3.1.1 Engine operation on board under a specified
test cycle may not always be possible, but the test procedure, as
approved by the Administration, should be as close as possible to
the procedure defined in the NOx Technical Code, paragraph
3.2.
3.1.2 Regarding the E3 test cycle, if the actual
propeller curve differs from the E3 curve, the load point used should
be set using the engine speed, or the corresponding mean effective
pressure (MEP) or mean indicated pressure (MIP), given for the relevant
mode of that cycle.
3.1.3 If the number of measuring points on-board
is different from those on the test bed, the number of measurement
points and the weighting factors should be approved by the Administration.
3.1.4 Regarding the E2/E3/D2 test cycles, a minimum
of load points should be used of which the combined nominal weighing
factor, as given in the NOx Technical Code, paragraph
3.2, is greater than 0.50.
3.1.5 Regarding the C1 test cycle, a minimum number
of one load point should be used from each of the rated, intermediate
and idle speed sections.
3.1.6 If the number of measuring points on board
is different from those on the test bed, the nominal weighting factors
at each load point should be increased proportionally in order to
sum to unity (1.0).
3.1.7 An example of the selection of load points
and revised weighting factors are given in appendix 2.
3.1.8 The actual load points used to demonstrate
compliance should be within ± 5% of the rated power at the
modal point except in the case of 100% load where the range should
be +0 to - 10%. For example, at the 75% load point the acceptable
range should be 70% - 80% of rated power.
3.1.9 At each selected load point, except idle,
and after the initial transition period (if applicable), the engine
power should be maintained at the load set point within a 5% coefficient
of variance (%C.O.V.) over a 10-minute interval. A worked example
of the coefficient of variance calculation is given in appendix 3.
3.1.10 Regarding the C1 test cycle, the idle speed
tolerance should be declared, subject to the approval of the Administration.