CS 25.1503 Airspeed limitations: general

ED Decision 2003/2/RM

When airspeed limitations are a function of weight, weight distribution, altitude, or Mach number, limitations corresponding to each critical combination of these factors must be established.

CS 25.1505 Maximum operating limit speed

ED Decision 2003/2/RM

The maximum operating limit speed (VMO/MMO, airspeed or Mach number, whichever is critical at a particular altitude) is a speed that may not be deliberately exceeded in any regime of flight (climb, cruise, or descent), unless a higher speed is authorised for flight test or pilot training operations. VMO/MMO must be established so that it is not greater than the design cruising speed VC and so that it is sufficiently below VD/MD or VDF/MDF, to make it highly improbable that the latter speeds will be inadvertently exceeded in operations. The speed margin between VMO/MMO and VD/MD or VDF/MDF may not be less than that determined under CS 25.335(b) or found necessary during the flight tests conducted under CS 25.253.

CS 25.1507 Manoeuvring speed

ED Decision 2003/2/RM

The manoeuvring speed must be established so that it does not exceed the design manoeuvring speed VA determined under CS 25.335(c).

CS 25.1511 Flap extended speed

ED Decision 2003/2/RM

The established flap extended speed VFE must be established so that it does not exceed the design flap speed VF chosen under CS 25.335(e) and 25.345, for the corresponding wing-flap positions and engine powers.

CS 25.1513 Minimum control speed

ED Decision 2003/2/RM

The minimum control speed VMC determined under CS 25.149 must be established as an operating limitation.

CS 25.1515 Landing gear speeds

ED Decision 2003/2/RM

(a) The established landing gear operating speed or speeds, VLO, may not exceed the speed at which it is safe both to extend and to retract the landing gear, as determined under CS 25.729 or by the flight characteristics. If the extension speed is not the same as the retraction speed, the two speeds must be designated as VLO(EXT) and VLO(RET), respectively.

(b) The established landing gear extended speed VLE may not exceed the speed at which it is safe to fly with the landing gear secured in the fully extended position, and that determined under CS 25.729.

CS 25.1516 Other speed limitations

ED Decision 2003/2/RM

Any other limitation associated with speed must be established.

CS 25.1517 Rough air speed, VRA

ED Decision 2005/006/R

(a) A rough air speed, VRA for use as the recommended turbulence penetration air speed, and a rough air Mach number MRA, for use as the recommended turbulence penetration Mach number, must be established to ensure that likely speed variation during rough air encounters will not cause the overspeed warning to operate too frequently.

(b) At altitudes where VMO is not limited by Mach number, in the absence of a rational investigation substantiating the use of other values, VRA must be less than VMO - 35 KTAS.

(c) At altitudes where VMO is limited by Mach number, MRA may be chosen to provide an optimum margin between low and high speed buffet boundaries.

[Amdt 25/1]

CS 25.1519 Weight, centre of gravity and weight distribution

ED Decision 2016/010/R

(See AMC 25.1519)

The aeroplane weight, centre of gravity, and weight distribution limitations determined under CS 25.23 to CS 25.27 must be established as operating limitations.

[Amdt 25/18]

AMC 25.1519 Weight, centre of gravity and weight distribution

ED Decision 2003/2/RM

A statement of the maximum certificated take-off and landing weights, and the minimum certificated take-off and landing weights, should be established, together with the maximum ramp or taxying weight, the maximum zero-fuel weight and any other fixed limit on weight, including weight limitations resulting from such factors as brake energy limits, tyre limits, etc., established in accordance with the airworthiness standards of CS-25. Any limitations on aeroplane loading associated with the stated weight limitations (e.g. fuel load and usage, maximum fuel for landing) should be considered.

CS 25.1521 Powerplant limitations

ED Decision 2015/008/R

(See AMC 25.1521)

(a) General. The powerplant limitations prescribed in this paragraph must be established so that they do not exceed the corresponding limits for which the engines or propellers are type certificated and do not exceed the values on which compliance with any other requirement of this Code is based.

(b) Reserved.

(c) Turbine engine installations. Operating limitations relating to the following must be established for turbine engine installations:

(1) Horsepower, torque or thrust, rpm, gas temperature, and time for –

(i) Maximum continuous power or thrust (relating to augmented or unaugmented operation as applicable).

(ii) Take-off power or thrust (relating to augmented or unaugmented operation as applicable).

(2) Fuel designation or specification.

(3)  Maximum time interval between engine run-ups from idle, run-up power setting, duration at power, and the associated minimum ambient temperature, if any, demonstrated for the maximum time interval, for ground operation in icing conditions, as defined in CS 25.1093(b)(2).

(4) Any other parameter for which a limitation has been established as part of the engine type certificate except that a limitation need not be established for a parameter that cannot be exceeded during normal operation due to the design of the installation or to another established limitation.

(d) Ambient temperature. An ambient temperature limitation (including limitations for winterisation installations, if applicable) must be established as the maximum ambient atmospheric temperature established in accordance with CS 25.1043(b).

[Amdt 25/16]

AMC 25.1521 Power-plant limitations

ED Decision 2003/2/RM

1  In furnishing limitations, consideration should be given to the following. The list does not necessarily include all the items to be considered for a given aeroplane.

a. Rotational speeds.

b. Exhaust and/or turbine gas temperature.

c. Oil temperatures and pressures.

d. Fuel temperatures and pressures.

e. Water and/or water methanol usage.

f. Anti-icing.

g. Specifications of approved fuels, oils and additives.

2 Other parameters, e.g. time, altitude, ambient temperatures, airspeed, may be necessary in defining power-plant limitations.

3 All operating phases should be considered in establishing the power-plant limitations.

CS 25.1523 Minimum flight crew

ED Decision 2016/010/R

(See AMC 25.1523)

The minimum flight crew must be established (see AMC 25.1523) so that it is sufficient for safe operation, considering –

(a) The workload on individual crew members;

(b) The accessibility and ease of operation of necessary controls by the appropriate crew member; and

(c) The kind of operation authorised under CS 25.1525.

The criteria used in making the determinations required by this paragraph are set forth in Appendix D.

[Amdt 25/18]

AMC 25.1523 Minimum flight crew

ED Decision 2003/2/RM

1 Both the number and identity of the flight crew members should be established.

2 If the minimum flight crew varies with the kinds of operation to which the aeroplane is limited, the approved number and identity of the flight crew members should be stated for each kind of operation.

3 If a particular flight crew member's station has to be occupied at all material times, this should be stated when specifying the minimum flight crew.

CS 25.1525 Kinds of operation

ED Decision 2003/2/RM

The kinds of operation to which the aeroplane is limited are established by the category in which it is eligible for certification and by the installed equipment.

CS 25.1527 Ambient air temperature and operating altitude

ED Decision 2003/2/RM

The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited by flight, structural, powerplant, functional, or equipment characteristics, must be established.

CS 25.1529 Instructions for Continued Airworthiness

ED Decision 2003/2/RM

Instructions for Continued Airworthiness in accordance with Appendix H must be prepared.

CS 25.1531 Manoeuvring flight load factors

ED Decision 2003/2/RM

Load factor limitations, not exceeding the positive limit load factors determined from the manoeuvring diagram in CS 25.333(b), must be established.

CS 25.1533 Additional operating limitations

ED Decision 2016/010/R

(See AMC 25.1533)

(a) Additional operating limitations must be established as follows:

(1) The maximum take-off weights must be established as the weights at which compliance is shown with the applicable provisions of this CS-25 (including the take-off climb provisions of CS 25.121(a) to (c), for altitudes and ambient temperatures).

(2) The maximum landing weights must be established as the weights at which compliance is shown with the applicable provisions of this CS-25 (including the landing and approach climb provisions of CS 25.119 and 25.121(d) for altitudes and ambient temperatures).

(3) The minimum take-off distances must be established as the distances at which compliance is shown with the applicable provisions of this CS-25 (including the provisions of CS 25.109 and 25.113, for weights, altitudes, temperatures, wind components, runway surface conditions (dry and wet) and runway gradients) for smooth, hard-surfaced runways. Additionally, at the option of the applicant, wet runway take-off distances may be established for runway surfaces that have been grooved or treated with a porous friction course and may be approved for use on runways where such surfaces have been designed, constructed and maintained in a manner acceptable to the Agency. (See AMC 25.1533(a)(3).)

(b) The extremes for variable factors (such as altitude, temperature, wind, runway gradients) are those at which compliance with the applicable provisions of this CS-25 is shown.

(c)  For aeroplanes certified in accordance with CS 25.1420(a)(1) or (a)(2), an operating limitation must be established to:

(1)  Prohibit intentional flight, including take-off and landing, into icing conditions defined in Appendix O for which the aeroplane has not been certified to safely operate; and

(2)  Require exiting all icing conditions if icing conditions defined in Appendix O are encountered for which the aeroplane has not been certified to safely operate.

[Amdt 25/16]

[Amdt 25/18]

AMC 25.1533(a)(3) Take-off distances on runways with a grooved or porous friction course surface

ED Decision 2003/2/RM

Runways that have a grooved or porous friction course (PFC) surface can maintain a significantly higher wheel-braking coefficient of friction when wet than can runways that lack such surface treatments. Where take-off distance information specifically applicable to such runways has been established, this higher level of friction has been taken into account in accordance with CS 25.109(d). It is therefore essential that such information is only approved for use on runways having a grooved or PFC surface that has been constructed and maintained to acceptable standards. FAA AC 150/532012B ‘Measurement, Construction and Maintenance of Skid-Resistant Airport Paving Surfaces’ provides guidance on such standards. Where such operational approval has not been obtained, the performance information applicable to a smooth, hard-surfaced runway must be used.

CS 25.1535 ETOPS Design approval

ED Decision 2018/005/R

For an aeroplane configuration to be capable of ETOPS, the following are required:

(a)  Compliance with the requirements of CS-25 considering the maximum flight duration and the longest diversion time for which approval is being sought.

(b)  For Early ETOPS, approval of the engine for ETOPS capability in compliance with CS-E 1040.

(c)  Consideration must have been given to the crew workload and operational implications and the flight crew’s and passengers’ physiological needs of continued operations with failure effects for the longest diversion time for which approval is being sought.

(d)  The appropriate capability and limitations must have been established. (See AMC 20-6.)

(See AMC 20-6)

[Amdt 25/10]

[Amdt 25/21]