TGA Limits
Thread Starter
Joined: Dec 2004
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From: sussex
TGA Limits
Hi, wondered if someone could tell me what the letters TGA stand for first of all! Secondly, I understand it provides a gradient of 2.1% under certain conditions which I have a list of. What I need help with is what relevance 2.1% has. I have been told its a certification limit. Any references would be useful. Thanks.
Joined: Apr 2005
Posts: 209
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From: Australia
You may be referring to TOGA? "TakeOff and Go-Around" thrust.
Basically your maximum power available for takeoffs or "going around" (aborting a landing).
There are certain climb gradients an aircraft must achieve when taking off etc to avoid hitting terrain and obstacles. These are based on using max power.........not always, but generally speaking.
Does that answer your question?
The gradient expressed in a % can be converted to a climb angle and also a rate of climb (based on your ground speed).
ie: a 5% gradient is approximately 3 degrees. If you multiply your ground speed by the % number you get a rough required rate of climb to clear obstacles...........eg: 5 x 120kts = 600fpm (feet per minute).
The various certified minimum limits vary WRT how many engines you have 2, 3 or 4 and at what stage you are during the takeoff.
Basically your maximum power available for takeoffs or "going around" (aborting a landing).
There are certain climb gradients an aircraft must achieve when taking off etc to avoid hitting terrain and obstacles. These are based on using max power.........not always, but generally speaking.
Does that answer your question?
The gradient expressed in a % can be converted to a climb angle and also a rate of climb (based on your ground speed).
ie: a 5% gradient is approximately 3 degrees. If you multiply your ground speed by the % number you get a rough required rate of climb to clear obstacles...........eg: 5 x 120kts = 600fpm (feet per minute).
The various certified minimum limits vary WRT how many engines you have 2, 3 or 4 and at what stage you are during the takeoff.
Joined: Sep 1999
Posts: 47
Likes: 0
From: 8N 98E
TGA
TGA stands for Temperature Go Around.
If, for example, your doing a single engine approach above a certain weight and/or high OAT and/or high altitude airport, you may not have sufficient performance to carry out a go-around safely in the 'normal' go-around config. In this case there is a TGA performance chart (usually in the QRH) which will guide you to the appropriate single engine approach config and go-around flap setting in the event of a missed approach.
As an example, in the case of the A330 the normal single engine approach config is config 3 and config 2 selected for the go-around. If you are above a certain weight and/or environmental conditions then the approach would be in config 3 (as normal) but config 1+F used for any subsequent go-around.
Hope that answers your question.
If, for example, your doing a single engine approach above a certain weight and/or high OAT and/or high altitude airport, you may not have sufficient performance to carry out a go-around safely in the 'normal' go-around config. In this case there is a TGA performance chart (usually in the QRH) which will guide you to the appropriate single engine approach config and go-around flap setting in the event of a missed approach.
As an example, in the case of the A330 the normal single engine approach config is config 3 and config 2 selected for the go-around. If you are above a certain weight and/or environmental conditions then the approach would be in config 3 (as normal) but config 1+F used for any subsequent go-around.
Hope that answers your question.
Last edited by Abacus; 26th July 2008 at 13:13.
Joined: Jun 2004
Posts: 1,843
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From: Australia
2.1% OEI Climb Gradient, 2.4% Gross and 1.6% Net for Second Segment climb, 35 foot screen heights for Takeoff.............Lines drawn in the sand
Comforting isn't it. 2.1% achievable during a OEI missed approach, when the PANS-OPS missed approach obstacle-clear gradient requirement is 2.5%
Best Regards,
Old Smokey
Comforting isn't it. 2.1% achievable during a OEI missed approach, when the PANS-OPS missed approach obstacle-clear gradient requirement is 2.5%
Best Regards,
Old Smokey
They are gross figures though? 
