GENERAL
(a)The fuel/energy scheme and, in particular, the final fuel/energy reserve and the additional fuel/energy depend on the certified minimum performance (CMP) of the VCA, established by considering the effect of single failures and combinations of failures that are not extremely improbable on the nominal performance parameters. For some VCA designs, a failure or a combination of failures in the fuel/energy system may lead to the most detrimental effect on the aircraft range during cruise phase. Such failure(s) would then become, for the respective flight phase and performance parameter, the critical failure for performance (CFP). The CFP affects the aircraft systems and CSFL ability. The CFP considers all types of failures that are not extremely improbable. Critical failures may be different per flight phase and performance parameter.
(b)The CMP and CFP are defined in Annex I — definitions (133) and (135) respectively. Definitions of the CMP and CFP are also included in MOC VTOL.2000. The CMP is established during type certification, similarly to Category A helicopter’s performance. Failures to be considered have been adapted for VCA, to be able to accommodate an arbitrary number of lift/thrust units and other systems affecting CSFL.
(c)The goal of the fuel/energy scheme is to ensure that a flight can be conducted safely; in particular, that the VCA can reach the selected vertiport(s), diversion location(s) or VEMS operating site(s). For VCA that use conventional fuel for propulsion, this depends primarily on the quantity of fuel on board, while for VCA with electric propulsion it may be other factors that are critical, e.g. component temperature limitations following a CFP. For some configurations, it is likely that the VCA has plenty of remaining energy after a CFP but cannot reach a vertiport or a diversion location on a particular day because the energy is not accessible, e.g. in the case of component overheat. The CMP data allows the operator to plan the range of the VCA if affected by the CFP, as well as other flight parameters such as rate of climb, thus assessing the suitability of vertiports, diversion locations or VEMS operating sites along the route before each flight.