SB v AMM

[airbirduk]

Some advice needed please, totally hypthectical situation.....

I have an SB to accomplish that involves carrying out a boroscope inspection and looking for cracks. I find a crack and according to the SB as long as I meet what conditions it states I can release it to re-inspect at next A check. Ok fine, nowhere does it mention the AMM. So I close the SB recording everything where necessary.

In the mean time I have looked in the AMM and found that some very restrictive limits are stated for the area that I was inspecting. Infact I would have only been able to release everything for 50FH.

So my question is:-

which is correct, releasing to the SB or should the AMM still come into play?
Is the AMM the overriding document in all cases?

Like I said this has not actually happened I am just confused!!!!!!

[Genghis the Engineer]

If the SB details an amendment to the AMM, and is supported by an authority AD, then I think you're fine in assuming that the SB overrules the AMM. But, you say it doesn't reference the AMM.

If the SB is not supported by an AD - or does not list any AMM amendment, then I'd take the most restrictive of the two to be on the safe side. Which in this case probably means write it up as a 50hr Boro until below whichever is the most severe of the SB/AMM cracking limits.

That said, I'd personally pick up the phone to the TC holder's support department - it sounds suspiciously like a left and right hand not talking properly, and maybe they don't realise there's a discrepancy and need to be aware of it. It does happen - a properly constructed SB or similar document should reference all affected parts of the AFM/AMM, but it's frightening how often this gets missed, I had the great pleasure of bouncing a load of paperwork recently back to a certain national airworthiness authority because THEY had failed to do so.

G

Hoping desperately this is no type that I'm signatory for.



On a lighthearted note, your phrasing reminds me of a scene from Reggie Perrin, where Reggie goes to Doc Morrisey complaining that his "friend" had an embarrassing medical problem.

Doc: "So you're quite sure this is your friend and not you"
Reggie: "Absolutely Doc"
Doc: "Shame, if it was you I could sign you off work for a month".

[mymymy]

Hello airbirduk,
at our carrier, AMM prevails. SB limits can be used ONLY with approval from engineering dept in the form of a production permit.

3m


:p

[matkat]

This is definately a RH/LH situation 2 different limits can not apply and I would ask the SB issuer to clarify the situation and ammend as necessary.For the time being take the lower limit i.e. the AMM as gospel and ensure a 50FH repetitive inspection is called up.
Great job for spotting this.
matkat

[STC]

If the SB is not supported by an AD

Service bulletins do not have to be enabled by AD. They do however have to be approved by the civil airworthiness authority of the aircraft's state of design.

In some countries, the term "Mandatory Service Bulletin" is used to define changes that are the result of Airworthiness Directives.

Service bulletins by their very nature contain information that supercedes the AMM. Why bother issuing supplementary documents that just parrot the AMM?

Not all service bulletins are mandatory therefore technicians should work with their engineering/maintenance departments to determine if the contents of any particular SB will be adopted.

And...when working with a service bulletin, follow it to the letter. Do not mix in AMM content without consulting the OEM.

Many SBs are produced as a result of an operator asking for reduced tolerances or greater flexibility. So don't be surprised to see SB tolerances deviate from the AMM.

[airbirduk]

Dear all,

Many thanks for your information. It is appreciated

[anguspm]

Very Suprised to see no one commenting on which document is the latest issue. ie the most recently issued of the two.

This situation exists with a number of documents relating to the A300. Not only in the AMM vs IPC relationship but also regarding Vendor vs MPD limits. From the planning/schedule creation point of view it can be a minefield.

In this particular instance I would sign off with the lower limit as this would be sure to get the back office staff investigating it and making the appropriate phone calls etc.....

[matkat]

Gentlemen,this is becoming an overcomplicated issue.Firstly no SB is mandatory it does not matter what it says the manufacturer will call it what it wants but is not required to be done,if it becomes mandatory it will be Supported by an AD which will reference the SB,therefore the AMM will always be the primary approved document,and written on the SB it will tell you that if there is a conflict of instructions the AMM takes precedence.Being that the SB is not mandatory the issue date of the SB to AMM is irrelevent as if the SB does become mandatory then the AD will say that the AD takes precedence over the AMM and an ammendement to the AMM will be issued.Please further note that the I.P.C.& the vendor manual are unapproved documents but the MPD&AMM are approved documents therefore these 2 are always the documents that are relevent.Please note that the vendor manual should not be confused with the component maintenance manual(CMM)which is also an approved document.
matkat

[anguspm]

matkat,

Agree with most of what you are saying but there exists now situations where an SB and AMM are both referenced by the MPD.

For the A300 the AMM/MPD/CPCP/SSID are all issued at different times and with SB's being revised outside this there exists conflicts where the SB has different limits to the AMM yet both are mandated by the MPD. Hence why I believe the issue date does take effect. Incidently that was the response received from AI when the question was put to them for a definitive answer.

[TeamTerminal]

As this question was proposed as hypothetical & not a current situation, a couple of points should be noted.

1. The AMM/MPD/MRB will usually (but not always) establish the hierarchal order of documents. This is usually found up the front before you get to the bit that tells you how to do what you do. It can take some finding.

2. Often (but again not always) an approved maintenance system will also spell this out if it is not in the OEM books, including the system of maintenances status in this structure.

3. If you are operating to a system of maintenance & the system of maintenance states that you will comply with mandatory service bulletins, then under your own system an AD is not required to make it mandatory. IE the regulator does not need to get involved to require compliance.

It is not inknown for an operator to be penalised for not performing mandatory SB's without an AD in such circumstance.


Check your system you may find the answer there.

TT

[matkat]

Team terminal please give me a factual instance of when an operator has been penalised for not complying with a SB,how can it be possible that they can be penalised for not complying with a Non-mandatory issue? As i previously quoted there is no such thing as a "Mandatory Service bulletin" the issuer of the bulletin can call it what they want but it does not need to be complied with,as that can only be done via AD.I agree with you that the MPD can have a SB in it but this is from the Manufacturer(the MPD)and again can only be mandated via an AD.The reason that a SB would be in the MPD is if there is at that time no fix for the discrepancy and it was recurrent.The MPD provides "Scheduled" maintenance for a particular operator and is agreed with the relevent NAA,please bear in mind that a SB is issued by the manufacturer and not the NAA,the relevent NAA will review the SB and decide whether it warrants an AD therefore making it mandatory if not it will remain an SB and will not be so.
matkat
If in doubt please call the FAA field office in LGW for confrmation.
+44 208 754 88199

[Blacksheep]

To be slightly pedantic, in the hypothetical situation cited, the SB will be issued by the engine manufacturer and and the SB will be approved data, while the AMM isn't. For engines the engine manual carries more weight than the AMM every time.

For the more realistic situation of a confict between an airframe SB and the AMM we must first qualify the conditions I discuss - Boeing aircraft, Boeing SB.

Notwithstanding matkat's belief that the AMM is an approved document, Boeing have many times advised that since the AMM is not approved by the FAA, the AMM and IPC are "provided for the information and advice of maintenance personnel only and certifications can only be made to the approved drawings, which are the only FAA approved documents" Overestimating the status of the AMM and IPC has led many an LAE astray, I'm afraid. Although the AMM is based upon the approved drawings, the latest manfacturer's drawing approved by their regulatory body will always overrule the AMM or IPC. Boeing (or other manufacturer's) SBs will generally be drafted on the basis of new drawings, therefore it is most likely that an SB will supersede the AMM. The proper response to a conflict is therefore, to release the aircraft to the most restrictive of the possible outcomes while the conflict is referred back to the manufacturer, quoting chapter and verse. In most cases you will find the SB wins. and the manufacturer advises that an AMM revision will be issued shortly. Such matters are the bread and butter of Technical Services or Development Engineers, so I'm surprised no-one seems to have considered consulting them.

[DoctorA300]

20 years up to my neck in grease, and I learn something new every day.
Thank's Blackie, or should I call you YODA.
Brgds
Doc

[Blacksheep]

25 years up to my neck in grease, follwed by another 15 up to my neck in ADs, SBs, STCs, Assembly Drawings, Detail Drawings, Material Specifications, Process Data and Standards turned me into YODA, Doc.

Maintenance asks a question and Engineering provide the answer. Its what we do and there's a lot of duff gen in the previous answers.

[matkat]

a) Maintenance record entries. Except as provided in paragraphs (b) and (c) of this section, each person who maintains, performs preventive maintenance, rebuilds, or alters an aircraft, airframe, aircraft engine, propeller, appliance, or component part shall make an entry in the maintenance record of that equipment containing the following information:

(1) A description (or reference to data acceptable to the Administrator) of work performed

Taken from FAR 43,it would seem none of us are right as the data must be acceptable to the administrator it also appears to me that it would be a massive grey area.
Blacksheep please provide references if you are to say theres a lot of duff gen here without refs who is to say you are not providing it yourself!,this is a very complex subject and I have also been doing it as many years as you so lets get definate answers between us and learn.
Best regards
matkat

[Blacksheep]

matkat - you're right that this is a massive grey area, which is why the proper response to a conflict between two documents must be to refer back to the aircraft type certificate holder. Data acceptable to the administrator is not the same as data approved by the administrator. The AMM may be acceptable but it is not approved. On the other hand, modifications that alter the type certificate must be approved.

In general the AMM would be correct but once in service, modifications to aircraft result in changes to the maintenance documents to reflect those changes. The document for accomplishing the change necessarily precedes the maintenance manual revision and generally has direct or delegated approval from the regulator, so the SB should carry more weight. This is why Boeing told us on several occasions that the AMM is "provided for the information and advice of maintenance personnel". The Boeing IPC is not even published by Boeing - they delegate that task to a sub-contracted technical publications company.

Boeing advise that the original FAA approved drawings from which the AMM is drafted [maintenance tasks are drafted in full text as approved 'drawings'] are the only certification authority. Unfortunately, as they are produced and checked by human beings, these 'drawings' sometimes contain mistakes that were not detected during the approval process. The test schedule 'drawings' are revised when an SB is published but they are not easily available to operators - In fifteen years we have only been supplied with copies on two occasions, both in such circumstances as we are discussing here. While the AMM must remain the main document relied upon by maintenance personnel it should be used with caution - it is not as authoritative as many people give it credit.

So, where conflict such as that described in airbirduk's original post exists, Maintenance should refer any conflict between the AMM and other controlled data to Engineering for clarification by the type certificate holder, so they in turn can verify their approved data and give an authoritative reply. How to proceed while the problem is sorted out is a matter for Engineering, Quality Assurance or even the operator's local regulator, not maintenance personnel. A grey area indeed - there never is a final definitive answer, but that's what makes the back-room boys' job satisfying and worthwhile, is it not?

Yoda.

[Kanga767]

Blacksheep -

The AMM is ALWAYS the overriding authority over an engine manual.

For example, an engine power assurance check is always done to the AMM and not the engine MM if there is data for such in both manuals.
In fact, in this example, if there is data in the AFM, it even overrides the AMM.

The only document that can override the AMM/AFM is an AD.


Its one of those quirky things.


K

[Blacksheep]

The only superseding authority? Really? ADs certainly overrule anything else - they are based upon the latest design data available and are not only approved by the regulator, but are also issued directly by the regulator.

I agree that for something concerning engine power runs and other work related to the engine as installed on the aircraft - where the engine QEC build up includes customized aircraft system related equipment and the controls are certified to the particular airframe type - the AMM has priority over the engine manual, but not for questions regarding the build up and internal inspection of the bare engine.

Airworthines Directives and Service Bulletins containing an approval statement (i.e. the majority) are based upon drawings and empirical data produced by the manufacturer and approved by the regulatory authority - approved data. The AMM and other such manuals are not 'approved documents'. The answer remains as given previously - in the event of a conflict between maintenance documents the proper procedure is to refer the matter directly back to the type certificate holder.

[Kanga767]

For engines the engine manual carries more weight than the AMM every time.


Where no conflicting data exists in the AMM, of course you use the engine manual!

My statement was to indicate that the AMM is the overriding authority where data exists in both the AMM and engine manual, which is at odds with your post.

As far as the AMM not being an approved document - In Australia at least, every time work is done on an aircraft it MUST be in accordance with approved Data, if the AMM isn't approved data, then I'm in the Poo!!!


K

[Blacksheep]

The confusion seems to be over the difference between "Approved Design Data" and "data approved for use". Approved Design Data must always take precedence. Since even the designers can get it wrong and the regulators, no matter how good, then sometimes fail to pick up the errors, conflicts between documents must occasionally be referred back for double checking.

The following obviously only applies to Boeing aircraft but serves to illustrate the principles involved. On the 'Approved' status of manuals, just go through your Boeing Representative or your usual company channels to ask Customer Support Engineering at BoeCom for yourself to verify this:

On more than one occasion when questioning conflicts such as we are discussing, we told Boeing that we must certify work according to the AMM or the IPC. Their response is always that the AMM and IPC are not approved by the FAA. They are based upon approved data but can only include revised approved data after a significant delay. Only approved data such as Approved Design Drawings can be used for certification purposes. (Note that Tasks such as the test or inspection procedures in the AMM originate in Approved Design "Drawings" although they consist entirely of text)

The operator's regulatory authorities will approve the AMM and IPC for use but that is not the same thing as approving the data contained in them. Approved Design Data originated by the Type Certificate holder and approved by the regulator of the country of manufacture may therefore supersede the information contained in the AMM or IPC.

Once the original Type Certificate is issued, the AMM and other maintenance documents are issued as representing that configuration. Design changes after initial type certification are approved by the FAA as changes to the Type Certificate and introduced onto newly built aircraft by Production Changes such as PRRs or PRRBs for example. These changes may also be issued for post delivery incorporation as Service Bulletins (SB) approved by the FAA. Such SBs contain a statement that they are approved by the FAA and (almost always) cross refer to the original production change number. Airworthiness Directives are issued by the FAA themselves, are applicable equally to both the operator and the manufacturer and thus supersede all other documents. An AD may make an already approved SB mandatory.

As for Aussie Rules Kanga, don't worry too much about the Poo. Although Yanks and Poms do realize that CASA know more about aircraft design than the FAA, many Ozzie LAEs are aware that one of CASA's induction procedures for new staff is to shove a poker firmly up their backsides! :D

When in doubt, ask the originator and you can't go far wrong.

[Kanga767]

Thanks Blacksheep!

Although just a line LAME, I do have an interest in the documentation and type certification side of things.

I think I learned something out of this discussion.

K

[Blacksheep]

You're welcome Kanga.

...and by the way there's no such thing as "just a line LAME" The Line is the foundation for all who work in aircraft maintenance engineering. I still miss it.