CS-E 880  Tests with Refrigerant Injection for Take-Off and/or 2½-Minute OEI Power

ED Decision 2003/9/RM

(a)     Engines for Rotorcraft. The variation of the tests prescribed in this subpart E when using refrigerant injection must be agreed in consultation with the Agency.

(b)     Engines for Aeroplanes. Refrigerant Injection Used to Increase ISA Take-off and/or 2½-Minute OEI Performance. The following variations to the tests prescribed in this subpart E must be made:

(1)     Calibration Tests. (See CS-E 730). Add a calibration with refrigerant injection to demonstrate that the predicted power/thrust output will be achieved at the conditions demanding maximum refrigerant flow for each rating. This additional calibration may be made on a separate Engine if desired.

(2)     Endurance Test (See CS-E 740(c)). Run all normal Take-off periods (and/or 2½-Minute OEI if applicable) of Part 1 of each of the stages with refrigerant injection to achieve a mean refrigerant flow rate of at least 50% of the maximum, whilst maintaining at least the minimum declared power/thrust output and maximum declared turbine entry temperature.

(3)     Accelerations (See CS-E 740(c) and (d)). All the appropriate accelerations of Part 1 of each of the stages must be made with refrigerant injection selected.

(4)     Idle conditions used for power orthrust response (See CS-E 745). The idle conditions appropriate to the use of maximum refrigerant injection flow, as well as without, must be established.

(5)     Over-speed Test (See CS-E 830). Two Over-speeds will need to be declared if the Take-off maximum rotational speed with refrigerant injection differs from the Take-off maximum rotational speed without refrigerant injection. Only an Over-speed test with refrigerant injection need be run if all the critical conditions are more severe with refrigerant injection, than without. The 15-minute Over-speed test with refrigerant injection need not be run non-stop, but the duration of the individual periods of running at this condition must be not less than 3 minutes.

(c)      Engines for Aeroplanes. Refrigerant Injection Used to Restore ISA Take-off and/or 2½-Minute OEI Performance at Higher Ambient Temperature. The following variations to the tests prescribed in this subpart E must be made:

(1)     Calibration Tests. (See CS-E 730). Add a calibration with refrigerant injection to demonstrate that the predicted power/thrust will be achieved at the maximum declared air intake temperature whilst running within the appropriate operating limitations. This additional calibration may be made on a separate Engine if desired.

(2)     Endurance Test (See CS-E 740(c)). Run all the Take-off periods of Part 1 of any 10 of the stages with refrigerant injection to achieve a mean refrigerant flow rate of at least 50% of the maximum, whilst maintaining at least minimum declared power/thrust output and maximum declared turbine entry temperature. If a 2½-Minute OEI Rating is also sought then all the Take-off and 2½-Minute OEI periods of Part 1 in stages 3 to 12 must be run as above.

(3)     Accelerations (See CS-E 740(c) and (d)). All the appropriate accelerations of Part 1 of each of the 10 required stages must be made with refrigerant injection selected.

(4)     Idle conditions used for power or thrust response (See CS-E 745). The idle conditions appropriate to the use of maximum refrigerant injection flow, as well as without, must be established.

(5)     Over-speed (See CS-E 830). Run either without refrigerant injection at the ambient air intake temperature or with refrigerant injection with the air intake temperature raised to the highest sea-level temperature at which refrigerant is to be used, depending on which involves the more severe running conditions. If the test is run with refrigerant injection, the 15-minute period need not be run non-stop, but the duration of the individual periods of running at this condition must be not less than 3 minutes. The test may be run, if desired as part of the endurance test. Alternatively, test evidence from an Engine of similar design may be provided.