INSTALLATION PROCEDURES

INSTALLATION PROCEDURES

The information given in the following paragraphs is of a general nature, and is intended as a guide to the procedures associated with the installation of the principal components of air conditioning systems. Full details are contained in the Aircraft Maintenance Manuals for specific aircraft types. Therefore, reference must be made to these publications.

Compressors and Blowers

(a)      Before installation a check should be made to ensure that units are free from damage and that ducts, air inlets and outlets, and mating surfaces are free from oil, dust and other foreign matter. Rotors should also be checked for freedom of rotation observing any special precautions and procedures specified for the appropriate types of unit.

(b)      Pipes, metering units and filters of bearing lubricating oil systems should also be inspected for cleanliness and signs of cracks or other damage. Priming of the lubricating oil system should be carried out as specified in the Component and Aircraft Maintenance Manuals.

(c)      Units must be adequately supported during installation to ensure that their weight is not allowed to bear on r arts of the main drive; for example, a quill shaft which drives a displacement blower. In some aircraft employing compressors a special hoist is provided for installation and removal of units and this should be used in the prescribed manner.

(d)      After a compressor or blower has been lowered on to the engine or gearbox mounting pad, its securing nuts or bolts, as appropriate, should be torque-tightened to the values specified in the Aircraft Maintenance Manual. In some compressor installations the units must also be secured by bolting them to the casing of their respective engines via link assemblies.

(e)      Inlet and outlet duct attachment flanges should be clean and free from damage. In displacement blower systems, manifolds normally provide for the attachment of duct sections to the blower casing. The bolts securing each manifold to the blower, are, in some cases, of different lengths. Therefore to avoid distortion of the inner face of the blower casing they must be refitted in their correct position before tightening. New sealing rings should be fitted between duct sections and corresponding attachment points on compressors and blowers. The sections should fit squarely and not be subjected to undue strain or load, or be in contact with other components which may abrade duct surfaces.