@Genista So from the manuals, NA (Noise abatement) button activates this mode called NAP, noise abatement profile, that essentially is a vertical mode activated.
And in fact it does limit the engine power in orde to reduce noise, by:
Inhibiting Flex EPR, and changing it to NEPR (Noise EPR)
Activates NA on the Flight mode anunciator, that comands the Flight Director to initiate during the takeoff a rotation of 3deg/sec until it achieves a pitch of 22deg or a speed of V2+10kt, wichever comes first.
At 400ft (lower than any possible selected THR RED) by manual selection of CLB THR reduces pitch and power even further to achieve lower noise leves.
At ACCEL ALT selection of PROF or LVLCH reverts to a normal acceleration (250kt) and continues normal climb.
[image: 91f25876-8b4e-4a00-bec3-2044bf530ff5.png]