Originally Posted by ICAO Doc 9863 (ACAS)
5.2.1.8 Respond to RAs by disconnecting the autopilot and by using prompt, smooth control inputs;
manoeuvre in the direction and with the vertical rate ACAS requires. To achieve the required vertical rate
(normally 1 500 ft per minute) on aircraft where the RA is displayed on a vertical speed indicator (VSI), it is
recommended that the aircraft’s pitch be changed using the guidelines shown in the table below. Referring
to the VSI or vertical speed tape, make any further pitch adjustments necessary to place the vertical speed
in the green area.
Originally Posted by ICAO Doc 9863 (ACAS)
5.2.1.9 For ACAS to provide safe vertical separation, the PF is expected to initiate the appropriate
RA manoeuvre within 5 seconds of when the RA is first displayed. Deviations from assigned altitude, when
responding to an RA, typically will be no more than 300 to 500 ft. RA manoeuvres should use vertical
speeds within the green areas, or the indicated pitch angle, and avoid red areas on vertical speed indicators
or tapes, or outlined pitch avoidance areas.
Originally Posted by ICAO Doc 8168 (flight proc)
c) in the event of an RA, pilots shall:
1) respond immediately by following the RA as indicated, unless doing so would jeopardize the safety of the
aeroplane;
Conclusion, never follow an RA with AP engaged...whatever the A/C type.