This requirement applies to an operator who must comply with Subpart 121.Z of CASR and is not taking advantage of EX74/24 (formerly EX97/22).
Other requirements for engine trend monitoring systems apply to aeroplanes classified as a prescribed single-engine aeroplane (PSEA). You can find these under regulation 135.240 of CASR due to Appendix 2 of Civil Aviation Order 100.5.
You must fit your aeroplane with an automatic electronic condition trend monitoring system for the engine if you are both:
- conducting a VFR flight by day
- carrying more than 9 passengers.