Table of Contents Hide
- Brief Description of the Occurrence
- Investigation Agency
- Details of the Investigation
- Initiating the Landing Approach
- What did the Aircrew not do?
- Point of Interest during the Investigation
- The last few minutes!
- Cause of Occurence
- Wreckage Details
- Chain of Events
- Somatogravic Illusion
- Safety Standards at Afriqiyah Airways
Brief Description of the Occurrence
Afriqiyah Airways Flight 771 (Airbus A330-200) was a scheduled international flight on 12 May 2010 from Johannesburg, South Africa, to Tripoli, Libya. While making a nonprecision approach on Runway 09L of the Tripoli Airport, the aircrew initiated a ‘Go Around’ after failing to get a visual reference. The aircraft later crashed outside the airport parameters, just 1200 meters short of the intended runway 09L. The impact was forceful and disintegrated the aircraft into pieces. The aircraft also caught the post-impact fire. All 104 passengers on board died except one nine-year Dutch boy who survived the crash.
Despite all the advancements in technology and systems, humans are still the weakest link in the entire chain of events!
The Libyan Civil Aviation Authority (LYCAA) was the leading investigation agency as per ICAO Annexure 6 since the crash occurred in Libya. However, it was also assisted by the Bureau of Enquiry and Analysis for Civil Aviation Authority (BEA), France, and South African Civil Aviation Authority. Airbus also sent its technical team to Libya.
Details of the Investigation
The investigation team recovered the Flight Data Recorder and Cockpit Voice Recorder from the crash site. The information from these recorders was quite helpful to the investigators in establishing the cause of the occurrence. Some of the pertinent details of the investigation are covered here.
Initiating the Landing Approach
Prior to initiating the landing approach, the air crew contacted the Area Control Centre as per the defined procedure. The ACC cleared them for landing at Runway 09L. For the information purposes, the intended runway for landing was a non-precision approach runway which means that there are no navigation aids like ILS (Instrument Landing System) available at this end of the runway. The aircraft had to make its own landing trajectory with the help of the onboard system followed by a manual handling of the pilots.
While the ACC gave them clearance for landing, it also asked them to visualize the runway and confirm the ATC. However, The flight crew failed to get any visual ground references before initiating their approach to land. Since it was the home base for the aircrew so it should not have been an issue for the aircrew, they must have been well acquainted with this airfield. Even in the absence of a non-precision approach, radio beacons gave a reference point to the aircraft during the landing.
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What did the Aircrew not do?
The aircrew, however, had not decided to follow the onboard computer or the self-selected glide path for the landing approach. The First Officer initially set a landing managed by the onboard computers. The aircrew also received a radio call from a pilot who had just landed lately. He warned them about limited visibility due to low dark cloud layers at the short finals.
The aircrew disconnected the computer-managed approach and opted for the 3 degrees guide path approach. This action was supposed to take place at the threshold reference point of the radio beacons, but the FO did it immediately. The landing gears were brought down, and the aircraft crossed the reference threshold at 1000 feet AGL (200 feet below the prescribed altitude).
Point of Interest during the Investigation
The same aircrew on the same aircraft had experienced a similar incident a few weeks earlier when they descended too early on the same Runway 09L, and they had to abort the approach. But they never reported this incident.
The last few minutes!
The final approach was being managed by the FO and the Captain was observing him. When the aircraft reached 720 feet [Minimum Descent Altitude (MDA)], the runway was still not visual. At this stage, they had to take a decision to continue or abort the approach. The Captain decided to continue the approach. The FO did not abort the approach and continued despite not getting visual with the runway. He actually did not challenge the Captain’s decision.
The GPWS (Ground Proximity Warning System) sounded a warning at 280 feet “Too low terrain.” The Captain asked FO to execute a Go-Around. As soon as the aircraft gained 450 feet, the FO did a little nose-down movement with his joystick. The Captain immediately took the controls from FO. He increased the altitude of the aircraft and then suddenly put the nose down. A few seconds later, the aircraft impacted the ground.
Cause of Occurence
The prime cause of the occurrence was attributed to the pilot’s error. The factors contributing to the prime cause were lack of crew resource management, Somatogravic illusions (false sensory illusions), and initial side stick actions of the FO. Fatigue was also ascertained as a possible contributory factor in this accident.
The analysis of investigation is divided into different segments.
- The first picture above ( FIG 1) shows that the wreckage spread (distribution) is in the direction of the flight path. So, it was basically a high speed and shallow angle impact.
- The aircraft impacted the ground at high speed. The reason being, the nose hit the ground at the IP (Impact point) first. Due to high acceleration, the engines and wings went ahead of the nose. The vertical tail also went ahead due to the high-speed impact.
- This is typically high-speed impact wreckage.
The vertical tail got detached from the fuselage, as seen in the picture above (FIG 2). A large amount of aircraft debris can also be seen lying around the vertical tail.
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Chain of Events
- The first event in the chain had already started when the aircrew made a late decision to follow the onboard computers or the manually selected glide path for the landing approach.
- The aircrew discarded the cloud warning at short finals issued by the pilot who had landed lately at the Tripoli International Airport.
The Domino Effect Begins
- Due to the early selection of the glide path, the aircraft started to descent earlier than it should have been. With this configuration, it had already been put on a course to reach the ground well before the runway threshold, but the aircrew never cared for this grave error. The Captain and the other Relief Officer did not observe this mistake. The Domino effect had already started!
- They were already 200 feet below the prescribed altitude at the reference threshold.
- They had experienced a similar incident earlier in the near past, but they never reported it. This shows an ineffective reporting system and lack of aircrew training in the organization where employees cannot provide feedback on every encountered issue. This is the reason for repeated occurrences in aviation.
Lack of Crew Resource Management
- After reaching the MDA (Minimum Descent Approach) and further below, the Captain commanded the FO to continue approach despite not visualizing the intended runway. The FO continued the approach. A clear show of poor crew resource management.
- The aircrew made the same mistake as they did earlier a few days back. They opted for a Go-around as soon as the GPWS warned them for low terrain. Had they reviewed their earlier mistake and devised a procedure, they would not have repeated the same mistake. They failed to anticipate the potential risks associated with nonprecision approaches.
- The Captain took control and increased the altitude of the aircraft, followed by a sudden nose-down movement. Why? Because he felt and thought that too much nose-up movement might cause the aircraft to stall. He had already increased the engine power earlier to gain the altitude.
- During the last few minutes, the Captain experienced the effects of Somatogravic illusions (false sensory illusions).
- Flap and gear retraction, along with changes in thrust to achieve and maintain a specific climbing flight path, involve considerable changes in ‘acceleration.’ These changes are conducive to a Somatogravic Illusion.
- This illusion forces the brain to initiate the climb; however, it also sends a perception to the brain for excessive pitch-up movement. This leads to a fear that the aircraft might stall due to the high angle of attack. The instinctive reaction to this sensation is to push the nose down to believe that a reduction in pitch will help achieve a normal climb.
- The same phenomena occurred in this accident.
Safety Standards at Afriqiyah Airways
- Analysis of the investigation also gives some insight into the training and safety standards of the airline, and It shows that the aircrew was not trained enough to handle such a nature of emergencies. Training also seemed to be a weaker area of the airline.
- Secondly, repetition of the same mistake also suggests that the airline’s Safety Management System was not strong. Moreover, it also suggested no strong reporting or feedback system to monitor all types of minor occurrences taking place prior, during, or post-flight.
- Moreover, these factors also suggest a weak organizational culture of an airline where people tend to hide minor things (self mistakes) from the Safety and Quality department.
- These unreported incidents actually lead to major incidents.
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The organizations’ safety systems aim to mitigate risks below a certain threshold level since risk cannot be eliminated. These systems identify daily hazards in an aviation environment and manage risks accordingly. The safety records of the safest airlines show that they have a strong safety culture in their organizations.
Airlines with weaker Safety Management System (SMS) will continue to experience incidents and accidents in the future unless they become more concerned for the safety of the people on board and their own people.