A13 Control system loads

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

A13 Control system loads ED Decision 2003/18/RM (a) *Primary flight controls and systems*. Each primary flight control and system must be designed as follows: (1) The flight control system and its supporting structure must be designed for loads corresponding to 125% of the computed hinge moments of the movable control surface in the conditions prescribed in paragraph [A11](#_DxCrossRefBm584936948) of this Appendix. in addition - (i) The system limit loads need not exceed those that could be produced by the pilot and automatic devices operating the controls; and (ii) The design must provide a rugged system for service use, including jamming, ground gusts, taxying downwind, control inertia, and friction. (2) Acceptable maximum and minimum limit pilot forces for elevator, aileron, and rudder controls are shown in the table in CS-VLA 387(b). These pilots loads must be assumed to act at the appropriate control grips or pads as they would under flight conditions, and to be reacted at the attachments of the control system to the control surface horn. (b) *Dual controls*. If there are dual controls, the systems must be designed for pilots operating in opposition, using individual pilot loads equal to 75% of those obtained in accordance with subparagraph (a) of this paragraph, except that individual pilot loads may not be less than the minimum limit pilot forces shown in the table in [CS-VLA 397(b)](#_DxCrossRefBm584936696). (c) *Ground gust conditions*. Ground gust conditions must meet the requirements of [CS-VLA 415](#_DxCrossRefBm584936704). (d) *Secondary controls and systems*. Secondary controls and systems must meet the requirements of [CS-VLA 405](#_DxCrossRefBm584936700). Table 1 – Limit flight load factors <table border="0" cellpadding="0" cellspacing="0" width="101%"><thead><tr><td colspan="6" valign="top" width="100%"><p>LIMIT FLIGHT LOAD FACTORS </p></td></tr><tr><td valign="top" width="22%"><p>Normal Category </p></td><td valign="top" width="22%"><p>Utility category </p></td><td valign="top" width="22%"><p>Aerobatic category </p></td></tr></thead><tr><td rowspan="6" valign="top" width="11%"><p>FLIGHT </p><p>LOAD </p><p>FACTORS </p></td><td rowspan="4" valign="top" width="11%"><p>Flaps </p><p>Up </p></td><td valign="top" width="10%"><p>n1 </p></td><td valign="top" width="22%"><p>3.8 </p></td><td valign="top" width="22%"><p>4.4 </p></td><td valign="top" width="22%"><p>6.0 </p></td></tr><tr><td valign="top" width="10%"><p>n2 </p></td><td colspan="3" valign="top" width="67%"><p>–0.5 n1 </p></td></tr><tr><td valign="top" width="10%"><p>n3 </p></td><td colspan="3" valign="top" width="67%"><p>Find n3 from Figure A1 </p></td></tr><tr><td valign="top" width="10%"><p>n4 </p></td><td colspan="3" valign="top" width="67%"><p>Find n4 from Figure A2 </p></td></tr><tr><td rowspan="2" valign="top" width="11%"><p>Flaps </p><p>Down </p></td><td valign="top" width="10%"><p>nflap </p></td><td colspan="3" valign="top" width="67%"><p>0.5 n1 </p></td></tr><tr><td valign="top" width="10%"><p>nflap </p></td><td colspan="3" valign="top" width="67%"><p>Zero* </p></td></tr></table> \*Vertical wing load may be assumed equal to zero and only the flap part of the wing need be checked for this condition. Table 2 - Average limit control surface loading <table border="0" cellpadding="0" cellspacing="0" width="101%"><thead><tr><td colspan="6" valign="top" width="100%"><p>AVERAGE LIMIT CONTROL SURFACE LOADING </p></td></tr><tr><td colspan="2" valign="top" width="14%"><p>SURFACE </p></td><td colspan="2" valign="top" width="24%"><p>DIRECTION OF LOADING</p></td><td valign="top" width="26%"><p>MAGNITUDE OF LOADING </p></td><td valign="top" width="34%"><p>CHORDWISE DISTRIBUTION </p></td></tr></thead><tr><td colspan="2" rowspan="2" valign="top" width="14%"><p>HORIZONTAL </p><p>TAIL I </p></td><td valign="top" width="5%"><p>(a)</p></td><td valign="top" width="19%"><p>Up and Down </p></td><td valign="top" width="26%"><p>Figure A4 Curve (2) </p></td><td rowspan="2" width="34%"><p><div class="image-container"><img alt="EASA EAR image" src="/static/files/file_CbObCD5goL3/image096.jpg"/></div></p></td></tr><tr><td valign="top" width="5%"><p>(b)</p></td><td valign="top" width="19%"><p>Unsymmetrical loading and Down)</p></td><td valign="top" width="26%"><p>100% <div class="image-container"><img alt="EASA EAR image" src="/static/files/file_CbObCD5goL3/image098.jpg"/></div> on one side aeroplane C_L</p><p>65% <div class="image-container"><img alt="EASA EAR image" src="/static/files/file_CbObCD5goL3/image098.jpg"/></div> on other side aeroplane C_L for normal and utility categories.</p><p>For aerobatic category see A11(c) </p></td></tr><tr><td colspan="2" rowspan="2" valign="top" width="14%"><p>VERTICAL TAIL II </p></td><td valign="top" width="5%"><p>(a)</p></td><td valign="top" width="19%"><p>Right and Left </p></td><td valign="top" width="26%"><p>Figure A4 Curve (1) </p></td><td valign="top" width="34%"><p>Same as (A) above </p></td></tr><tr><td valign="top" width="5%"><p>(b)</p></td><td valign="top" width="19%"><p>Right and Left </p></td><td valign="top" width="26%"><p>Figure A4 Curve (1) </p></td><td valign="top" width="34%"><p>Same as (B) above </p></td></tr><tr><td colspan="2" valign="top" width="14%"><p>AILERON III </p></td><td valign="top" width="5%"><p>(a)</p></td><td valign="top" width="19%"><p>Up and Down </p></td><td valign="top" width="26%"><p>Figure A5 Curve (5) </p></td><td width="34%"><p><div class="image-container"><img alt="EASA EAR image" src="/static/files/file_CbObCD5goL3/image101.jpg"/></div></p></td></tr><tr><td colspan="2" rowspan="2" valign="top" width="14%"><p>WING FLAP IV </p></td><td valign="top" width="5%"><p>(a)</p></td><td valign="top" width="19%"><p>Up </p></td><td valign="top" width="26%"><p>Figure A5 Curve (4) </p></td><td rowspan="2" width="34%"><p><div class="image-container"><img alt="EASA EAR image" src="/static/files/file_CbObCD5goL3/image103.jpg"/></div></p></td></tr><tr><td valign="top" width="5%"><p>(b)</p></td><td valign="top" width="19%"><p>Down </p></td><td valign="top" width="26%"><p>0·25 x Up load (a) </p></td></tr><tr><td colspan="2" valign="top" width="14%"><p>TRIM TAB V </p></td><td valign="top" width="5%"><p>(a)</p></td><td valign="top" width="19%"><p>Up and Down </p></td><td valign="top" width="26%"><p>Figure A5 Curve (3) </p></td><td valign="top" width="34%"><p>Same as (D) above </p></td></tr><tr><td valign="top" width="7%"><p>Note:</p></td><td colspan="5" valign="top" width="92%"><p>The surface loadings I, II, III an V above are based on speeds V_Amin and V_Cmin. The loading of IV is based on V_Fmin.</p><p>If values of speeds greater than these minimums are selected for design, the appropriate surface loadings must be multiplied by ratio <div class="image-container"><img alt="EASA EAR image" src="/static/files/file_CbObCD5goL3/image105.jpg"/></div>. For conditions I, II, III and V the multiplying factor used must be the higher of <div class="image-container"><img alt="EASA EAR image" src="/static/files/file_CbObCD5goL3/image107.jpg"/></div>or <div class="image-container"><img alt="EASA EAR image" src="/static/files/file_CbObCD5goL3/image109.jpg"/></div></p></td></tr><tr height="0"></tr></table>  FIGURE A1 CHART FOR FINDING n3 FACTOR AT SPEED VC.  FIGURE A2 CHART FOR FINDING n4 FACTOR AT SPEED VC. Table 3 - Determination of minimum design speeds – Equations <table border="0" cellpadding="0" cellspacing="0" width="606"><tr><td valign="top" width="606"><p> V_Dmin = 10·86 <div class="image-container"><img alt="EASA EAR image" src="/static/files/file_CbObCD5goL3/image115.jpg"/></div> but need not exceed 1·4 <div class="image-container"><img alt="EASA EAR image" src="/static/files/file_CbObCD5goL3/image117.jpg"/></div> V_Cmin</p></td></tr><tr><td valign="top" width="606"><p> V_Cmin = 7·69 <div class="image-container"><img alt="EASA EAR image" src="/static/files/file_CbObCD5goL3/image115.jpg"/></div> but need not exceed 0·9 V_H</p></td></tr><tr><td valign="top" width="606"><p> V_Amin = 6·79 <div class="image-container"><img alt="EASA EAR image" src="/static/files/file_CbObCD5goL3/image115.jpg"/></div> but need not exceed V_C used in design</p></td></tr><tr><td valign="top" width="606"><p> V_Fmin = 4·98 <div class="image-container"><img alt="EASA EAR image" src="/static/files/file_CbObCD5goL3/image115.jpg"/></div></p></td></tr></table> (Speeds are in knots, W in kg, S in m2)  1. Conditions ‘C’ or ‘F’ need only be investigated when n3  or n4  is greater than n1  or n2  , respectively. 2. Condition ‘G’ need not be investigated when the supplementary condition specified in [CS-VLA 369](#_DxCrossRefBm584936675) is investigated. FIGURE A3 FLIGHT ENVELOPE.  FIGURE A4 AVERAGE LIMIT CONTROL SURFACE LOADING.  FIGURE A5 AVERAGE LIMIT CONTROL SURFACE LOADING.