MEL definition
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This is what EASA states in its document 'Certification Specificationsand Guidance Material for Master Minimum Equipment List CS-MMEL':
So it is very, very, very clear till what stage a defect needs to be entered in the Tech Log, rectified by an engineer or possibly deferred under the MEL: the release of the parking brake for taxi.
You'd be surprised how many pilots don't grasp this simple fact
So it is very, very, very clear till what stage a defect needs to be entered in the Tech Log, rectified by an engineer or possibly deferred under the MEL: the release of the parking brake for taxi.
You'd be surprised how many pilots don't grasp this simple fact
I just have a doubt about this. Imagine you have closed the doors, about to push back and you have an ECAM : IR1 fault. Obviously you check the MEL it’s a go Item. Only thing you have to do to switch IR3 to captain side. My question is: Do I need to call maintenance to release the aircraft in that condition? From what I understand it’s not required; We must refer to the MEL until aircraft moves on his own power but it does not say we need maintenance to release the aircraft again in case of failure.. According to our FOM, the captain takes the responsibility of the aircraft after doors are closed. My understanding is that before taxi, in case of failure, we refer to MEL but if no maintenance action is required therefore there is no need to call maintenance again. Isn’t it?
I had this issue today in Shanghai Hongqiao but the IR self recovered after realignment. Pilots flying in China know the nightmare it is to get ground personal after doors closed... xD
Only half a speed-brake
Airline's Operating Manual, more specifically the Operator's Approved MEL Preamble is where you find the binding definition.
With the exception of some strange ideas or achieved flexibility goals, the general idea is
A moment of dispatch is defined. Typically the first movement under own power for the purpose of taking-off.
Before dispatch, any failure
- should be written in the book
- must be approved for release by the responsible maintenance officer as per MEL which is binding
- MEL paperwork needs to be filled and signed by an authorized person (captain in some cases)
After dispatch
- the MEL (which is by its definition more restrictive compared to ABN section of AFM / FCOM) does not need to be taken into account
These would be the legal boundaries.
"Refer to MEL" at a time when MEL is still controlling = "Apply the authorized procedures, close with a new maintenance release"
There is no other explanation.
With the exception of some strange ideas or achieved flexibility goals, the general idea is
A moment of dispatch is defined. Typically the first movement under own power for the purpose of taking-off.
Before dispatch, any failure
- should be written in the book
- must be approved for release by the responsible maintenance officer as per MEL which is binding
- MEL paperwork needs to be filled and signed by an authorized person (captain in some cases)
After dispatch
- the MEL (which is by its definition more restrictive compared to ABN section of AFM / FCOM) does not need to be taken into account
These would be the legal boundaries.
"Refer to MEL" at a time when MEL is still controlling = "Apply the authorized procedures, close with a new maintenance release"
There is no other explanation.
Last edited by FlightDetent; 2nd Dec 2019 at 22:09.
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Hi FlightDetent,
Thank you for your time. Like you mentioned, any failure should be written in the techlog but I failed to find official documents saying black and white than maintenance shall release the aircraft again. I asked one TRI from my airline and he agrees with what you say. I just wish it was a little more explicit in our manuals xD.
Thank you for your time. Like you mentioned, any failure should be written in the techlog but I failed to find official documents saying black and white than maintenance shall release the aircraft again. I asked one TRI from my airline and he agrees with what you say. I just wish it was a little more explicit in our manuals xD.
Only half a speed-brake
I worded the above (and erased some) strictly on purpose so that the naked truth stands out.
- post the dispatch moment: crew decides what to do (does not exclude liaison)
- pre-dispatch, only three options exist
a) the A/C is deemed faultless
b) the snags are processed and signed-off
c) it is effectively grounded with an open defect.
This knowledge helps to interpret the various guidance found in the manuals, and apply their advice in the correct sequence and order of priority.
The Continued Airworthiness (of which I know absolute zilch) is a standalone area of industry expertise, and they have relevant NAA branch telling them how to arrange things too. Another point, imagine if we admitted Airbus-language was a standalone linguistic category, you personally operate in a quad-language environment! On top of it, various Tech Logs have various protocols on who is allowed to sign what, etc, etc...
Out in the field, same like you experienced, I think everyone follows rules and decision-making algorithms that attempt to achieve the above while having weak, contradictory or even missing links.
I am not sure who's quantum computer is the fastest, Google, IBM or Intel. In case you wanted to fry its quarks, ask a simple question: How do I officially record a successful inflight reset after landing on an outstation, so that no delay, operational or financial penalty is incurred as a consequence.
BTW (rhetorical) : What actually is the Maintenance Release and when you really need to have (a new) one? (varies between operateors)
- post the dispatch moment: crew decides what to do (does not exclude liaison)
- pre-dispatch, only three options exist
a) the A/C is deemed faultless
b) the snags are processed and signed-off
c) it is effectively grounded with an open defect.
This knowledge helps to interpret the various guidance found in the manuals, and apply their advice in the correct sequence and order of priority.
The Continued Airworthiness (of which I know absolute zilch) is a standalone area of industry expertise, and they have relevant NAA branch telling them how to arrange things too. Another point, imagine if we admitted Airbus-language was a standalone linguistic category, you personally operate in a quad-language environment! On top of it, various Tech Logs have various protocols on who is allowed to sign what, etc, etc...
Out in the field, same like you experienced, I think everyone follows rules and decision-making algorithms that attempt to achieve the above while having weak, contradictory or even missing links.
I am not sure who's quantum computer is the fastest, Google, IBM or Intel. In case you wanted to fry its quarks, ask a simple question: How do I officially record a successful inflight reset after landing on an outstation, so that no delay, operational or financial penalty is incurred as a consequence.
BTW (rhetorical) : What actually is the Maintenance Release and when you really need to have (a new) one? (varies between operateors)
That's a different discussion jaja. An interesting discussion for those quiet cruise portions on a long flight indeed, but still a different discussion.
Now we can produce a long list of failures and ask 'would you take off'. Or we can ask one simple question: why have the regulators chosen the moment of taxi as the start of a flight with respect to defect handling? Apparently they trust our professionalism.
Fair enough, no?
Now we can produce a long list of failures and ask 'would you take off'. Or we can ask one simple question: why have the regulators chosen the moment of taxi as the start of a flight with respect to defect handling? Apparently they trust our professionalism.
Fair enough, no?
Last edited by hans brinker; 4th Dec 2019 at 14:48.
To answer your question from last year. No, I would not, because a turn off light is FD (Flight crew Deferrable) so I can MEL it while holding short, and continue. I would however return to the gate for a door unsafe warning, even if it is FD, and the ECAM tells me I can continue.
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In my opinion the MEL should be applied up until setting takeoff power if you have failures on startup/taxi, and when airborne you look into the Abnormal checklist. That is the way we used to do it.
Let me give an example why : on taxi out you have an ECAM warning, and this failure is a “NO DISPATCH” according to the MEL. Common sense would be not to continue the flight, but as it is company (EASA reg) procedure in many places, it is up to captain to decide if it is OK to continue (after using “good airmanship etc”.
In todays complex aircraft it should not be up to the captain to decide that. The MEL should be used/applied up to setting takeoff power
Only half a speed-brake
hans, I'd argue what is displayed here is not cavalier (ehm) attitudes but the word of applicable law. At least that's what I tried to relay in my post, happy to underline the intention now. And that law does not preclude you from returning back. Au contraire it forces you to apply judgement and exercise authority when taking the decision whether to fly or taxy back.
Moreover, the principle of dispatch moment being the start of taxi under own power is also known to the people who write and certify the MMEL.
Your second point is an excellent illustration to the different protocols (with missing links that I allude to above): Imagine that in pinteam's situation: his entry in the logbook must be counter-signed by approved line-maintenance. So, unlike you, he has the need to continue without recording it pre-takeoff, and the law entitles him to do so. Different strokes for different players.
Writing the above I already got two ideas (case studies) where - based on your wisdomly posting history - I'd bet half a bitcoin you personally (in the door warning situation) would just set the burners full and be gone to worry about the paperwork later.
But there's a better story, not a week old. Upon receiving the taxi instruction, I flicked the taxi LT switch and nothing happed. That's pre-dispatch.
- hhhmmm ....?
Moreover, the principle of dispatch moment being the start of taxi under own power is also known to the people who write and certify the MMEL.
Your second point is an excellent illustration to the different protocols (with missing links that I allude to above): Imagine that in pinteam's situation: his entry in the logbook must be counter-signed by approved line-maintenance. So, unlike you, he has the need to continue without recording it pre-takeoff, and the law entitles him to do so. Different strokes for different players.
Writing the above I already got two ideas (case studies) where - based on your wisdomly posting history - I'd bet half a bitcoin you personally (in the door warning situation) would just set the burners full and be gone to worry about the paperwork later.
But there's a better story, not a week old. Upon receiving the taxi instruction, I flicked the taxi LT switch and nothing happed. That's pre-dispatch.
- hhhmmm ....?
Only half a speed-brake
hans, I'd argue what is displayed here is not cavalier (ehm) attitudes but the word of applicable law. At least that's what I tried to relay in my post, happy to underline the intention now. And that law does not preclude you from returning back. Au contraire it forces you to apply judgement and exercise authority when taking the decision whether to fly or taxy back.
Moreover, the principle of dispatch moment being the start of taxi under own power is also known to the people who write and certify the MMEL.
Your second point is an excellent illustration to the different protocols (with missing links that I allude to above): Imagine that in pinteam's situation: his entry in the logbook must be counter-signed by approved line-maintenance. So, unlike you, he has the need to continue without recording it pre-takeoff, and the law entitles him to do so. Different strokes for different players.
Writing the above I already got two ideas (case studies) where - based on your wisdomly posting history - I'd bet half a bitcoin you personally (in the door warning situation) would just set the burners full and be gone to worry about the paperwork later.
But there's a better story, not a week old. Upon receiving the taxi instruction, I flicked the taxi LT switch and nothing happed. That's pre-dispatch.
- hhhmmm ....?
Moreover, the principle of dispatch moment being the start of taxi under own power is also known to the people who write and certify the MMEL.
Your second point is an excellent illustration to the different protocols (with missing links that I allude to above): Imagine that in pinteam's situation: his entry in the logbook must be counter-signed by approved line-maintenance. So, unlike you, he has the need to continue without recording it pre-takeoff, and the law entitles him to do so. Different strokes for different players.
Writing the above I already got two ideas (case studies) where - based on your wisdomly posting history - I'd bet half a bitcoin you personally (in the door warning situation) would just set the burners full and be gone to worry about the paperwork later.
But there's a better story, not a week old. Upon receiving the taxi instruction, I flicked the taxi LT switch and nothing happed. That's pre-dispatch.
- hhhmmm ....?
Also, in a previous post you questioned what to do about successful reset of systems in flight, we have an "info only" write up in the AML for that.
Last edited by hans brinker; 4th Dec 2019 at 05:54.
Only half a speed-brake
You are not listening, that's what disappoints me (also underestimating my imagination about the case studies, a little 
) . It is not the airlines, it is the law. The Airlines OTOH put protocols and more restrictive rules forward, exactly in the direction you guys are thinking.
You are right about pinteam's case, I mixed that up.
The "info only" is an agreed dinousaur and is specifically prohibited with many airlines on the EU side. It carries no meaning, once a record is done it becomes an issue to be solved. Pilots have no say how to interpret an failure, the authorized Maintrol shift leader does. I assume in your case the "for info" has an explicit definition somewhere in the Continued Airworthiness QA manuals, hence you can use it. No surprise, there is a reason why the good US airlines on average are ahead of the world.
Let's not fight in close quarters. What is the broader perspective?
- everyone has the same goal, only getting airborne with an airworthy aircraft that you trust and that includes neat and proper paperwork trail
- everyone is trying to do their honest best, playing the cards at hand and following the rules
- but we are not walking on the same path towards that goal.
This thread is about discussing what type of gear either of the parties carry on their trail. You mentioned the US being viewed as cowboys, the look from the opposite direction look is EU formalists. Guess what, I think this is bloody relevant - dare to read my mind with more success this time?
) . It is not the airlines, it is the law. The Airlines OTOH put protocols and more restrictive rules forward, exactly in the direction you guys are thinking.You are right about pinteam's case, I mixed that up.
The "info only" is an agreed dinousaur and is specifically prohibited with many airlines on the EU side. It carries no meaning, once a record is done it becomes an issue to be solved. Pilots have no say how to interpret an failure, the authorized Maintrol shift leader does. I assume in your case the "for info" has an explicit definition somewhere in the Continued Airworthiness QA manuals, hence you can use it. No surprise, there is a reason why the good US airlines on average are ahead of the world.
Let's not fight in close quarters. What is the broader perspective?
- everyone has the same goal, only getting airborne with an airworthy aircraft that you trust and that includes neat and proper paperwork trail
- everyone is trying to do their honest best, playing the cards at hand and following the rules
- but we are not walking on the same path towards that goal.
This thread is about discussing what type of gear either of the parties carry on their trail. You mentioned the US being viewed as cowboys, the look from the opposite direction look is EU formalists. Guess what, I think this is bloody relevant - dare to read my mind with more success this time?
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Up to approx. 15-20 years ago, the MEL was applicable up to setting T/O thrust. Then JAA changed the regulation to what we have today (see EASA extract below)
The aircraft does not become any more airworthy, just because you have started to taxi.
So if a defect is a NO GO item according to the MEL, is does not have any positive effect on the airworthiness off the aircraft that you have started to taxi. I think we can agree on that?
Then EASA says the following : “any decision to continue the flight should be subject to pilot judgement and good airmanship”
OK now, so the aircraft manufacturer has evaluated system integrity and have come up with a list in the MMEL of NO GO items. This is because the aircraft manufacturer thinks is a not a good idea getting airborne with these defects. So how do you think a captain can use his/her “pilot judgement and good airmanship” and evaluate that is OK to fly with this defect, just because we have started to taxi ? You can not !
Please note the following very important words from EASA : “The operator should include guidance in the MEL on how to deal with any failures that occur between the commencement of the flight and the start of the take-off”. This actually means the operator has to produce what you can call an “On ground abnormal procedure”. But off course nobody has the resources to do that, so instead you should do what we did before : MEL is applicable up until setting T/O thrust
AMC1 ORO.MLR.105(d)(3) Minimum equipment listEXTENT OF THE MELThe operator should include guidance in the MEL on how to deal with any failures that occur between the commencement of the flight and the start of the take-off . If a failure occurs between the commencement of the flight and the start of the take-off , any decision to continue the flight should be subject to pilot judgement and good airmanship. The pilot-in-command/commander may refer to the MEL before any decision to continue the flight is taken.
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OK now, so the aircraft manufacturer has evaluated system integrity and have come up with a list in the MMEL of NO GO items. This is because the aircraft manufacturer thinks is a not a good idea getting airborne with these defects. So how do you think a captain can use his/her “pilot judgement and good airmanship” and evaluate that is OK to fly with this defect, just because we have started to taxi ? You can not !
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Yes you can because many « No dispatch » conditions are extremely conservative. And if you are outstation with no maintenance, you happy that you can legally proceed. I mean come on, modern airliners have so many redundancies. So if I understand correctly you would not go if you lose 1 computer out of 3 on a an A320 cause Mel says no dispatch but would happily fly a Cessna 172 relying on one engine? xD. I’m obviously not talking about hydraulic or serious failure that is a no brainer to go back. Once again it’s all about good judgement and airmanship.
In my humble opnion, if you don`t have anything serious and professional to add to this discussion, then please leave the discussion to others.
I wish you a good day
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I just gave my point of view why I think it’s safe depending of the case to continue the flight following a failure after taxi.
The law says we can. Deal with it.
have a good day too. =)
Yes you can because many « No dispatch » conditions are extremely conservative. And if you are outstation with no maintenance, you happy that you can legally proceed. I mean come on, modern airliners have so many redundancies. So if I understand correctly you would not go if you lose 1 computer out of 3 on a an A320 cause Mel says no dispatch but would happily fly a Cessna 172 relying on one engine? xD. I’m obviously not talking about hydraulic or serious failure that is a no brainer to go back. Once again it’s all about good judgement and airmanship.
I don't fly single engine myself but as far as I can remember you cannot fly commercial single engine with pax. Do you think that is a n extremely conservative attitude from the regulator?
Only half a speed-brake
hans brinker My last post, if you'd take my word for it, was written with enthusiasm. Instead of displaying that, the resulting verbiage came out quite confrontational, nasty. Sorry about that.
Line up and with the tkof clearance turn on the LDG lights but one of them is not working: The EU rules allow you to go straight away. I understand that the US rule is to vacate at the first exit, fill the paperwork and start over. I am not entirely convinced this would actually happen.
The idea I had is that the formalist EU are not allowed to interpret the "meaning of rules" but required to stick to them at all times. Butterfly wing effect, then we try not to create rules which will be impossible to follow. (Loose reference: AC 120-71 - Effective SOP section of the document, namely Once established, the SOPs must be applied with consistency and uniformity throughout the operation).
---
Line up and with the tkof clearance turn on the LDG lights but one of them is not working: The EU rules allow you to go straight away. I understand that the US rule is to vacate at the first exit, fill the paperwork and start over. I am not entirely convinced this would actually happen.
The idea I had is that the formalist EU are not allowed to interpret the "meaning of rules" but required to stick to them at all times. Butterfly wing effect, then we try not to create rules which will be impossible to follow. (Loose reference: AC 120-71 - Effective SOP section of the document, namely Once established, the SOPs must be applied with consistency and uniformity throughout the operation).
---
jaja If something has changed 20 years ago, based on 40 years of previous experience and the new version is in force today, it still is 60 years of experience - combined.
You constantly refer to somebody departing with a NO GO item. Why would anyone do that?
Quoting the AMC --- that acronym actually means the mandatory and only (unless otherwise approved by the NAA) approved means of compliance --- That's an important one.
It says the MEL (OM-B section MEL) does not get approved by the NAA until a procedure for the taxi-phase is drawn and inserted there. For which a typical wording is "open the MEL and use the NO DISPATCH / DISPATCH POSSIBLE as a key to figure out whether to taxi back or go, if unsure must contact the MCC duty officer".
When you say nobody has that text, my mileage really varies. It sounds like an incomplete and non-compliant OM. I could see the NAA being at fault where you stand but not the legislation itself - proven by that very quote.
---
@pinteam The two of us and hans operate the same airplane. I strongly suggest that if the MMEL says NO DISPATCH on that thing, you really do not want to fly it.
Remember, what the evaluation criteria between NO DISPATCH and RELIEF POSSIBLE are. It is the expected combined effect after another, independently caused, failure on the same system. The resulting state becomes the key. Hence you can do 1 brake inop, but not 2. Or taxi and tkof LT inop for a night - but only as long as both LDG LTs are operative.
Another example: during F/CTL controls check while taxiing already, ELAC 1 PITCH FAULT. Reset per QRH, re-action the F/CTL check (part of the QRH proc): the failure re-appears. That is a NO GO by the book. Seeing those words means the smart engineers decided the state after ELAC 1 PITCH FAULT does not have the redundancies anymore.
Compare that ELAC 1 PITCH against the case of a single PACK (go item): if the opposite would fail, you lose all pressurization sources, but the hull will contain pressure somewhat - there still is a backup in place. Touch your heart, not much of it!
Well, where it says NO DISPATCH for the ELAC 1 PTICH FAULT it means the equivalent result after a second failure would be worse than having no packs at all.
You constantly refer to somebody departing with a NO GO item. Why would anyone do that?
Quoting the AMC --- that acronym actually means the mandatory and only (unless otherwise approved by the NAA) approved means of compliance --- That's an important one.
It says the MEL (OM-B section MEL) does not get approved by the NAA until a procedure for the taxi-phase is drawn and inserted there. For which a typical wording is "open the MEL and use the NO DISPATCH / DISPATCH POSSIBLE as a key to figure out whether to taxi back or go, if unsure must contact the MCC duty officer".
When you say nobody has that text, my mileage really varies. It sounds like an incomplete and non-compliant OM. I could see the NAA being at fault where you stand but not the legislation itself - proven by that very quote.
---
@pinteam The two of us and hans operate the same airplane. I strongly suggest that if the MMEL says NO DISPATCH on that thing, you really do not want to fly it.
Remember, what the evaluation criteria between NO DISPATCH and RELIEF POSSIBLE are. It is the expected combined effect after another, independently caused, failure on the same system. The resulting state becomes the key. Hence you can do 1 brake inop, but not 2. Or taxi and tkof LT inop for a night - but only as long as both LDG LTs are operative.
Another example: during F/CTL controls check while taxiing already, ELAC 1 PITCH FAULT. Reset per QRH, re-action the F/CTL check (part of the QRH proc): the failure re-appears. That is a NO GO by the book. Seeing those words means the smart engineers decided the state after ELAC 1 PITCH FAULT does not have the redundancies anymore.
Compare that ELAC 1 PITCH against the case of a single PACK (go item): if the opposite would fail, you lose all pressurization sources, but the hull will contain pressure somewhat - there still is a backup in place. Touch your heart, not much of it!
Well, where it says NO DISPATCH for the ELAC 1 PTICH FAULT it means the equivalent result after a second failure would be worse than having no packs at all.
Last edited by FlightDetent; 4th Dec 2019 at 17:39.
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In aviation it pays to be conservative, and the reason for 3 computers isn't just redundancy, but being able to vote. I for sure would go back to the gate with any no-dispatch discrepancy. The fact that you and I (both experienced pilots) disagree about this is all the proof I need to conclude it should not be left to the judgement of the pilot.
I don't fly single engine myself but as far as I can remember you cannot fly commercial single engine with pax. Do you think that is a n extremely conservative attitude from the regulator?
I don't fly single engine myself but as far as I can remember you cannot fly commercial single engine with pax. Do you think that is a n extremely conservative attitude from the regulator?
Many of my flights are shorts ones and we carry lots of fuel. Our company is very conservative for the fuel policy and our aircraft are very well maintained. We very seldom have MEL at the first place. Maybe I sounded like a cowboy but I’m not, and the decision to go back to the gate or not would be taken with the FO and maybe with the company if I have time to stop and send and Acars message or give a call. I never had to make that decision yet actually; Only had “can go failure” maybe twice in 5 years.
Commercial Single engine operation is allowed in some countries, I flew Cessna Caravan for 2 and half years in Zambia. But yes, I undestand why it’s forbidden in most countries. = )
Last edited by pineteam; 5th Dec 2019 at 09:17. Reason: Typo
Hello Hans Brinker,
Many of my flights are shorts ones and we carry lots of fuel. Our company is very conservative for the fuel policy and our aircraft are very well maintained. We very seldom have MEL at the first place. Maybe I sounded like a cowboy but I’m not, and the decision to go back to the gate or not would be taken with the FO and maybe with the company if I have time to stop and send and Acars message or give a call. I never had to make that decision yet actually; Only had “can go failure” maybe twice in 5 years.
Commercial Single engine operation is allowed in some countries, I flew Cessna Caravan for 2 and half years in Zambia. But yes, I undestand why it’s forbidden in most countries. = )
I wasn't suggesting you are a cowboy, it is my companies policy to handle problems during taxi out this way. I really mean it should not be up to the judgement of the pilot, because in my opinion that puts to much go pressure on the pilot. In my company we have a flow chart (posted above). Even if I can reset the system (with an published reset procedure or phone help from MOC), I have to enter the successful reset in the AML for tracking and advise MOC. For anything else, back I go.
Also I meant to say SE IFR Commercial, but even that may be allowed in some places...