1Civil Aviation Order 108.29 Instrument 2007

I, WILLIAM BRUCE BYRON, Director of Aviation Safety, on behalf of CASA, make this instrument under subregulation 36A (2) of the Civil Aviation Regulations 1988.

[Signed Bruce Byron]

Bruce Byron
Director of Aviation Safety and
Chief Executive Officer

19 December 2007

Civil Aviation Order 108.29 Instrument 2007

1 Name of instrument

This instrument is the Civil Aviation Order 108.29 Instrument 2007.

2 Commencement

This instrument commences on the day after it is registered.

3 New Civil Aviation Order 108.29

Civil Aviation Order 108.29 is repealed and a new Civil Aviation Order 108.29 substituted as set out in Schedule 1.

Schedule 1 Civil Aviation Order 108.29

Specification — timber for use in aircraft propellers

1 Application

This Civil Aviation Order specifies the requirements to be observed in the selection of timber for use in the manufacture of laminated wooden propellers.

2 Approved timbers

Approved types of timber are listed in Appendix I. The Director may approve additional types on the provision of satisfactory evidence regarding their suitability for use in propellers.

3 Quality

3.1The timber must be clearly identified with respect of species and must be of known origin.

3.2The timber must be in the form of selected planks which must be free from warp. Sloping grain is permitted but not exceeding 1 in 12, as determined by the splitting test or alternatively as described in Appendix II.

Note Deviation of grain due to knots of permissible size may be disregarded.

3.3The timber must be clean and free from obvious and incipient decay and from knots, shakes, splits, seasoning checks, internal checks, fractures, brittle heart, compression failures, bark pockets, gum pockets or gum veins, callus tissue, insect attack, wane or want, but the following imperfections are permitted:

(a) pin-knots not exceeding 3 mm diameter and not closer than 50 mm;

(b) pin-holes not exceeding 1.5 mm diameter, not more than 3 in any 10 000 sq mm of surface area and no 2 of which are closer than 50 mm to each other;

(c) small, isolated imperfections which do not significantly affect the strength of the timber, such as wavy grain, interlocked grain, flecks, spots, fine drying checks and blemishes.

4 Seasoning

The timber must have been either air-dried or kiln-dried to a moisture content within the limits specified in subsection 5. Mountain ash and alpine ash after seasoning to 12% moisture content must be reconditioned for 6 hours at 100C (saturated conditions) following which the material must be air or kiln dried to the requirements of subsection 5.