How to - Brake To Vacate (BTV) - Setup & Operation

The Brake To Vacate (BTV) function optimizes the autobrake deceleration on landing in order to reach the selected runway exit point/ manually entered landing distance. The system takes into account the selected runway condition/braking action in its calculations.

Once armed, the system works autonomously to delay braking in order to reduce brake wear, optimize the runway occupancy time (ROT) and improve passenger comfort.

SETTING UP BTV

In order for BTV to function, it needs information such as your target stopping distance. This information can be provided by Runway and Runway Exit Selection on the On-board Airport Navigation System (OANS) on the ND.

Exit Selection on the OANS on ND 

Step 1: Choose Landing Runway on FMS

• Press the F-PLN shortcut key to go to the FMS F-PLN page

• At the bottom left corner, select your DEST airport and select the Landing RWY
  - you can also select your APPR and STAR on this page, however the BTV system only requires the runway at minimum to function

• Choose TMPY F-PLN and then INSERT TMPY to confirm the selection.

(Click to enlarge image)

Step 2: Set OANS to your DEST airport

 Whilst on the OANS display, the currently displayed airport moving map (AMM) can be changed via the ARPT SEL function page as follows:

• Change to PLAN mode via the ND Mode Selector Knob

• Change the range to ZOOM via the ND Range Selector knob

• Move the KCCU cursor to the ND screen by
  - Clicking anywhere on the ND screen, OR
  - Clicking the ND key on the KCCU

• Click the Additional Function Button at the bottom-right corner of the ND

• Select the (A) ARPT SEL tab

• Choose from the (B) FMS AIRPORTS list to display your Destination

• Click the (D) DISPLAY AIRPORT button to make it the active displayed airport.

  

(Click to enlarge image)

Step 2: Choose Landing Runway and Runway Exit on the OANS

• Click-and-drag to center the map on your desired runway.

• Click on the Runway Identifier with a green triangle next to the threshold. You will see a FOR BTV: SELECT EXIT message appear on the top left corner as confirmation.

• Then select the desired Runway Exit by moving your cursor to the taxiway identifier and clicking it.
  You can also unselect it the same way by clicking on it again

Once a target Exit is chosen,

• A blue line will appear along the landing runway to the selected exit showing the chosen BTV target exit, AND

• On the top left corner of the ND, you will see the chosen RWY (and its LDA), EXIT as well as the corresponding Runway Occupancy Time (ROT)(in seconds) and TURNAROUND time (in minutes) for MAX REV or REV IDLE usage respectively.

(Click to enlarge image)

BTV ARMING &  ENGAGEMENT

The BTV autobrake mode arms when the following conditions are met:

• A BTV Runway and Exit is selected, AND

• A/BRK ROTARY SELECTOR is set to BTV

(Click to enlarge image)

Once successfully armed,

• The PFD FMA will show BTV in blue

 
(Click to enlarge image)

The BTV autobrake mode engages on landing if any one of the conditions is met:

• immediately after ground spoilers extension if the NLG is on ground; OR

• 5s after ground spoilers extension if NLG is not on ground

(Click to enlarge image)

BTV DISARMING & DISENGAGEMENT

The autobrake disarms if any one of the conditions is met:

• The A/BRK ROTARY SELECTOR is reset to DISARM, OR

• The selected landing runway on the OANS is modified, OR

• The BTV exit is deselected, OR

• The FMS runway is changed to a runway that is different from the selected landing runway, OR

• A go-around is performed below 600 ft.
  The reversion occurs during the go-around, when the aircraft climbs above 600 ft. The computation is based on the minimum between the radio altitude, and the aircraft height above the runway threshold.
   

The autobrake disengages if any one of the conditions is met:

• The aircraft ground speed reaches the BTV disconnection speed (approx. 10 kt), OR

• The flight crew uses the brake pedals, OR

• The flight crew presses the A/THR instinctive disconnect pushbutton, OR

• The ground spoilers retract or disarm.
   

When autobrake disengages the the following happens:

• An AUTO BRK OFF aural alert sounds

• The MASTER CAUT lights comes on

• The AUTO BRK OFF memo appears on the PFD and WD.