Child Theme Translations with PoEdit

Found a solution that works for me:

add_action( 'after_setup_theme', 'avia_lang_setup' );
function avia_lang_setup() {
    $lang = apply_filters('parent-theme-slug', get_template_directory()  . '/lang');
    load_theme_textdomain('avia_framework', $lang);
    load_child_theme_textdomain( 'child-theme-text-domain', get_stylesheet_directory() . '/lang' );
}

Note:
Exchange “parent-theme-slug” (typically the parent theme name in small letters) and “child-theme-text-domain” (child theme text domain of your choice)