Go around thurst and MCT
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If it's the same thrust as TO (its sometimes called TOGA) then the same limitations will apply.
If its a different rating then the manual should give limitations.
I find it hard to believe anyone's using MCT as their go-around thrust, since it's leaving performance 'on the table'.
If its a different rating then the manual should give limitations.
I find it hard to believe anyone's using MCT as their go-around thrust, since it's leaving performance 'on the table'.
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Your theory sounds very simple and logical. However, we sit in the cruise scratching our heads over the fact that on the ThrustLimit page on the FMS our cruise N1 is higher than MCT N1....
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In such circumstances I suggest you check the Powerplant Limitations section of your Flight Manual and regard that as authoritative. If it says Max Continuous is below the supposed cruise N1, I'd be reluctant to go above the book MCT, without knowing a lot more.... wouldn't be the first malprogrammed FMS.
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It depends on your engine. RR suggests that for the Tay 620/650 (when fitted on Fokkers) that the TOGA thrust can be used for 5 minutes N=2 and 10 minutes for N-1 and MCT is exactly what it says on the tin.
PM
PM
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Oh, we've done that; it says see ThrustLimit page in FMS!! More interesting is it adds a caveat that FMS figures are only valid if two ADC's are functional, but gives no advice on setting cruise thrust if you lose an ADC. Good game!
To answer the original question though, on my aircraft the answer is - it depends. Since we have flat rated engines GA N1 may or may not take the temps over the normal limit. If they don't, then there is no limit. If they do then we are time limited
To answer the original question though, on my aircraft the answer is - it depends. Since we have flat rated engines GA N1 may or may not take the temps over the normal limit. If they don't, then there is no limit. If they do then we are time limited
ECON cruise, LR cruise...
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Guess your CRZ is higher than GA as per FMC N1 LIMIT page during cruise because CRZ is calculated as per actual conditions, and GA is calculated based upon landing field elevation + parameters entered on the DES FCST page.
Try the same exercise on the ground and enter a low level as your cruise altitude - that should produce a CRZ N1 well below the GA limit.
If not - 
Try the same exercise on the ground and enter a low level as your cruise altitude - that should produce a CRZ N1 well below the GA limit.
If not -
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Raw N1 (physical rpm) isn't a useful number for comparing performance in widely different conditions (cruise vs airfield elevation & temp).
A performance guy/gal could correct these values back to standard day conditions and give you a rational basis for your observation. Good question to ask the OEM - and you may not be the first to ask the question.
A performance guy/gal could correct these values back to standard day conditions and give you a rational basis for your observation. Good question to ask the OEM - and you may not be the first to ask the question.
I find it hard to believe anyone's using MCT as their go-around thrust, since it's leaving performance 'on the table'.
