Aircraft Powerplant Major Repairs and Modifications

Propeller & Powerplant (Aircraft)

• Separation or disassembly of a crankcase or crankshaft of a reciprocating engine with an integral supercharger is an example of a Powerplant Major Repair.
• Any maintenance operation requiring the cold and hot sections of the engine is classed as a Powerplant major alteration.
• Special repairs to structural engine parts, using welding, plating, metalizing or other methods is an example of a Powerplant major repair.
• Changing the hub design is a Propeller Major Modification, or a Propeller Major Repair.
• Removing accessories listed as required equipment on the aircraft or engine specifications is a Powerplant Major Modification.
• Conversions of any sort for using fuel rating or a grade other than that listed in the engine specifications is a Powerplant major modification.
• Installation of an accessory not approved for the engine is a Powerplant major modification/alteration.
• Maintenance operations requiring disassembly of a non-float type carburetor is classed as a Powerplant Major Repair.
• Changes to the basic design of or the relocation of brackets or braces of the propeller control are considered as Propeller Minor Repair.
• Replacing a carburetor with the same type as specified by the manufacturer is a Powerplant Major Alteration.
• Repair of dents, cuts, scars, nicks, etc. on a propeller is considered a Propeller Major Alteration.
• Assembly and disassembly of a ground adjustable propeller is considered Propeller Minor Repair.
• Changes of engine cowling which do not effect engine cooling are classed as a Powerplant Minor Alteration.
• Overhaul of pressure type carburetor mechanical accessories is considered as Appliance Major Repair.
• Repair operation of hydraulic/pneumatic accessories is classed as Appliance Major Alteration.
• Any change to the basic design of navigational equipment approved under type certificate is classed as an Appliance Major Alteration.

Appliance

• Rewinding the field coil of an electrical accessory is an example of Appliance Major Repair.
• Replacement of an autopilot with manufactured parts is Appliance major repair.
• Calibration and repair of instruments is classed as Appliance Major Repair.
• Modification of a basic design not in accordance with appliance recommendations is Appliance major modification.
• Change in basic design made in accordance with "ASSEC" or landing gear shock strut manufacturer in accordance with ATO airworthiness directives are Appliance Major Alteration.

Airframe

• Restoration of engine mounts to a safe condition after damage is classed as Powerplant Major Repair.
• Strengthening or reinforcing the fuselage longeron is classed as Airframe Major Alteration.
• Modifications of the following type to a power plant or airframe not listed in manufacturer specifications are classed as Aircraft Major Alteration.
• Modification to basic design of the exhaust system is considered as Aircraft Major Alteration.
• Changes to the basic design of fuel or oil system is classed as Airframe Major Modification
• Replacement of components, such as landing gears with parts supplied by the original manufacturer in accordance with drawings is considered as Components Major Repair.
• Repair made on the hydraulic/pneumatic system is classed as Preventive Maintenance
• Changes to structural elements to improve service life or reduce cost are classed as a Airframe Minor Repair.
• Installation or removal of equipment of equal weight in the same location as last listed optional equipment is classed as Airframe Minor Alteration
• Replacing defective safety wiring or cotter pins is classed as Preventive Maintenance.
• Simple minor preservations and replacement of small parts is classed as Airframe Minor Repair.
• Replacing or cleaning spark plugs and gap clearance is considered as Preventive Maintenance.
• Making simple fabric pitches not required rib stitching or removal of structural parts is considered as Preventive Maintenance. -Troubleshooting and repairing broken circuit is considered as Preventive Maintenance.

CFR

• Issuance of an Airworthiness Certificate is governed by 14 CFR Part 21.
• Airworthiness standards for an airplane in the normal category are in 14 CFR Part 23.
• Information regarding instrument range markings for an airplane in the normal category is in 14 CFR Part 23.
• Checklist for performing annual or 100-hour inspections is in Appendix of 14CFR Part 43.
• Recommended statement for recording approval/disapproval of aircraft is in 14 CFR Part 43.
• Mechanic certificates and general operating rules for holders is in 14 CFR Part 65.
• Operating conditions that make 100-hour inspection mandatory is in 14 CFR Part 91