ISA
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@jmarkows Yes, ISA temp is -50
So what that's saying is that the ISA standard temperature is -50C. You want the difference between OAT and ISA (if ISA shows -50C and OAT is -40C, you want the ISA+10 table for example). The tables will give you OAT and IOAT also that you can use to double check, the values should line up.
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Yeah ISA on this plane isn't displayed in this plane like on most. Airbus for example will take the difference between ISA and OAT and display THAT, as ISA. In this plane it seems to display what ISA should be and you have to take the OAT (not the IOAT, which to me seems more like TAT) and that ISA value to find the correct performance table to use
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Yeah ISA on this plane isn't displayed in this plane like on most. Airbus for example will take the difference between ISA and OAT and display THAT, as ISA. In this plane it seems to display what ISA should be and you have to take the OAT (not the IOAT, which to me seems more like TAT) and that ISA value to find the correct performance table to use
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@jmarkows Yes, ISA temp is -50
So what that's saying is that the ISA standard temperature is -50C. You want the difference between OAT and ISA (if ISA shows -50C and OAT is -40C, you want the ISA+10 table for example). The tables will give you OAT and IOAT also that you can use to double check, the values should line up.
@Kaaplink Is that the order? (ISA - OAT), or does it not matter?
Tks!
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It's simply the difference between ISA and OAT. You will come up with either a + or a - difference from ISA. With that you enter the tables. Say you're at FL370. Either the POH (ISA Power setting table) or the aircraft will tell you that ISA is -57°C. Now check you're OAT (IOAT). If your OAT is -47°C, then you're at ISA+10 (10°C warmer).
Caution against comparing IOAT value on the instrument against the table value. This value changes with speed, and as your power setting is not set yet, the difference in values might differ as you try to set the power setting.
