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-   -   CAMO and TSN data (https://www.pprune.org/engineers-technicians/616406-camo-tsn-data.html)

swan1980 17th Dec 2018 16:17

CAMO and TSN data
 
Hi all,
I am trying to increase my knowledge of the Continuing Airworthiness Management.

As Part145, we receive components of different type to be repaired. Usually all goes smooth, but it can happen to receive parts (a generator, an APU etc) for which the operator "forgets" to include the TSN/TSO.

Some operators are diligent and able to provide the missing data within few hours, but others are sometimes stubborn. So we have units with apparent no history. This is a problem, because we need to be overcautious in replacing life limited parts.

Now, I cannot believe an operator does not have the TSN/TSO, otherwise what is the point of the a/c log book......

My question: in order to be compliant with airworthiness, is it mandatory to the operator to flow down all the data of the a/c part they need to repair? As a matter of safety, a unit with no TSN/TSO info is equivalent to a unit picked up from the street. therefore how to take it back to zero unit without stripping and refurbishing at 100%?

Many thanks for your knowledge sharing

Rigga 19th Dec 2018 20:00

It is normally considered to be cost effective to monitor and control time/cycle sensitive components and larger operators manage to do this with ease and often with an amount of real-time accuracy. Most operators records lag behind slightly - meaning that the records need a small amount of time for the paperwork to catch up with the component when it is removed.
Some operators just don’t get it!
If the operators cannot supply correct TSN/TSO data the component cannot be partially maintained and can only be reset to ‘Zero’ by a complete overhaul. That is the price of inadequate record keeping by an operator.

swan1980 19th Dec 2018 21:18

Hi Rigga! Many thanks for the information.
I am sometimes confused by different ideas on this subject, coming from colleagues with larger experience than mine. It is definitely a complex field, and EASA rules do not look "clear" enough to my untrained eye.
In addition, I believe the operator needs sometimes to be educated on this issue.
However, I got complaint from some of them, and this can lead them to use other shops. So it is a very tough balance to handle a customer to be happy, and avoid to mess up in an audit from the authority. Of course, no one wants to pay a complete overhaul "just because TSO is missing....".
Again, many thanks.

wrench1 20th Dec 2018 22:38


Originally Posted by swan1980 (Post 10339689)
However, I got complaint from some of them, and this can lead them to use other shops. So it is a very tough balance to handle a customer to be happy, and avoid to mess up in an audit from the authority. Of course, no one wants to pay a complete overhaul "just because TSO is missing....".

For comparison, under the FARs (FAA) every owner/operator is required to maintain and track all articles and products with life limited parts. And in some operations, they are required to maintain and track overhaul times. If an owner/operator fails to maintain that record they are in violation of the regulations.

On the other hand, there is no regulation they must forward these times when they remove an article or product from service and route it for replacement or overhaul. However, since a repair shop requires that specific information in order to provide the most cost-effective and complete service it falls to the owner/operator to provide all required records or face the consequences: a complete overhaul with replacement of all life limited parts. Don't sell yourself short.

woptb 22nd Dec 2018 13:01

Airworthiness always remains the responsibility of the owner/CAMO. You need to get your maintenance contract sorted from the off; You only do maintenance,as ordered to the required standard, any roadblocks outside whats detailed in the work order/contract you 'must' refer to the CAMO,its their equipment,they make the decision. If you require a TSO/TSN and don't have it,you can't do the required and if its not detailed in the contract or work order,you 'must' go back to them.

NutLoose 24th Dec 2018 01:07

An odd one here is in piston engines, the likes of Lycoming are the only ones that can zero time a Lycoming engine, so an overhauled engine from another company will come back with zero hours since overhaul but with the hours the engine has run to date, so you can have an engine with 4000 hours but zero run, took a bit of explaining that one once.

wrench1 25th Dec 2018 13:43


Originally Posted by NutLoose (Post 10343370)
An odd one here is in piston engines, the likes of Lycoming are the only ones that can zero time a Lycoming engine, so an overhauled engine from another company will come back with zero hours since overhaul but with the hours the engine has run to date, so you can have an engine with 4000 hours but zero run, took a bit of explaining that one once.

Agree. Luckily on this side there are specific regulatory terms for the difference: overhaul and rebuilt. But that doesn't stop from some people intermixing them. The kicker is an OEM rebuilt TSN:0 engine will have still used parts in it. However, recip engines aren't the only thing I've seen "rebuilt." Several aircraft models can have their airframe zero-timed as well like a SA315B Lama helicopter. The OEM would strip it down and reset the aircraft totoal time to zero. However they would add a slash and ID number to the existing aircraft serial number to differentiate from non-rebuilt ones.

Ultranomad 26th Dec 2018 13:46


Originally Posted by NutLoose (Post 10343370)
An odd one here is in piston engines, the likes of Lycoming are the only ones that can zero time a Lycoming engine, so an overhauled engine from another company will come back with zero hours since overhaul but with the hours the engine has run to date, so you can have an engine with 4000 hours but zero run, took a bit of explaining that one once.

Not exactly so. An engine zero-timed at the factory is not quite the same as the old engine. Zero-timing is a result of pool-based overhaul where lots of engines are completely disassembled. Parts that are beyond repair are rejected, and serviceable/repairable ones go into a pool, so they have a pool of crankcases, a pool of crankshafts, etc., out of which they make engines (to new engine tolerances). Thus, the parts of a zero-timed engine may have been in use but do not necessarily correspond to one and the same engine. Thus, the engine "personality" is lost, and the only way out is to start counting the operating time from zero again. The engine gets a new number, too (which may be a completely new number or e.g. the original crankcase number plus a suffix - it's up to the manufacturer to define it).

NutLoose 27th Dec 2018 17:21

Ultra there are 3 types,
New outright
Zero timed which is overhauled to new limits
Overhauled which overhauled to overhaul limits

There are other companies that do zero timed engines but cannot sell them as that so they sell them as to zero timed limits under some other name..
My occasion with the CAA was on an audit with an engine that had been factory overhauled twice, so the Lycoming cert in the front of the logbook said it had 4k hours on it, but the logbook entry started with zero, he couldn't get his head around it coming out of the factory with more hours than the overhaul hours limit, but with zero hours in the logbook, until I explained it to him

Rigga 27th Dec 2018 20:38

Not many light aircraft surveyors about - and all surveyors don't seem to have the luxury of their own 'judgement' anymore! All done 'by the book' now....and then they change the way they interpret the book!!

swan1980 7th Jan 2019 10:39


Originally Posted by wrench1 (Post 10341004)
For comparison, under the FARs (FAA) every owner/operator is required to maintain and track all articles and products with life limited parts. And in some operations, they are required to maintain and track overhaul times. If an owner/operator fails to maintain that record they are in violation of the regulations.

On the other hand, there is no regulation they must forward these times when they remove an article or product from service and route it for replacement or overhaul. However, since a repair shop requires that specific information in order to provide the most cost-effective and complete service it falls to the owner/operator to provide all required records or face the consequences: a complete overhaul with replacement of all life limited parts. Don't sell yourself short.

Wrench1, many thanks!
This is very clear and almost "self explanatory". Still quite surprised by the number of people (me included!) so ignorant of the CAMO responsibilities.

An interesting variation of the topic is the casual MRO broker walking in with units taken for scrapped aircraft.... pretending maintenance with zero history (again, how is it possible??). Looks to me sometimes people thinks aviation follows the same rules of automotive repairs....


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