windshear
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Stable T/O EPR Before TO/GA Press On B747-400?

Mon Nov 30, 2009 8:04 am

Dear Aviation experts...

What EPR thrust setting do the pilots spool up to before pressing TO/GA on aircraft with PW/RR engines?

I know that on GE engines aircraft this value is 70% N1.

Boaz.
"If you believe breaking is possible, believe in fixing also"-Rebbe Nachman
 
airbuster
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RE: Stable T/O EPR Before TO/GA Press On B747-400?

Mon Nov 30, 2009 9:35 am

RR TAY: 1.3 EPR, it's more or less 70% N1

I don't know about the RB211 but guess it'll be somewhat the same.

rgds

AB
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747classic
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RE: Stable T/O EPR Before TO/GA Press On B747-400?

Mon Nov 30, 2009 10:36 am

PW 4000 engines on MD11 need 1.1 EPR , before engaging TO/GA.

Ref : FCOM2 MD11.

Regards Peter.

[Edited 2009-11-30 02:37:22]
Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
Bellerophon
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RE: Stable T/O EPR Before TO/GA Press On B747-400?

Mon Nov 30, 2009 11:25 am

Windshear

...What EPR thrust setting do the pilots spool up to before pressing TO/GA on aircraft with PW/RR engines?...

For a B747-400 with RB211 engines, my airline requires the engines to be stable at 1.20 EPR (roughly 60% N1) prior to pressing TOGA.

Best Regards

Bellerophon
 
windshear
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RE: Stable T/O EPR Before TO/GA Press On B747-400?

Mon Nov 30, 2009 12:04 pm



Quoting Bellerophon (Reply 3):
For a B747-400 with RB211 engines, my airline requires the engines to be stable at 1.20 EPR (roughly 60% N1) prior to pressing TOGA.

Very nice thanks... Now all I need is the info on the PW engined 747-400. perhaps it is the same?

Boaz.
"If you believe breaking is possible, believe in fixing also"-Rebbe Nachman
 
jayeshrulz
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RE: Stable T/O EPR Before TO/GA Press On B747-400?

Mon Nov 30, 2009 2:26 pm

Sorry but what is EPR?
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airbuske
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RE: Stable T/O EPR Before TO/GA Press On B747-400?

Mon Nov 30, 2009 2:40 pm



Quoting Windshear (Reply 4):
Very nice thanks... Now all I need is the info on the PW engined 747-400. perhaps it is the same?

Hello Windshear,

According to NW B747-400 AOM Volume I, TO/GA switch is to be pushed at 1.1EPR by 50 KIAS. Above 50 KIAS, autothrottle engagement is inhibited until the aircraft is above 400 feet AGL.

Hope it helps.

Jinal
 
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747classic
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RE: Stable T/O EPR Before TO/GA Press On B747-400?

Mon Nov 30, 2009 3:04 pm



Quoting Jayeshrulz (Reply 5):
Sorry but what is EPR?

At present, the thrust of an engine in flight can not be measured. As a result, one has to resort to other measurable variables that represent the thrust.
In the real world they use two variables for that : EPR or N1, depending on manufacturer.
EPR = Engine Pressure Ratio
This is the ratio of turbine exit to compressor inlet pressure and this is used to measure the thrust of a jet engine.(P&W , RR )
Another way to measure the thrust is via the low pressure rotor speed N1 (GE).

Both methods have their advantages and disadvantages and are applied at the preference of the manufacturer.

Quoting Windshear (Reply 4):
Now all I need is the info on the PW engined 747-400. perhaps it is the same?

IMO all PW 4000 engines (as also installed at the 747-400) have to be at or above 1.1 EPR and stabilized before engaging the TO/GA switch.
I checked this with the MD11/PW 4462 and the B767-300ER/PW 4062 .
I am searching for the 747-400/PW 4056 in my library, but couldn't find it (yet).
Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
PGNCS
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RE: Stable T/O EPR Before TO/GA Press On B747-400?

Mon Nov 30, 2009 3:28 pm



Quoting 747classic (Reply 7):
Quoting Windshear (Reply 4):
Now all I need is the info on the PW engined 747-400. perhaps it is the same?

IMO all PW 4000 engines (as also installed at the 747-400) have to be at or above 1.1 EPR and stabilized before engaging the TO/GA switch.

Have flown the 744 and 767 with PW 4000 series engines, and in our procedures 1.1 EPR was set by hand, then TOGA (in 744, on throttles) or EPR (in 767) switch pushed.
 
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CCA
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RE: Stable T/O EPR Before TO/GA Press On B747-400?

Mon Nov 30, 2009 10:26 pm

We use both PW and RR on the 744 and we set 1.1 EPR for both prior to pressing the TOGA switch.
P1 in A330, A340, A346, B742, B744, B748.
 
tdscanuck
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RE: Stable T/O EPR Before TO/GA Press On B747-400?

Tue Dec 01, 2009 3:08 am



Quoting 747classic (Reply 7):
In the real world they use two variables for that : EPR or N1, depending on manufacturer.
EPR = Engine Pressure Ratio

There are two others...THR and TPR.

TPR (Turbofan Pressure Ratio) is what RR uses on the 787...it's like a normalized EPR.

THR is what Airbus has on the A380 and, as I understand it, is basically current thrust as a % of max thrust in the current mode.

Tom.
 
ex52tech
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RE: Stable T/O EPR Before TO/GA Press On B747-400?

Tue Dec 01, 2009 5:32 am



Quoting 747classic (Reply 7):

This is the ratio of turbine exit to compressor inlet pressure and this is used to measure the thrust of a jet engine.(P&W , RR )
Another way to measure the thrust is via the low pressure rotor speed N1 (GE).

Just an FYI here, but GE did offer "optional" EPR, but it was strictly a reading of exhaust pressure, and it was much higher than what you guys are used to, T.O. would be in the neighborhood of 8.0 to 9.0 EPR. Most carriers used it as an advisory system to troubleshoot problems not as a means to set power for flight.
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windshear
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RE: Stable T/O EPR Before TO/GA Press On B747-400?

Tue Dec 01, 2009 5:44 pm

So PW is set to 1.1 and RR are set to 1.2?

I thought I saw RR set to 1.17 or 1.18 in an aviation video, but you all helped me.

Boaz.
"If you believe breaking is possible, believe in fixing also"-Rebbe Nachman

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