U/S On Fit Spares

[timothy taylor]

We have a regular problem with rotable parts from overhaul that turn out to be u/s on fit.

Sometimes after days of further trouble shooting and further components replaced. This leads to no confidence in spares that we recieve.

Is this an industry wide problem or are we unlucky?

[Dufo]

Same problems at our place.. with green-tagged parts 'inherited' from previous operator. From hydraulic shuttle valves to trim synchronizer..and more.

[Germstone]

Very common Nothing worse than doing the same job twice.

Almost as annoying as the aircrew not giving full details of a defect :-p

[TARTAN]

All too often, in order to save money, the cheapest spare on offer is the
one that is bought but there is usually a reason why it is priced low and
that might be because it has been on the shelf for a long time. Some
units are shelf lifed.

Also, 'As Removed' units with the condition only being INS
are always suspect and really should be sent to an MRO to confirm
their serviceability prior to attempting to fit them again.

I would be surprised if the units which fail, all the have been recently
overhauled. Are you certain this is the case or are they ones that have been
'S' / 'SOS' tagged or are they just INS?

As for the vertical gyros, are they 'shock watched'? As you are aware,
they are extremely sensitive instruments and it doesn't take much of a
drop to make them U/S. The only way to make certain that they are
not dropped is to 'hand carry' them. It is only asking for trouble if they
are shipped by a third party courier.

On many occasions OHC/REP units are returned as being 'failed on
fit' but are actually found to be SER after being sent to the MRO as
a Warranty Claim because the original removed unit was not at fault
in the first place, the fault later found to be further along the line.

Just some thoughts. If your faults are none of the above then you are
indeed very unlucky.

[FMU]

In-house component workshops closed down and now outsourced. Part suppliers obtain spares from the cheapest source. Component fails on fitment or a few cycles latter with same fault it was previously removed for. Overhaul worshop says " No Fault Found" NFF. Welcome to our world.

[NutLoose]

I went through 4 Alternators all overhauled units from the manufacturer, before I got one to work, in the end I insisted on one from a different batch, I also change voltage regulators and over vaults during the process, you never expect to get 3 duff alternators in a row, but I did....... welcome to my world!

[Wirelock]

the shop report can give some clues. as said before items that returned from repair with no fault found maybe havent been fixed. the J10 harness on the cfm56-5 is a good example. however it must be said that it might be difficult, for some parts, to replicate faults in parts in the shop and think that they are serviceable. i recall when we got the same faulty j10 harness 3 different occasions.