ED Decision 2003/15/RM
(a) Unless otherwise prescribed, the performance requirements of this Subpart must be met for still air and a standard atmosphere.
(b) The performance must correspond to the engine power available under the particular ambient atmospheric conditions, the particular flight condition, and the relative humidity specified in sub-paragraphs (d) or (e), as appropriate.
(c) The available power must correspond to engine power, not exceeding the approved power, less:
(1) Installation losses; and
(2) The power absorbed by the accessories and services appropriate to the particular ambient atmospheric conditions and the particular flight condition.
(d) For reciprocating engine-powered rotorcraft, the performance, as affected by engine power, must be based on a relative humidity of 80% in a standard atmosphere.
(e) For turbine engine-powered rotorcraft, the performance, as affected by engine power, must be based on a relative humidity of:
(1) 80%, at and below standard temperature; and
(2) 34%, at and above standard temperature plus 28°C (50°F) between these two temperatures, the relative humidity must vary linearly.
(f) For turbine engine-powered rotorcraft, a means must be provided to permit the pilot to determine prior to take-off that each engine is capable of developing the power necessary to achieve the applicable rotorcraft performance prescribed in this Subpart.
ED Decision 2018/015/R15/R
This AMC provides further guidance and acceptable means of compliance to supplement FAA AC 27-1B Change 7 AC 27.45. § 27.45 PERFORMANCE – GENERAL which is the EASA acceptable means of compliance, as provided for in AMC 27 General. However, some aspects of the FAA AC are deemed by EASA to be at variance with EASA’s interpretation or its regulatory system. EASA’s interpretation of these aspects is described below. Paragraphs of FAA AC 27.45. § 27.45 that are not amended below are considered to be EASA acceptable means of compliance.
b. Procedures
(7) Engine Failure Testing Considerations
(i) For all tests used to investigate the behaviour of the rotorcraft following an engine failure, the failure of the engine is usually simulated in some way. When engines are controlled with a hydro-mechanical governing system, it is common practice to close the throttle quickly to idle. For rotorcraft equipped with engine electronic control systems, and particularly those with a 2-minute/30-second OEI rating structure, it is common practice to simulate an OEI condition by using reduced power on all engines by means of a flight test tool.
(ii) In every case, it must be demonstrated that all aspects of rotorcraft and powerplant behaviour are identical to those that would occur in the event of an actual engine failure with the remaining engine developing minimum-specification power. Of particular concern are ‘dead engine’ power decay characteristics, ‘live engine’ acceleration characteristics, and rotor RPM control.
(iii) To this end, it is expected that a number of actual engine shut down tests will be conducted to generate sufficient data to validate the fidelity of the flight test tool and methodology, which will then allow its use in developing regulatory performance data. In general, it is best to conduct the tests in a low hover with the rotorcraft stabilised below the HV low point. An engine is then shut down and, following the appropriate pilot intervention time, the collective control is raised to cushion the landing.
[Amdt No: 27/6]
CS 27.49 Performance at minimum operating speed
ED Decision 2007/013/R
(a) For helicopters:
(1) The hovering ceiling must be determined over the ranges of weight, altitude, and temperature for which certification is requested, with:
(i) Take-off power;
(ii) The landing gear extended; and
(iii) The helicopter in ground effect at a height consistent with normal take-off procedures; and
(2) The hovering ceiling determined in sub-paragraph (a)(1) of this paragraph must be at least:
(i) For reciprocating engine-powered helicopters, 1219 m (4 000 ft) at maximum weight with a standard atmosphere; or
(ii) For turbine engine-powered helicopters, 762 m (2 500 ft) pressure altitude at maximum weight at a temperature of standard +22°C (+40°F).
(3) The out-of-ground effect hovering performance must be determined over the ranges of weight, altitude, and temperature for which certification is requested, using take-off power.
(b) For rotorcraft other than helicopters, the steady rate of climb at the minimum operating speed must be determined, over the ranges of weight, altitude, and temperature for which certification is requested, with:
(1) Take-off power; and
(2) The landing gear extended.
[Amdt. No.: 27/1]
ED Decision 2007/013/R
The take-off, with take-off power and r.p.m. at the most critical center of gravity, and with weight from the maximum weight at sea-level to the weight for which take-off certification is requested for each altitude covered by this paragraph:
(a) May not require exceptional piloting skill or exceptionally favourable conditions throughout the ranges of altitude from standard sea-level conditions to the maximum altitude for which take-off and landing certification is requested, and
(b) Must be made in such a manner that a landing can be made safely at any point along the flight path if an engine fails. This must be demonstrated up to the maximum altitude for which take-off and landing certification is requested or 2134 m (7,000 ft) density altitude, whichever is less.
[Amdt. No.: 27/1]
CS 27.65 Climb: all-engines-operating
ED Decision 2003/15/RM
(a) For rotorcraft other than helicopters –
(1) The steady rate of climb, at VY must be determined:
(i) With maximum continuous power on each engine;
(ii) With the landing gear retracted; and
(iii) For the weights, altitudes, and temperatures for which certification is requested; and
(2) The climb gradient, at the rate of climb determined in accordance with subparagraph (a)(1), must be either:
(i) At least 1:10 if the horizontal distance required to take off and climb over a 15 m (50 ft) obstacle is determined for each weight, altitude, and temperature within the range for which certification is requested; or
(ii) At least 1:6 under standard sea-level conditions.
(b) Each helicopter must meet the following requirements:
(1) VY must be determined:
(i) For standard sea-level conditions;
(ii) At maximum weight; and
(iii) With maximum continuous power on each engine.
(2) The steady rate of climb must be determined:
(i) At the climb speed selected by the applicant at or below VNE;
(ii) Within the range from sealevel up to the maximum altitude for which certification is requested;
(iii) For the weights and temperatures that correspond to the altitude range set forth in sub-paragraph (b)(2)(ii) and for which certification is requested; and
(iv) With maximum continuous power on each engine.
CS 27.67 Climb: one-engine-inoperative
ED Decision 2003/15/RM
For multi-engine helicopters, the steady rate of climb (or descent), at VY (or at the speed for minimum rate of descent), must be determined with:
(a) Maximum weight;
(b) The critical engine inoperative and the remaining engines at either –
(1) Maximum continuous power and, for helicopters for which certification for the use of 30-minute one engine inoperative (OEI) power is requested, at 30-minute OEI power; or
(2) Continuous OEI power for helicopters for which certification for the use of continuous OEI power is requested.
ED Decision 2003/15/RM
For single-engine helicopters and multi-engine helicopters that do not meet the category A engine isolation requirements of CS-27, the minimum rate of descent airspeed and the best angle-of-glide airspeed must be determined in autorotation at:
(a) Maximum weight; and
(b) Rotor speed(s) selected by the applicant.
ED Decision 2007/013/R
(a) The rotorcraft must be able to be landed with no excessive vertical acceleration, no tendency to bounce, nose over, ground loop, porpoise, or water loop, and without exceptional piloting skill or exceptionally favourable conditions, with:
(1) Approach or autorotation speeds appropriate to the type of rotorcraft and selected by the applicant;
(2) The approach and landing made with:
(i) Power off, for single-engine rotorcraft and entered from steady state autorotation; or
(ii) One-engine inoperative (OEI) for multi-engine rotorcraft, with each operating engine within approved operating limitations, and entered from an established OEI approach.
(b) Multi-engine rotorcraft must be able to be landed safely after complete power failure under normal operating conditions.
[Amdt. No.: 27/1]
CS 27.79 Limiting height-speed envelope
ED Decision 2007/013/R
(a) If there is any combination of height and forward speed, including hover, under which a safe landing cannot be made under the applicable power failure condition in sub-paragraph (b), a limiting height-speed envelope must be established, including all pertinent information, for that condition, throughout the ranges of:
(1) Altitude, from standard sea-level conditions to the maximum altitude capability of the rotorcraft, or 2134 m (7 000 ft) density altitude, whichever is less; and
(2) Weight from the maximum weight at sea-level to the weight selected by the applicant for each altitude covered by sub-paragraph (a)(1) of this paragraph. For helicopters, the weight at altitudes above sea-level may not be less than the maximum weight or the highest weight allowing hovering out of ground effect whichever is lower.
(b) The applicable power failure conditions are:
(1) For single-engine helicopters, full autorotation;
(2) For multi-engine helicopters, OEI, where engine isolation features ensure continued operation of the remaining engines, and the remaining engine(s) within approved limits and at the minimum installed specification power available for the most critical combination of approved ambient temperature and pressure altitude resulting in 2134 m (7000 ft) density altitude or the maximum altitude capability of the helicopter, whichever is less, and
(3) For other rotorcraft, conditions appropriate to the type.
[Amdt. No.: 27/1]