CS-VLA 21 Proof of compliance

• ED Decision 2003/18/RM found in: CS-VLA Amdt 1 - Very Light Aeroplanes (Mar 2009)

CS-VLA 21 Proof of compliance ED Decision 2003/18/RM (a) Each requirement of this subpart must be met at each appropriate combination of weight and centre of gravity within the range of loading conditions for which certification is requested. This must be shown - (1) By tests upon an aeroplane of the type for which certification is requested, or by calculations based on, and equal in accuracy to, the results of testing; and (2) By systematic investigation of each probable combination of weight and centre of gravity, if compliance cannot be reasonably inferred upon combinations investigated. (b) The following general tolerances are allowed during flight testing. However, greater tolerances may be allowed in particular tests. <table border="0" cellpadding="0" cellspacing="0" width="567"><tr><td valign="top" width="284"><p>Item </p></td><td valign="top" width="284"><p>Tolerance </p></td></tr><tr><td valign="top" width="284"><p>Weight </p></td><td valign="top" width="284"><p>+5% ,-10% </p></td></tr><tr><td valign="top" width="284"><p>Critical items affected by weight </p></td><td valign="top" width="284"><p>+5%, -1% </p></td></tr><tr><td valign="top" width="284"><p>C.G. </p></td><td valign="top" width="284"><p>±7% total travel. </p></td></tr></table> (c) Substantiation of the data and characteristics to be determined according to this subpart may not require exceptional piloting skill, alertness or exceptionally favourable conditions. (See [AMC VLA 21(c)](#_DxCrossRefBm584936610).) (d) Consideration must be given to significant variations of performance and in-flight characteristics caused by rain and the accumulation of insects. (See [AMC VLA 21(d)](#_DxCrossRefBm584936609).)