Basically the FAA categorizes repairs into minor and major. The real difference depends on whether or not any significant changes take place during the repair.The following form outline can help make the determination. The most important considerations are listed in Item 11.0

The DER can help make this assessment for you quckly and efficiently. Minor repairs are outlined in FAA guidance materials and simply swapping out standard aerospace parts like washers, nuts, bolts, screws is generally not  concern except for specific applications.

Developing a major repair for the part 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.

MAJOR REPAIR ___ MINOR REPAIR _____
DATE: _____________________
QC/ENG: ___________________

PURPOSE: To aid inspectors, quality and engineering staff in making the
determination whether or not a repair is classified as major or minor.

0.0 Is there a FSDO Major/Minor Quality Policy Agreement in place? ____ Yes ____ No
1.0 Customer Name: _________________________

2.0 Work Order: ______________
3.0 Mechanic or Contact Name: ________________

4.0 Phone: __________________
5.0 Part Name: ________________

6.0 Part Number: __________________________
7.0 OEM and CMM: _____________________________________________________
8.0 Problem Description:
______________________________________________________________________
______________________________________________________________________
9.0 Photos available: ___ Yes ___ No
10.0 Customer Advised: ___ Yes ___ No
11.0 Do any of the following change by the required repair? ___ Yes ___ No
a) Structural/Stress ___ b) Maintainability ___ c) Reliability ___ d) Thermodynamics___
e) Aerodynamics___ f) Metallurgy ____ g) Airworthiness___ h) Weight ____
i) Flammability ____ j) Approved lube and oils____ k) Instr. for Cont. Airworth. ____
l) Other____
12.0 Are standard parts (nuts, bolts, washers, etc) required? ___ Yes ___ No
13.0 Aircraft structural part or an accessory part? ____Struct. _____Access.
14.0 Electronic component replacement or fabrication repair? ___ Yes ___ No
15.0 Repair requiring the use of alternate coatings? ___ Yes ___ No
If item 11.0, 13.0, 14.0 or 15.0 is YES this is a MAJOR REPAIR. Follow guidelines for data
submittal to DER or engineering staff. Otherwise repair is MINOR - QC/ENG buyoff.