What happened
On 11 October 2012, a Boeing 737-800, registration EI-DLD, was preparing for a commercial flight from Eindhoven Airport to London Stansted. During the taxi phase, the crew was operating under the direction of Eindhoven Ground Control. The aircraft was instructed to backtrack along runway 04, with specific instructions to turn right at the 'Foxtral' intersection.
As the aircraft approached the intersection, the ground controller instructed the crew to turn right and advised them to contact the tower frequency for departure, concluding with a friendly greeting. Misinterpreting this instruction and the controller's well-wishes as permission to depart, the crew performed a 180-degree turn on the runway and initiated takeoff. The aircraft departed the runway without receiving formal takeoff clearance from the Air Traffic Control tower.
The investigation
The Dutch Safety Board examined the communications between the flight crew and air traffic controllers, as well as the airport's operational procedures. The investigation looked into the taxi instructions provided by Ground Control and the specific instructions regarding runway maintenance work occurring at the time. The board also reviewed the airline's airfield briefing documents and the standard phraseology used by the Royal Netherlands Air Force controllers at the base.
Findings
Several contributing factors led to the unauthorized departure:
- The Ground Controller used non-standard radio phraseology when instructing the aircraft to vacate the runway, which created ambiguity.
- The crew incorrectly interpreted the controller's instruction to contact the tower and the subsequent friendly greeting as an implicit authorization to take off.
- Although the captain expressed some uncertainty regarding whether takeoff clearance had been granted, the crew failed to contact the tower or ground control to confirm their status.
- The aircraft's airfield briefing contained airport limitations—such as the requirement to take off from the beginning of the runway—in small, inconspicuous print, making them easy to overlook.
- The crew was unaware of a specific memo regarding interim taxi procedures necessitated by ongoing maintenance work on the parallel taxiway.
- There was a procedural discrepancy where the Ground Controller, rather than the Tower Controller, provided permission to backtrack on the active runway.
Safety action
Following the investigation, the airline updated its airfield briefing for Eindhoven Airport to ensure that all operational restrictions and limitations are clearly and prominently displayed to flight crews.