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jfkflyer
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Takeoff Thrust options

Thu Dec 22, 2016 11:02 pm

What options are there for Airbus? Boeing? Embraer? Canadair/bombardier?

From what I understand there is only
TOGA
FLEX
FULL THROTTLE


Whats is the difference between TOGA/FLEX? which one is more powerful? are they both found on the same aircraft make/model, or is it different by manufacturer?
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BravoOne
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Re: Takeoff Thrust options

Fri Dec 23, 2016 12:39 am

TOGA has nothing to di with thrust settings,

AT Assumed Temp
Flex
Normal
Bump Thrust

Are but a few power setting and depending on the engine/airframe combination there are a multitude of options. Full Throttle? I think that is some sort of drink?
 
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Starlionblue
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Re: Takeoff Thrust options

Fri Dec 23, 2016 1:03 am

Airbus 330 and 350 have the same three take-off thrust options. I assume they are the same on 320 family, 340 and 380.
- TOGA: Full thrust. 5 minutes maximum with all engines, 10 with an engine out.
- Flex: Assumed temperature thrust.
- Derate: Derated thrust.

Flex is set by entering a Flex value in the INIT B page. The Flex value represents the maximum temperature at which it is valid, e.g. F36 means it can be used up to 36 degrees. If you lose an engine on take-off, you can at any time set TOGA. However the performance calculation has allowed for an engine failure and you will climb out safely with Flex set.

Derate is used to lower the VMCG value, typically on short or contaminated runways, and is set by entering a Derate value in the INIT B page. If you lose an engine on take-off you should NOT set TOGA below F speed as you may exceed the lateral authority of the rudder.

For Flex or Derate, the thrust levers go to the MCT/FLX detent. For TOGA, they go to the TOGA detent.

Almost every take-off I've seen has been with Flex. None have been with derate.

A further option if you need more performance is to turn the packs off on a TOGA take-off.
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pilotkev1
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Re: Takeoff Thrust options

Fri Dec 23, 2016 1:27 am

Two normal modes on the ERJ-135/145LR/XR

- Alternate Takeoff (ALT T/O-1)
Automagically ensures the best engine durability and economy of operation, based on the inputs into the Takeoff Data section of the EICAS, which is set with a little knob on the overhead. ATTCS is active so that T/O-1 is triggered in case of engine failure
- Maximum Takeoff-1 (T/O-1)
Max takeoff power, only used when ALT T/O-1 is not authorized due to ambient takeoff conditions.

In the XR, AE-3007A1E engines has an Extended Takeoff (E-T/O) mode that is essentially a "bump thrust" option. This engages in the event of an engine failure in the XR.
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skyhawkmatthew
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Re: Takeoff Thrust options

Fri Dec 23, 2016 2:49 am

On the 777, we have a few different options as well, different names but more or less the same in principle as what Starlionblue described for the Airbus.

The first variation we can make is a fixed derate - TO1 or TO2. These are customer selectable, and at my company are 10 and 20%. These effectively reduce the "maximum output" of the engines, enabling lower speeds due to reduced VMCA and VMCG.

Having decided whether to use a fixed derate, we can then make a further "assumed temperature" thrust reduction on top of that, as long as the runway is not contaminated.

Pressing the TO/GA switches after lift-off will cancel all derates and thrust reductions. As Starlionblue mentioned, you must be careful if you are slow, as your original takeoff performance data was calculated with the derate applied so you could be flying too slow to maintain control with maximum thrust on one side.

Like on the Airbus, we can get a bit more performance by turning off the packs, or running APU-to-pack if we still require cabin cooling.

In addition, the GE90-115B has an extra "Bump" thrust setting that is only available in certain elevation and temperature conditions, and is essentially the opposite of a derate: a special "overboost" mode that gives you the full 115,000lb of thrust.
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Starlionblue
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Re: Takeoff Thrust options

Fri Dec 23, 2016 5:01 am

skyhawkmatthew wrote:
On the 777, we have a few different options as well, different names but more or less the same in principle as what Starlionblue described for the Airbus.

The first variation we can make is a fixed derate - TO1 or TO2. These are customer selectable, and at my company are 10 and 20%. These effectively reduce the "maximum output" of the engines, enabling lower speeds due to reduced VMCA and VMCG.

Having decided whether to use a fixed derate, we can then make a further "assumed temperature" thrust reduction on top of that, as long as the runway is not contaminated.

Pressing the TO/GA switches after lift-off will cancel all derates and thrust reductions. As Starlionblue mentioned, you must be careful if you are slow, as your original takeoff performance data was calculated with the derate applied so you could be flying too slow to maintain control with maximum thrust on one side.

Like on the Airbus, we can get a bit more performance by turning off the packs, or running APU-to-pack if we still require cabin cooling.

In addition, the GE90-115B has an extra "Bump" thrust setting that is only available in certain elevation and temperature conditions, and is essentially the opposite of a derate: a special "overboost" mode that gives you the full 115,000lb of thrust.


Very interesting thanks.

I see only one conceptual difference. On the 'bus we cannot use derate and flex together. It is one or the other.
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BravoOne
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Re: Takeoff Thrust options

Fri Dec 23, 2016 5:54 pm

Does the Bus have a Takeoff Bump?
 
Qantas744er
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Re: Takeoff Thrust options

Fri Dec 23, 2016 6:39 pm

skyhawkmatthew wrote:
On the 777, we have a few different options as well, different names but more or less the same in principle as what Starlionblue described for the Airbus.

The first variation we can make is a fixed derate - TO1 or TO2. These are customer selectable, and at my company are 10 and 20%. These effectively reduce the "maximum output" of the engines, enabling lower speeds due to reduced VMCA and VMCG.

Having decided whether to use a fixed derate, we can then make a further "assumed temperature" thrust reduction on top of that, as long as the runway is not contaminated.

Pressing the TO/GA switches after lift-off will cancel all derates and thrust reductions. As Starlionblue mentioned, you must be careful if you are slow, as your original takeoff performance data was calculated with the derate applied so you could be flying too slow to maintain control with maximum thrust on one side.

Like on the Airbus, we can get a bit more performance by turning off the packs, or running APU-to-pack if we still require cabin cooling.

In addition, the GE90-115B has an extra "Bump" thrust setting that is only available in certain elevation and temperature conditions, and is essentially the opposite of a derate: a special "overboost" mode that gives you the full 115,000lb of thrust.



The Thrust Bump option on the GE90-110B1L1 (B77L/F), and GE90-115B1L1 (B77W) is available between pressure altitudes of -2000ft and 3000ft and temperatures between 32C and 53C.

The full 115,300lbs are available at all times on the -300ER as are the full ~110,300lbs on the -200LR/F, up to the flat rating of 30C. The Thrust Bump adds another 2.5% ~2,890lbs, giving the -115B1L1 up to 118,200lbs of takeoff thrust (~113,100lbs on the -110B1L1). Naturally, each Bump application eats into the engines on wing time as the temps within the engines are higher when the option is selected for takeoff, up to thrust reduction height. (Reduction typically being 800 to 1500ft depending on operator).

The Thrust Bump is a Boeing/GE customer option ($$$). The major users are EK/CX/QR/EY. No need purchasing it, when you dont operate in the afromentioned environment. A non-thrust bump optioned GE90-110/115 is a -110B1/115B1, the L1 represents the Thrust Bump option. This is merely a FADEC3 software rating, and there is no hardware changes on the engine. It can be optioned at time of order, or at a later time when the engine is in service.

Note, the -115B1/-115B1L1 is a customer option on the B77L/F. The only customers I am aware of, are ET, QR, EU.
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77west
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Re: Takeoff Thrust options

Fri Dec 23, 2016 9:09 pm

I thought the GE90 thrust bump only increased the flat-rate temperature, not actually increased the certified max thrust?

It was explained on here a while back that below 30degC there is no effect from the bump, but it allows the engine to maintain the rated 110,300 or 115,300 thrust above the 30degC flat rate temp.

Yes, the engine will be spinning faster, and increase wear, but it is not actually providing more thrust?
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Francoflier
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Re: Takeoff Thrust options

Fri Dec 23, 2016 10:03 pm

I'm not sure either about these pressure altitude limits. Pretty much the only reason CX went for the thrust bump, for instance, is to operate out of JNB, which is much higher than 3000'...?
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77west
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Re: Takeoff Thrust options

Fri Dec 23, 2016 10:13 pm

Francoflier wrote:
I'm not sure either about these pressure altitude limits. Pretty much the only reason CX went for the thrust bump, for instance, is to operate out of JNB, which is much higher than 3000'...?


This is what I found: (Seems to confirm up to 3000ft)

http://www.flightglobal.com/news/articl ... 90-212144/

The TO-B option will not display on the CDU THRUST LIM page if the outside temp is less than about 32degC. I believe it will not show either above 3000ft, but I have only seen the first statement with my own eyes in a sim.
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Qantas744er
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Re: Takeoff Thrust options

Fri Dec 23, 2016 10:35 pm

Francoflier wrote:
I'm not sure either about these pressure altitude limits. Pretty much the only reason CX went for the thrust bump, for instance, is to operate out of JNB, which is much higher than 3000'...?
77west wrote:
Francoflier wrote:
I'm not sure either about these pressure altitude limits. Pretty much the only reason CX went for the thrust bump, for instance, is to operate out of JNB, which is much higher than 3000'...?


This is what I found: (Seems to confirm up to 3000ft)

http://www.flightglobal.com/news/articl ... 90-212144/

The TO-B option will not display on the CDU THRUST LIM page if the outside temp is less than about 32degC. I believe it will not show either above 3000ft, but I have only seen the first statement with my own eyes in a sim.


-2000 to 3000ft pressure altitude and 32 - 53C are straight out of the FCOM. PM me if you would like further info!

Thrust Bump does not change the 30C flat rating for the GE90-110B1L1/-115B1L1. It does however, increase thrust 2.5% (as mentioned in my previous post), beyond the 110,300/115,300lbs. It does so precisely by allowing the FADEC to temporarily increase the maximum EGT and thust allowing the maxium. N1 speed to be greater. End result being more thrust!

The price is increased wear/tear and reduced EGT margins over time. GE does require a sufficent EGT margin for the individual engine to have Thrust Bump enabled.

While the B77L/W FMC will not show you the new rating under Bump, the 737NG does.

On the CFM56-7E26, the standard TO rating is 26k lbs, and when you select TO-B, it is 27k lbs. The FMC on the 737NG does show the thrust for each available rating. TO-B 27k, TO 26k, TO-1 24k, TO-2 22k. Note: TO-B is of course a customer option ($$$).

AA is one of the operators that purchased the TO-B option. Their contract with the engine manufacturer, stipulates that it is only to be used at SNA.

Going back to the B77W, TO-B cannot be selected at JNB (it is blanked out in the FMC when outside of the FADEC envelope) due to the pressure altitude. CX does however make good use of it at LAX, HKG etc. for MTOW departures in the hot summer months.
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Qantas744er
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Re: Takeoff Thrust options

Sat Dec 24, 2016 12:35 am

77west wrote:
Francoflier wrote:
I'm not sure either about these pressure altitude limits. Pretty much the only reason CX went for the thrust bump, for instance, is to operate out of JNB, which is much higher than 3000'...?


This is what I found: (Seems to confirm up to 3000ft)

http://www.flightglobal.com/news/articl ... 90-212144/

The TO-B option will not display on the CDU THRUST LIM page if the outside temp is less than about 32degC. I believe it will not show either above 3000ft, but I have only seen the first statement with my own eyes in a sim.


Thinking about it, I do remember Boeing taking the first CX B77W to KCOS for some tests. It may very well be, that CX paid Boeing/GE to option a different/expanded Thrust Bump envelope for their B77W's.

Hopefully CX Flyboy can chime in!
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77west
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Re: Takeoff Thrust options

Sat Dec 24, 2016 1:25 am

Qantas744er wrote:
77west wrote:
Francoflier wrote:
I'm not sure either about these pressure altitude limits. Pretty much the only reason CX went for the thrust bump, for instance, is to operate out of JNB, which is much higher than 3000'...?


This is what I found: (Seems to confirm up to 3000ft)

http://www.flightglobal.com/news/articl ... 90-212144/

The TO-B option will not display on the CDU THRUST LIM page if the outside temp is less than about 32degC. I believe it will not show either above 3000ft, but I have only seen the first statement with my own eyes in a sim.


Thinking about it, I do remember Boeing taking the first CX B77W to KCOS for some tests. It may very well be, that CX paid Boeing/GE to option a different/expanded Thrust Bump envelope for their B77W's.

Hopefully CX Flyboy can chime in!


They did, and it was related to the TO-B but I can't seem to find the article. I do recall reading it though, years ago now.

The GE90 has a bit of reserve left in it; they did test it to 127,000lbf after all.

Something else no one has mentioned: Water injection! While not used on modern frames, this was used on certain JT9D (7Q?) models back in the early days of the 747.
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thegman
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Re: Takeoff Thrust options

Sat Dec 24, 2016 1:44 am

McDonnell Douglas C-17A:

Max = max power
DRT = derated thrust

Command guidance gives a preference of DRT for all takeoffs unless you cannot get good TOLD numbers.
 
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Starlionblue
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Re: Takeoff Thrust options

Sat Dec 24, 2016 3:17 am

BravoOne wrote:
Does the Bus have a Takeoff Bump?


I can't speak for all 'buses, but the Trent 772B on the 330 has a thrust bump, as indicated by the "B" in the designation. The plain vanilla Trent 772 has no "B".
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zeke
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Re: Takeoff Thrust options

Sat Dec 24, 2016 4:01 am

Qantas744er wrote:
Thinking about it, I do remember Boeing taking the first CX B77W to KCOS for some tests. It may very well be, that CX paid Boeing/GE to option a different/expanded Thrust Bump envelope for their B77W's.


CX did purchase the thrust bump.
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zeke
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Re: Takeoff Thrust options

Sat Dec 24, 2016 4:14 am

Starlionblue wrote:
I can't speak for all 'buses, but the Trent 772B on the 330 has a thrust bump, as indicated by the "B" in the designation. The plain vanilla Trent 772 has no "B".


The B & C are designed to achieve full thrust over a wider range of atmospheric/takeoff conditions whilst being transparent to the crew, from the TCDS.

"The Trent 772B-60 has the same ratings as the 772-60 except between 610 m (2,000 ft) and 2440 m (8,000 ft) altitude or when the ambient temperature is greater than ISA + 15ºC, where the 772B-60 produces increased thrust at take-off rating. The magnitude of this increase varies with altitude and ambient temperature and is limited to a maximum of 5.4%.

The Trent 772C-60 has the same ratings as the 772B-60 except at altitudes above 2440 m (8,000 ft) where the 772C can provide more thrust in both Take-Off and Continuous conditions. The extent of this thrust increase is dependent upon altitude, temperature and Mach number, but is limited to a maximum of 8.5%. From 3048 m (10,000 ft) to 4877 m (16,000 ft) there is a Take-Off thrust increase of 3% for day temperatures of ISA +28ºC and above, this reduces to 0% at ISA +18ºC and below. At altitudes greater than 3962 m (13,000 ft) and Mach numbers greater than 0.4 a further thrust increase results from maximum continuous thrust exceeding maximum Take-Off thrust, this increases the maximum Take-Off thrust below ISA +15ºC by a maximum of 5.0% relative to the Trent 772B-60 at 4877 m (16,000 ft), 0.5 Mn. Max Continuous thrust is increased by up to 8.5% relative to the Trent 772B-60 rating for altitudes between 4572 m (15,000 ft) and 7620 m (25,000 ft) for Mach numbers between 0.3 and 0.6 and temperatures from ISA to ISA +30ºC. "
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Chaostheory
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Re: Takeoff Thrust options

Sat Dec 24, 2016 5:31 am

BravoOne wrote:
Does the Bus have a Takeoff Bump?


Depends on which 'bus you're talking about.

A320 with older engines - yes
Some CF6-80 A330s depending on variant.

I think that's it for Airbus aircraft.

Qantas744er, your bump explanation is a little off.

The bump on the 77W does NOT increase thrust beyond the 115.3 rating. It does however restore thrust loss, up to 2.5%, due to higher temps.

Saudia has the 77W bump too.
 
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77west
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Re: Takeoff Thrust options

Sat Dec 24, 2016 6:05 am

Chaostheory wrote:
BravoOne wrote:
Does the Bus have a Takeoff Bump?

Qantas744er, your bump explanation is a little off.

The bump on the 77W does NOT increase thrust beyond the 115.3 rating. It does however restore thrust loss, up to 2.5%, due to higher temps.

Saudia has the 77W bump too.


This is what I thought; that the EGT MAX increase and spinning faster offsets the thrust loss from high ambiant temperatures. The actual produced max thrust remains 110,300 or 115,300 lbf. This is why below 32degC it is not used, as the engine is capable of producing these thrust ratings up to about 32degC. But with bump, it can hold the 110,300 or 115,300 a bit higher, which would benefit MTOW ops from hot and low places like DXB, LAX, but not hot and high DEN or JNB.
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skyhawkmatthew
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Re: Takeoff Thrust options

Sat Dec 24, 2016 9:30 am

CX GE90 bump thrust envelope is 4000 - 9500 feet PA and 14 – 32°C, i.e. JNB.
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