The flight on Wednesday was heading from Surabaya, Indonesia's second-largest city, to the capital, Jakarta. Aviation is a main mode of travel in the sprawling nation of 17,000 islands, and the incident has raised safety concerns. YouTube footage showed the pilot appeared to stagger through a metal detector at a security checkpoint and security guards picked up his belongings that were falling on the floor as he seemed out of control. "The pilot had committed serious violation of standard operation procedure that endangered passengers," Burhan said. "We apologize for the discomfort. I have to be responsible for that and therefore I and my production director resign." The airline previously had dismissed reports that the 32-year-old pilot Tekad Purna was drunk, saying initial tests of drug and alcohol were negative. Director General of Air Transportation Suprasetyo has asked Citilink to make sure the pilot underwent a medical check. Purna is under investigation for possible drunkenness or drug use.