CS 27.1503 Airspeed limitations: general
ED Decision 2003/15/RM
(a) An operating speed range must be established.
(b) When airspeed limitations are a function of weight, weight distribution, altitude, rotor speed, power, or other factors, airspeed limitations corresponding with the critical combinations of these factors must be established.
ED Decision 2003/15/RM
(a) The never-exceed speed, VNE, must be established so that it is:
(1) Not less than 74 km/h (40 knots) (CAS); and
(2) Not more than the lesser of:
(i) 0.9 times the maximum forward speeds established under CS 27.309;
(ii) 0.9 times the maximum speed shown under CS 27.251 and 27.629; or
(iii) 0.9 times the maximum speed substantiated for advancing blade tip mach number effects.
(b) VNE may vary with altitude, rpm, temperature, and weight, if:
(1) No more than two of these variables (or no more than two instruments integrating more than one of these variables) are used at one time; and
(2) The ranges of these variables (or of the indications on instruments integrating more than one of these variables) are large enough to allow an operationally practical and safe variation of VNE.
(c) For helicopters, a stabilised power-off VNE denoted as VNE (power-off) may be established at a speed less than VNE established pursuant to sub-paragraph (a), if the following conditions are met:
(1) VNE (power-off) is not less than a speed midway between the power-on VNE and the speed used in meeting the requirements of:
(i) CS 27.65(b) for single engine helicopters; and
(ii) CS 27.67 for multi-engine helicopters.
(2) VNE (power-off) is –
(i) A constant airspeed;
(ii) A constant amount less than power-on VNE; or
(iii) A constant airspeed for a portion of the altitude range for which certification is requested, and a constant amount less than power-on VNE for the remainder of the altitude range.
ED Decision 2003/15/RM
(a) Maximum power-off (autorotation). The maximum power-off rotor speed must be established so that it does not exceed 95% of the lesser of –
(1) The maximum design rpm determined under CS 27.309(b); and
(2) The maximum rpm shown during the type tests.
(b) Minimum power-off. The minimum power-off rotor speed must be established so that it is not less than 105% of the greater of:
(1) The minimum shown during the type tests; and
(2) The minimum determined by design substantiation.
(c) Minimum power-on. The minimum power-on rotor speed must be established so that it is:
(1) Not less than the greater of:
(i) The minimum shown during the type tests; and
(ii) The minimum determined by design substantiation; and
(2) Not more than a value determined under CS 27.33(a)(1) and (b)(1).
CS 27.1519 Weight and centre of gravity
ED Decision 2003/15/RM
The weight and centre of gravity limitations determined under CS 27.25 and 27.27, respectively, must be established as operating limitations.
CS 27.1521 Powerplant limitations
ED Decision 2012/021/R
(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 are type certificated.
(b) Take-off operation. The powerplant take-off operation must be limited by:
(1) The maximum rotational speed, which may not be greater than:
(i) The maximum value determined by the rotor design; or
(ii) The maximum value shown during the type tests;
(2) The maximum allowable manifold pressure (for reciprocating engines);
(3) The time limit for the use of the power corresponding to the limitations established in sub-paragraphs (b)(1) and (2);
(4) If the time limit in sub-paragraph (b)(3) exceeds 2 minutes, the maximum allowable cylinder head, coolant outlet, or oil temperatures;
(5) The gas temperature limits for turbine engines over the range of operating and atmospheric conditions for which certification is requested.
(c) Continuous operation. The continuous operation must be limited by:
(1) The maximum rotational speed which may not be greater than:
(i) The maximum value determined by the rotor design; or
(ii) The maximum value shown during the type tests;
(2) The minimum rotational speed shown under the rotor speed requirements in CS 27.1509(c); and
(3) The gas temperature limits for turbine engines over the range of operating and atmospheric conditions for which certification is requested.
(d) Fuel grade or designation. The minimum fuel grade (for reciprocating engines), or fuel designation (for turbine engines), must be established so that it is not less than that required for operation of the engines within the limitations in sub-paragraphs (b) and (c).
(e) Turboshaft engine torque. For rotorcraft with main rotors driven by turboshaft engines, and that do not have a torque limiting device in the transmission system, the following apply:
(1) A limit engine torque must be established if the maximum torque that the engine can exert is greater than:
(i) The torque that the rotor drive system is designed to transmit; or
(ii) The torque that the main rotor assembly is designed to withstand in showing compliance with CS 27.547(d).
(2) The limit engine torque established under sub-paragraph (e)(1) may not exceed either torque specified in sub-paragraph (e)(1)(i) or (ii).
(f) Ambient temperature. For turbine engines, ambient temperature limitations (including limitations for winterization installations, if applicable) must be established as the maximum ambient atmospheric temperature at which compliance with the cooling provisions of CS 27.1041 to 27.1045 is shown.
(g) Two and one-half minute OEI power operation. Unless otherwise authorised, the use of 2½-minute OEI power must be limited to engine failure operation of multi-engine, turbine-powered rotorcraft for not longer that 2½ minutes after failure of an engine. The use of 2½-minute OEI power must also be limited by:
(1) The maximum rotational speed, which may not be greater than:
(i) The maximum value determined by the rotor design; or
(ii) The maximum demonstrated during the type tests;
(2) The maximum allowable gas temperature; and
(3) The maximum allowable torque.
(h) Thirty-minute OEI power operation.
Unless otherwise authorised, the use of 30-minute OEI power must be limited to multi-engine, turbine-powered rotorcraft for not longer than 30 minutes after failure of an engine. The use of 30-minute OEI power must also be limited by:
(1) The maximum rotational speed which may not be greater than –
(i) The maximum value determined by the rotor design; or
(ii) The maximum value demonstrated during the type tests;
(2) The maximum allowable gas temperature; and
(3) The maximum allowable torque.
(i) Continuous OEI power operation. Unless otherwise authorised, the use of continuous OEI power must be limited to multi-engine, turbine-powered rotorcraft for continued flight after failure of an engine. The use of continuous OEI power must also be limited by:
(1) The maximum rotational speed, which may not be greater than –
(i) The maximum value determined by the rotor design; or
(ii) The maximum value demonstrated during the type tests;
(2) The maximum allowable gas temperature; and
(3) The maximum allowable torque.
(j) Rated 30-second OEI power operation. Rated 30-second OEI power is permitted only on multi-engine, turbine-powered rotorcraft, also certificated for the use of rated 2-minute OEI power, and can only be used for continued operation of the remaining engine(s) after a failure or precautionary shutdown of an engine. It must be shown that following application of 30-second OEI power, any damage will be readily detectable by the applicable inspections and other related procedures furnished in accordance with paragraph A27.4 of Appendix A of this CS-27. The use of 30-second OEI power must be limited to not more than 30 seconds for any period in which that power is used, and by:
(1) The maximum rotational speed which may not be greater than:
(i) The maximum value determined by the rotor design: or
(ii) The maximum value demonstrated during the type tests:
(2) The maximum allowable gas temperature; and
(3) The maximum allowable torque.
(k) Rated 2-minute OEI power operation. Rated 2-minute OEI power is permitted only on multi-engine, turbine-powered rotorcraft, also certificated for the use of rated 30-second OEI power, and can only be used for continued operation of the remaining engine(s) after a failure or precautionary shutdown of an engine. It must be shown that following application of 2-minute OEI power, any damage will be readily detectable by the applicable inspections and other related procedures furnished in accordance with A27.4 of appendix A of this CS-27. The use of 2-minute OEI power must be limited to not more than 2 minutes for any period in which that power is used, and by:
(1) The maximum rotational speed, which may not be greater than:
(i) The maximum value determined by the rotor design; or
(ii) The maximum value demonstrated during the type tests;
(2) The maximum allowable gas temperature; and
(3) The maximum allowable torque.
[Amdt 27/3]
CS 27.1523 Minimum flight crew
ED Decision 2003/15/RM
The minimum flight crew must be established 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 kinds of operation authorised under CS 27.1525.
CS 27.1525 Kinds of operations
ED Decision 2003/15/RM
The kinds of operations (such as VFR, IFR, day, night, or icing) for which the rotorcraft is approved are established by demonstrated compliance with the applicable certification requirements and by the installed equipment.
CS 27.1527 Maximum operating altitude
ED Decision 2003/15/RM
The maximum altitude up to which operation is allowed, as limited by flight, structural, powerplant, functional, or equipment characteristics, must be established.
CS 27.1529 Instructions for Continued Airworthiness
ED Decision 2003/15/RM
Instructions for Continued Airworthiness in accordance with Appendix A must be prepared.
Appendix A – Instructions for Continued Airworthiness
ED Decision 2020/006/R
A27.1 General
(a) This appendix specifies requirements for the preparation of instructions for continued airworthiness as required by CS 27.1529.
(b) The instructions for continued airworthiness for each rotorcraft must include the instructions for continued airworthiness for each engine and rotor (hereinafter designated ‘products’), for each appliance required by any applicable CS or operating rule, and any required information relating to the interface of those appliances and products with the rotorcraft. If instructions for continued airworthiness are not supplied by the manufacturer of an appliance or product installed in the rotorcraft the instructions for continued airworthiness for the rotorcraft must include the information essential to the continued airworthiness of the rotorcraft.
A27.2 Format
(a) The instructions for continued airworthiness must be in the form of a manual or manuals as appropriate for the quantity of data to be provided.
(b) The format of the manual or manuals must provide for a practical arrangement.
A27.3 Content
The contents of the manual or manuals must be prepared in a language acceptable to the Agency. The instructions for continued airworthiness must contain the following manuals or sections, as appropriate, and information:
(a) Rotorcraft maintenance manual or section
(1) Introduction information that includes an explanation of the rotorcraft’s features and data to the extent necessary for maintenance or preventive maintenance.
(2) A description of the rotorcraft and its systems and installations including its engines, rotors, and appliances.
(3) Basic control and operation information describing how the rotorcraft components and systems are controlled and how they operate, including any special procedures and limitations that apply.
(4) Servicing information that covers details regarding servicing points, capacities of tanks, reservoirs, types of fluids to be used, pressures applicable to the various systems, location of access panels for inspection and servicing, locations of lubrication points, the lubricants to be used, equipment required for servicing, tow instructions and limitations, mooring, jacking, and levelling information.
(b) Maintenance instructions
(1) Scheduling information for each part of the rotorcraft and its engines, auxiliary power units, rotors, accessories, instruments and equipment that provides the recommended periods at which they should be cleaned, inspected, adjusted, tested, and lubricated, and the degree of inspection, the applicable wear tolerances, and work recommended at these periods. However, it is allowed to refer to an accessory, instrument, or equipment manufacturer as the source of this information if it is shown that the item has an exceptionally high degree of complexity requiring specialised maintenance techniques, test equipment, or expertise. The recommended overhaul periods and necessary cross references to the Airworthiness Limitations section of the manual must also be included. In addition an inspection program that includes the frequency and extent of the inspections necessary to provide for the continued airworthiness of the rotorcraft must be included.
(2) Troubleshooting information describing probable malfunctions, how to recognise those malfunctions, and the remedial action for those malfunctions.
(3) Information describing the order and method of removing and replacing products and parts with any necessary precautions to be taken.
(4) Other general procedural instructions including procedures for system testing during ground running, symmetry checks, weighing and determining the centre of gravity, lifting and shoring, and storage limitations.
(c) Diagrams of structural access plates and information needed to gain access for inspections when access plates are not provided.
(d) Details for the application of special inspection techniques including radiographic and ultrasonic testing where such processes are specified.
(e) Information needed to apply protective treatments to the structure after inspection.
(f) All data relative to structural fasteners such as identification, discard recommendations, and torque values.
(g) A list of special tools needed.
A27.4 Airworthiness Limitations Section
The instructions for continued airworthiness must contain a section titled airworthiness limitations, that is segregated and clearly distinguishable from the rest of the document. This section must set forth each mandatory replacement time, structural inspection interval, and related structural inspection procedure required for type-certification. If the instructions for continued airworthiness consist of multiple documents, the section required by this paragraph must be included in the principal manual. This section must contain a legible statement in a prominent location that reads: ‘the airworthiness limitations section is approved and variations must also be approved.’
A.27.5 Information system security Instructions for Continued Airworthiness
The applicant must prepare Instructions for Continued Airworthiness (ICA) that are applicable to aircraft information system security protection as required by CS 27.1319 (see AMC 20-42 Section 9).
[Amdt No: 27/2]
[Amdt No: 27/3]
[Amdt No: 27/7]