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THE HONG KONG GOVERNMENT GAZETTE, MARCH 25, 1937.
No. 212.
DIRECTORATE OF AIR SERVICES, HONG KONG.
Notice to Aircraft Owners and Ground Engineers.
No. 8 of the year 1937.
FAIREY-REED METAL AIRSCREWS :
DETAIL INSPECTION,
1. Instances have occurred of transverse fatigue failure of the blade sheet of Fairey-Reed metal airscrews, the fractures commencing at the holes for the hub bolts or the bolts securing the hub blocks, or in the vicinity of the identification marks, and extending towards the leading and trailing edges.
2. As the result of these failures, it is necessary that, in future, periodic detail inspection of these airscrews be made in the vicinity of the hub blocks and of the identification
marks.
3. This detail inspection is to be made after each period not exceeding 200 hours flying, of all Fairey-Reed metal airscrews. A similar inspection is also to be made after each intermediate period not exceeding 50 hours flying, of the air- screws enumerated in para. 10 below, and of any of those listed in para. 11 which may be declared serviceable by the makers.
4. These inspections are additional to the normal routine inspections, during which the exposed parts of the blade sheets must be carefully examined for cracks, particularly in the vicinity of the blade roots and of the deeply impressed identification marks which appear on a few early airscrews of this type.
5. For the purpose of detail inspection, the airscrews are to be removed from the hubs, spinners from the airscrews, and boss blocks from the blade sheets. The blade sheets are then to be cleaned and inspected for cracks, particularly in the vicinity of the bolt holes and in regions where any attrition or corrosion has occurred. This inspection is to be made with the aid of a magnifying glass. Inspection for cracks is facilitated by anodic treatment of the blade sheets, and if this treatment has not already been given, it is advisable for the blade sheets to be anodised as soon as this can be arranged.
6. Any airscrews found to contain cracks are to be withdrawn from use, and the matter is to be reported to the Director of Air Services, Harbour Department, Hong Kong.
7. If no cracks are found, any attrition or corrosion marks are to be removed from the blade sheet and boss blocks. by means of coarse emery followed by fine emery, and the airscrews are to be re-assembled. During the latter operation, a layer of tung oil varnish is to be inserted between the blade sheet and the boss blocks and care is to be taken to ensure even tightening of the bolts locating the blocks. When the bolts removed are of the obsolete type in which the nuts are secured by riveting, these are to be replaced, where possible,