This section sets out a few operational safety topics with respect to commercial air transport, principally involving large aeroplanes. These topics are illustrated with the latest reports published by the BEA and certain reports from foreign investigations which the BEA was involved in as accredited representative.
The crew have to pay particular attention to the management of the aeroplane’s energy from the beginning of the descent, and continue to do so during the approach up until landing. Whatever the level of automatic control chosen by the crew, notably during the final approach, they must be familiar with it and aware of the associated limitations. During the approach, the crew are expected to follow the instructions published in the AIP and those given by air traffic control. They must also comply with the procedures and techniques specified in the manufacturer’s and operator’s documents, notably with respect to the configuration and the reduction in speed, while at the same time, adapting to the operational context of the flight. The implementation of the CRM principles and in particular, appropriate monitoring by the PM, shall contribute to the management of the aeroplane’s energy.
Incorrectly managed energy exposes the crew to the risks of a runway excursion, a hard landing, landing before the runway, a tailstrike or even a stall.
1. Non-stabilized approach, long landing, runway overrun
The Embraer EMB145 registered F-HYOG ran over the end of the runway while landing at Paris-Orly on 20 October 2022 in stormy conditions. The investigation showed that weak CRM contributed to the final approach being flown at a speed which was too high, above the approach slope and in a different configuration to that specified in the briefing. The crew did not detect the change in wind direction with a tailwind component which had become significant. The PM’s uncoordinated intervention on the controls to the detriment of his required monitoring role, meant that the crew did not envisage carrying out a missed approach. This resulted in a long landing at high speed.
2. Non-stabilized approach, activation of MSAW and Glide Slope alerts
The investigation into the incident to the Airbus A318 registered F-GUGM on 12 September 2020 during the approach to Paris-Orly showed that the crew who were not under any outside pressure, carried out a high-speed approach and continued with the landing despite being largely destabilized. The MSAW alert (Minimum Safe Altitude Warning available to air traffic controllers at certain aerodromes) and the Glide Slope alert (on the aircraft) were triggered during the approach. The investigation found that the crew carried out the approach outside the scope of SOPs and did not follow the flight profile recommended by the manufacturer. This profile enables the crew to manage the approach energy in a manner which is compatible with a safe landing. During the final approach, the crew’s focus on reabsorbing the excessive energy contributed to a deterioration in the monitoring by the PM. At 500 ft agl, the aeroplane was at a speed of Vref+26 kt. The report underlined that without being aware of it, the crew at this point, probably had very few mental resources available to deal with an unexpected event.
3. Acquisition of a false glide slope signal on approach, increase in pitch attitude with autopilot engaged, activation of the flight envelope protections
The investigation into the incident to the Airbus A318 registered F-GUGD on 20 December 2019 on approach to Hyères showed that the crew had taken into account the tailwind threat for landing. However, they did not take into account the prior impact of this component on the approach path. In a short space of time, the crew tried to control the speed and intercept the glide slope from above. They progressively lost situational awareness: they did not detect that the aeroplane levelled off or the change in pitch attitude when the guidance system intercepted a false glide slope signal. The LOW ENERGY alert and the ALPHA FLOOR protection were activated.
4. PREDICTIVE WINDSHEAR warning on final, partial and subtle incapacitation of co-pilot during go-around, lateral and vertical flight path deviations, LOW ENERGY alert, conflict with a departing aeroplane
During the incident to the Airbus A350-900 registered F-HREV on 4 February 2020 at Paris-Orly, the captain, who was initially the PM, had to take the aeroplane’s controls in an uncoordinated manner during the missed approach phase following a WINDSHEAR AHEAD warning and the copilot’s (initially PF) subtle incapacitation. In this extremely dynamic phase, large variations in energy were observed, shown by several variations in altitude well above and below the go-around altitude along with the activation of the LOW ENERGY alert.
5. Disconnection of autothrust on final, activation of AOA limiter protection
On 28 January 2019, at the end of the initial approach to Mascate (Oman), the crew of the Airbus A320 registered SX-ODS, who were being radar vectored, set the flaps to position 1. At 2,260 ft, at an indicated airspeed of 186 kt and when the vertical speed was 2,100 ft/min, the captain (PM) disconnected the autopilot and took the controls. During the right turn onto final, at 1,840 ft, the captain disconnected the A/THR by reducing the power to idle. On final, the controls were returned to the copilot. With the autothrust disconnected and the thrust levers set to IDLE, the aeroplane’s speed decreased. At 290 ft, when the indicated airspeed was 116 kt, the ALPHA FLOOR protection was activated and the thrust increased to TOGA. The minimum altitude recorded before partially intercepting the approach slope was 210 ft.
During the flare for landing on runway 27L at London Heathrow on 2 January 2022, the Airbus A350-1000 registered G-XWBC “floated” and the crew believed it would not land within the runway touchdown zone. A go-around was initiated at low height and low speed. It took several seconds for the engine in IDLE to develop TOGA thrust. The aeroplane, which had insufficient energy to immediately gain height, came into contact with the ground. At this point, the pitch-rate applied in order to continue the go-around caused the aeroplane to pitch up to such an extent that the tail struck the runway.
