CS-25 BOOK 1(2) V1, in terms of calibrated airspeed, isselected by the applicant; however, V1 may not beless than VEF plus the speed gained with thecritical engine inoperative during the time intervalbetween the instant at which the critical engine isfailed, and the instant at which the pilotrecognises and reacts to the engine failure, asindicated by the pilot’s initiation of the firstaction (e.g. applying brakes, reducing thrust,deploying speed brakes) to stop the aeroplaneduring accelerate-stop tests.(b) V2MIN, in terms of calibrated airspeed, maynot be less than –(1) 1·13 VSR for –(i) Two-engined and three-enginedturbo-propeller powered aeroplanes; and(ii) Turbojet powered aeroplaneswithout provisions for obtaining asignificant reduction in the one-engineinoperative power-on stall speed;(2) 1·08 VSR for –(i) Turbo-propeller poweredaeroplanes with more than three engines;and(ii) Turbojet powered aeroplaneswith provisions for obtaining a significantreduction in the one-engine-inoperativepower-on stall speed: and(3) 1·10 times VMC established under CS25.149.(c) V2, in terms of calibrated airspeed, must beselected by the applicant to provide at least thegradient of climb required by CS 25.121(b) but maynot be less than –(1) V2MIN;(2) VR plus the speed increment attained(in accordance with CS 25.111(c)(2)) beforereaching a height of 11 m (35 ft) above the takeoff surface; and(3) A speed that provides themanoeuvring capability specified in CS 25.143(h).(d) VMU is the calibrated airspeed at and abovewhich the aeroplane can safely lift off the ground,and continue the take-off. VMU speeds must beselected by the applicant throughout the range ofthrust-to-weight ratios to be certificated. Thesespeeds may be established from free air data if thesedata are verified by ground take-off tests. (See AMC25.107(d).)(e) VR, in terms of calibrated air speed, must beselected in accordance with the conditions of subparagraphs (1) to (4) of this paragraph:(1) VR may not be less than –(i) V1;(ii) 105% of VMC;(iii) The speed (determined inaccordance with CS 25.111(c)(2)) thatallows reaching V2 before reaching a heightof 11 m (35 ft) above the take-off surface;or(iv) A speed that, if the aeroplane isrotated at its maximum practicable rate, willresult in a VLOF of not less than-(A) 110% of VMU in the allengines-operating condition,and 105% of VMU determinedat the thrust-to-weight ratiocorresponding to the oneengine-inoperative condition;or(B) If the VMU attitude is limitedby the geometry of theaeroplane (i.e., tail contactwith the runway), 108% ofVMU in the all-enginesoperating condition and 104%of VMU determined at thethrust-to-weight ratiocorresponding to the oneengine-inoperative condition.(See AMC 25.107(e)(1)(iv).)(2) For any given set of conditions (suchas weight, configuration, and temperature), asingle value of VR, obtained in accordance withthis paragraph, must be used to show compliancewith both the one-engine-inoperative and the allengines-operating take-off provisions.(3) It must be shown that the one-engineinoperative take-off distance, using a rotationspeed of 9.3 km/h (5 knots) less than VRestablished in accordance with sub-paragraphs(e)(1) and (2) of this paragraph, does not exceedthe corresponding one-engine-inoperative take-offdistance using the established VR. The take-offdistances must be determined in accordance withCS 25.113(a)(1). (See AMC 25.107(e)(3).)(4) Reasonably expected variations inservice from the established take-off proceduresfor the operation of the aeroplane (such as overrotation of the aeroplane and out-of-trimconditions) may not result in unsafe flightcharacteristics or in marked increases in the1-B-5Annex to ED Decision 2008/006/RAmendment 5
CS-25 BOOK 1scheduled take-off distances established inaccordance with CS 25.113(a). (See AMC No. 1to CS25.107 (e) (4) and AMC No. 2 to CS25.107(e) (4).)(f) VLOF is the calibrated airspeed at which theaeroplane first becomes airborne.(g) VFTO, in terms of calibrated airspeed, mustbe selected by the applicant to provide at least thegradient of climb required by CS 25.121(c), but maynot less than –(1) 1.18 VSR; and(2) A speed that provides themanoeuvring capability specified in CS 25.143(h).(h) In determining the take-off speeds V1, VR,and V2 for flight in icing conditions, the values ofVMCG, VMC, and VMU determined for non-icingconditions may be used.CS 25.109 Accelerate-stop distance(a) (See AMC 25.109(a) and (b).) Theaccelerate-stop distance on a dry runway is thegreater of the following distances:(1) The sum of the distances necessary to –(i) Accelerate the aeroplane from astanding start with all engines operating toVEF for take-off from a dry runway;(ii) Allow the aeroplane toaccelerate from VEF to the highest speedreached during the rejected take-off,assuming the critical engine fails at VEF andthe pilot takes the first action to reject thetake-off at the V1 for take-off from a dryrunway; and(iii) Come to a full stop on a dryrunway from the speed reached asprescribed in sub-paragraph (a)(1)(ii) of thisparagraph; plus(iv) A distance equivalent to2 seconds at the V1 for take-off from a dryrunway.(2) The sum of the distances necessary to –(i) Accelerate the aeroplane from astanding start with all engines operating tothe highest speed reached during therejected take-off, assuming the pilot takesthe first action to reject the take-off at theV1 for take-off from a dry runway; and(ii) With all engines still operating,come to a full stop on a dry runway fromthe speed reached as prescribed in subparagraph (a)(2)(i) of this paragraph; plus(iii) A distance equivalent to2 seconds at the V1 for take-off from a dryrunway.(b) (See AMC 25.109(a) and (b).) Theaccelerate-stop distance on a wet runway is thegreater of the following distances:(1) The accelerate-stop distance on a dryrunway determined in accordance with subparagraph (a) of this paragraph; or(2) The accelerate-stop distancedetermined in accordance with sub-paragraph (a)of this paragraph, except that the runway is wetand the corresponding wet runway values of VEFand V1 are used. In determining the wet runwayaccelerate-stop distance, the stopping force fromthe wheel brakes may never exceed:(i) The wheel brakes stopping forcedetermined in meeting the requirements ofCS 25.101(i) and sub-paragraph (a) of thisparagraph; and(ii) The force resulting from the wetrunway braking coefficient of frictiondetermined in accordance with subparagraphs (c) or (d) of this paragraph, asapplicable, taking into account thedistribution of the normal load betweenbraked and unbraked wheels at the mostadverse centre of gravity position approvedfor take-off.(c) The wet runway braking coefficient offriction for a smooth wet runway is defined as acurve of friction coefficient versus ground speed andmust be computed as follows:(1) The maximum tyre-to-ground wetrunway braking coefficient of friction is definedas (see Figure 1):where:Tyre Pressure = maximum aeroplane operatingtyre pressure (psi)μt/gMAX = maximum tyre-to-ground brakingcoefficientV = aeroplane true ground speed (knots); andLinear interpolation may be used for tyre pressuresother than those listed.1-B-6Annex to ED Decision 2008/006/RAmendment 5
CS-25 BOOK 1(2) (See AMC 25.109(c)(2) Themaximum tyre-to-ground wet runway brakingcoefficient of friction must be adjusted to takeinto account the efficiency of the anti-skid systemon a wet runway. Anti-skid system operation mustbe demonstrated by flight testing on a smooth wetrunway and its efficiency must be determined.Unless a specific anti-skid system efficiency isdetermined from a quantitative analysis of theflight testing on a smooth wet runway, themaximum tyre-to-ground wet runway brakingcoefficient of friction determined in subparagraph (c)(1) of this paragraph must bemultiplied by the efficiency value associated withthe type of anti-skid system installed on theaeroplane:Type of anti-skid system Efficiency valueOn-off 0⋅30Quasi-modulating 0⋅50Fully modulating 0⋅80(d) At the option of the applicant, a higher wetrunway braking coefficient of friction may be usedfor runway surfaces that have been grooved ortreated with a porous friction course material. Forgrooved and porous friction course runways,(1) 70% of the dry runway brakingcoefficient of friction used to determine the dryrunway accelerate-stop distance; or(2) (See AMC 25.109(d)(2).) The wetrunway braking coefficient of friction defined insub-paragraph (c) of this paragraph, except that aspecific anti-skid efficiency, if determined, isappropriate for a grooved or porous frictioncourse wet runway and the maximum tyre-toground wet runway braking coefficient of frictionis defined as (see Figure 2):where:Tyre Pressure = maximum aeroplane operatingtyre pressure (psi)μt/gMAX = maximum tyre-to-ground brakingcoefficientV = aeroplane true ground speed (knots); andLinear interpolation may be used for tyre pressuresother than those listed.Tyre Pressure (psi) Maximum Braking Coefficient (tyre-to-ground)50 ( ) ( ) ( )μt/gMAX=−⋅+ ⋅−⋅+ ⋅0 03501000 3061000 8511000 8833 2V V V100 ( ) ( ) ( )μt/gMAX=−⋅+ ⋅−⋅+ ⋅0 04371000 3201000 8051000 8043 2V V V200 ( ) ( ) ( )μt/gMAX=−⋅+ ⋅−⋅+ ⋅0 03311000 2521000 6581000 6923 2V V V300 ( ) ( ) ( )μt/gMAX=−⋅+ ⋅−⋅+ ⋅0 04011000 2631000 6111000 6143 2V V VFigure 1
Tyre Pressure(psi) Maximum Braking Coefficient (tyre-to-ground)50 () ( ) ( ) ( ) ()μt/gMAX=⋅−⋅+⋅−⋅+⋅+⋅0 1471001 051002 6731002 6831000 4031000 8595 4 3 2V V V V V100 () ( ) ( ) ( ) ()μt/gMAX=⋅−⋅+⋅−⋅+⋅+⋅0 11061000 8131002 131002 201000 3171000 8075 4 3 2V V V V V200 () ( ) ( ) ( ) ()μt/gMAX= ⋅−⋅+⋅−⋅+⋅+ 0 04981000 3981001 141001 2851000 1401000 7015 4 3 2V V V V V.300 () ( ) ( ) ( ) ()μt/gMAX=⋅−⋅+⋅−⋅−⋅+⋅0 03141000 2471000 7031000 7791000 009541000 6145 4 3 2V V V V VFigure 21-B-7Annex to ED Decision 2008/006/RAmendment 5CS-25 BOOK 1(e) Except as provided in sub-paragraph (f)(1)of this paragraph, means other than wheel brakesmay be used to determine the accelerate-stop distanceif that means –(1) Is safe and reliable;(2) Is used so that consistent results canbe expected under normal operating conditions;and(3) Is such that exceptional skill is notrequired to control the aeroplane.(f) The effects of available reverse thrust –(1) Must not be included as an additionalmeans of deceleration when determining theaccelerate-stop distance on a dry runway; and(2) May be included as an additionalmeans of deceleration using recommended reversethrust procedures when determining theaccelerate-stop distance on a wet runway,provided the requirements of sub-paragraph (e) ofthis paragraph are met. (See AMC 25.109(f).)(g) The landing gear must remain extendedthroughout the accelerate-stop distance.(h) If the accelerate-stop distance includes astopway with surface characteristics substantiallydifferent from those of the runway, the take-off datamust include operational correction factors for theaccelerate-stop distance. The correction factors mustaccount for the particular surface characteristics ofthe stopway and the variations in these characteristicswith seasonal weather conditions (such astemperature, rain, snow and ice) within theestablished operational limits.(i) A flight test demonstration of the maximumbrake kinetic energy accelerate-stop distance must beconducted with not more than 10% of the allowablebrake wear range remaining on each of the aeroplanewheel brakes.CS 25.111 Take-off path(See AMC 25.111)(a) The take-off path extends from a standingstart to a point in the take-off at which the aeroplaneis 457 m (1500 ft) above the take-off surface, or atwhich the transition from the take-off to the en-routeconfiguration is completed and VFTO is reached,whichever point is higher. In addition –(1) The take-off path must be based onthe procedures prescribed in CS 25.101(f);(2) The aeroplane must be accelerated onthe ground to VEF, at which point the criticalengine must be made inoperative and remaininoperative for the rest of the take-off; and(3) After reaching VEF, the aeroplanemust be accelerated to V2.(b) During the acceleration to speed V2, thenose gear may be raised off the ground at a speed notless than VR. However, landing gear retraction maynot be begun until the aeroplane is airborne. (SeeAMC 25.111(b).)(c) During the take-off path determination inaccordance with sub-paragraphs (a) and (b) of thisparagraph –(1) The slope of the airborne part of thetake-off path must be positive at each point;(2) The aeroplane must reach V2 before itis 11 m (35 ft) above the take-off surface andmust continue at a speed as close as practical to,but not less than V2 until it is 122 m (400 ft)above the take-off surface;(3) At each point along the take-off path,starting at the point at which the aeroplanereaches 122 m (400 ft) above the take-off surface,the available gradient of climb may not be lessthan –(i) 1·2% for two-engined aeroplanes;(ii) 1·5% for three-engined aeroplanes; and(iii) 1·7% for four-engined aeroplanes,(4) The aeroplane configuration may notbe changed, except for gear retraction andautomatic propeller feathering, and no change inpower or thrust that requires action by the pilotmay be made, until the aeroplane is 122 m (400 ft)above the take-off surface; and(5) If CS 25.105(a)(2) requires the takeoff path to be determined for flight in icingconditions, the airborne part of the take-off mustbe based on the aeroplane drag:(i) With the “Take-off Ice”accretion defined in Appendix C, from aheight of 11 m (35 ft) above the take-offsurface up to the point where the aeroplaneis 122 m (400 ft) above the take-off surface;and(ii) With the “Final Take-off Ice”accretion defined in Appendix C, from thepoint where the aeroplane is 122 m (400 ft)above the take-off surface to the end of thetake-off path.(d) The take-off path must be determined by acontinuous demonstrated take-off or by synthesis1-B-8Annex to ED Decision 2008/006/RAmendment 5CS-25 BOOK 1from segments. If the take-off path is determined bythe segmental method –(1) The segments must be clearly definedand must relate to the distinct changes in theconfiguration, power or thrust, and speed;(2) The weight of the aeroplane, theconfiguration, and the power or thrust must beconstant throughout each segment and mustcorrespond to the most critical conditionprevailing in the segment;(3) The flight path must be based on theaeroplane’s performance without ground effect;and(4) The take-off path data must bechecked by continuous demonstrated take-offs upto the point at which the aeroplane is out ofground effect and its speed is stabilised, to ensurethat the path is conservative to the continuouspath.The aeroplane is considered to be out of the groundeffect when it reaches a height equal to its wing span.(e) Not required for CS–25.CS 25.113 Take-off distance and takeoff run(a) Take-off distance on a dry runway is thegreater of –(1) The horizontal distance along thetake-off path from the start of the take-off to thepoint at which the aeroplane is 11 m (35 ft) abovethe take-off surface, determined under CS 25.111for a dry runway; or(2) 115% of the horizontal distance alongthe take-off path, with all engines operating, fromthe start of the take-off to the point at which theaeroplane is 11 m (35 ft) above the take-offsurface, as determined by a procedure consistentwith CS 25.111. (See AMC 25.113(a)(2), (b)(2)and (c)(2).)(b) Take-off distance on a wet runway is thegreater of –(1) The take-off distance on a dry runwaydetermined in accordance with sub-paragraph (a)of this paragraph; or(2) The horizontal distance along thetake-off path from the start of the take-off to thepoint at which the aeroplane is 4,6 m (15 ft) abovethe take-off surface, achieved in a mannerconsistent with the achievement of V2 beforereaching 11 m (35 ft) above the take-off surface,determined under CS 25.111 for a wet runway.(See AMC 113(a)(2), (b)(2) and (c)(2).)(c) If the take-off distance does not include aclearway, the take-off run is equal to the take-offdistance. If the take-off distance includes a clearway–(1) The take-off run on a dry runway isthe greater of –(i) The horizontal distance alongthe take-off path from the start of the takeoff to a point equidistant between the pointat which VLOF is reached and the point atwhich the aeroplane is 11 m (35 ft) abovethe take-off surface, as determined under CS25.111 for a dry runway; or(ii) 115% of the horizontal distancealong the take-off path, with all enginesoperating, from the start of the take-off to apoint equidistant between the point at whichVLOF is reached and the point at which theaeroplane is 11 m (35 ft) above the take-offsurface, determined by a procedureconsistent with CS 25.111. (See AMC25.113(a)(2), (b)(2) and (c)(2).)(2) The take-off run on a wet runway isthe greater of –(i) The horizontal distance alongthe take-off path from the start of the takeoff to the point at which the aeroplane is 4,6m (15 ft) above the take-off surface,achieved in a manner consistent with theachievement of V2 before reaching 11 m (35ft) above the take-off surface, determinedunder CS 25.111 for a wet runway; or(ii) 115% of the horizontal distancealong the take-off path, with all enginesoperating, from the start of the take-off to apoint equidistant between the point at whichVLOF is reached and the point at which theaeroplane is 11 m (35 ft) above the take-offsurface, determined by a procedureconsistent with CS 25.111. (See AMC25.113(a)(2).)CS 25.115 Take-off flight path(a) The take-off flight path must be consideredto begin 11 m (35 ft) above the take-off surface at theend of the take-off distance determined in accordancewith CS 25.113 (a) or (b) as appropriate for therunway surface condition.(b) The net take-off flight path data must bedetermined so that they represent the actual take-offflight paths (determined in accordance with1-B-9
Annex to ED Decision 2008/006/RAmendment 5CS-25 BOOK 1CS25.111 and with sub-paragraph (a) of thisparagraph) reduced at each point by a gradient ofclimb equal to –(1) 0·8% for two-engined aeroplanes;(2) 0·9% for three-engined aeroplanes;and(3) 1·0% for four-engined aeroplanes.(c) The prescribed reduction in climb gradientmay be applied as an equivalent reduction inacceleration along that part of the take-off flight pathat which the aeroplane is accelerated in level flight.CS 25.117 Climb: generalCompliance with the requirements of CS 25.119 and25.121 must be shown at each weight, altitude, andambient temperature within the operational limitsestablished for the aeroplane and with the mostunfavourable centre of gravity for eachconfiguration.CS 25.119 Landing climb: all-enginesoperatingIn the landing configuration, the steady gradient ofclimb may not be less than 3·2%, with the engines atthe power or thrust that is available 8 seconds afterinitiation of movement of the power or thrustcontrols from the minimum flight idle to the goaround power or thrust setting (see AMC 25.119);and(a) In non-icing conditions, with a climbspeed of VREF determined in accordance with CS25.125(b)(2)(i); and(b) In icing conditions with the “Landing Ice”accretion defined in Appendix C, and with a climbspeed of VREF determined in accordance with CS25.125(b)(2)(ii).CS 25.121 Climb: one-engineinoperative(See AMC 25.121)(a) Take-off; landing gear extended. (See AMC25.121(a).) In the critical take-off configurationexisting along the flight path (between the points atwhich the aeroplane reaches VLOF and at which thelanding gear is fully retracted) and in theconfiguration used in CS 25.111 but without groundeffect, the steady gradient of climb must be positivefor two-engined aeroplanes, and not less than 0·3%for three-engined aeroplanes or 0·5% for fourengined aeroplanes, at VLOF and with –(1) The critical engine inoperative and theremaining engines at the power or thrust availablewhen retraction of the landing gear is begun inaccordance with CS 25.111 unless there is a morecritical power operating condition existing lateralong the flight path but before the point at whichthe landing gear is fully retracted (see AMC25.121(a)(1)); and(2) The weight equal to the weightexisting when retraction of the landing gear isbegun determined under CS 25.111.(b) Take-off; landing gear retracted. In thetake-off configuration existing at the point of theflight path at which the landing gear is fullyretracted, and in the configuration used in CS 25.111but without ground effect,(1) The steady gradient of climb may notbe less than 2·4% for two-engined aeroplanes,2·7% for three-engined aeroplanes and 3·0% forfour-engined aeroplanes, at V2 with –(i) The critical engine inoperative,the remaining engines at the take-off poweror thrust available at the time the landinggear is fully retracted, determined under CS25.111, unless there is a more critical poweroperating condition existing later along theflight path but before the point where theaeroplane reaches a height of 122 m (400 ft)above the take-off surface (see AMC25.121(b)(1)(i)); and(ii) The weight equal to the weightexisting when the aeroplane’s landing gearis fully retracted, determined under CS25.111.(2) The requirements of sub-paragraph(b)(1) of this paragraph must be met:(i) In non-icing conditions; and(ii) In icing conditions with the“Take-off Ice” accretion defined inAppendix C, if in the configuration of CS25.121(b) with the “Take-off Ice” accretion:(A) The stall speed atmaximum take-off weight exceeds thatin non-icing conditions by more thanthe greater of 5.6 km/h (3 knots) CASor 3% of VSR; or(B) The degradation of thegradient of climb determined inaccordance with CS 25.121(b) isgreater than one-half of the applicableactual-to-net take-off flight pathgradient reduction defined in CS25.115(b).1-B-10Annex to ED Decision 2008/006/RAmendment 5CS-25 BOOK 1(c) Final take-off. In the en-route configurationat the end of the take-off path determined inaccordance with CS 25.111:(1) The steady gradient of climb may notbe less than 1·2% for two-engined aeroplanes,1·5% for three-engined aeroplanes, and 1·7% forfour-engined aeroplanes, at VFTO and with –(i) The critical engine inoperativeand the remaining engines at the availablemaximum continuous power or thrust; and(ii) The weight equal to the weightexisting at the end of the take-off path,determined under CS 25.111.(2) The requirements of sub-paragraph(c)(1) of this paragraph must be met:(i) In non-icing conditions; and(ii) In icing conditions with the“Final Take-off Ice” accretion defined inAppendix C, if in the configuration of CS25.121(b) with the “Take-off Ice” accretion:(A) The stall speed atmaximum take-off weight exceeds thatin non-icing conditions by more thanthe greater of 5.6 km/h (3 knots) CASor 3% of VSR; or(B) The degradation of thegradient of climb determined inaccordance with CS 25.121(b) isgreater than one-half of the applicableactual-to-net take-off flight pathgradient reduction defined in CS25.115(b).(d) Approach. In a configuration correspondingto the normal all-engines-operating procedure inwhich VSR for this configuration does not exceed110% of the VSR for the related all-engines-operatinglanding configuration:(1) The steady gradient of climb may notbe less than 2·1% for two-engined aeroplanes,2·4% for three-engined aeroplanes and 2·7% forfour-engined aeroplanes, with –(i) The critical engine inoperative,the remaining engines at the go-aroundpower or thrust setting;(ii) The maximum landing weight;(iii) A climb speed established inconnection with normal landing procedures,but not more than 1·4 VSR; and(iv) Landing gear retracted.(2) The requirements of sub-paragraph(d)(1) of this paragraph must be met:(i) In non-icing conditions; and(ii) In icing conditions with theApproach Ice accretion defined in AppendixC. The climb speed selected for non-icingconditions may be used if the climb speedfor icing conditions, computed inaccordance with sub-paragraph (d)(1)(iii) ofthis paragraph, does not exceed that for nonicing conditions by more than the greater of5.6 km/h (3 knots) CAS or 3%.CS 25.123 En-route flight paths(See AMC 25.123)(a) For the en-route configuration, the flightpaths prescribed in sub-paragraphs (b) and (c) of thisparagraph must be determined at each weight,altitude, and ambient temperature, within theoperating limits established for the aeroplane. Thevariation of weight along the flight path, accountingfor the progressive consumption of fuel and oil bythe operating engines, may be included in thecomputation. The flight paths must be determined ata selected speed not less than VFTO, with –
(1) The most unfavourable centre ofgravity;(2) The critical engines inoperative;(3) The remaining engines at the availablemaximum continuous power or thrust; and(4) The means for controlling the enginecooling air supply in the position that providesadequate cooling in the hot-day condition.(b) The one-engine-inoperative net flight pathdata must represent the actual climb performancediminished by a gradient of climb of 1·1% for twoengined aeroplanes, 1·4% for three-enginedaeroplanes, and 1·6% for four-engined aeroplanes.(1) In non-icing conditions; and(2) In icing conditions with the “En-routeIce” accretion defined in Appendix C, if:(i) A speed of 1.18VSR with the“En-route Ice ” accretion exceeds the enroute speed selected in non-icing conditionsby more than the greater of 5.6 km/h (3knots) CAS or 3% of VSR, or(ii) The degradation of the gradientof climb is greater than one-half of theapplicable actual-to-net flight path reductiondefined in sub-paragraph (b) of thisparagraph.1-B-11Annex to ED Decision 2008/006/RAmendment 5CS-25 BOOK 1(c) For three- or four-engined aeroplanes, thetwo-engine-inoperative net flight path data mustrepresent the actual climb performance diminished bya gradient climb of 0·3% for three-enginedaeroplanes and 0·5% for four-engined aeroplanes.CS 25.125 Landing(a) The horizontal distance necessary to landand to come to a complete stop from a point 15 m (50ft) above the landing surface must be determined (forstandard temperatures, at each weight, altitude andwind within the operational limits established by theapplicant for the aeroplane):(1) In non-icing conditions; and(2) In icing conditions with the “LandingIce” accretion defined in Appendix C if VREF foricing conditions exceeds VREF for non-icingconditions by more than 9.3 km/h (5 knots) CASat the maximum landing weight.(b) In determining the distance in (a):(1) The aeroplane must be in the landingconfiguration.(2) A stabilised approach, with acalibrated airspeed of not less than VREF, must bemaintained down to the 15 m (50 ft) height.(i) In non-icing conditions, VREFmay not be less than:(A) 1.23 VSR0;(B) VMCL established underCS25.149(f); and(C) A speed that provides themanoeuvring capability specified inCS25.143(h).(ii) In icing conditions, VREF maynot be less than:(A) The speed determined insub-paragraph (b)(2)(i) of thisparagraph;(B) 1.23 VSR0 with the"Landing Ice" accretion defined inAppendix C if that speed exceeds VREFfor non-icing conditions by more than9.3 km/h (5 knots) CAS; and(C) A speed that provides themanoeuvring capability specified inCS 25.143(h) with the landing iceaccretion defined in appendix C.(3) Changes in configuration, power orthrust, and speed, must be made in accordancewith the established procedures for serviceoperation. (See AMC 25.125(b)(3).)(4) The landing must be made withoutexcessive vertical acceleration, tendency tobounce, nose over or ground loop.(5) The landings may not requireexceptional piloting skill or alertness.(c) The landing distance must be determined ona level, smooth, dry, hard-surfaced runway. (SeeAMC 25.125(c).) In addition –(1) The pressures on the wheel brakingsystems may not exceed those specified by thebrake manufacturer;(2) The brakes may not be used so as tocause excessive wear of brakes or tyres (see AMC25.125(c)(2)); and(3) Means other than wheel brakes maybe used if that means –(i) Is safe and reliable;(ii) Is used so that consistent resultscan be expected in service; and(iii) Is such that exceptional skill isnot required to control the aeroplane.(d) Reserved.(e) Reserved.(f) The landing distance data must includecorrection factors for not more than 50% of thenominal wind components along the landing pathopposite to the direction of landing, and not less than150% of the nominal wind components along thelanding path in the direction of landing.(g) If any device is used that depends on theoperation of any engine, and if the landing distancewould be noticeably increased when a landing ismade with that engine inoperative, the landingdistance must be determined with that engineinoperative unless the use of compensating meanswill result in a landing distance not more than thatwith each engine operating.CONTROLLABILITY ANDMANOEUVRABILITYCS 25.143 General(a) (See AMC 25.143(a).) The aeroplane mustbe safely controllable and manoeuvrable during –(1) Take-off;1-B-12Annex to ED Decision 2008/006/RAmendment 5CS-25 BOOK 1(2) Climb;(3) Level flight;(4) Descent; and(5) Landing.(b) (See AMC 25.143(b).) It must be possible tomake a smooth transition from one flight condition toany other flight condition without exceptionalpiloting skill, alertness, or strength, and withoutdanger of exceeding the aeroplane limit-load factorunder any probable operating conditions, including –(1) The sudden failure of the criticalengine. (See AMC 25.143(b)(1).)(2) For aeroplanes with three or moreengines, the sudden failure of the second criticalengine when the aeroplane is in the en-route,approach, or landing configuration and is trimmedwith the critical engine inoperative; and(3) Configuration changes, includingdeployment or retraction of deceleration devices.(c) The aeroplane must be shown to be safelycontrollable and manoeuvrable with the critical iceaccretion appropriate to the phase of flight defined inappendix C, and with the critical engine inoperativeand its propeller (if applicable) in the minimum dragposition:(1) At the minimum V2 for take-off;(2) During an approach and go-around;and(3) During an approach and landing.(d) The following table prescribes, forconventional wheel type controls, the maximumcontrol forces permitted during the testing requiredby sub-paragraphs (a) through (c) of this paragraph.(See AMC 25.143(d)):
Force, in newton (pounds),applied to the control wheel orrudder pedalsPitch Roll YawFor short term application forpitch and roll control – twohands available for control334(75)222(50)–For short term application forpitch and roll control – onehand available for control222(50)111(25)–For short term application foryaw control– – 667(150)For long term application 44,5(10)22 (5) 89(20)(e) Approved operating procedures orconventional operating practices must be followedwhen demonstrating compliance with the controlforce limitations for short term application that areprescribed in sub-paragraph (d) of this paragraph.The aeroplane must be in trim, or as near to being intrim as practical, in the immediately preceding steadyflight condition. For the take-off condition, theaeroplane must be trimmed according to the approvedoperating procedures.(f) When demonstrating compliance with thecontrol force limitations for long term applicationthat are prescribed in sub-paragraph (d) of thisparagraph, the aeroplane must be in trim, or as nearto being in trim as practical.(g) When manoeuvring at a constant airspeed orMach number (up to VFC/MFC), the stick forces andthe gradient of the stick force versus manoeuvringload factor must lie within satisfactory limits. Thestick forces must not be so great as to make excessivedemands on the pilot’s strength when manoeuvringthe aeroplane (see AMC No. 1 to CS 25.143 (g)), andmust not be so low that the aeroplane can easily beoverstressed inadvertently. Changes of gradient thatoccur with changes of load factor must not causeundue difficulty in maintaining control of theaeroplane, and local gradients must not be so low asto result in a danger of over-controlling. (See AMCNo. 2 to CS 25.143 (g)).(h) (See AMC 25.143(h)). The manoeuvringcapabilities in a constant speed coordinated turn atforward centre of gravity, as specified in thefollowing table, must be free of stall warning or othercharacteristics that might interfere with normalmanoeuvring.1-B-13Annex to ED Decision 2008/006/RAmendment 5CS-25 BOOK 1(1)A combination of weight, altitude andtemperature (WAT) such that the thrust or powersetting produces the minimum climb gradientspecified in CS 25.121 for the flight condition.(2)Airspeed approved for all-enginesoperating initial climb.(3)That thrust or power setting which, inthe event of failure of the critical engine and withoutany crew action to adjust the thrust or power of theremaining engines, would result in the thrust orpower specified for the take-off condition at V2, orany lesser thrust or power setting that is used for allengines-operating initial climb procedures.(i) When demonstrating compliance with CS25.143 in icing conditions -(1) Controllability must be demonstratedwith the ice accretion described in Appendix C,that is most critical for the particular flight phase.(2) It must be shown that a push force isrequired throughout a pushover manoeuvre downto a zero g load factor, or the lowest load factorobtainable if limited by elevator power or otherdesign characteristic of the flight control system.It must be possible to promptly recover from themanoeuvre without exceeding a pull control forceof 222 N. (50 lbf); and(3) Any changes in force that the pilotmust apply to the pitch control to maintain speedwith increasing sideslip angle must be steadilyincreasing with no force reversals, unless thechange in control force is gradual and easilycontrollable by the pilot without using exceptionalpiloting skill, alertness, or strength.(j) For flight in icing conditions before the iceprotection system has been activated and isperforming its intended function, the followingrequirements apply:(1) If activating the ice protection systemdepends on the pilot seeing a specified iceaccretion on a reference surface (not just the firstindication of icing), the requirements of CS25.143 apply with the ice accretion defined inappendix C, part II(e).(2) For other means of activating the iceprotection system, it must be demonstrated inflight with the ice accretion defined in appendixC, part II(e) that:(i) The aeroplane is controllable ina pull-up manoeuvre up to 1.5 g load factor;and(ii) There is no pitch control forcereversal during a pushover manoeuvre downto 0.5 g load factor.
CS 25.145 Longitudinal control(a) (See AMC 25.145(a).) It must be possibleat any point between the trim speed prescribed in CS25.103(b)(6) and stall identification (as defined in CS25.201(d)), to pitch the nose downward so that theacceleration to this selected trim speed is promptwith –(1) The aeroplane trimmed at the trimspeed prescribed in CS 25.103(b)(6);(2) The landing gear extended;(3) The wing-flaps (i) retracted and (ii)extended; and(4) Power (i) off and (ii) at maximumcontinuous power on the engines.(b) With the landing gear extended, no changein trim control, or exertion of more than 222 N (50pounds) control force (representative of themaximum short term force that can be applied readilyby one hand) may be required for the followingmanoeuvres:(1) With power off, wing-flaps retracted,and the aeroplane trimmed at 1·3 VSR1 , extend theCONFIGURATION SPEED MANOEUVRING BANKANGLE IN ACOORDINATED TURNTHRUST/POWERSETTINGTAKE-OFF V2 30° ASYMMETRIC WAT-LIMITED(1)TAKE-OFF V2 + xx(2)40° ALL ENGINES OPERATING CLIMB(3)EN-ROUTE VFTO 40° ASYMMETRIC WAT-LIMITED(1)LANDING VREF 40° SYMMETRIC FOR –3° FLIGHT PATHANGLE1-B-14Annex to ED Decision 2008/006/RAmendment 5CS-25 BOOK 1wing-flaps as rapidly as possible while maintainingthe airspeed at approximately 30% above thereference stall speed existing at each instantthroughout the manoeuvre. (See AMC 25.145(b)(1),(b)(2) and (b)(3).)(2) Repeat sub-paragraph (b)(1) of thisparagraph except initially extend the wing-flapsand then retract them as rapidly as possible. (SeeAMC 25.145(b)(2) and AMC 25.145(b)(1), (b)(2)and (b)(3).)(3) Repeat sub-paragraph (b)(2) of thisparagraph except at the go-around power or thrustsetting. (See AMC 25.145(b)(1), (b)(2) and(b)(3).)(4) With power off, wing-flaps retractedand the aeroplane trimmed at 1·3 VSR1 , rapidly setgo-around power or thrust while maintaining thesame airspeed.(5) Repeat sub-paragraph (b)(4) of thisparagraph except with wing-flaps extended.(6) With power off, wing-flaps extendedand the aeroplane trimmed at 1·3 VSR1 obtain andmaintain airspeeds between VSW and either 1·6VSR1 , or VFE, whichever is the lower.(c) It must be possible, without exceptionalpiloting skill, to prevent loss of altitude whencomplete retraction of the high lift devices from anyposition is begun during steady, straight, level flightat 1·08 VSR1 , for propeller powered aeroplanes or1·13 VSR1 , for turbo-jet powered aeroplanes, with –(1) Simultaneous movement of the poweror thrust controls to the go-around power or thrustsetting;(2) The landing gear extended; and(3) The critical combinations of landingweights and altitudes.(d) Revoked(e) (See AMC 25.145(e).) If gated high-liftdevice control positions are provided, sub-paragraph(c) of this paragraph applies to retractions of thehigh-lift devices from any position from themaximum landing position to the first gated position,between gated positions, and from the last gatedposition to the fully retracted position. Therequirements of sub-paragraph (c) of this paragraphalso apply to retractions from each approved landingposition to the control position(s) associated with thehigh-lift device configuration(s) used to establish thego-around procedure(s) from that landing position. Inaddition, the first gated control position from themaximum landing position must correspond with aconfiguration of the high-lift devices used toestablish a go-around procedure from a landingconfiguration. Each gated control position mustrequire a separate and distinct motion of the controlto pass through the gated position and must havefeatures to prevent inadvertent movement of thecontrol through the gated position. It must only bepossible to make this separate and distinct motiononce the control has reached the gated position.CS 25.147 Directional and lateralcontrol(a) Directional control; general. (See AMC25.147(a).) It must be possible, with the wings level,to yaw into the operative engine and to safely make areasonably sudden change in heading of up to 15º inthe direction of the critical inoperative engine. Thismust be shown at 1·3 VSR1 , for heading changes up to15º (except that the heading change at which therudder pedal force is 667 N (150 lbf) need not beexceeded), and with –(1) The critical engine inoperative and itspropeller in the minimum drag position;(2) The power required for level flight at1.3 VSR1 , but not more than maximum continuouspower;(3) The most unfavourable centre ofgravity;(4) Landing gear retracted;(5) Wing-flaps in the approach position;and(6) Maximum landing weight.(b) Directional control; aeroplanes with four ormore engines. Aeroplanes with four or more enginesmust meet the requirements of sub-paragraph (a) ofthis paragraph except that –(1) The two critical engines must beinoperative with their propellers (if applicable) inthe minimum drag position;(2) Reserved; and(3) The wing-flaps must be in the mostfavourable climb position.(c) Lateral control; general. It must be possibleto make 20º banked turns, with and against theinoperative engine, from steady flight at a speedequal to 1·3 VSR1 , with –(1) The critical engine inoperative and itspropeller (if applicable) in the minimum dragposition;(2) The remaining engines at maximumcontinuous power;(3) The most unfavourable centre ofgravity;1-B-15Annex to ED Decision 2008/006/RAmendment 5CS-25 BOOK 1(4) Landing gear both retracted andextended;
(5) Wing-flaps in the most favourableclimb position; and(6) Maximum take-off weight;(d) Lateral control; roll capability. With thecritical engine inoperative, roll response must allownormal manoeuvres. Lateral control must besufficient, at the speeds likely to be used with oneengine inoperative, to provide a roll rate necessaryfor safety without excessive control forces or travel.(See AMC 25.147(d).)(e) Lateral control; aeroplanes with four ormore engines. Aeroplanes with four or more enginesmust be able to make 20º banked turns, with andagainst the inoperative engines, from steady flight ata speed equal to 1·3 VSR1 , with maximum continuouspower, and with the aeroplane in the configurationprescribed by sub-paragraph (b) of this paragraph.(f) Lateral control; all engines operating. Withthe engines operating, roll response must allownormal manoeuvres (such as recovery from upsetsproduced by gusts and the initiation of evasivemanoeuvres). There must be enough excess lateralcontrol in sideslips (up to sideslip angles that mightbe required in normal operation), to allow a limitedamount of manoeuvring and to correct for gusts.Lateral control must be enough at any speed up toVFC/MFC to provide a peak roll rate necessary forsafety, without excessive control forces or travel.(See AMC 25.147(f).)CS 25.149 Minimum control speed(See AMC 25.149)(a) In establishing the minimum control speedsrequired by this paragraph, the method used tosimulate critical engine failure must represent themost critical mode of powerplant failure with respectto controllability expected in service.(b) VMC is the calibrated airspeed, at which,when the critical engine is suddenly madeinoperative, it is possible to maintain control of theaeroplane with that engine still inoperative, andmaintain straight flight with an angle of bank of notmore than 5º.(c) VMC may not exceed 1·13 VSR with –(1) Maximum available take-off power orthrust on the engines;(2) The most unfavourable centre ofgravity;(3) The aeroplane trimmed for take-off;(4) The maximum sea-level take-offweight (or any lesser weight necessary to showVMC);(5) The aeroplane in the most criticaltake-off configuration existing along the flightpath after the aeroplane becomes airborne, exceptwith the landing gear retracted;(6) The aeroplane airborne and theground effect negligible; and(7) If applicable, the propeller of theinoperative engine –(i) Windmilling;(ii) In the most probable positionfor the specific design of the propellercontrol; or(iii) Feathered, if the aeroplane hasan automatic feathering device acceptablefor showing compliance with the climbrequirements of CS 25.121.(d) The rudder forces required to maintaincontrol at VMC may not exceed 667 N (150 lbf) normay it be necessary to reduce power or thrust of theoperative engines. During recovery, the aeroplanemay not assume any dangerous attitude or requireexceptional piloting skill, alertness, or strength toprevent a heading change of more than 20º.(e) VMCG, the minimum control speed on theground, is the calibrated airspeed during the take-offrun at which, when the critical engine is suddenlymade inoperative, it is possible to maintain control ofthe aeroplane using the rudder control alone (withoutthe use of nose-wheel steering), as limited by 667 Nof force (150 lbf), and the lateral control to the extentof keeping the wings level to enable the take-off tobe safely continued using normal piloting skill. In thedetermination of VMCG, assuming that the path of theaeroplane accelerating with all engines operating isalong the centreline of the runway, its path from thepoint at which the critical engine is made inoperativeto the point at which recovery to a direction parallelto the centreline is completed, may not deviate morethan 9.1 m (30 ft) laterally from the centreline at anypoint. VMCG must be established, with –(1) The aeroplane in each take-offconfiguration or, at the option of the applicant, inthe most critical take-off configuration;(2) Maximum available take-off power orthrust on the operating engines;(3) The most unfavourable centre ofgravity;The aeroplane trimmed for take-off; and1-B-16Annex to ED Decision 2008/006/RAmendment 5CS-25 BOOK 1(5) The most unfavourable weight in therange of take-off weights. (See AMC 25.149(e).)(f) (See AMC 25.149 (f)) VMCL, the minimumcontrol speed during approach and landing with allengines operating, is the calibrated airspeed at which,when the critical engine is suddenly madeinoperative, it is possible to maintain control of theaeroplane with that engine still inoperative, andmaintain straight flight with an angle of bank of notmore than 5º. VMCL must be established with –(1) The aeroplane in the most criticalconfiguration (or, at the option of the applicant,each configuration) for approach and landing withall engines operating;
(2) The most unfavourable centre ofgravity;(3) The aeroplane trimmed for approachwith all engines operating;(4) The most unfavourable weight, or, atthe option of the applicant, as a function ofweight;(5) For propeller aeroplanes, the propellerof the inoperative engine in the position itachieves without pilot action, assuming the enginefails while at the power or thrust necessary tomaintain a 3 degree approach path angle; and(6) Go-around power or thrust setting onthe operating engine(s).(g) (See AMC 25.149(g)) For aeroplanes withthree or more engines, VMCL-2, the minimum controlspeed during approach and landing with one criticalengine inoperative, is the calibrated airspeed atwhich, when a second critical engine is suddenlymade inoperative, it is possible to maintain control ofthe aeroplane with both engines still inoperative, andmaintain straight flight with an angle of bank of notmore than 5º. VMCL-2 must be established with –(1) The aeroplane in the most criticalconfiguration (or, at the option of the applicant,each configuration) for approach and landing withone critical engine inoperative;(2) The most unfavourable centre ofgravity;(3) The aeroplane trimmed for approachwith one critical engine inoperative;(4) The most unfavourable weight, or, atthe option of the applicant, as a function ofweight;(5) For propeller aeroplanes, the propellerof the more critical engine in the position itachieves without pilot action, assuming the enginefails while at the power or thrust necessary tomaintain a 3 degree approach path angle, and thepropeller of the other inoperative enginefeathered;(6) The power or thrust on the operatingengine(s) necessary to maintain an approach pathangle of 3º when one critical engine isinoperative; and(7) The power or thrust on the operatingengine(s) rapidly changed, immediately after thesecond critical engine is made inoperative, fromthe power or thrust prescribed in sub-paragraph(g)(6) of this paragraph to –(i) Minimum power or thrust; and(ii) Go-around power or thrustsetting.(h) In demonstrations of VMCL and VMCL-2 –(1) The rudder force may not exceed 667N (150 lbf);(2) The aeroplane may not exhibithazardous flight characteristics or requireexceptional piloting skill, alertness or strength;(3) Lateral control must be sufficient toroll the aeroplane, from an initial condition ofsteady straight flight, through an angle of 20º inthe direction necessary to initiate a turn awayfrom the inoperative engine(s), in not more than 5seconds (see AMC 25.149(h)(3)); and(4) For propeller aeroplanes, hazardousflight characteristics must not be exhibited due toany propeller position achieved when the enginefails or during any likely subsequent movementsof the engine or propeller controls (see AMC25.149 (h)(4)).TRIMCS 25.161 Trim(a) General. Each aeroplane must meet the trimrequirements of this paragraph after being trimmed,and without further pressure upon, or movement of,either the primary controls or their correspondingtrim controls by the pilot or the automatic pilot.(b) Lateral and directional trim. The aeroplanemust maintain lateral and directional trim with themost adverse lateral displacement of the centre ofgravity within the relevant operating limitations,during normally expected conditions of operation(including operation at any speed from 1·3 VSR1 , toVMO/MMO).
