how to fix permission on default apps in el capitan
You cannot modify system files/applications in El Capitan due to System Integrity Protection (SIP): some system locations are completely locked unless you boot into recovery  and disable SIP through csrutil in the command line ('csrutil disable') 

See http://arstechnica.co.uk/apple/2015/09/os-x-10-11-el-capitan-the-ars-technica-review/ for more.