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Embraer EICAS question

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Embraer EICAS question

Old 26th Dec 2020, 21:57
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Embraer EICAS question

Hi folks and Merry Christmas,

can somebody explain to me what ITT RED/AMBER LINE indicates? (Number 12).


AOM says that is maximum allowable ITT for the current phase.

Additionally that “red line change to amber after end of the takeoff phase. The red line will be shown in flight if the ITT goes above the CON thrust rating limit.”

I am confused.

During takeoff run there is RED line then before V1 disappears and AMBER line appears (with higher value).

Then AMBER line stays for whole flight.

But what does it show really?


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Old 26th Dec 2020, 23:20
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Certainly not rated on it, but my interpretation of what you have written is RED during takeoff as during that phase you can use full rated thrust, so your ITT limit will correspond to that thrust limit. However, after takeoff, you can "only" use MCT, which will have a lower ITT limit, hence the amber radial line - because the MCT ITT limit is not the max rated ITT limit. If you go above the MCT ITT limit, then your "next" limit becomes the max rated ITT limit, shown by the red line.
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Old 27th Dec 2020, 00:45
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It's not uncommon for engines to have a slightly higher Max EGT/ITT limit for a five (or ten) minute Takeoff rating than for continuous operation.
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Old 27th Dec 2020, 06:27
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It means "don't go any higher than that".
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Old 27th Dec 2020, 12:32
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Originally Posted by KRviator View Post
Certainly not rated on it, but my interpretation of what you have written is RED during takeoff as during that phase you can use full rated thrust, so your ITT limit will correspond to that thrust limit. However, after takeoff, you can "only" use MCT, which will have a lower ITT limit, hence the amber radial line - because the MCT ITT limit is not the max rated ITT limit. If you go above the MCT ITT limit, then your "next" limit becomes the max rated ITT limit, shown by the red line.
Yeah it does make sense what you wrote but lines appears in opposite - RED lower limit during roll and in second phase of takeoff AMBER appears but with higher limit.
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Old 28th Dec 2020, 02:45
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I assume you are asking about a 190 variant with CF34 engines. The following is based on a general understanding of propulsion systems and not based on being especially knowledgeable about the 190.

That engine has a “normal” takeoff rating and egt limit, and a “max” takeoff rating and egt limit. Notice the green “ATTCS” (automatic takeoff thrust control system) indication at the top of the display. That indicates the activation of a feature that automatically pushes the power on the remaining engine up to the max takeoff rating if an engine fails. Prior to V1, the egt display shows the red line for the normal takeoff rating. You would abort if egt exceeded this limit prior to v1. After v1 you would continue if an engine exceeded the egt limit, ATTCS would increase the thrust on the remaining engine to the max takeoff rating, and the egt limit after v1 would initially be the max takeoff egt limit. After 5 minutes (or after exiting the engine control's takeoff rating envelope, whichever occurs first) the egt limit would be lowered to the max continuous limit. As the OP noted, the normal takeoff egt limit for some engine models is lower than the max continuous egt limit.

I don’t know the 190 display system philosophy behind the line being amber rather than red. The approved egt exceedance times for the engine are very short, but maybe the display goes red if an exceedance lasts longer than the approved few seconds.

I would suggest consulting an approved training source to understand detailed, model-specific powersetting procedures, engine limits, ATTCS, and displays.

Last edited by Dave Therhino; 28th Dec 2020 at 04:18.
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Old 28th Dec 2020, 05:03
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Originally Posted by Zorro_PL View Post
Hi folks and Merry Christmas,

can somebody explain to me what ITT RED/AMBER LINE indicates? (Number 12).


AOM says that is maximum allowable ITT for the current phase.

Additionally that “red line change to amber after end of the takeoff phase. The red line will be shown in flight if the ITT goes above the CON thrust rating limit.”

I am confused.

During takeoff run there is RED line then before V1 disappears and AMBER line appears (with higher value).

Then AMBER line stays for whole flight.

But what does it show really?
It’s been 10 years since I’ve flown one, but the Take off phase ends at 1000ft AAH when the PM presses FLCH and starts the flap retraction schedule.

So at that point, the limit mark will change from RED (absolute max) to Amber, max CON (max for climb/cruise/descent)
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Old 28th Dec 2020, 16:58
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Dave - you hit the point. I dived again into this subject and came to the same conclusions today.
PS. But you made interesting note about ATTCS.

Thanks also to Roj for your few cents
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Old 28th Dec 2020, 18:04
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My knowledge of ATTCS comes from knowing the FAA rules and policy for it, and from being familiar with some of the earlier implementations like the 727, which had earlier avionics. What I described may not be fully accurate for a modern implementation, particularly with respect to FMC and display functions.
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