31 July 2011 C1 CIVIL AVIATION DEPARTMENT HONG KONG ...

CIVIL AVIATION DEPARTMENTHONG KONG, CHINAAirworthiness NoticeTHIS NOTICE GIVES DETAILS OF A MANDATORY ACTIONCOTTON, LINEN AND SYNTHETIC FABRIC-COVERED AIRCRAFT1 IntroductionNo. 20Issue 630 May 2006This Notice contains requirements in respect of the issue or renewal of Certificates ofAirworthiness and Permits to Fly applicable to aircraft excluding microlights, thathave fabric covering. Fabric coverings may be manufactured from natural materialssuch as linen or cotton, or other Aviation Approved fabrics produced from polyesteror glass fibre.2 Structural Damage and Deterioration2.1 Removal of the fabric covering of some older types of aircraft has revealedcases of unsuspected structural damage and deterioration. It is thereforeimportant that during routine inspections, any sign of distortion, slackness,wrinkling or discoloration of the covering material is investigated and thecause established.2.2 The use of good maintenance practices, incorporation of adequate andcorrectly placed drain holes, regular cleaning and storage of the aircraft in adry hangar will retard deterioration. Damage will be reduced by using properground handling techniques and equipment. Planned periodic inspections ofaircraft coverings, structural elements and their attachments are essential inpreventing damage and deterioration from going unnoticed.2.3 Following incidents such as heavy landings, high 'g' loadings, ground loopsand collisions, the aircraft must be inspected to detect any hidden damage ordistortion.2.3.1 This may involve removal of the covering material or provision ofaccess openings and may include inspections using NDT techniques.Experience has shown that structures can appear undamaged untilmanually loaded during a physical check. Wherever possible, themanufacturer's inspection recommendations should be used. In theabsence of specific guidance, refer to UKCAA CAP562 Civil AircraftAirworthiness Information and Procedures (CAAIP) and/or consult aAN-20 P.130 May 2006