Warning sound on high altitude airport

[radekpl 0]

Hello, I am Newbie here. 1. I am trying start form Cusco or other "high altitude" airport. How to disable warning sound which appear after loading aircraft into airport? This warning sound end when I climb over 16-17000ft this warning sound end, when I select flaps 25. So I think it is flaps warning. But flaps warning switch (before FO) doesn work. Thanks for your help.

[ZachLW 37]

The Alt Horn silence button is located on the pressurization panel on the overhead. It's small and black, but hard to miss if you're looking for it. I'm confused by the rest.

[radekpl 0]

Thank. Yes I missed it.