Incident Overview
A flight operated by Alitalia, designated as Alitalia 638 heavy, landed on runway 9R at Chicago O'Hare International Airport without receiving landing clearance from the air traffic control tower. The incident occurred during a localizer approach for runway 9R, with the captain piloting the aircraft and the first officer managing radio communications.
Sequence of Events
According to the investigation, the captain stated that the radio frequency was extremely busy and that they did not receive any frequency change instruction during the approach. The O'Hare tower controller responsible for arrivals on runway 9R observed the aircraft and attempted to establish communication by inquiring on the tower frequency, "Alitalia 638 heavy are you with me, sir?" No response was received. The controller repeated the transmission and then broadcasted, "Alitalia 638 heavy, are you with me, sir, execute a missed approach."
Meanwhile, the first officer made a call to what he believed was O'Hare tower, reporting that the flight was on short final. The Chicago Approach Control controller then transmitted, "short final, go over to tower one two one seven five," and repeated the instruction two more times.
Actions by the Flight Crew
The captain checked the runways, saw no conflicting traffic, and proceeded to land the aircraft without having received clearance from the tower.
Investigation Findings
Investigation at the Terminal Radar Air Traffic Control facility in Elgin, Illinois, revealed that the controller did not issue the instruction to the airplane to switch over to O'Hare tower's radio frequency.