Minimum Operational Performance Specification for Inflight Icing Detection Systems
This document contains Minimum Operational Performance Specification (MOPS) of ACTIVE on-board INFLIGHT Icing Detection Systems (FIDS). This MOPS specifies FIDS Operational Performance which is the minimum necessary to satisfy regulatory requirements for the design and manufacture of the equipment to a minimum standard and guidance towards acceptable means of compliance when installed on an AIRCRAFT.</p> <p>Detection of ICE accreted on the AIRCRAFT during ground operations is not considered in this document. This MOPS was written for the use of FIDS on AIRCRAFT as defined in 1.3 and 2.3; Expected minimum performance specifications for FIDS and their FUNCTIONS are provided in Section 3; The minimum performance requirements as defined in Section 3 do not consider SYSTEM performance as installed on the AIRCRAFT. Performance in excess of the minimum performance may be required by the SYSTEM installed on an AIRCRAFT in order to meet regulatory or operational requirements. This topic is considered in Section 6.
Rationale: Revision of AS5498A to:
- correct the identified editorial and technical errors and add some clarifications in the Appendix A1.1 of the document:
o TECHNICAL : on the value of the Thermal Diffusivity
o TECHNICAL : Correct an error in the Discrimination Time calculation formula used in the spreadsheet to generate data of the requirements tables.
o CLARIFICATIONS: Clarify the default value of the surface temperature (Tsurf) and indicate the default value of the barometric pressure to be used.
- Address and resolve the impacts of the corrections on the document (e.g. updated requirements in the test matrix tables).
PLEASE NOTE Some discrimination time values given in revision A (AS5498A) of the document either for Aircraft or Rotorcraft are too long and do not correspond to the requirements of the equation stated. However, as this document is considered guidance material rather than certification requirements, and the current revision requires confirmation of the acceptable discrimination time with the aircraft manufacturer prior to certification, this is not considered to be a safety issue. Revision B (AS5498B) of the document is under development to correct these issues and is expected to be available by the end of 2021..