Apparently the button <i>erases tape when pushed for two seconds, provided the airplane is on the ground and the parking brake handle is on.</i><p><a href="http:&#x2F;&#x2F;www.a320homecockpit.de&#x2F;downloads&#x2F;a320flightdeckdocumentation26202.pdf" rel="nofollow">http:&#x2F;&#x2F;www.a320homecockpit.de&#x2F;downloads&#x2F;a320flightdeckdocume...</a>