Wake Turbulence Diamond DA62 Accident in Dubai (G-MDME of Flight Calibration Services) UPDATED 1 June 2020 with Final Report
On 2o June 2019 the the Air Accident Investigation Sector (AAIS) of the UAE General Civil Aviation Authority (GCAA) released their preliminary report into the loss on 16 May 2019 of Diamond DA62 G-MDME of Flight Calibration Services Ltd (FCSL) at Dubai International Airport.
The aircraft, with 4 persons on board, was flying approaches to runway 30L as part of a ground lighting calibration linked to runway refurbishment. Dubai has two parallel runways, 12R/30L and 12L/30R. The distance between the runway centerlines is approximately 380 meters. These flights were conducted under visual flight rules (VFR), with air traffic communicating with the DA62 on a separate frequency. The investigators say that:
The prevailing meteorological conditions at the time of the Accident were fine with ceiling and visibility ok (CAVOK). Low level winds were recorded at 1,000 ft with a speed of 6 kt from 020 degrees, and a speed of 11 kt from 010 degrees at 1,500 ft. Sunset on 16 May 2019 in Dubai was at 1857
At 1929, the Aircraft entered the final to runway 30L for the tenth approach, following a Thai Airways Airbus A350-900, which was flying the approach to the parallel runway 30R. The Airbus was approximately 3.7 nautical miles (nm) ahead of the DA62. When the DA62 leveled off after turning onto final at an altitude of approximately 1,100 feet (ft) and at an airspeed of approximately 130 knots (kt), it rolled slightly but was recovered after nine seconds. Seven seconds later, the [DA62] abruptly rolled to the left until it became inverted and it then entered a steep dive. The aircraft impacted the ground approximately 3.5 nm from the runway 30L threshold.
… the Aircraft impacted the ground at an elevation of approximately 130 ft while travelling at high speed in the direction opposite to the direction of flight, on a heading of approximately 100 degrees.
All four persons onboard the Aircraft sustained fatal injuries…[and]…the aircraft was destroyed by impact forces and the subsequent fire.
The Safety Investigation
The 406 MHz Emergency Locator Transmitter (ELT) installation was damaged in the impact, with the antenna and electrical cables severed from the unit. Consequently, no signals were detected from it.
The investigators state that at a meeting with the airport before the calibration flights commenced, it was agreed that:
The DA62 would apply own separation to other arriving aircraft to the parallel runway 30R while operating under VFR, which meant that ATC would not be responsible for providing wake turbulence separation.
The investigators reviewed the airport radar data:
Observations of previous approaches during the same calibration flight indicated that the DA62 consistently followed preceding traffic on approach to the parallel runway 30R at distances which were below the specified minimum separation, and less than the distances discussed during the pre-departure meeting.
The radar monitor recording indicated that there was an air traffic control (ATC) inconsistency in advising the DA62 of the expected occurrence of hazards caused by wake turbulence from traffic on approach to the parallel runway 30R. Based on these observations, the Investigation believes that there is sufficient reason to issue a prompt safety recommendation to re-emphasize to pilots and air traffic controllers the importance of maintaining a minimum safe distance and issuing essential traffic information such as advising aircraft of the expected occurrence of hazards caused by wake turbulence.
Initial Safety Actions
DANS and Dubai Airports agreed to continue the calibration flights and necessary instrument calibration flights in a sterile airport environment and issued temporary instructions for the required days, in which ATC procedures were detailed. All commercial operation…ceased during these flights on 24th, 26th and 27th May 2019.
The GCAA is in the process of publishing a Safety Decision containing mandatory requirements for ensuring that ATC procedures are developed, implemented and maintained for issuing essential traffic information, including the advice to aircraft of the expected occurrence of hazards caused by turbulent wake. Additionally, a Safety Decision is being prepared to ensure standardised procedures are developed, implemented and maintained for the management of unusual or abnormal aircraft operations, including calibration flights, as it was found that regulations, standards and recommended practices and procedures did not specifically cover the management of such operations, e.g. calibration flights.
The Operator has contacted all company pilots to raise their awareness of minimum separation criteria as detailed in a Eurocontrol document titled “European Wake Turbulence Categorisation and Separation Minima on Approach and Departure”. A training course on wake turbulence effects during take-off and landing, and a practical upset recovery training is being developed. The Operator is in the process of reviewing the procedures and processes for calibration flights.
Preliminary Safety Recommendation
In their Preliminary report the AAIS recommended that:
The GCAA issue a safety alert to all air navigation service providers in the United Arab Emirates and to all operators of light aircraft, to enhance awareness among pilots and air traffic controllers of their separation procedures, particularly under visual flight rules.
Final Report (UPDATE 1 June 2020)
GCAA AAIS have issued their final report.
GCAA AAIS Findings
(a) The Aircraft was certified, equipped, and maintained in accordance with the existing requirements of the Civil Aviation Regulations of the European Union Aviation Safety Agency (EASA) and the Civil Aviation Authority of the United Kingdom (UK CAA).
(b) The Aircraft was manufactured in November 2017 and had accumulated a total of 720 hours and 337 flights.
(d) A deferred defect related to unserviceable auxiliary fuel tank gauges was recorded in the Acceptable Deferred Defects Record.
(e) The onboard reference pages to the Airplane Flight Manual had not been revised and were out of date.
(f) An onboard flight data recording system was not required to be fitted to the Aircraft.
Flight Crew and Flight Operations Findings
(a) The flight crewmembers were licensed and qualified for the flight in accordance with the existing requirements of the Civil Aviation Regulations of the UK CAA.
(b) The flight crewmembers were well-rested prior to the flight.
(c) The Commander was most likely the pilot in control of the Aircraft.
(d) The Commander did not file a new flight plan, but informed ATC verbally about the number of persons onboard prior to taxiing at OMDB.
(e) The Aircraft took off from OMDB with a higher than permissible maximum take-off weight.
(f) The Aircraft’s center of gravity during takeoff could not be determined.
(g) On the positioning flight from OMSJ, the flight crew elected to remain above the approach path of the preceding air traffic.
(h) According to international standards, separation from other traffic during VFR flights is provided by the commander.
(i) On the approaches during the VFR calibration flight, the self-separation to other air traffic was less than the ICAO recommended IFR wake turbulence separation, and less than the increased separation provided by ATC.
The investigators comment in Section 1.17.2 that:
FCSL generally operates the DA62 with two pilots for positioning flights and for operation of flight missions. However, the FCSL Operations Manual does not provide flight operations procedures specific to a multi-crew environment.
They note in Sections 2.3. 2.4 and 2.6 that:
The Operator did not provide the flight crew with upset recovery training. The Investigation could not determine whether this would have provided the Commander with skills to react differently and recover the Aircraft.
The Commander was sufficiently aware of the specific runway arrangement at Dubai International Airport, where he had performed calibration flights on a number of occasions. In his email, he advised that on many of the circuits, he “can tighten things significantly”. His statement that he was “content to be tighter than the IFR wake minima behind aircraft positioning for the other runway” indicated that he had underestimated the risks associated with wake vortices. This attitude was exhibited by the Commander during the meeting prior to the calibration flight on the day of the Accident, where his only concern was about A380 generated wake vortices.
The personal attributes of both pilots describe a steep trans-cockpit authority gradient, where the Commander was in charge and the Copilot would have found it difficult to challenge the Commander’s decisions.
Operator Organisational Findings
(a) The Operator’s flight inspection service was approved by the UK CAA for the purpose of inspecting air traffic service equipment within the United Kingdom.
(b) As a provider of a UK CAA-approved flight inspection service, the Operator used approved flight inspection equipment, software, operating instructions, and aircraft types.
(c) The Operator filed an online declaration with the UK CAA for commercial calibration flights in 2017, in accordance with EASA Part-SPO.
(d) According to the Operator’s information, the company had been a UK CAA approved flight inspection organization since 2005.
(e) It could not be confirmed by the Investigation that the UK CAA had audited the Operator’s flight operation activities and procedures prior to the Accident.
(f) [A one day] audit of the Operator [by a single inpsector of the UK CAA General Aviation Unit] following the Accident identified 18 Level Two findings, not relevant to the circumstances of the Accident.
The investigators also comment in Section 1.17.1 that:
FCSL owned and operated six flight inspection aircraft, comprising one Piper Chieftain PA31 and five Diamond DA62s. Two of the aircraft were permanently based at FCSL’s maintenance facility at Sharjah International Airport, the United Arab Emirates.
Section 2.10 states:
According to [the operator's SMS] manual, the company directors have the final accountability for all safety issues. In the interview with the CEO, it was established that he delegated his SMS accountability and responsibility to operational managers. The CEO referred to his role as a “financial director” who had no role in the SMS, and he excluded himself from all SMS functions. The director responsible for flight operations was acting as Safety Manager and had been designated as the accountable manager [sic] for the SMS. During the review of the SMS manual and the interview with the CEO, the Investigation noticed that the described procedures and the day-to-day management of the Operator’s SMS did not align. The Investigation found that some SMS functions, such as reporting of occurrences or a verbal risk assessment, were present within FCSL. However, the management’s attitude towards the SMS, the delegation of safety accountabilities and responsibilities, nonconformances with SMS procedures, did not ensure the effective management of safety.
Section 2.11-2.13 state:
EASA’s regulations are not intended to approve commercial specialized operations under EASA Part-SPO Specialized Operation. However, the information requested by [the UK CAA] online declaration process is primarily collecting administrative information and is not adequate to determine probable operational risks.
An accountable manager officially declares that the management system documentation including the operations manual reflect the applicable Part-SPO requirements, that all flights will be carried out in accordance with the procedures and instructions specified in the operations manual, and that all flight crew members, are trained in accordance with the applicable requirements. The UK CAA inspector responsible for an operator’s declaration may request additional information, if required. However, the UK CAA advised that on-site audits of an operator under Part-SPO may not be conducted for up to four years from the date of declaration.
The Investigation is concerned that the process adopted by the UK CAA, reflected a self-regulating approach for a sector in the commercial aviation service industry, which was not adequately developed. This approach lacks the regulatory and safety oversight that is expected by the public and organizations requesting these services within the UK or internationally.
When the Operator extended their aviation activities beyond UK borders, the General Civil Aviation Authority of the UAE requested a no-objection statement from the UK CAA, as they relied on the UK CAA’s understanding and regulatory oversight of the Operator.
As a result of the Accident, the UK CAA conducted a one-person, one-day oversight audit of the Operator on 30 July 2019. The Air Accident Investigation Sector of the United Arab Emirates issued a Preliminary Investigation Report on 20 June 2019, which provided basic factual information as was evident at the time. The ‘History of Flight’ section of the Preliminary Report provided information regarding the identified self-separation issues between the DA62 and the preceding Airbus A350. However, the scope of the audit was not relevant to the known factual information contained in the Preliminary Report. Instead, the audit report stated that “Generally, there were good procedures in place and the company is active in developing new equipment for flight calibration.”
The audit identified a total of 18 Level Two findings, including 16 findings of issues related to the content of the Operations Manual. A review of these issues identified that they were most likely already present when the Operator filed the initial declaration for EASA Part-SPO in 2017 and during six declarations which were re-filed since then. The Investigation is concerned about the UK CAA approach to accepting commercial UK aviation service providers, and their conduct of regulatory oversight of operations under EASA Part-SPO Specialised Operations. The July 2019 audit appears to have been the CAA’s first oversight activity since the Operator started operation in 2005. Although a fatal Accident occurred, minimal resources were deployed for an audit scope that resembled a baseline audit. The auditor’s acceptance of missing procedures, missing forms, and incomplete hazard logs reflected an inappropriate reaction by the UK CAA to the fatal Accident and the inherent risks of the operation.
(a) The online declaration application facilitated by the UK CAA, based on EASA Part SPO, did not provide sufficient information for the UK CAA to establish a relevant risk profile for the Operator’s activities.
(b) Wake vortices from the A350, recorded by the LIDAR station DXB2, had drifted into the approach path of runway 30L at the time of the DA62’s loss of control.
We observe that oddly no findings directly related to the airport, ANSP or the local regulator.
GCAA AAIS Probable Cause and Contributory Factors
AAIS confirmed that the accident..
…was due to an in-flight loss of control during the approach to runway 30L caused by an encounter with wake vortices generated by a preceding Airbus A350-900 aircraft, which was approximately 3.7 nm and 90 seconds ahead on the approach to runway 30R.
They determined the contributory factors to be:
…the Commander’s decision to reduce the self-separation from preceding air traffic during approaches to runway 30R, and wind conditions in which the wake vortices from the approach path to runway 30R drifted across into the approach path to runway 30L, were contributing factors to the Accident.
The Operator lacked an effective safety management system, which prevented the identification of operational hazards during calibration flights, in particular calibration flights carried out at airports during times when more than one runway is in operation.
The UK CAA did not exercise effective oversight of the Operator. This prevented an informed baseline assessment of operational risk, and resulted in the Operator providing commercial aviation services without adequate regulatory involvement.
dans and Dubai Airports continued the calibration flights in May 2019 in a sterile airport environment, where only other VFR aircraft in a lower or the same wake turbulence category, were permitted to operate. Meetings with stakeholders were recorded and acknowledged by all participants. A 4-minute separation was applied to departing and arriving IFR aircraft, with information provided on the aircraft wake turbulence category and a caution of possible wake turbulence. Flight Calibration Services Limited (FCSL) was required to provide a safety assessment and concept of operations to dans, which included all calibration activities.
FCSL contacted all company pilots to raise their awareness of minimum self-separation criteria as detailed in a Eurocontrol document titled European Wake Turbulence Categorizations and Separation Minima on Approach and Departure. A training course on wake turbulence effects during takeoff and landing, and practical upset recovery training was developed.
As a result of the UK CAA’s own audit of its oversight work, the UK CAA has reviewed the working processes to assess operational risks of newly declared SPO operators and are in the process of changing how it verifies the operators’ continued compliance with the applicable requirements in accordance with EASA Air Operations Regulation ARO.GEN.300 Oversight (a)(2). The UK CAA reviewed and are in the process of changing the online declaration form to include more information in order for the inspector to better assess the complexity and operational risks posed by the operator. General Aviation Part-SPO operators and processes were reviewed to include an added assessment of complexity and an audit during the first 12 months from the date of declaration for new operators. Those operators who have already declared and are not already known to the UK CAA in terms of other oversight functions, will be subject to an on-site audit over the next 12 months. FSCL’s operation was re-assessed as ‘high complexity’ and will require an audit by the UK CAA every 12 months. The UK CAA received responses from FSCL to the audit findings. Sixteen of the eighteen findings were viewed as sufficiently rectified and closed. The next on-site audit was scheduled for July 2020.
GCAA AAIS Safety Recommendations
- As a result of the investigation, the AAIS issued a number of safety recommendations to EASA and the UK CAA requesting them to review the oversight requirements and processes, and to equip commercially operated light aircraft with cockpit image and audio recording systems.
- The AAIS made recommendations to the operator to conduct a comprehensive review to improve the safety management system and the effectiveness of its pilot training with particular attention on pilot decision-making.
- Recommendations were issued to the GCAA to ensure that UAE air navigation service providers review working processes for air traffic controllers, to ensure that the risk of wake turbulence encounters to calibration flights was mitigated.
- The AAIS recommended that Dubai Airports review and enhance existing risk assessment and mitigation measures for calibration flights, and that the air navigation service provider review and enhance the air traffic services manual and other relevant instructions to consistently provide essential traffic information, and to review and enhance existing calibration flight procedures to effectively mitigate the risk of wake turbulence encounters.
- The AAIS finally recommended that Transport Canada, as the state of certification and design, review the emergency locator transmitter system installation on the DA62 to improve the crashworthiness of the system, and consequently, the survivability of the occupants in the case of an accident
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