Auto brakes and speed brakes?

Question

What do these instruments do on a plane and how do they help. I have a bit of knowlage about Auto brakes do they go to RTO thn 1 and 2 or somethink ..... thanks

Answer 1

Autobrakes are sensors on the wheels that automatically apply the brakes... RTO is Refused takeoff mode and will apply the brakes once the speed reaches a certain point and the throttles are reduced to idle or reverse... that setting is used in case the takeoff must be aborted for whatever reason...

The settings by number are different between airplanes but they all mean the same thing... when the autobrakes are set to a number or "MAX" they will automatically engage the brakes when the airplane touches down... most of the time, the pilots will go with a setting of 1 or 2... many smaller airplanes are not equipped with autobrakes and the pilots must slow the airplane down manually... the settings above 2 up to MAX are for short runways and emergencies...


Speed brakes are entirely different... they are the spoilers that are deployed as soon as the main gear touches down... they act as wind catchers that make the airplane as UN-aerodynamic as possible and use the friction that results to slow the airplane down... they can be used in flight as well if the pilots need to slow the airplane down...

Answer 2

Auto brakes: Sensors in the landing gear that apply the brakes upon an aircraft touching the ground... there are usually four settings to Autobrakes: RTO or Rejected/Refused Takeoff, this setting is used when a pilot must abort the takeoff roll for any reason, Autobrakes only apply above a certain speed for rejected takeoffs. 1: minimum setting, 2: intermediate setting, 3: advanced settings, Airline pilots use 3 in most cases to stop quickly and get off at the designated taxiway

the difference between auto brakes and speed brakes is that auto brakes (as discussed) are sensors in the landing gear assembly, speed brakes (also known as Spoilers) are panels on the wing that flip up and disrupt the airflow on top of the wing, thereby slowing the aircraft down so it cannot take off again by accident upon landing

Answer 3

Auto Brakes automatically apply braking action to the wheels in event of a landing or a rejected take off. No pilot imput is required

Speed brakes can be used in the air to help turning, slowing the aircraft down. But most importantly it is deployed when the wheels touch down. It kills the air flowing over the wing so the aircraft will sink and more weight is put on the wheels. This allows greater braking force and action form the aircraft.

Answer 4

ALOPILOT is right-on again, though I keep hearing/seeing/reading that the RTO detent is "Rejected Take-Off" rather than "Refused Take-Off"...but we both may be right (both terms being used in the industry).
The 1, 2, 3 and MAX detents or settings are selected based on any/combo of airplane weight, runway length and surface winds...and maybe severity of sudden runway incursion.

Both AutoBrakes and Armed Speedbrakes (or AutoSpeedbrakes) are tools designed to increase convinience and more importantly safety by reducing pilot workload at that critical pre-touchdown/post-touchdown moment when "all brains, eyes and hands are needed on the primary controls for a neat slowdown.

Answer 5

Just a side note, speedbrakes destroy lift. Some aircraft are very aerodynamically efficient. That makes it very difficult to "get down and slow down" at the same time. A good example of this is frequently in a traffic pattern. ATC has you keep up your speed for sequencing. Then they give you a descent, a turn on base, and "slow to 170." Good luck! So you use the speedbrakes to slow, and keep them out to aid in your descent (along with extending the flaps on schedule as you slow).

Not all of the speedbrake panels open up in flight. But once on the ground and the tires start rotating, the spoilers come out, which are all speedbrake panels. That destroys the lift on the ground so that the tires and brakes are more effective.