What happened
On 6 June 2020, an Etihad Airways Boeing B787-10, registration A6-BMD, was conducting a cargo flight from Beijing to Abu Dhabi International Airport. While performing an RNP AR approach to runway 31L, the aircraft drifted below its intended vertical path. As the aircraft reached approximately 210 feet radio altitude and 1.3 nautical miles from the runway threshold, the crew observed four red lights on the precision approach path indicator (PAPI). Consequently, the commander decided to initiate a go-around, which was executed by the pilot flying.
The investigation
The UAE Air Accident Investigation Sector (AAIS) conducted an inquiry into the serious incident, focusing on the events leading to the vertical profile deviation. The investigation examined the flight crew's actions, the aircraft's automated systems, and the role of air traffic control. Investigators analyzed the cockpit voice recorder, flight data, and the meteorological conditions present at the time of the approach.
Findings
- The primary cause of the descent below the vertical profile was the incorrect local pressure (QNH) altimeter setting.
- The flight crew failed to update the altimeter to the local Abu Dhabi QNH after receiving the digital ATIS information.
- During the descent, the crew was heavily focused on managing high-energy flight parameters, which led to the error when transitioning from standard pressure (1013 hPa) to the local setting.
- The crew did not utilize the Vertical Situation Display (VSD) to effectively monitor the aircraft's position relative to the vertical path.
- The additional pilot on the jump seat did not provide effective monitoring of the barometric settings.
- Air traffic controllers did not provide the local QNH during initial descent clearances, nor did they alert the crew to check their settings when a minimum safe altitude warning (MSAW) was triggered on their radar.
- Reduced forward visibility due to haze layers in the region may have impacted the crew's visual assessment at higher altitudes.