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Old 12th December 2008 | 08:51
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A37575
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Joined: Apr 2005
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From: Australia
For the 737 the use of autobrake for landing is not necessary unless the runway is limited. You have to read the Boeing FCTM wording carefully. Mine states "Boeing recommends that whenever runway limited, using higher than normal approach speeds, landing on slippery runways or landing in a crosswind the autobrake sysytem be used". The FCTM then expands that by stating when to use max, Med or min (or their equivalent numbers such as 1,2,3 or Max. By "landing in a crosswind" the intent is that it assumes a strong crosswind - not just a few knots.

Obviously if there is no problem with runway length and runway is dry there is nothing to gain by using autobrake except to increase maintenance costs by the fact that the brakes are applied at high speed immediately on wheel spin-up. Providing you you fly the aircraft at the correct speed and touch down at the correct point with little or no float, then the combined retardation effect of spoilers and immediate reverse thrust will easily reduce the aircraft energy such that you would not touch the brakes until the speed is down to 80 knots or less.

On the other hand if you are used to sloppy flying habits and habitually come in with unwarranted excess speed and touch down long after a lengthy float then use of autobrake will not correct your sloppy flying but will give you a head start in the stopping process. But to routinely select autobrake for all normal landings regardless of excess runway length is just plain lazy flying. If you desire to make a certain taxiway not far up the runway even though there is excess runway available over the flight manual factored figure, then go ahead and fill your boots with the autobrake. The way some pilots love the autobrakes for all landings regardless of excess length available makes one wonder if they would send out a Pan call if they had to use manual brakes one day.

If however there is a airport requirement not to use reverse (or only idle reverse)because of noise abatement reasons then the use of an appropriate autobrake setting may be worth considering.
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