CS-E 740 Endurance Tests

ED Decision 208/014/R

(a)The specifications of CS-E 740 must be varied and supplemented as necessary to comply with CS-E 690(a), CS-E 750 and CS-E 890.

(b)(1) The test must be performed in the order defined in the appropriate schedule (either as prescribed in paragraphs (c)(1), (2) and (3) below, or as defined by the applicant in a test plan when paragraph (c)(4) below is used), and in suitable non-stop stages. An alternative schedule may be used if it is agreed to be at least as severe. In the event of a stop occurring during any stage, the stage must be repeated unless it is considered to be unnecessary. The complete test may need to be repeated if an excessive number of stops occur.

(2)The time taken in changing power and/or thrust settings during the entire test must not be deducted from the prescribed periods at the higher settings.

(3)Throughout each stage of the endurance test, the rotational speed must be maintained at, or within agreed limits of, the declared value appropriate to a particular condition. The determination of the necessary rotational speed tolerance will take account of the Engine speed, test equipment and any other relevant factors (see also CS-E 740(f)(1)).

(4)On turbo-propeller Engines, a representative flight Propeller must be fitted.

(5)The Engine must be subjected to an agreed extent of pre-assembly inspection, and a record must be made of the dimensions that are liable to change by reason of wear, distortion and creep. A record must also be made of the calibrations and settings of separately functioning Engine components and equipment (e.g. the control system, pumps, actuators, valves).

(6)The thrust or power of the Engine achieved throughout the endurance test must be at least 100 % of the value associated with the particular Engine rating being tested, in order to substantiate the thrust or power ratings established under CS-E 40. Alternatively, if the Engine cannot achieve the rated minimum physical thrust or power requirement, this may be acceptable if the applicant provides data or analysis that shows that any difference is inconsequential to the durability of those Engine parts that are subjected to thrust or power loads.

(c)Schedules

(1)Schedule for Standard Ratings (Take-off and Maximum Continuous)

25 6-hour stages, each stage comprising:

Part 1 1 hour of alternate 5-minute periods at Take-off Power or Thrust and minimum ground idle, or, for rotorcraft Engines, minimum test bed idle.

Part 2

(A)Stages 1 to 15, each of 30 minutes duration, at Maximum Continuous Power or Thrust.

(B)Stages 16 to 25, each of 30 minutes duration, at Take-off Power or Thrust.

For Engines for Aeroplanes. Where Engine rotational speeds between Maximum Continuous and Take-off may be used in service, e.g. for reduced thrust take-off or due to variations in the ambient temperature, and these speeds would not be adequately covered by other Parts of the endurance test, then the following Part 2 must be substituted:

(C)Stages 1 to 10, each of 30 minutes duration at Maximum Continuous Power or Thrust.

(D)Stages 11 to 15, each of 30 minutes duration at Take-off Power or Thrust.

(E)Stages 16 to 25, each of 30 minutes duration covering the range in 6 approximately equal speed increments between Maximum Continuous and Takeoff Power or Thrust.

Part 3 1 hour and 30 minutes at Maximum Continuous Power or Thrust.

Part 4 2 hours and 30 minutes covering the range in 15 approximately equal speed increments from Ground Idling up to but not including Maximum Continuous Power or Thrust.

Part 5 30 minutes of accelerations and decelerations consisting of 6 cycles from Ground Idling to Take-off Power or Thrust, maintaining Take-off Power or Thrust for a period of 30 seconds, the remaining time being at Ground Idling.

(2)(i) Schedule for Standard Ratings with 2½-Minute OEI and/or Continuous OEI Rating and/or 30-Minute OEI Rating and/or 30-Minute Power (when appropriate).

25 6-hour stages, each stage comprising:

Part 1 1 hour of alternate 5-minute periods at Take-off Power or Thrust and minimum ground idle, or, for rotorcraft Engines, minimum test bed idle, except that –

(A)In Stages 3 to 20, in place of two of the 5-minute periods at Take-off Power or Thrust, run 2½ minutes at Take-off Power or Thrust followed by 2½ minutes at 2½-Minute OEI Power or Thrust.

(B)In Stages 21 to 25, in place of three of the 5-minute periods at Take-off Power or Thrust, run 1 minute at Take-off Power or Thrust followed by 2 minutes at 2½Minute OEI Power or Thrust and 2 minutes at Take-off Power or Thrust.

Part 2

(A)Stages 1 to 15, each of 30 minutes duration at Maximum Continuous Power or Thrust.

(B)Stages 16 to 25, each of 30 minutes duration at Take-off Power or Thrust, except that in one stage a period of 5 minutes in the middle of a 30-minute period must be run at 2½-Minute OEI Power or Thrust.

For Engines for Aeroplanes. Where Engine rotational speeds between Maximum Continuous and Take-off may be used in service, e.g. for reduced thrust take-off or due to variations in the ambient temperature, and these speeds would not be adequately covered by other Parts of the endurance test, then the following Part 2 must be substituted:

(C)Stages 1 to 15, each of 30 minutes duration at Maximum Continuous Power or Thrust.

(D)Stages 16 to 20, each of 30 minutes duration at Take-off Power or Thrust except that in Stage 16 a period of 5 minutes in the middle of the 30-minute period must be run at 2½-Minute OEI Power/Thrust.

(E)Stages 21 to 25, each of 30 minutes duration covering the range in six approximately equal speed increments between Maximum Continuous and Take-off Power or Thrust.

Part 3

(A)For Engines for Aeroplanes:

30 minutes at Maximum Continuous Power or Thrust followed by one hour at Continuous OEI Power or Thrust.

(B)For Engines for Rotorcraft –

Either (for Engines to be approved with a Continuous OEI rating) 30 minutes at Maximum Continuous Power followed by 1 hour at Continuous OEI Power or (for Engines to be approved with a 30-Minute OEI Rating) 1 hour at Maximum Continuous Power followed by 30 minutes at 30-Minute OEI Power. A Continuous OEI Rating and a 30-Minute OEI Rating at a higher power level can be cleared in the same test, if desired, by running 30 minutes at Maximum Continuous Power followed by 30 minutes at Continuous OEI Power and then 30 minutes at 30-Minute OEI Power.

For an Engine to be approved with the 30-Minute Power rating, the Engine must be run for continuous periods of 30 minutes at the power level and associated operating limitations of the 30-Minute Power rating. These periods must be alternated with periods at Maximum Continuous Power, or less. The accumulated total additional running time shall be 25 hours at the 30-Minute Power rating, and the time spent at ‘standard’ Take-off Power shall not be counted towards this total.

Part 4 2 hours and 30 minutes covering the range in 15 approximately equal increments from Ground Idling, or, for rotorcraft Engines, minimum test bed idle, up to but not including Maximum Continuous Power.

Part 5 30 minutes of accelerations and decelerations consisting of 6 cycles from Ground Idling, or, for rotorcraft Engines, minimum test bed idle, to Take-off Power or Thrust, maintaining Take-off Power or Thrust for a period of 30 seconds, the remaining time being at Ground Idling, or, for rotorcraft Engines, minimum test bed idle.

(ii)If only one additional rating is required, then the periods at the rating that is not required must be run at the power or thrust level appropriate to the next rating down the scale.

(iii)If a constructor desires an en-route OEI rating for 30 minutes only, then the appropriate FAR 33.87 Schedule may be used in place of this Schedule. If this option is taken and a 2½ - Minute OEI Power rating is also desired, then the appropriate Schedule of FAR 33.87 must be used.

(3)For Engines with 30-Second and 2-Minute OEI Power ratings (See AMC E 740(c)(3)),

(i)If a Continuous OEI Power rating is associated with the 30-Second and 2-Minute OEI Power ratings, the following tests must be conducted and must be complemented by the additional test of CS-E 740(c)(3)(iii):

25 six-hour stages, each stage comprising –

Part 1 One hour of alternate 5 minute periods at Take-off Power and minimum test bed idle.

Part 2

(A)Stages 1 to 15, each of 30 minutes duration at Maximum Continuous Power.

(B)Stages 16 to 25, each of 30 minutes duration at Take-off Power.

Part 3 One hour at Maximum Continuous Power, followed by one hour at Continuous OEI Power.

Part 4 2 hours covering the range in 12 approximately equal increments from minimum test bed idle up to, but not including, Maximum Continuous Power.

Part 5 30 minutes of accelerations and decelerations consisting of 6 cycles from minimum test bed idle to Take-off Power, maintaining Take-off Power for a period of 30 seconds, the remaining time being at minimum test bed idle.

(ii)If a 30-Minute OEI Power rating is associated with the 30-Second and 2-Minute OEI Power ratings, the following tests must be conducted and must be complemented by the additional test of CS-E 740(c)(3)(iii):

25 six-hours stages, each stage comprising:

Part 1: One hour of alternate 5-minute periods at Take-off Power and minimum test bed idle.

Part 2:

(A)Stages 1 to 15, each of 30 minutes duration at Maximum Continuous Power.

(B)Stages 16 to 25, each of 30 minutes duration at Take-off Power.

Part 3: One hour at Maximum Continuous Power, followed by thirty minutes at 30-Minute OEI Power.

Part 4: Two hours and thirty minutes covering the range in 15 approximately equal increments from minimum test bed idle to Maximum Continuous Power.

Part 5: 30 minutes of accelerations and decelerations consisting of 6 cycles from minimum test bed idle to Take-off power, maintaining Take-off Power for a period of 30 seconds, the remaining time being at minimum test bed idle.

(iii)The following test sequence must be performed four times for a total time of not less than 120 minutes. If a stop occurs during this test, the interrupted sequence must be repeated unless it is shown that the severity of the test is not reduced if it were continued:

Part 1: Three minutes at Take-off Power.

Part 2: Thirty seconds at 30-Second OEI Power.

Part 3: Two minutes at 2-Minute OEI Power.

Part 4: Five minutes at whichever is the greatest of, as applicable, 30-Minute OEI Power, Continuous OEI Power and Maximum Continuous Power, except that during the first test sequence this period must be sixty-five minutes. However, where the greatest is the 30-Minute OEI Power, that sixty-five minutes period must consist of thirty minutes at 30-Minute OEI Power followed by thirty-five minutes at whichever is the greater of Continuous OEI Power and Maximum Continuous Power, as applicable.

Part 5: One minute at 50 percent of Take-off Power.

Part 6: Thirty seconds at 30-Second OEI Power.

Part 7: Two minutes at 2-Minute OEI Power.

Part 8: One minute at flight idle.

(4)

Alternate Endurance Testing – Turbofan Engine

The following alternate endurance testing may be used by the applicant for the purpose of testing turbofan Engines instead of the abovementioned test schedule as per CS- E 740(c)(1). In particular, this may be suitable when running this schedule would require substantial modifications of the Engine such that it would deviate excessively from the type-design definition. The alternate endurance test must, however, provide a severity at least equivalent to the intent of the endurance test prescribed by CS-E 740(c)(1) (here designated as the ‘classic’ endurance test).

(i)

Alternate Test Definition

The test must be defined considering the following elements:

(A)

Test Vehicle Definition;

(B)

Critical Point Analysis (CPA);

(C)

Engine Operating Limits Demonstration (type certification data sheet (TCDS) physical speeds and temperatures);

(D)

Test Severity Demonstration over extended operating periods;

(E)

Additional Severity Testing;

(F)

Incremental Cruise Power and Thrust;

(G)

Ancillary TCDS Limits Demonstration.

The compliance document(s) addressing the proposed test schedule and full assessment of the above elements must be agreed with EASA in advance of test commencement.

(ii)

Test Vehicle Definition

The test must be performed using a test vehicle that adequately conforms to the Engine type design.

Exceptions could include external test equipment, controls systems settings, and other modifications required to achieve the test conditions detailed below;

however, Engine hardware modifications should be minimised to preserve the Engine type-design hardware configuration and Engine cycle match. Hardware modifications may be temporarily applied to achieve specific test conditions (e.g.

for the physical core speed operating limits test segment).

(iii)

Critical Point Analysis (CPA)

Using a thermodynamic Engine model representative of a production Engine

(accounting for new and deteriorated Engine conditions) in conjunction with the aeroplane flight envelope, the applicant will identify the critical points (rotor physical speeds, temperatures, altitude, etc.) representing the most severe operation and the extent of exposure to those levels.

For the purpose of operating limits demonstrations, the CPA must establish the extent of exposure to the operating limits levels and close proximity to those levels.

The CPA must also establish maximum levels of corresponding rotor speed for an operating limit temperature case, and maximum levels of temperature for an operating limit speed case. If it is found that operating limits conditions could at any point be coincident, then this will need to be reflected in the demonstration.

The applicant will then conduct analyses to identify the areas in the declared flight envelope where endurance test critical components are exposed to the most damaging conditions. Critical components are the components within the Engine that are most limiting in terms of useful (serviceable) life under the endurance test conditions.

If the maximum critical component temperature method is used (see (v) Test

Severity Demonstration Over Extended Operating Periods), then the applicant’s

CPA will identify the maximum critical component temperature (this would normally, but not necessarily, be an operating limit Engine condition on a fully deteriorated Engine). The capability must also be demonstrated to establish Engine condition settings to achieve the same critical component temperatures during the test severity demonstration.

Failure modes of endurance test critical components must also be identified in the CPA process for assessment and possible demonstration within the alternate endurance test to support the severity equivalence demonstration (further demonstration may also be necessary in compliance with CS-E 170).

(iv)

Engine Operating Limits Demonstrations (TCDS Physical Rotor Speeds and Turbine

Gas Temperatures)

TCDS physical rotor speed and turbine gas temperature limiting conditions must be demonstrated as detailed in this paragraph.

Declared rotor operating limits values will be demonstrated in the Engine operating limits demonstration sections of the test and established in accordance with CS-

E 740(f).

Concurrent operating limits demonstration of speed and turbine gas temperature for a particular rotor is required unless the CPA indicates it is not possible to occur in service within the declared operating envelope. The corresponding speed or temperature identified in the CPA must be met or exceeded on average during the demonstrations below.

(1)

Core Speed Operating Limits Demonstration

The greater of maximum take-off (MTO) and maximum continuous (MCT) physical core speed operating limits in conjunction with at least the level of the corresponding temperature, as identified in the CPA, must be demonstrated for a minimum of 10 minutes. However, if the CPA for a new

Engine design shows that more than 10 minutes could occur in service, or that physical core speed operating limits could be encountered regularly in service, then the core speed operating limit test time will be extended accordingly. Where the CPA shows a longer period is required for MCT, the testing will be extended at MCT conditions to cover that period.

When demonstrated in conjunction with meeting the minimum severity requirements of CS-E 740(c)(4)(v), this demonstration comprises the appropriate period of the test for establishing the TCDS MTO- and MCT-declared core speed limits in accordance with CS-E 740(f).

(2)

Fan Speed Operating Limits Demonstration

The MTO fan physical speed operating limit must be demonstrated for a minimum of 30 minutes. The MCT fan physical speed operating limit must be demonstrated for a minimum of 90 minutes. Both cases must be demonstrated in conjunction with at least the level of corresponding temperature, as identified in the CPA.

If MTO and MCT have the same declared fan speed operating limit, then

120 minutes must be demonstrated.

Additional time may be necessary if the applicant’s CPA indicates that additional time at MTO or MCT physical fan speed operating limit could occur in service within the declared operating envelope. In conjunction with meeting minimum severity requirements, this demonstration comprises the appropriate period of the test for establishing the TCDS MTO- and MCT-declared fan speed limits in accordance with CS-E 740(f).

(3)

Turbine Exhaust Gas Temperature (EGT) Operating Limits Demonstration

The conditions necessary to demonstrate the MTO exhaust gas temperature

(EGT)operating limit must be continuously run for 10 minutes in conjunction with at least the level of corresponding rotor speeds as identified in the CPA.

Three snap/burst accelerations (throttle move in 1 second or shorter) from idle to the MTO EGT operating limit (hold operating limit for a duration of 90 seconds each) must also be run. The conditions necessary to demonstrate the MCT EGT operating limit must be continuously run for 90 minutes in conjunction with at least the level of corresponding rotor speeds as identified in the CPA.

Additional time at any or all these conditions may be necessary if the applicant’s CPA indicates that additional time at the EGT operating limit may occur in service.

EGT operating limits demonstration for alternate endurance testing also requires the equivalent severity to the intent of the specifications in CS-

E 740(a), (b) and (c)(1) to be demonstrated by running significant time and cycles at or above the maximum critical component temperature, as identified in the CPA as per CS-E 740(c)(4)(iii), and must be performed when showing compliance with CS-E 740(c)(4)(v).

Additional testing required to show compliance with CS-E 740(c)(4)(v) must be addressed in accordance with CS-E 740(c)(4)(vi).

(v)

Test Severity Demonstration Over Extended Operating Periods

Limiting temperature for MTO and MCT must be demonstrated for extended periods to achieve the equivalent cumulative damage for the critical component as would be achieved by the conditions prescribed in CS-E 740(c)(1) (also referred to as the ‘reference severity’; see also AMC E 740(c)(4), Section 5(b)).

The limiting temperature is either the turbine gas path temperature operating limit or the gas path temperature that corresponds to the maximum critical component temperature where this has been established for both a production Engine and the test Engine, as defined by the applicant’s CPA (refer to AMC E 740(c)(4) for further considerations of severity assessment). The applicant should therefore decide which limiting temperature method will be used during the test.

The duration and the split between MTO and MCT operation are to be determined and justified by the applicant.

The applicant must determine the mix of cycles and cycle durations that best represent the Engine design and operation. A methodology showing how creep damage, and other damage, to critical components accumulates is necessary for a comparative severity assessment to the intent of the test schedule specified in CS- E 740(c)(1).

During this testing phase, rotor physical speeds must be maintained at the highest levels feasible with a test vehicle that meets type design as per the specifications in CS-E 740(c)(4)(ii), and on average should be held within ± 3 % of the limiting speeds.

(vi)

Additional Severity Testing

The need for additional severity testing must be determined and agreed with EASA on completion of the scheduled test severity demonstration of CS-E 740(c)(4)(v).

The additional testing must be completed to the same target EGT conditions

(necessary if the conditions did not meet those that were assumed in the original analysis that was used to establish the test schedule) in order to compensate for the missed cumulative severity equivalence. Additional cyclic content may also be included, if necessary, to address other damage mechanism demonstration identified in the CPA, for which target conditions should be justified.

(vii)

Incremental Cruise Power and Thrust

The following incremental acceleration must be completed 25 times: 2 hours and 30 minutes, covering the range in 15 approximately equal speed increments from ground idle up to but not including MCT thrust or power.

(viii)Ancillary Type Certification Data Sheet Limits Demonstration

The alternate test must take into account specifications CS-E 690(a)(3), CS-E 740(e) and (f), and CS-E 750. Minor facilitating modifications may need to be made to run the conditions as required. The applicant must propose test sequence intervals equivalent to the stages specified in CS-E 690(a)(3) and CS-E 740(e) that are acceptable to EASA.

(d)Accelerations and Decelerations

(1)During scheduled accelerations and decelerations in Parts 1 and 5,

(i)For aeroplane Engines, the thrust or power control lever must be moved from one extreme position to the other in a time not greater than one second.

(ii)For rotorcraft Engines, the power demand must be increased to Take-off from the minimum test bed idle in a time not greater than one second.

(2)Observations

(i)Turbine Engines for Aeroplanes.

(A)Readings of power/ thrust, speed and EGT must be recorded at every significant change of Engine conditions. Following accelerations, the over-run of speed and temperature above the steady conditions at Take-off must be noted.

(B)Observations of all parameters must be recorded on first establishing steady running conditions and thence, during periods of continuous steady running, at approximately 30-minute intervals.

(C)During cyclic or other running, sufficient observations must be made to establish the power/thrust, speed and temperature conditions of the Engine whenever significant readings can be taken.

(ii)Turbine Engines for Rotorcraft.

Readings of power, rotational speed, nozzle position and EGT must be taken at idling speed and at the maximum speed obtained on acceleration. The over run of speed and temperature above the steady conditions at Take-off Power must be noted. These observations are likely to be affected by the types of instruments used and must therefore be coupled with this information in the endurance test report.

(e)Oil Pressure. The whole of the endurance test must be run with the oil pressure set to a value which is within the limits declared for Engine acceptance, except that –

(1)Stage 22 of the test schedule specified in CS-E 740(c)(1), (2) and (3), or an equivalent demonstration in the alternate endurance test specified in CS-E 740(c)(4), if applicable, must be run with the pressure set to give that declared as the minimum for completion of the flight, at MCT conditions; and

(2)One other stage, or an equivalent demonstration in the alternate endurance test specified in CS-E 740(c)(4), if applicable, must be run with the pressure set to give that declared as the maximum normal, at MCT conditions. During this stage, the oil temperature need not be held at its maximum value. Alternatively, this test may be omitted from the endurance test if appropriate evidence is available from other testing.

(f)Operating Limitations. The normal Engine operating limitations of power, rotational speed, EGT, bleed, oil temperature, etc., to be established under CS-E 40(d) and CS-E 40(g), will be based on the mean values obtained during the appropriate periods of the endurance test, including, when applicable, the mean values obtained during the applications of the 30-Second and 2- Minute OEI Power conditions in the 2-hour additional endurance test sequence of CS-E 740 (c)(3)(iii). The EGT limitations may be derived from an analysis when the applicant uses the alternate test specified in CS-E 740(c)(4) (see CS-E 740(f)(4)(ii) below).

Similarly, the degrees of compressor and turbine bleed that may be approved are the percentages of the mass flow which have been demonstrated during the endurance test, except as provided by CS-E 690(a)(3)(ii).

(1)The characteristics of multi-spool Engines may be such that it is not possible to obtain the maximum rotational speed of each spool simultaneously at sea-level test bed conditions, without making the Engine unacceptably non-standard, or running it in a non-representative manner. In such circumstances, the endurance test must be run at the turbine entry temperatures for which approval is sought, and evidence from supplementary endurance testing, to a schedule acceptable to the Agency, must be provided to substantiate the approval of any higher rotational speed limitations desired. (See AMC E 740(f)(1))

(2)If Stages 3, 7, 13, 17 and 23, or an equivalent demonstration in the alternate endurance test specified in CS-E 740(c)(4), if applicable, with bleed(s) in operation, require the use of a rotational speed less than the maximum without bleed (as permitted by CS-E 690(a)(1)(iii)), these Stages , or the equivalent demonstration, need not be included in the assessment of the mean rotational speed value, subject to agreement by the Agency.

(3)In the case of Engines incorporating free power-turbines, if the requisite periods are not run at the maximum power-turbine torque for which approval is sought, evidence of additional running will be required. This may be obtained from tests equivalent to the endurance test on a similar Engine, the endurance test Engine or the relevant parts of it. In all such additional running the appropriate periods must be run at the maximum rotational speed for which approval of the maximum torque is required.

(4)Temperatures.

(i)All periods of the test corresponding to a rating to be approved must be run at the appropriate maximum turbine entry temperature for this rating unless otherwise agreed. The means of achieving this (e.g. by adjustment of the nozzle areas, the use of bleed) must be justified.

(ii)In the case of the alternate test specified in CS-E 740(c)(4), the TCDS-declared EGT operating limits temperatures for MTO and MCT will be determined by analysis upon completion of the test and are established as the lower of the following values: (A) Values no greater than the EGT values demonstrated in the EGT operating limits demonstration as per CS-E 740(c)(4)(iv)(3); (B) Derived EGT values for MTO and MCT for which the severity demonstration for the entire test can be shown to have cumulative severity, for the critical component, greater than or equal to the reference severity. Depending on the option chosen in CS-E 740(c)(4)(v), EGT values used in this analysis will be either the turbine gas path temperature established during the test or the gas path temperature that corresponds to the maximum critical component temperature.

(iii)In general, essentially the average of the maximum temperatures achieved during the appropriate periods of the test will be utilised to establish the operating limitations of temperature for the Engine. The average EGTs will be reduced, however, by the amounts necessary to ensure that the turbine entry temperatures in flight do not exceed the turbine entry temperatures established by endurance test at the appropriate rating conditions. During the accelerations and short periods at Take-off Power, attempts must be made to run at maximum temperatures but if, owing to the unstabilised conditions, lower temperature readings are recorded, these need not be included in calculating the average.

(iv)Engines for Aeroplanes. Where the Engine characteristics are such that an acceleration from cold produces a transient over-temperature in excess of that for steady state running, a maximum EGT operating limit for acceleration with a time limitation of either up to 30 seconds or up to 2 minutes may be approved. (A) In the case of the classic endurance test, transient EGT operating limits may be approved as specified in CS-E 740(f)(5). (B) In the case of the alternate endurance test specified in CS-E 740(c)(4), transient EGT operating limits may be approved as specified in CS-E 740(f)(5). (C) Approval for short-period transient conditions at 2½-Minute OEI Thrust or Power will not be considered and any temperature clearance required must be demonstrated normally during the 2½-Minute OEI periods of the endurance test.

(v)Engines for Rotorcraft. Where the Engine characteristics are such that an acceleration from cold produces a transient over-temperature in excess of that for steady state running, a maximum EGT operating limit for acceleration with a time limitation of 2 minutes may be approved by running at the required temperature for the first 2 minutes of each prescribed period at Take-off Power conditions in excess of 2 minutes (and for the whole of all the 30-second Take-off Power periods for single-engined rotorcraft). Approval for short period transient conditions at 2½- Minute OEI Power will not be considered, and any temperature clearance required must be demonstrated normally during the endurance test.

(vi)For all Take-off Power/Thrust periods of 5 minutes or greater, 5 minutes must be run at the maximum oil inlet temperature declared for the condition, with the remainder of each 30-minute period at Take-off Power/Thrust being run at the normal oil temperature for take-off. If a 10-minute Take-off Power/Thrust Rating is sought, then 10 minutes of each 30-minute period at Take-off Power/Thrust must be run at the maximum oil temperature. For all MCT Power/Thrust periods 30 minutes must be run at the maximum oil inlet temperature declared for the condition, the remainder of each 1½ hour period at MCT Power/Thrust being run at the normal oil temperature for climb/cruise.

(vii)Where necessary to cater for short-duration rise of indicated oil temperature under service conditions above the maximum established during the endurance test such higher temperature may be approved as the Maximum Oil Temperature (with an appropriate time limitation) without additional endurance testing, provided that it can be demonstrated that –

(A)The temperature rise under service conditions is the result of a local increase in the oil temperature at the temperature sensing position (e.g. as may occur on reducing power at the top of the climb when fuel is used as the oil cooling medium),

(B)There is no significant increase in the maximum local temperature of either the Engine components or the oil in any Engine Critical Part, and

(C)There is no undue deterioration of the oil in such circumstances and no adverse effect on any system using the oil as a working fluid (e.g. Propeller control).

(5)

Transient Engine rotor shaft over-speed, transient Engine exhaust gas over-temperature and transient Engine over-torque limit approval.

Under certain operating conditions, for instance following acceleration to a required rated thrust or power condition, rotorcraft and aeroplane turbine Engines may systematically experience transient rotor shaft speed, exhaust gas temperature, or torque excursions exceeding the steady state operating values for that rating.

Such transients are predictable and constitute an inherent characteristic of the Engine (inadvertent transients are addressed separately by CS-E 820, CS-E 830 and CS-E 870).

For normal ratings, maximum operating limits for transients with a time limitation of either up to 30 seconds or up to 2 minutes may be approved if requested by the applicant.

For OEI ratings, maximum operating limits for transients with a time limitation of 10 seconds may be approved.

(i)

If the number of occurrences:

(A)of up to 30 seconds of either transient rotor shaft over-speed, transient exhaust gas over-temperature or transient over-torque; or

(B)of up to 2 minutes of transient exhaust gas over-temperature is limited during in-service operation, that number of the accelerations required by paragraphs (c)(1) to (c)(4) of CS-E 740 must be performed at the over-speed, over- temperature or over-torque limits.

(ii)

If the number of occurrences:

(A)of up to 30 seconds of either transient rotor shaft over-speed, transient exhaust gas over-temperature or transient over-torque; or

(B)of up to 2 minutes of transient exhaust gas over-temperature is not limited during in-service operation,

(C)in the case of the classic endurance test, transient operating limits may be approved as follows:

for up to 30 seconds transient approval, by running the Engine at the required over-speed, over-temperature or over-torque limit for the required time limitation of 50 % of the prescribed periods at Take-off

Thrust or Power conditions following an acceleration;

for up to 2 minutes transient approval, by running the Engine at the required over-temperature for the required time limitation of each prescribed period at Take-off Thrust or Power conditions for 5 minutes or longer, and throughout all the 30-second periods at Take-off Thrust or Power following an acceleration;

(D)in the case of the alternate endurance test specified in CS-E 740(c)(4), transient operating limits may be approved as follows:

transient operating limits of up to 30 seconds may be approved by running the Engine at the required temperature for the required time limitation as part of at least 155 periods at Take-off Thrust or Power conditions following an acceleration;

transient EGT operating limits of up to 2 minutes may be approved by running the Engine at the required temperature for the required time limitation as part of at least 310 periods at Take-off Thrust or Power conditions following an acceleration.

(iii)

The Engine hardware configuration must not be altered for the sole purpose of justifying transients as part of the endurance test.

(g)Incremental Periods.

(1)If a significant vibration response is found to exist on relevant components in the course of establishing compliance with CS-E 650 at any condition within the operating range of the Engine (not prohibited under CS-E 650(f)), not less than 10 hours, but not exceeding 50 %, of the incremental periods of Part 4 in CS-E 740(c)(1), (2) or (3) of the endurance test, or CS-E 740(c)(4)(vii) of the alternate endurance test, if applicable, must be run with the rotational speed varied continuously over the range for which vibrations of the largest amplitude were disclosed by the vibration survey; if there are other ranges of rotational speed within the operational range of the Engine where approximately the same amplitude exists, a further 10 hours must be run in the same way for each such range. The speed variation must be effected by automatic means using a method acceptable to the Agency. (See AMC E 740(g)(1))

(2)In the case of Engines operating at constant speed, the thrust and/or power may be varied in lieu of speed, in Part 4 of the endurance test.

(3)In the case of free power-turbine Engines, the normal operating range of power-turbine speed must be covered. This may be run concurrently with the range of gas generator speed.

(4)In the case of a free power-turbine Engine for Rotorcraft, 10 minutes of Part 4 in each stage of the endurance test must be run at the Maximum Power-turbine Speed for Autorotation with the gas generator producing the most critical conditions associated with this flight configuration.

(h)Engine Performance Target after Test Completion. After completion of the endurance test, the Engine must be able to provide the rated thrust or power levels without exceeding operating limitations.

(i)Inspection Checks

(1)After completion of the test, the Engine must be subject to a strip inspection, and the dimensions measured in accordance with CS-E 740(b)(5) must be re-measured and recorded. The condition of the Engine must be satisfactory for safe continued operation. Separately functioning Engine components and equipment must be functionally checked prior to strip to ensure that any changes in function or settings are satisfactory for normal operation.

(2)Engines with 30-Second and 2-Minute OEI Power ratings must be subjected to a full strip inspection after completing the additional endurance test of CS-E 740(c)(3)(iii). (See AMC E 740(i)(2))

(i)If the Engine was not subjected to a strip examination before commencing the additional endurance test, then the strip inspection specifications of CS-E 740(i)(1) apply on completion of the test.

(ii)If it is proposed to subject the Engine to a strip examination before commencing the additional endurance test, the Engine must be reassembled using the same parts used during the 150 hours test run, except those parts described as consumable in the Engine documentation.

(iii)After this additional endurance test, the Engine may exhibit deterioration in excess of that permitted in CS-E 740(i)(1), and it is accepted that some Engine parts may be unsuitable for further use. It must be shown by inspection, analysis and/or test, or by any combination thereof, that the structural integrity of the Engine is maintained.

[Amdt No: E/1]

[Amdt No: E/4]

[Amdt No: E/5]