What happened
On May 3, 1986, an Iberia Airlines Boeing 727-256, registration EC-DDV, was performing a scheduled flight from Malaga to Zurich. During the approach to Zurich Airport, the crew was utilizing a VOR/DME procedure for runway 14, which was in use because the primary ILS was out of service for equipment installation.
As the aircraft progressed on the approach, the pilot in command inadvertently directed the aircraft toward the threshold of runway 149°, which aligned closely with the start of runway 16. The crew did not realize they were approaching the wrong runway until approximately 25 seconds before touchdown. Upon realizing the error, the pilot attempted a rapid correction maneuver to align with runway 14. During this maneuver, the right wingtip made contact with the runway surface, sliding for approximately 240 meters before the right main landing gear touched down. The aircraft subsequently veered into a drainage ditch before the pilot managed to steer it back onto the runway to complete the rollout.
The investigation
The investigation examined the technical aspects of the VOR/DME approach procedure and the flight crew's actions. It was established that the VOR/DME 14 approach was inherently problematic because its centerline did not align with the runway axis, requiring a 10-degree left turn during the final stages of the approach. Furthermore, the approach track suggested runway 16 to the pilots.
Investigators also reviewed the flight data, which showed the aircraft was flying at a high speed and was not in a stabilized configuration during the final stages of the approach. The investigation noted that the crew was heavily occupied with configuring the aircraft (extending gear and flaps) at a critical moment, which contributed to the late identification of the runway error.
Findings
- The primary cause of the incident was the erroneable approach to the wrong runway due to a flawed VOR/DME procedure that visually suggested runway 16.
- The approach procedure lacked adequate warnings regarding the high risk of runway confusion.
- The flight crew performed a late verification of the assigned runway.
- The pilot chose to attempt a difficult correction maneuver rather than initiating a missed approach (go-around) upon discovering the error.
- The final approach was unstabilized due to the late execution of the correction maneuver.
- The VOR/DME 14 procedure was technically difficult for large aircraft, as it was impossible to maintain a stabilized approach from the published endpoint.
Safety action
The commission recommended reviewing the necessity of the VOR/DME approach for runway 14, noting that the procedure had been suspended since May 16, 1986. The report suggested that if such non-precision procedures are necessary, they must be thoroughly vetted and published with clear warnings to prevent runway confusion.