A350 goes astray as Pilot incapacitation occurs over Paris

The Airbus A350 was on final approach at Orly Airport in Paris. Two minutes to touchdown, the aircraft systems warn the crew of a wind-shear prediction on their path. The crew discontinue the approach and fly the missed approach procedure. Safety is compromised. The aircraft climbs over their assigned altitude and strays away from their designated path. There is another aircraft taking off nearby.

There is a struggle by both crews to comprehend what was going on. Finally, the crew manages to engage the auto-pilot(AP) that they had disengaged before the predictive wind shear warning. Probably the crew failed to notice this change. In reality, for those few minutes, no one was flying the aircraft. Cognitive incapacitation sets in.

Flight Path
The investigation

The French authorities (BEA) investigate the incident. The Final Report is available here. The key points are:

  1. Inadequate Go-Around preparedness
  2. Startle effect
  3. Cognitive incapacitation
  4. Mode awareness
mindFly analysis

The safety investigation focuses on the pilot flying i.e. the co-pilot. However, there are three pilots in the cockpit. The investigation and many other investigations have focussed on the pilot flying and the errors committed. The investigations fail to look at the collective action and the action of other crew in the cockpit. NTSB investigated the Air Canada 759 incident at San Francisco. The crew did not sight multiple aircraft on the taxiway. The safety investigators did not examine the role of the co-pilot as a pilot monitoring and supporting pilot in-depth. In this incident, the report states that cognitive incapacitation affected only the pilot flying, i.e. the Co-Pilot. In reality, incapacitation affects all three pilots. When the Co-Pilot failed to control the aircraft trajectory, the Captain too failed to notice the change of AP disconnection. The same goes for the relief pilot. Both the Captain & Co-Pilot were trying to give inputs to the automation through the FCU panel but failed since the AP was not engaged.

Change blindness

The Co-Pilot flying the approach at Orly disconnects the autopilot and almost simultaneously gets a safety predictive wind shear warning. Change blindness is defined as the failure to detect when a change is made to a visual stimulus (Simons and Levin, 1997). It occurs when the local visual transient produced by a change is obscured by a larger visual transient, such as an eye blink (O’Regan et al., 2000), saccadic eye movement (Grimes, 1996McConkie and Currie, 1996), screen flicker (Rensink et al., 1997), or a cut or pan in a motion picture (Simons, 1996Levin and Simons, 1997); or when the local visual transient produced by a change coincides with multiple local transients at other locations, known as mud-splashes, which act as distractions, causing the change to be disregarded (O’Regan et al., 1999).

Both crews did not notice that the AP is not connected. The predictive wind shear warning was the bigger change. The Captain selected a southerly heading but the aircraft did not turn and the crew did not comprehend.

In-attentional deafness

The aircraft deviated from the assigned altitude and the safety C chord alert triggered. The C chord sounded for about 54 seconds (view the video at the end). The crew did not act to correct the flight path for almost 17 seconds. Thereafter they selected Open Descent. This long interval could be due to the crew’s attention focussed on a particular area. During In-attentional Deafness, Visual Load Leads to Time-Specific Suppression of Auditory Evoked Responses (https://doi.org/10.1523/JNEUROSCI.2931-15.2015).

Load-induced modulation of visual responses leads to the phenomenon of “inattentional blindness”: observers fail to notice unattended stimuli when these are presented during task conditions of high perceptual load (Cartwright-Finch and Lavie, 2007). This occurs even when subjects are instructed to detect any additional stimuli beyond the task set (for review, see Macdonald and Lavie, 2008Carmel et al., 2011Lavie et al., 2014).

Startle V/S Surprise

There is a difference between startle and Surprise. The safety investigation focuses on Startle but the event is a Surprise even (The para header is ‘Surprise’ though). The psychology of surprise is about how people respond to unexpected events (Wickens, 2001). A response to a sudden, intense stimulus causes Startle. When the crew is not prepared for the moment, they are taken by surprise. It can also trigger when a strategy deployed does not work as expected. Startle and surprise are often cited as potentially contributing factors to aircraft incidents due to their possible negative effects on flight crew performance. For further understanding please read my blog on the subject.

Strartle v/s Surprise
Pilot Monitoring

Pilot’s are expected to demonstrate certain competencies and observable behaviors. Of the 9 competencies, Pilot Monitoring is not a defined competency. Trainers may club it under situational awareness. It is however an important subject. In the study by BEA on Go Around awareness, the survey indicates that many pilot monitoring (PM’s) do not know where and when to look during a go-around. Therefore, ‘Pilot Monitoring’ must be included in the list of pilot competencies.

BEA (France) Investigation Video
FMA Call outs

Flight Mode Annunciator call outs are mandatory. They are also helpful in enhancing mode awareness, a part of situational awareness. During approach and especially a go-around, they present the current of automation engagement and armed status. It is difficult asking the Pilot Flying to call out all the FMA changes especially in a highly coupled go-around. It could help if the Pilot Monitoring could make FMA call out changes. The PM will stay in loop and secondly present the correct picture of automation engagement status. In most go-arounds, from my experience there has been no FMA calls by the pilot flying due to preoccupation with the maneuver.

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