Embraer EICAS question
Thread Starter
Join Date: Apr 2007
Location: Poland
Posts: 20
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?
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?
Join Date: Jan 2009
Location: Cab of a Freight Train
Age: 37
Posts: 635
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.
Thread Starter
Join Date: Apr 2007
Location: Poland
Posts: 20
Originally Posted by KRviator
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.
Join Date: Jan 2013
Location: Seattle Area
Posts: 250
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.
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.
Join Date: Oct 2009
Location: Australia the Awesome
Posts: 261
Originally Posted by Zorro_PL
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?
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?
So at that point, the limit mark will change from RED (absolute max) to Amber, max CON (max for climb/cruise/descent)
Join Date: Jan 2013
Location: Seattle Area
Posts: 250
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.
