What happened
On October 6, 2016, at approximately 19:30 UTC, an incident occurred at Kraków Airport (EPKT) involving two aircraft: an ATR72 positioned on runway 27 and a B752 on approach. After the tower controller confirmed the ATR72 crew was ready for immediate departure, the B752 crew was instructed to continue their approach, with the notification that a departure from runway 27 would occur prior to their landing.
Shortly after, at approximately 19:31 UTC, the tower frequency (129.250 MHz) became blocked by interference. This interference prevented the controller from establishing communication with either the ATR72 crew or the B752 crew. In an attempt to maintain safety, the controller attempted to reach both crews using the emergency frequency (121.5 MHz).
After three attempts on the emergency frequency, the ATR72 crew responded and acknowledged the instruction to wait for the departure from runway 27, as well as the notification regarding the blocked tower frequency. Simultaneously, the controller instructed the B752 crew to execute a go-around, which the crew performed successfully. The frequency interference cleared at approximately 19:37 UTC, allowing the ATR72 to depart. The B752 landed safely at 19:44 UTC.
The investigation
The investigation focused on the period of communication loss and the subsequent management of the aircraft in the vicinity of the airport. The investigation examined the sequence of instructions issued by the tower controller and the effectiveness of the transition to the emergency frequency.
Findings
- The primary issue was the unidentified radio frequency interference on the tower frequency (129.250 MHz).
- The controller successfully utilized the emergency frequency to re-establish contact with the aircraft crews.
- The B752 crew followed instructions to perform a missed approach to ensure separation from the departing aircraft.