Shelf-life fuelpump 912

Yes !  The fuelpump I bought yesterday was made in October 2024 and it would be resonable if the 5 years should start ticking from this afternoon when it is first exposed to fuel and mechanical work. / Pierre 

Hello All

Shelf life is a different thing on parts materials or special requirements spelled out as in electrical parts like the ECU..  In the ECU for example it has a specific requirement for testing at every 2 years when sitting on the shelf.  It has no replacement time once in use and in a running engine.  (the main issue is the corrosion of the connections in storage and keeping the internal parts operational) 

In the case of rubber (real or synthetic) there are several factors.  How they are stored and what they may be exposed to.  For O rings as an example, once installed in an engine are not exposed for the most part to environmental issues, they normally can run to TBO.  Fuel system parts are specifically called out in the 5 year rubber parts change list due to exposure to fuels and fuel vapor.  In the case of parts like the fuel pump the date of manufacture starts that time line whether it is in a box or on the engine.  As stated for certified you would have to trash the part when it is timed out sitting on the shelf.  This is not a hard part to defend as the pump manufacturer will not support any pump more than 5 years old.  As I stated before, if it is experimental you can experiment and run it 20 years if you like.  I for one would not install any timed out part as the FAA/NTSB would still call you out if you did.  

As a note, the timeline on rubber spares in MIL SPEC is 60 months from date of manufacture.  Given we will never know when the date was since we all rely on a supply chain to have them made and distributed, the best we can do is recommend a best date to install or discard the part.  Rotax buys such parts, distributes it, the distributor sells it to a Service Centre or Repair Station, it may or may not be installed right away....you see the issue.  This is why they say do not hold it for more than 48 months before installation.  Once installed then it is covered by what is stated in the maintenance manuals on recommended time change.   

Cheers

RW,

Are you saying that the 48 month allowed shelf life applies only to sundry rubber parts that may not be dated by the manufacturer? And, that since a fuel pump has a stamped date it is treated differently?  The time limits section of the 912/914 MML refers you to SL-912-022, which clearly states rubber parts have a shelf life up to 48 months, in addition to the service life of 5 years.  However, fuel pumps are not addressed directly.  I don’t see anything in any documentation that directly allows, or disallows, a shelf life for fuel pumps in addition to the 5 year service life. But what you are saying would mean that distributors would need to sell only currently dated pumps. No matter the answer, it’s not very clear.  I can say this, I would not want to put a four year old pump on my aircraft then run it for 5 years.  

Hi Jeff,

"I can say this, I would not want to put a four year old pump on my aircraft then run it for 5 years."

My first Rotax 9 (1999 model) aircraft came to me with an incomplete service history, compounded by my total lack of Rotax knowledge, with Hobbs 300 hrs & 10 years .

I flew it for about 18 months before becoming aware of the 5 year rubber replacement recommendation. I started progressively replacing  hoses, carb rubbers, straight away, continued to fly. 

At a guess, I purchased a new fuel pump at about 18 months into ownership. The installed pump, the style before a drain spigot, appeared to be working well, so I put the new pump "on the shelf".

5 years after doing, what was likly its first rubber replacement,  I did my second replacement AND replaced the still functioning /delivering good pressure, fuel pump.

There was never a leak or drop in efficiency - I don't have the aircraft any more but still have the original pump.

I flew that aircraft for 10-12 years - engine purred the whole time.

I tell this story not to recomend but to reassure  - there is considerable redundancy factored in to the Rotax 5 year rubber replacement.😈

I understand that a lot of people have never looked after certified engines.  Certified parts from Rotax are normally at least 10% more cost than the experimental.  This is to cover the cost of tracking and Form 1 (similar to 8130-3) as required in assemblies.  In a certified engine all parts are tracked from original supply from the OEM.    All assemblies have to be recorded as to if they are replaced by notations in the log book by a Form 1 tag (FAA 8130-3)  Tracking small parts like O rings for example would be done in certified spares by batch numbers.  The batch number tells the OEM when it was originally supplied and should be tracked in the work order and noted.  If you have such a part without a serial then yes the 48 month shelf life would be the maximum time to be without installing.  Once it is installed it then takes on the calendar life published for installed parts that we find in the MML.    In the case of an installed carburetor rubber part that would be 5 years from the life of it being installed.  This is not the case with serialized parts that have limited calendar life, like a fuel pump assembly.  

Now to the point here, this is clearly best practice and required for certified parts.  If you are flying as an experimental you can do whatever you want.  One has to look at where you fly, many countries in Latin America insist that even experimental follow similar rules.  In the USA as experimental you can do what you want as long as someone will sign off your condition inspection.  

Cheers