be a poor decision on a few occasions. It is quite interesting what the MEL permits vs No-Go items. Some items if granted an MEL INOP status require a number of caveats. Only a LAME** is qualified to ever issue an INOP status to aircraft equipment in accordance with the MEL. Here are a few examples with caveats… Must be rectified within 24 hours short haul/48 hours long haul, or upon arrival at an engineering supported base, whichever is sooner. No transit permitted ^^ If an evacuation slide-raft was accidentally deployed at an airport that does not have replacement equipment, the aircraft can still operate its next flight/s back to base where the issue can be easily resolved. However less passengers can be carried along with seats in proximity of the U/S slide must be blocked out and crew ensure that no passengers occupy any of them at any time. If the aircraft is performing an overwater flight in excess of specific number of nautical miles from land even fewer passengers may be carried. The specific numbers and particular rules are all included in the MEL. Another similar example would be if a passenger had discarded a still lit cigarette into the washroom waste-bin causing the automatic extinguisher to fire, the affected washroom must be locked out for the remainder of flights until it returns to base where a replacement extinguisher can be installed. Item requires resolution within 7 days - Caveats Apply: If a seat recline function has failed allowing the seat back to spontaneously recline, that seat must be blocked in addition to ALL the seats in the row behind. There is a longer intervention period permissible for this however most airlines are fiscally motivated to resolve such an issue ASAP with 3-5 seats blocked out. Flight may be operated - NO PAX Ferry Flight Only: While operating a multi sector international flight we lost one of the main landing gear's door when the gear was extended. The damage also included brake hydraulic lines being severed. The MEL stated we could ferry the aircraft back to an engineering supported base but we could not carry passengers. It also stated the maximum airspeed permissible which was a great deal lower than normal resulting in a very long flight back home. NO GO Item. Aircraft may not be ferried or operated until issue is resolved Flying to a remote regional airport in a very isolated area the leading edge of the wing struck a 'bush turkey', an extremely large bird. It destroyed the leading edge slats on one side. Because of the No Go status another aircraft had to be ferried to our out station carrying two LAMEs** (a senior/supervisory LAME** is always required to sign off work and can not sign off themselves) along with replacement slats and required tooling to execute the task. We took the replacement aircraft and very delayed passengers back to our port of origin while the LAMEs** repaired the slats of our original aircraft. The crew that ferried the repair equipment and engineers then ferried the now repaired aircraft back to its base. I hope those examples gave you a better understanding of how MELs work and your concerns with reverse thrust systems and APUs were addressed. Cheers, Anton ^^ The time allowed takes into consideration a domestic/short haul aircraft will be rotating back through an engineering supported base within that time, while an aircraft operating multiple sectors outbound until reaching its terminating port and then returning back to an engineering supported base. In either case if the aircraft is not scheduled to be back in an engineering supported base within the allowed time frame then it must either be ferried back or contracted to another airline's engineering facility The respective aircraft is also prohibited from arriving at an engineering supported base as scheduled and then depart again with the issue unresolved even if planned for later that day. ** pronounced 'lay-mee' | Licensed Aircraft Maintenance Engineer

There are lots of these. Some times two identical items have different restrictions. One example on the aircraft I fly the captains radio control panel can not be inop While the FOs can. They are identical units and the usual solution at an airport with no maintenance is to have a contract mechanic switch the units and Mel the FOs unit. The reason for this is not obvious but makes perfect sense when you consider the electrical system of the aircraft the captains radio control unit is connected to the essential bus which is the most redundant power supply on the aircraft and the only one with battery power in Flight hence the captains side must be operating.

Unoperative ought to be INOPerative 1st off. And replay the clip, systems that can be MEL'ed have one or even two back up, redundant systems. An APU generates power while the plane is on the ground and can be MEL'ed, since the planes engines also do that,as does portable ground power at the terminal gate. A lav may be taken out of service (too often because someone dropped their phone down the bowl and into the mechanics of the lav ) Certainly not a reason to scrap a plane Think of your car. It comes with 4 tires and a spare donut tire. If you find a flat in the morning, you can put the donut on, but it is only rated for a limited speed and distance. That is the same concept as a MEL. And the MEL can be a huge benefit to the passengers scheduled to fly on that aircraft. Often an issue develops not inbound to an airline hub,but to an outlaying station where the airline does not have mechanics. A contract with a local aircraft mechanic service can inspect the affected aircraft upon arrival and determine if the issue can be MEL'ed , and if so they can do that and the paperwork the FAA requires, and the outbound flight can operate, usually close to schedule, and the planeload of people can make it to their destinations.

Yes they do

@@ender2gold693 you did not watch the video? not a single airbus aircraft. all boeing in the video. You fool!

@Damsom and? that proves what exactly

Your ignorance of aviation is unmatched. Airbus does provide MMEL for all aircraft of the type to their operators for them to create their own MEL for respective Airbus aircraft.

@@damsom1431 Yeah sure, clearly you have watched the video......barely recognized a single Airbus even.