I have come across a new feature called BTE (Brake to Exit) on the 777X, but I am unable to find any documentation related to that. There are vendors who are working on this technology for the 777X.
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11$\begingroup$ Hint: watch the spelling: searching for "brake..." instead of "break..." will give much better results ;-) $\endgroup$– PerlDuckSep 6, 2019 at 8:17
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11$\begingroup$ @PerlDuck I dunno. After the 737 MAX debacle "Break to exit" does sound like it might be a new Boeing feature... $\endgroup$– MachavitySep 6, 2019 at 12:45
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13$\begingroup$ The feature is as follows: during high-speed taxi, the pilots remove their seatbelts and brake sharply. They then exit the plane via the windshields. $\endgroup$– David RicherbySep 6, 2019 at 16:39
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2 Answers
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It is a system that Airbus already uses in the A380 and some A350's. They call it BTV (Brake to Vacate).
It allows the pilot to select a certain runway exit in advance (e.g. while approaching). After touchdown, the plane automatically brakes so it can vacate the runway at that given exit.
When the pilot chooses a runway exit point, the system indicates the estimated runway occupancy time and the minimum turnaround time. During the subsequent landing phase, and according to encountered runway conditions (i.e. 'wet' or 'dry'), the aircraft's deceleration is automatically regulated so it reaches the chosen exit at the correct speed.
(emphasis mine)
The BTE system by Boeing is a similar system with a different name. A related article in Avionics International about the B777X states:
“We have also added new safety features like optimal runway exiting and brake-to-exit, which will allow a pilot to tie an airplane’s rollout and stopping distance to a specific runway exit,” said Kirk Scarbrough, Boeing’s 777X systems chief engineer.
See also
- What is Brake To Vacate (BTV)?
- FAST magazine from Airbus, issue #44(PDF, 10MB) from July 2009, section "Brake-to-Vacate system", pages 17-25
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$\begingroup$ thanks for the info. Any idea if it helps while landing in cross winds to do the course correction? $\endgroup$– NitinGSep 6, 2019 at 11:17
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5$\begingroup$ @NitinG I can only tell for Airbus' BTV. It doesn't do anything actively while the plane is still in the air and subject to crosswinds. It just announces to the pilots that the desired exit can or cannot be achieved via the PFD and an aural message ("RWY TOO SHORT"). Only when the plane has actually touched down it will apply the wheel brakes (automatically) and possibly tell (read: yell at) the pilot to apply reverse thrust if needed. It doesn't do any course correction while airborne, it just hits the wheel brakes. $\endgroup$– PerlDuckSep 6, 2019 at 11:59
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1$\begingroup$ @NitinG, It is just a slightly smarter autobrake that you tell the point where you want to be down to taxi speed and it automatically selects the deceleration rate according to how much distance remains at the moment it activates after touch-down. $\endgroup$ Jun 20, 2022 at 20:59
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BTV was optional for the A-380 and standard for the A-350. Additionally, the A-380 had a selector knob to select BTV or Conventional Auto Brakes. We do not have that selector on the A-350. We simply have the choice of BTV or Auto Brakes Medium. I don't recall seeing anyone ever use anything other than BTV. It works very well. Former A-350/330 Captain
