The U.S. commercial aerospace industry has taken a more determined step in the direction of repairing electrical wiring harness products as opposed to replacing it with new.  This is a direct result of how the world has changed. Challenges that began September 11, 2001 have been magnified due to the recent energy crisis and ongoing economic downturn.

Not that many years ago, U.S. airlines, both large and small, either had the in-house shops to repair components themselves or replace them with new aftermarket spares, disregarding the cost.  With airlines now just trying to survive, this is no longer the direction being taken.  Today the airlines are trying to outsource more of the maintenance in an effort to reduce their own costs.  There is an advantage to this as there are many good Repair Stations in the country specializing in almost every component on the aircraft and/or the engine.

Because there are reputable Repair Stations available that really do have expertise, the benefit can be enormous for the world’s airlines.  Where the new ‘rub’ comes is in the component maintenance manuals (CMM) and what the component’s Original Equipment Manufacture (OEM) wants to allow their customers to repair.

There is a small minority of product that is manufactured as ‘non-repairable’ and for a couple of good reasons.  First, it may truly be cost prohibitive to repair, meaning it would cost more than it’s worth.  Secondly, the proprietary nature of the item may require constraints.  No one can blame a manufacturer that is trying to protect trade/design secrets.

However, the vast majority of items found on the aircraft are repairable.  With the industry fighting so hard to rebound, or to just survive, another alternative is needed.

One would be surprised at the things that can be accomplished with great quality and reliability.  A Repair Station that is also an OEM has the ability to perform repairs that would normally only be done at the OEM level.  These Repair Stations are therefore able to pass on a real savings to the operators.

Most aftermarket replacement items are very expensive.  This, of course, is due to the nature of single piece purchases versus quantity buys.  Additionally, a repair sent back to the OEM is generally thrown into the ‘production’ process flow.  As can be imagined, this creates a tremendously long turn around time.

An experienced, well-disciplined Repair Station can not only perform specified CMM repairs, but can also write the procedure and perform the same repairs that would normally be done at the OEM factory.  This can typically be accomplished in far less time.

The mechanism to make this happen is either approval from the airlines engineering (which is just as busy as the FAA engineers) or a DER approval.  A DER is an FAA certified Designated Engineering Representative.  These are individuals with many years experience with the airlines or manufacturers and have worked closely with and are certified by the FAA.  These individuals do the painstaking analysis that the FAA engineers don’t have the time to perform.

Electrical wiring harnesses are especially suited for this scenario. Many engine harnesses are covered with an outer braid layer for chafe resistance.  The harness OEM is selling these harnesses to an engine manufacturer or in the aftermarket to an airline.  The OEM has to write a CMM to support their product, but knows that neither of these customers have the means to braid new material on the outside of a worn harness.  He therefore states that if something over a minimum acceptable amount of abrasion has occurred the harness is either scrap or needs to be sent back to the manufacturer for repair.

A Third Party Repair Station with the proper equipment can come to the rescue at this point and write a repair procedure to strip and re-braid the harness.  This, of course, has to be approved by the airline or a DER, but the benefits can be significant.

Most OEM’s have in-house certified repair stations for processing returned product.  The catch is in many cases these organizations depend on support from different areas of production (i.e., harness braiding) so the OEM doesn’t have to duplicate equipment.  This can and does have a tremendous impact on turn-around time.

There can be a significant cost associated with a return to the OEM as well, because the repair station technicians are generally the best all- around technicians in the organization.  In most instances this translates to being the highest paid technicians coupled with standard production costing rates and a very expensive repair to go with the long turn-around time.  A third party repair station being run as a separate business can usually turn the parts around faster at a far more palatable price.

Over the past several years Parts Manufacture Approval (PMA) parts have been brought under closer scrutiny for fear of meeting the intended requirements.  Where these two scenarios differ is that repairs are still predominately governed by the OEM Component Maintenance Manual (CMM) and not entirely new documentation.  When the repair station and the DER have completed their justification, the product truly is as if it were repaired in the facility in which it was manufactured.

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