What happened
On 16 May 2019, a Diamond DA62, registration G-MDME, was conducting aerodrome ground lighting calibration checks at Dubai International Airport. The mission, operated by Flight Calibration Services Limited, involved performing various approaches and low passes over runway 30L as part of a southern runway refurbishment project. The flight was being conducted under visual flight rules (VFR).
During the tenth approach of the mission, the aircraft was following a Thai Airways Airbus A350-900 on the parallel runway 30R, maintaining a distance of approximately 3.7 nautical miles. After leveling off at roughly 1,100 feet with an airspeed of 130 knots, the aircraft experienced a brief roll that was recovered within nine seconds. However, seven seconds later, the aircraft underwent an abrupt left roll, became inverted, and entered a steep dive. The aircraft struck the ground approximately 3.5 nm from the runway 30L threshold, resulting in four fatalities.
The investigation
The UAE Air Accident Investigation Sector (AAIS) conducted an investigation into the crash, which destroyed the aircraft and caused environmental damage at the site. Investigators examined the wreckage, reviewed radar monitor recordings, and analyzed CCTV footage. The investigation also reviewed the pre-flight coordination between the flight crew, air traffic control (ATC), and airport representatives.
Radar data revealed that during previous approaches in the same flight, the G-MDME had consistently operated at distances from preceding traffic that were below the specified minimum separation and less than what had been agreed upon during the pre-departure meeting. Furthermore, investigators identified an inconsistency in how ATC communicated potential hazards, such as wake turbulence, to the aircraft.
Findings
- The aircraft was following a heavy predecessor on a parallel approach at a distance that was below the required minimum separation.
- The aircraft encountered significant aerodynamic disturbances while following the larger Airbus A350-900.
- There was a lack of consistent communication from ATC regarding the expected hazards caused by wake turbulence from traffic on the parallel runway.
- While the crew had agreed to apply their own separation under VFR, the actual separation maintained was insufficient to mitigate the risks of wake turbulence.