Autobrake on a 737
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Autobrake on a 737
I wonder if any here has a copy of the chrat issued in 737s (preferably 737-400s) that says what speed what autobrake setting goes to?
If they do, I would be VERY grateful if they wold send me the speeds on them.
Thanks,
Edward Ludlow
If they do, I would be VERY grateful if they wold send me the speeds on them.
Thanks,
Edward Ludlow
Guest
Posts: n/a
Hi Ed,
Excuse me for being sceptical about your identity, but yesterday you posted as a 13 year old looking for schooling advice and today you want the Autobrake speed for a 737-400.
Why do you want this information (Not that I have it)and indeed if you are genuine accept my apologies.
TBL
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Flying is fun, not funny
Excuse me for being sceptical about your identity, but yesterday you posted as a 13 year old looking for schooling advice and today you want the Autobrake speed for a 737-400.
Why do you want this information (Not that I have it)and indeed if you are genuine accept my apologies.
TBL
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Flying is fun, not funny
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OK, here goes:
Autobrake Selector, Brake Pressure PSI, Deceleration Rate in ft/sec/sec :
1, 1250, 4
2, 1500, 5
3, 2000, 7.2
MAX, 3000, 12 ft/sec/sec below 80 kts
MAX, 3000, 14 ft/sec/sec above 80 kts
RTO, FULL System pressure, Deceleration Rate Not Controlled Brake Pressure is Max System pressure with "on ramp"
There is an "on ramp" period where Autobrake pressure is applied over a period of time. Approximately 750 psi is applied in 1.75
sec then above mentioned pressures are reached in another 1.25sec for Autobrakes 1, 2, or 3 and approx. 1.0 sec for MAX. There
is a logic that says average wheel speed must be greater than 70kts to initiate Autobrakes. There is some confusion that it takes more brake pedal pressure than is being applied by the Autobrakes to disarm. A more accurate statement is that it takes 750 psi of brake pedal pressure at the brake shuttle valve to disarm any
Autobrake/RTO application. I hope this information is helpful.
The Autobrake system is much more complex than two paragraphs can describe.
Autobrake Selector, Brake Pressure PSI, Deceleration Rate in ft/sec/sec :
1, 1250, 4
2, 1500, 5
3, 2000, 7.2
MAX, 3000, 12 ft/sec/sec below 80 kts
MAX, 3000, 14 ft/sec/sec above 80 kts
RTO, FULL System pressure, Deceleration Rate Not Controlled Brake Pressure is Max System pressure with "on ramp"
There is an "on ramp" period where Autobrake pressure is applied over a period of time. Approximately 750 psi is applied in 1.75
sec then above mentioned pressures are reached in another 1.25sec for Autobrakes 1, 2, or 3 and approx. 1.0 sec for MAX. There
is a logic that says average wheel speed must be greater than 70kts to initiate Autobrakes. There is some confusion that it takes more brake pedal pressure than is being applied by the Autobrakes to disarm. A more accurate statement is that it takes 750 psi of brake pedal pressure at the brake shuttle valve to disarm any
Autobrake/RTO application. I hope this information is helpful.
The Autobrake system is much more complex than two paragraphs can describe.
Guest
Posts: n/a
Mearse,
Once you've answered that question, the autobrake distance table allows you to select a suitable autobrake setting to give a smooth deceleration to your chosen exit point on the runway. For instance, you may want to leave at a rapid exit taxiway 2/3rds down the runway.
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Once you've answered that question, the autobrake distance table allows you to select a suitable autobrake setting to give a smooth deceleration to your chosen exit point on the runway. For instance, you may want to leave at a rapid exit taxiway 2/3rds down the runway.
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