What happened
On February 7, 2001, an Iberia Airbus A320-214, registration EC-HKJ, was performing a scheduled domestic flight from Barcelona to Bilbao. During the final approach to runway 30, the aircraft encountered significant meteorological disturbances, including moderate to severe turbulence and strong, changing vertical and horizontal gusts.
As the aircraft descended below 200 feet radio-altitude, it experienced a high rate of descent of approximately 1,200 feet per minute. Despite the crew's attempts to pitch the aircraft up and reduce the vertical speed during the flare, the aircraft failed to respond to the control inputs. The aircraft impacted the runway threshold in a slight nose-down attitude, causing the nose landing gear to collapse. The aircraft continued along the runway for 1,100 meters, during which time the main gear tires burst and the aircraft eventually lost directional control. An emergency evacuation was conducted, resulting in one serious injury and several minor injuries among the passengers and crew.
The investigation
The CIAIAC investigation focused on the flight control system's behavior during the encounter with windshear and turbulence. Investigators examined the flight data recorder (DFDR) and cockpit voice recorder (CVR) to analyze the aircraft's response to pilot inputs. The investigation specifically looked at the interaction between the simultaneous sidestick inputs from both the pilot flying and the supervising captain, as well as the activation of the aircraft's automated protection systems.
Findings
- The aircraft encountered severe turbulence and windshear during the final approach phase.
- The activation of the angle of attack protection system prevented the crew from successfully pitching up to flare the aircraft.
- The flight control system logic failed to account for the simultaneous manual inputs from both pilots on the sidesticks, effectively ignoring the commands intended to recover the aircraft's attitude.
- The aircraft suffered extensive structural damage to the airframe, engine nacelles, and landing gear, rendering it beyond economical repair.
Safety action
Following the investigation, the following safety actions were noted:
- A preliminary safety recommendation was issued to the French Civil Aviation Authorities to coordinate with the manufacturer regarding safety measures for the A320 family.
- Airbus subsequently implemented software modifications to the ELAC (Elevator Aileron Computer) to address the control logic issue, which were retrofitted to the fleet by the end of 2002.
- Recommendations were made to Iberia regarding improved crew instruction to avoid simultaneous sidestick activation without using the override button, and to establish stricter operational restrictions for crew members performing line flying under supervision.