Solutions for the MRO industry.....

The aircraft industry is demanding and deservedly so. Quality and product performance are the cornerstone of any flying aircraft today. Despite all the efforts to make products last longer with the required strength and durability OEMs don’t always get it right or it may even be planned obsolescence.

In many cases the wear that parts see in service were not anticipated especially on aircraft which have been in service for a long period of time including legacy aircraft and rotorcraft. When parts wear or are exposed to harsh service environments galling, fretting, scoring and corrosion are often the byproduct. To address these the operator has three basic choices – a) replace the part with a new part, b) develop a major repair for the part or c) buy or create a PMA part.

So let's first examine what is involved with each option –

a) replace the part with a new part,

b) develop a major repair for the part or

c) buy or create a PMA part. 

a) Replace the part with a new part which is already FAA and OEM approved for installation on the aircraft. This was done through an FAA established process called Parts Manufacturing Authorization. This is the easiest but what are the costs - first the price is likely high. Second the part may not be in stock and there could be a long delay obtaining the part (weeks to 18 months) depending on the complexity. 

b) Develop a major repair for the part. It requires some engineering data which is generally easy to obtain or through the reverse engineering process. A repair needs to be drafted and executed to create a proof of concept. This is all done using an FAA DER (Designated Engineering Representative) who is delegated by the FAA to approve specific engineering data which may include repair procedures, drawings, etc to establish that the repaired part meets the pertinent design criteria for the form, fit and function of the part. If the repair is intended to be repeated this can be made into a Repair Specification. Usually a flat fee is charged and a repair can be developed and FAA approved within weeks.

c) Buy or create a PMA part. Well next to buying a new OEM part this is the second most expensive method unless you plan on selling your parts as a replacement for the OEM part. Again FAA procedures need to be followed and are usually performed by an FAA DER. Some projects can be simple whereas others complex so the generation of the required engineering data is time consuming. Usually this is an estimated charge in hours to complete the project and a significant amount of time. Typically this takes from 6 months to one year to accomplish. You are also charged an up front fee and then progress payments with the final payment due at final document submittal prior to issue of the PMA. If you want to install overseas an STC is required.

Our experience shows that the quickest road to getting your aircraft or rotorcraft operational again, typically while other maintenance or checks are performed, is to develop a major repair. All options are supported by FAA DERs but it depends on your goals and time horizon.