CS 25J1093 Air intake system icing protection
ED Decision 2016/010/R
(See AMC 25J1093)
(a) Each
non-essential APU air intake system, including any screen if used, which does
not comply with CS 25J1093(b) will be restricted to use in non-icing
conditions, unless it can be shown that the APU complete with air intake
system, if subjected to the icing conditions, defined in
Appendices C, O and P will not affect the safe operation of the
aeroplane.
b) For
essential APUs:
Each essential APU, with all icing protection
systems operating, and screen if used, must:
(1) operate
throughout its flight power range in the icing conditions defined in
Appendices C, O and P, and in falling and blowing snow within the limitations
established for the aeroplane for such operation, without the accumulation of
ice on the APU, air intake system components or airframe components that would
do any of the following:
(i) Adversely
affect installed APU operation or cause a sustained loss of power; or an
unacceptable increase in gas path operating temperature; or an airframe/APU
incompatibility; or
(ii) Result
in unacceptable temporary power loss or APU damage; or
(iii) Cause a
stall, surge, or flameout or loss of APU controllability (for example,
rollback).
(2) operate for a minimum of 30 minutes on the ground in the icing conditions shown in Table 1 of CS 25.1093(b)(2), unless replaced by similar test conditions that are more critical. These conditions must be demonstrated with the available icing protection (if applicable) at its critical condition, without adverse effect. The applicant must document the APU minimum ambient temperature demonstrated, if any, and establish the aeroplane operating limitations. (See AMC 25J1093(b))
[Amdt 25/1]
[Amdt 25/16]
[Amdt 25/18]