What happened
On 26 April 2004, at approximately 13:15 UTC, a serious air traffic incident occurred at Geneva Airport involving two commercial aircraft. The aircraft involved were an ATR 42-500 (DLH3703) and a Boe Boeing 737-300, registration PH-BDB (KLM1931).
During a period of heavy traffic, the aerodrome controller instructed the pilot of the ATR 42-500 to hold short of runway 05, noting that departure would follow the second landing aircraft. However, the pilot of the ATR 42-500 misunderstood the instruction, believing they were cleared to line up behind the preceding arrival. The aircraft subsequently entered the runway and positioned itself for takeoff.
As the Boeing 737-300 was on final approach, the pilot noticed the ATR 42-500 occupying the runway. At an altitude of approximately 300 feet, the crew of the Boeing 737-300 initiated a go-around to avoid a collision. The controller subsequently instructed the Boeing 737-300 to climb to 7,000 feet.
The investigation
The investigation by the Swiss Transportation Safety Investigation Board (SUST) focused on the sequence of communications and the controller's oversight. The investigation established that the aerodrome controller was managing a high volume of traffic, including several VFR aircraft, which required significant attention.
Investigators found that the controller had not visually confirmed that the runway was clear before issuing the landing clearance to the Boeing 73 and 7-300. Furthermore, the controller had not received a proper read-back of the hold-short instruction from the ATR 42-500, as the pilot had only responded with the term "roger," which is insufficient for confirming a clearance.
Findings
- The crew of the ATR 42-500 failed to read back a clearance they did not understand.
- The aerodrome controller issued a landing clearance without performing a visual check of the runway.
- The controller did not verify that the hold-short instruction had been properly acknowledged by the departing aircraft.
- The lack of a TWR coordinator during this period of heavy traffic contributed to the controller's inability to detect the error.