What happened
On 29 January 2015, a Ryanair Boeing 737-800, registration EI-EMK, was conducting a scheduled commercial flight from London Stansted to Bergerac-Roumanière airport. Due to the unavailability of ILS and DME equipment at the destination, the crew prepared for an NDB Y approach to runway 2/28.
During the approach, the crew initiated a descent while turning toward the inbound course. The first officer, acting as pilot flying, selected a vertical speed of -900 feet per minute and a target altitude of 900 feet. This maneuver caused the aircraft to descend below the minimum safe altitude (MSA) of 2,500 feet.
As the aircraft continued its descent in instrument meteorological conditions, the ground-based Minimum Safe Altitude Warning (MSAW) was activated in the Aquitaine-Approach control room. Despite this, the aircraft continued to descend for nearly two minutes. The situation escalated when the Enhanced Ground Proximity Warning System (E-GPWS) issued a "TERRAIN" alert. At this point, the aircraft was still approximately 8 NM from the runway threshold. The crew immediately initiated a missed approach by engaging the TOGA button, at which point the E-GPWS also issued a "PULL UP" warning. The aircraft eventually climbed to 4,000 feet, held at the BGC beacon, and successfully completed a second approach to land safely.
The investigation
The BEA investigation examined the flight data recorder, radar data, and cockpit voice recordings. The inquiry focused on the crew's use of the Flight Management System (FMS) and vertical speed modes, the accuracy of the approach preparation, and the effectiveness of air traffic control monitoring. The investigation also reviewed the controllers' knowledge of NDB procedures and the availability of MSAW displays at the local control unit.
Findings
Several factors contributed to the incident, most notably the crew's descent below the minimum safe altitude during a complex non-precision approach. Key findings included:
- Inadequate approach preparation and a lack of precision in the initial flight plan.
- A misunderstanding between the captain and the first officer regarding the required flight modes.
- A progressive loss of situational awareness by both pilots.
- The first officer's limited experience with this specific type of non-precision approach.
- The captain's distraction due to significant noise nuisance in his headset.
- A lack of effective monitoring by air traffic controllers, driven by insufficient knowledge of NDB procedures and the absence of a remote MSAW display at the Bergerac tower.
Safety action
Following the incident, Ryanair prohibited the use of vertical speed (V/S) mode for timed non-precision approaches to mitigate the risk of uncontrolled descents. Additionally, the BEA issued a recommendation to the DGAC to review and clarify instructions in the AIP France regarding entry into holding patterns to ensure more consistent pilot and controller practices.