Part 21 replacement aero engine parts

In certificated engines, Engine replacement parts must be approved under Title 14 of the Code     of Federal Regulations (14 CFR), part 21. Serviceable parts obtained from the engine manufacturer, authorized service facility, and those which are approved Federal Aviation Administration (FAA)/Parts Manufacture Approval (PMA), or Technical Standard Order (TSO), and meet the requirements of part 21 are acceptable for use as replacement parts. Used aero engine parts can be installed.

There has always been talk of standardising the quality system requirements for production certificate (PC), technical standard order (TSO) and parts manufacturer approval (PMA) holders. PMA holders have always argued their quality standards are no differnet to that of the OEMs for textron lycomng parts or continental aircraft engine parts 

Light aircraft spares

The name of the game now has become to hold in stock and have weekly shipments from the USA. Successful light aircraft spares companies have a vast inventory of parts to support Cessna, Piper, Lycoming, TCM and PT6A series engines

CESSNA - PIPER - LYCOMING - TCM - RAPCO Inc FAA-PMA approved replacement parts

Cessna spares and piper spares

Oil system lines inspection. The inspection of the plumbing for an oil system is similar to the inspection of any other plumbing system. The tubing, hose, tube fittings, hose fittings, hose clamps, and all other components of the system are inspected for cracks, holes, dents, bulges, and other signs of damage that might restrict the oil flow or cause a leak. All lines are inspected to ensure that they are properly supported and are not rubbing against a structure. Fittings should be checked for signs of improper installation, over-torquing, excessive tension, or other conditions which may lead to failure.

Oil filters. The oil filters provide an excellent method for discovering internal engine damage. During the inspection of engine oil filters, the residue on the screens, disks, or disposable filter cartridge and the residue in the filter housing are carefully examined for metal particles. A new engine or a newly-overhauled engine will often have a small amount of fine metal particles in the screen or filter, but this is not considered abnormal.

After the engine has been operated for a time and the oil has been changed one or more times, there should not be an appreciable amount of metal particles in the oil screen.      If an unusual residue of metal particles is found in the oil screen, the engine must be taken out of service and disassembled to determine the source of the particles.As an additional precaution, an oil analysis/trend analysis may prevent an engine failure in flight.

At oil changes, oil samples are often taken and sent to laboratories to be analyzed for wear by determining the amount of metal in the sample. Over time, a trend is developed and the engine can be removed from service before failure.

CYLINDER HOLD-DOWN N1 AND CAP SCREWS. Great care is required in tightening cylinder hold-down nuts and screws. They must be tightened to recommended torque limits to prevent stressing and to ensure even loading on cylinder flanges. Improper pre-stressing or loosening of any one of these nuts or cap screws will introduce the danger of progressive stud failure with the possible loss of the engine cylinder in flight.

REUSE OF SAFETYING DEVICES Do not use cotter pins and safety wire a second time. Flat, steel-type wrist pin retainers and lock washers, likewise, must be replaced at overhaul unless the manufacturer's recommendations permit their reuse.

SELF-LOCKING NUTS for aircraft engines and accessories. Self-locking nuts may be used on aircraft engines provided the following criteria are met:

a.When their use is specified by the engine manufacturer in the assembly drawing, parts list, and bills of material.

b.When the nuts will not fall inside the engine should they loosen and come off.

c. When there is at least one full thread protruding beyond the nut.

d. Where the temperature will not exceed the maximum limits established for the self-locking material used in the nut.