What happened
During an instrument flight rules (IFR) departure from Kitchener-Waterloo Regional Airport, a Cessna 421C was cleared to take off on runway 25. At approximately the same time, a Piper Seminole was taxiing via taxiway "C" for a local visual flight rules (VFR) flight. Because taxiway "C" intersects the departure path of runway 25, the Cessna 421C passed directly over the Piper Seminole as it crossed the runway, resulting in a runway incursion.
The investigation
Investigators examined the communication and coordination between the ground controller and the airport controller. The airport controller had authorized the use of runway 25 but failed to officially designate it as active or update the flight data strip bay with a runway strip header. This lack of documentation meant there was no visual signal that the runway status had changed.
Furthermore, the investigation found that the controllers operated under a lack of clarity regarding responsibility. The ground controller assumed the runway remained under ground control, while the airport controller assumed control had been transferred. The absence of a third controller, who was on a scheduled break, also removed a critical layer of oversight during a period of heavy traffic. Additionally, the method of communicating with Toronto ACC required clearance validation to pass through the ground controller rather than directly to the airport controller, which disrupted established safety checks.
Findings
- The airport controller issued takeoff clearance for runway 25 without formally designating it as the active runway or notifying the ground controller of the change.
- The failure to post a runway status strip and the lack of explicit communication regarding the runway's active status led to a breakdown in coordination.
- Both the ground and airport controllers failed to perform required coordination tasks, each assuming the other had managed the runway transfer.
- The controllers did not scan the maneuvering surfaces with enough detail or frequency to identify the approaching conflict.
- Local procedures regarding the timing and designation of temporary active runways were applied inconsistently.
- The lack of a third controller to act as a spotter during heavy traffic increased the risk of the incursion.
Safety action
Following the investigation, the Kitchener-Waterloo control tower updated its operational procedures. New instructions clarify that both the ground and airport controllers share the responsibility for ensuring runway status header strips are properly maintained. Specifically, if a ground controller transfers runway control by assigning an aircraft to depart, they must verify that the runway status display reflects that the airport controller now holds jurisdiction.