Auto-brake, for info:
http://www2.alpa.org/DesktopModules/...2156&Tabid=256
Slide 11 - re autobrake tuning, modulation - efficiency, compromise.
Slide 21 manual brakes, “
The antiskid system stops the airplane for all runway conditions in a shorter distance than is possible with either antiskid off or brake modulation”, i.e. max manual better than ‘max’ auto which is modulated.
Note 1 the presentation relates to flight testing, not commercial flight operations or procedures.
Note 2 the performance data terminology and calculations relate to the AFM - flight testing. Recent operational changes should require use of ‘Operational Landing Data’ replacing the previous Boeing ‘actual’ data (QRH); this should also be compatible with the new Global Reporting Format for runway condition - effective this month (Nov 2021).
https://www.caa.co.uk/Commercial-ind...orting-system/
Note 3 beware simulation, it may not accurately represent the aircraft in all conditions - runway surface, contaminant, etc; … unless the simulator is hooked up to the equipment in slides 10 & 12
General info:
http://www.icao.int/SAM/Documents/20...0Aeronaves.pdf
CCA re use of max manual vs auto RTO; is the alert a real time indication relating to brake pressure or just indicates a system state - no computation / modulation. The information above suggests that because max manual provides better (instantaneous) performance, it may be better to use manual in extreme circumstances; i.e. abnormal runway surface / conditions, alleviating interaction of reverse with ABS on very slippery runways.
However, operators may wish to balance these extremes with the realistic, but rare need for RTO, and choose Auto Brake as standard lest pilots are unable to perform as expected by theory.