Engineers Specs Vs. Functional Specs.

If a medical device were to fail engineering specs, but passed all functional testing, meaning that it met all final build specs, would this be considered a nonconformance?

Would there be any applicable regulatory issues?

The customer would never notice this issue.

 

{All comment by me is from NON-medical background}

I would flag it as non-conforming.
Engineering specs build in safety factors and allowances for excursions from typical use...functional testing tends to be in the heart of typical or 'intended' use.
Going by functional test, but outside of engineering specs, defines your area as the danger zone right outside of "OK" with little to no safety margin.

How that translates into Medical Device regulation...I haven't got a clue...

But driving a car over a bridge (function testing) doesn't mean the bridge will stand up to a 45 mph pulsing cross-wind (engineering consideration)...

 

A bit difficult to say without knowing some specifics.

If I have an 'engineering spec' that says a screw for a pole clamp has to be 2" long but the component turns out to be 2.25" long. No impact on the functional ability for the pole clamp to work but doesn't meet spec.

In this case, yes, a NC would be written for the component and the decision made to accept and use as is. You confirm that it poses no risk to the safety or efficacy of the system.

A rather simplistic case, I realize, but maybe it helps?

 

From a regulatory perspective, failing engineering spec means either the product has failed design verification (if stll in R&D phase) or a NC (if in the manufacturing phase). From a QA perspective going to functional after failing engineering is a waste of resources (unless it is conciously planned and you expect to gain some insight regarding the relevance of the engineering spec).

 

The functional spec pass is a subjective matter. The functional test does not put the device into all operating conditions.
If a wire crimp is bad and the function test pass, the wire crimp will give way by the time it reaches the user. It will not switch on there, let alone functioning ...
Functional spec is a design input which must get converted into an engineering spec either to build or buy. This engineering spec must be verified and validated.
Its a non-conformance. It is a regulatory issue in the sense the non-conformance could be changing the risk level of the medical device. I do not know your device in question.
About customer noticing or otherwise, its a case of a deviation that has to be addressed by you prior to going to customer and appropriately documented, and approved.