What happened
On January 30, 2004, at 11:44 UTC, a Boeing 737-800 operated by Turkish Airlines, flight THY 1874, was involved in a serious runway incursion at Milan Malpensa Airport. The aircraft was taxiing for departure and was in contact with the Ground controller. The controller had instructed the crew to taxi straight ahead, turn right onto taxiway K, F, and hold short of runway 35L. While the investigation noted that the clarity of the pilot's readback was uncertain, the controller responded to the readback with "That's correct."
Simultaneously, an Alitalia flight, AZA 33E, was cleared to land on runway 35L. Shortly after this clearance, the Turkish Airlines aircraft crossed runway 35L without authorization. This movement was detected by the Tower controller, who immediately instructed the Alitalia crew to perform a go-around because an unauthorized aircraft was crossing the runway.
The investigation
The ANSV investigation focused on the communication between the crew and air traffic control. On the ground frequency, the controller later queried the Turkish Airlines crew regarding their failure to hold short of runway 35L. The crew responded that they did not hear the instruction to hold short for the crossing, claiming instead that they believed they were instructed to taxi to runway 35R via taxiways W and K, F.
At Milan Malpensa, procedures for crossing runway 35L/17R require specific steps: aircraft must receive instructions including a hold short limit, contact the runway operations controller on a specific frequency (128.350 MHz) when approaching the limit, and receive a "runway clear" instruction before proceeding. The investigation found that the crew failed to follow these established airport procedures and did not obtain the necessary clearance from Malpensa Tower to cross the runway.
Findings
- The primary cause of the event was the unauthorized crossing of runway 35L by flight THY 1874.
- A contributing factor was the crew's failure to adhere to the established operational procedures for runway crossings at Milan Malpensa.
- There was a discrepancy in communication, as the crew claimed they did not receive the instruction to hold short of the runway.