History of flight
At the overnight into 19.03.2016 the Flydubai airline flight crew, consisting of the PIC and F/O, was performing the round-trip international scheduled passenger flight FDB 981/982 on route Dubai (OMDB) – Rostov-on-Don (URRR) – Dubai (OMDB) on the B737-8KN A6-FDN aircraft.
At 18:37 on 18.03.2016 the aircraft took off from the Dubai airport. The flight had been performed in IFR. At 18:59:30 FL360 was reached. The further flight has been performed on this very FL. The descent from FL has been initiated at 22:17. Before starting the descent, the crew contacted the ATC on the Rostov-on-Don airport actual weather and the active RWY data. In progress of the glide path descent to perform landing with magnetic heading 218° (RWY22) the crew relayed the presence of “windshear” on final to the ATC (as per the aboard windshear warning system activation).
At 22:42:05 from the altitude of 1080 ft (330 m) above runway level performed go-around. Further on the flight was proceeded at the holding area, first on FL080, then on FL150. At 00:23 on 19.03.2016, the crew requested descent for another approach. It was an ILS approach. The A/P was disengaged by the crew at the altitude of 2165 ft QNH (575 m QFE), and the A/T at the altitude of 1960 ft QNH (510 m QFE). .
In the progress of another approach the crew made the decision to initiate go-around and at 00:40:50, from the altitude of 830 ft (253 m) above the runway level, started the maneuver. After the reach of the altitude of 3350 ft (1020 m) above the runway level the aircraft transitioned to a steep descent and at 00:41:49 impacted the ground (it collided the surface of the artificial runway at the distance of about 120 m off the RWY22 threshold) with the nose-down pitch of about 50⁰ and IAS about 340 kt (630 km/h).
The remains of A6-FDN reassembled in a hangar for the investigation
Conclusion
The fatal air accident to the Boeing 737-8KN A6-FDN aircraft occurred during the second go around, due to an incorrect aircraft configuration and crew piloting, the subsequent loss of PIC’s situational awareness in nighttime in IMC. This resulted in a loss of control of the aircraft and its impact with the ground. The accident is classified as Loss of Control In-Flight (LOC-I) occurrence.
Contributing Factors
Most probably, the contributing factors to the accident were:
- the presence of turbulence and gusty wind with the parameters, classified as a moderateto- strong “windshear” that resulted in the need to perform two go-arounds;
- the lack of psychological readiness (not go-around minded) of the PIC to perform the second go-around as he had the dominant mindset on the landing performance exactly at the destination aerodrome, having formed out of the “emotional distress” after the first unsuccessful approach (despite the RWY had been in sight and the aircraft stabilized on the glide path, the PIC had been forced to initiate go-around due to the windshear warning activation), concern on the potential exceedance of the duty time to perform the return flight and the recommendation of the airline on the priority of landing at the destination aerodrome;
- the loss of the PIC’s leadership in the crew after the initiation of go-around and his “confusion” that led to the impossibility of the on-time transition of the flight mental mode from “approach with landing” into “go-around”;
- the absence of the instructions of the maneuver type specification at the go-around callout in the aircraft manufacturer documentation and the airline OM;
- the crew’s uncoordinated actions during the second go-around: on the low weight aircraft the crew was performing the standard go-around procedure (with the retraction of landing gear and flaps), but with the maximum available thrust, consistent with the Windshear Escape Maneuver procedure that led to the generation of the substantial excessive nose-up moment and significant (up to 50 lb/23 kg) “pushing” forces on the control column to counteract it;
- the failure of the PIC within a long time to create the pitch, required to perform goaround and maintain the required climb profile while piloting aircraft unbalanced in forces;
- the PIC’s insufficient knowledge and skills on the stabilizer manual trim operation, which led to the long-time (for 12 sec) continuous stabilizer nose-down trim with the subsequent substantial imbalance of the aircraft and its upset encounter with the generation of the negative G, which the crew had not been prepared to. The potential impact of the somatogravic “pitch-up illusion” on the PIC might have contributed to the long keeping the stabilizer trim switches pressed;
- the psychological incapacitation of the PIC that resulted in his total spatial disorientation, did not allow him to respond to the correct prompts of the F/O;
- the absence of the criteria of the psychological incapacitation in the airline OM, which prevented the F/O from the in-time recognition of the situation and undertaking more decisive actions;
- the possible «operational» tiredness of the crew: by the time of the accident the crew had been proceeding the flight for 6 hours, of which 2 hours under intense workload that implied the need to make non-standard decisions; in this context the fatal accident occurred at the worst possible time in terms of the circadian rhythms, when the human performance is severely degraded and is at its lower level along with the increase of the risk of errors.
- The lack of the objective information on the HUD operation (there were no flight tests of the unit carried out into the entire range of the operational G, including the negative ones; the impossibility to reproduce the real HUD readings in the progress of the accident flight, that is the image the pilot was watching with the consideration of his posture in the seat trough the stream video or at the FFS) did not allow making conclusion on its possible impact on the flight outcome. At the same time the investigation team is of the opinion that the specific features of the HUD indication and display in conditions existed during final phase of the accident flight (severe turbulence, the aircraft upset encounter with the resulting negative G, the significant difference between the actual and the target flight path) that generally do not occur under conditions of the standard simulator sessions, could have affected the situational awareness of the PIC, having been in the highly stressed state.
Safety Recommendations
It is recommended that FATA
5.1. Inform the flight personnel, the air training centers staff and the ATC officers on the results of the investigation in question at the subject-oriented debriefing meetings. 5.2. Consider the possibility of expediting of the Russian Federation transition to the flight operations on QNH. 5.3. Draw the attention of organizations, engaged in the aviation personnel testing for their compliance with the ICAO Language Proficiency Requirements, to the need for enhanced monitoring of the raters-examiners’ activities, as well as further develop the measures to exclude the assignment of the ICAO language proficiency level to persons, whose level in question does not meet the subject requirements. 5.4. Draw the attention of the air navigation service providers to the need for enhanced monitoring and responsibility of the instructor personnel, engaged in the officers’ simulator training, inter alia of the adherence to the R/T rules in English. 5.5. In association with Roshydromet and the State ATM Corporation, FSUE organize training with the ATC and meteorological services officers on the procedure of the information communication on windshear to the flight crews. 5.6. In view of the position of the aircraft manufacturer that the Boeing 737-800 operational documentation implies the presence of the pilots’ previous experience of operating the jet multiengine aircraft, familiarization with the basic systems and basic airmanship, assess the risks of the pilots’ approval for the type in case it is the first jet multi-engine airplane in the pilot’s career. If required, amend the current regulations. Assess the applicability of this safety recommendation as for the other aircraft types.
It is recommended that the Flydubai airline
5.7. Conduct the flight personnel training on the specific aspects of the stabilizer trim manual operation (the forces trim). 5.8. Consider the practicability of the HUD Model 4000 changing to Model 6000 (STC ST02522SE) to equip both pilots’ duty stations. 5.9. In association with the aircraft and HGS manufacturers, consider the practicability of the development of the additional instructional guidelines on the HUD use at the different stages of flight. 5.10. Consider the practicability of the elaboration of the flight personnel training programs, allowing for the incorporation of the practical familiarization (training) of the pilots with the upset conditions, including zero and negative G state. 5.11. Consider the practicability to amend the airline OM with the criteria of the psychological incapacitation and the respective recommended actions. 5.12. Consider the practicability of the elaboration of SOP in terms of specifying the type of the next maneuver (for example Go-Around, Windshear Escape Maneuver) as far as the callout by the PF is concerned37. 5.13. Consider the practicability to elaborate SOP in terms of monitoring of the trim duration and the current stabilizer position. 5.14. Evaluate the possible risks, associated with the partial blocking of the PFD at the significant forward deflection of the control column and take measures on the risks mitigation (if required).
It is recommended that FAA, Rockwell-Collins
5.15. Consider the practicability of the conduct of the additional flight tests of HGS into all the anticipated operating conditions and the entire range of G of the aircraft with these systems installed. 5.16. Taking into account the views of the experts in ergonomics and aviation psychology, consider the practicability of the improvement of the HUD information presentation in order to mitigate the risk of its erroneous interpretation. 5.17. In association with the designers and manufacturers of the aircraft, equipped with the HGS, consider the practicability of development of the additional guidance on the use of HUD at different stages of flight.
It is recommended that FAA, the other certification authorities (EASA, IAC Aviation Register, FATA etc.)
5.18. Consider the practicability of the amendment of the aviation regulations with the provisions on the mandatory flight assessment of the flight parameters indication systems to pilots into the entire operating range of the aircraft with such systems installed. 5.19. Consider the practicability of the amendment of the aviation regulations that determine the procedure of the STC issue for the indication systems to pilots, with the requirement to the manufacturer of the equipment in question to have the hardware/software package available to reproduce the indication as per the FDR data in real time and in the scope, sufficient for the investigation of the aircraft accidents and incidents.
It is recommended that the Boeing Company
5.20. Consider the practicability of the amendment of the FCT 737 NG (ТМ) Low Altitude Level Off - Low Gross Weight section with more detailed information on the criteria that the pilots should follow to determine the point, when the maximum thrust should be reduced, including goaround performance in windshear.
5.21. Consider the practicability to implement the design changes of the stabilizer control system to reduce the risk for the pilot to set stabilizer in-flight into out of trim position.
5.22. Consider the practicability of the elaboration of SOP in terms of specifying the type of the Go-Around maneuver (for example Go-Around, Windshear Escape Maneuver) as far as the callout by the PF is concerned.
5.23. In association with FAA assess the possible risks, arising due to the partial blockage of PFD at considerable forward deflection of the control column and take measures on their mitigation (if necessary).
5.24. Taking into consideration the information, stated in Section 1.18.2, consider the practicability of introduction of additions and amendments to FCOM and/or FCTM, explaining the stabilizer control sequence on the Boeing 737 aircraft under different conditions. Consider the applicability of this safety recommendation for the other aircraft families.
5.25. Consider the practicability of the introduction of additions and amendments to FCOM and/or FCTM, explaining general principles of the stabilizer use and forces trim, as well as the monitoring of the current stabilizer setting.
It is recommended that ICAO
5.26. Consider the practicability of establishing a working group to study the issues of the psychological incapacitation of the flight crewmembers and elaboration of the relevant recommendations to provide guidance to the operators and States in the OM draw up and approval.
Reacting to the final report’s release, FlyDubai released a statement in which it acknowledges IAC’s conclusions and recommendations. Claiming it was fully compliant with all regulatory requirements at the time of the accident, the airline states it took its obligations “seriously” and implemented “a number” of precautionary measures since 2016. “The airline made proactive operational enhancements to both simulator and classroom training to reinforce awareness and enhance understanding of spatial disorientation,” the statement reads. “Furthermore, flydubai made additions to the manufacturer’s standard operating procedures and manuals. All pilots have been trained on these enhancements which exceed regulatory requirements.”
In August 2018, the IAC announced that preparation of the final report was being finalized, as investigators had carried out all the essential activities. However, as they also wanted to pursue additional examination of the HUD, manufactured by Rockwell Collins, visual indications, which were deemed relevant to identifying the causes of the accident and possible safety enhancements, the actual release of the findings took place over one year later ‒ December 2019. FlyDubai’s Boeing 737-800 was the first crashed aircraft with the HUD system installed on board. The IAC was weighing the feasibility of a simulator experiment to reproduce the HUD indications that would have been displayed during the accident flight. However, despite the prolonged effort to gain more insight on a HUD’s possible impact on the flight outcome, the final report concludes stating that objective information is insufficient to make said conclusion. |
A6-FDN 737-800 Loss of Control during Go-Around
