Unstable Approach and Dual Control Incident Involving an Airbus A320 at Lyon-Saint Exupéry (SX-BHV)

Flight Details and Initial Configuration On 11 April 2012, an Airbus A320 registered SX-BHV, operated by Hermes Airlines, departed Ajaccio for Lyon-Saint Exupéry on a non-scheduled passenger flight. The flight was chartered by Air Méditerranée. The crew consisted of an instructor pilot serving as pilot not flying (PNF) and a trainee pilot serving as pilot flying (PF), along with five cabin crew members and 178 passengers. During pre-departure preparations, the PNF manually entered the Ajaccio ILS frequency into the MCDU to prepare for a potential quick return flight. This frequency remained active throughout the flight. ## Approach and Navigation Issues The flight was conducted at night in instrument meteorological conditions. The crew initially programmed the FMGS for an ILS approach to runway 18L, as indicated by the ATIS. However, the approach controller offered radar guidance for an ILS approach to runway 36L, which the crew accepted. During the arrival, the crew observed inconsistencies in the DME distances displayed on the navigation display. The PNF reported 99 NM, while the PF reported 40 NM. The controller, noting the aircraft was high on the approach path, requested confirmation of the 40 NM distance. The crew responded that they would need to make a 360-degree turn, but the controller interpreted this as a confirmation to land on runway 36. ## Alarm Activation and Dual Control The crew was occupied with resolving the ILS frequency discrepancy and a cross-checking error from another crew. The controller issued a heading of 270° to extend the path, but the crew turned approximately 30 seconds later. A two-minute discussion ensued between the PF and PNF regarding the MCDU approach insertion and ILS frequency validity. The controller then issued a heading of 320° to intercept the localizer axis. Because the correct ILS frequency was not active, the aircraft crossed the axis without intercepting it. The controller subsequently instructed the crew to turn right to heading 020°, descend to 3,000 ft, and cleared them for the ILS approach to runway 36L. The PNF then instructed the PF to display the correct frequency, changing it from 110.30 MHz to 110.75 MHz. As the aircraft was in a clean configuration at 230 kt and 2,460 ft altitude, the GPWS 'TERRAIN TERRAIN PULL UP PULL UP' alarm activated. The instructor took manual control, set the thrust levers to TOGA, and achieved a maximum pitch of 9.5° without announcing the takeover. The autopilots disengaged. Because the aircraft was in a clean configuration, the SRS mode did not engage, and the crew did not receive the expected pitch-up commands. The instructor then issued pitch-down commands. ## Resolution and Landing A few seconds later, an MSAW alarm activated, and the controller instructed the crew to maintain 2,500 ft, noting the aircraft was too low. The instructor continued pitch-down commands while converging on the localizer axis. The thrust levers were set to CLIMB, and the aircraft descended to 2,150 ft. At 320 kt and 900 ft height, the thrust levers were set to IDLE, triggering a second MSAW alarm. The controller again instructed the crew to check their altitude. Shortly after, the trainee pilot applied pitch-up inputs for about ten seconds while the instructor gave opposite commands, triggering a DUAL INPUT alarm for one minute. During this period of manual dual control, the PNF continued communicating with ATC and requested radar guidance for an approach interruption. The communications regarding control were confusing. The controller instructed the crew to climb to 5,000 ft. The aircraft climbed, and the thrust levers were set to CLIMB. The DUAL INPUT alarm stopped, and the instructor regained control. Autopilot AP2 was engaged, and the aircraft parameters stabilized. A second approach was conducted, and the crew landed safely on runway 36L.