Understanding human limitations in the cockpit for flight safety

BySebina Muwanga

Understanding human limitations in the cockpit for flight safety

A recent study by the Harvard School of Public Health involving 3500 pilots, revealed that 12.6 per cent of the study group may have clinical depression, and 4.1 per cent reported having suicidal thoughts two weeks prior to the study.

These figures do not make for good reading and will give frequent flyers a reality check. Pilots are not superhuman. The brighter side is that these conditions are attributed to factors outside the cockpit and there are known medical procedures to manage and treat them.

Clinical depression has known symptoms and is visible. It can be noticed by the individual or other crew members in time before they get into the cockpit.

However, there exists an invisible hazard, a serious concern for the aviation industry. It is encountered by most pilots who fly long enough in their career and could set in involuntarily during flight. Worse still, it affects normal pilots- even those with plenty of experience- and is mostly discovered by investigators after fatal accidents.

Spatial Disorientation

This is the inability of a pilot to correctly interpret aircraft attitude, altitude or airspeed in relation to the earth or other points of reference.

In order to know the causes of spatial disorientation, there is need to understand spatial orientation. This is the natural ability to maintain body posture or orientation in relation to the surrounding environment; the ability to know when one is sitting, standing, walking, looking up or down, looking left or right.

Spatial orientation is controlled by three systems; visual (eyes), vestibular (balance organs in the ears) and proprioceptive (limbs).  When on the ground, a human body coordinates all three with ease. Eyes provide visual reference, canals in the ears are responsible for lateral and vertical direction, pressure on the buttocks is an indicator of sitting while pressure on the feet and ankles is indicative of standing.

The visual system accounts for 80 per cent of spatial orientation while 20 per cent is shared by the other two systems.

Flying over the ocean on a moonless night deprives pilots use of the visual system for orientation. In such instances, and also when visibility is poor during bad weather and low cloud, crew use onboard instruments to navigate.

Pilots must undergo 40 hours of instrument rating training in order for their brains to get accustomed to relying on instruments, without any external visual reference for guidance.

However, competence and confidence to fly with instrument guidance does not completely eliminate the possibility of spatial disorientation. This is because during instrument flight, pilots do not use vision for external references, yet this is their most important orientation system.

Further, the human body is designed to maintain spatial orientation on the ground, not in the cockpit where it is subjected to acceleration and G-forces.

Loss of Situational Awareness

Aircraft accidents are never attributed to a single factor. Investigators consider multiple factors beginning with managerial failure, supervisory failure, factors contributing to the accident, and finally, the actual cause of the accident.

In accidents where spatial disorientation is determined to be a contributing factor, the crash is always preceded by a series of errors and omissions, leading to a high work load and stress.

During this period, pilots are overwhelmed with interpreting aural and visual information, flying the aircraft and coordinating with air traffic control. This places them in a situation conducive to confusion, loss of situational awareness, and ultimately, disorientation.

Using the analogy of a pitch black house where lights have gone out unexpectedly because of a blown fuse, an individual is bound to get confused if, within a space of 20 seconds, he/she has to;

  • Attend to wailing toddlers traumatized by sudden darkness in another room,
  • Answer a call on a cell phone ringing incessantly,
  • Try and figure out why the lights are out,
  • Call for help from other occupants within the building.

When all this happens at the same time, in the absence of vision, panic and confusion are likely to set in. During the process of moving quickly from one room to another, there is a possibility of missing the exit/entry point and colliding with a wall, chair, door, or missing a step.

The fact that this individual has occupied the same house for many years might count for nothing during the 20 second period. The suddenly high workload leads to confusion and stress, causing the individual to lose situational awareness and forget existence of known obstacles or dangers, like furniture and stairs.

In such a scenario, the individual’s first priority should be to restore vision before attending to other matters. This preempts panic, restores awareness, and averts potential accidents.

It is a lot more complicated for cockpit crew travelling at high speed without external visual references, in close proximity to the ground and with loads of information to process within a short time. Pilots may find themselves operating beyond the limits of the normal human orientation systems, and in the process, failing to manage situations.

Spatial disorientation has been determined to be a contributing factor in a number of air crash accidents. The final investigation reports in respect of Kenya Airways flight 507, Ethiopian Airlines flight 409, Flash Airlines flight 604 and Gulf Air flight 072 have the following in common;

  • Crew deviated from standard operating procedures laid down in the airline operations manuals, leading to a series of errors and omissions.
  • Control was lost as the aircraft accelerated either just after takeoff, or while executing a “go around” following an aborted landing.
  • The planes crashed at night, in Instrument Meteorological Conditions with no external visual references available to the crew.
  • Crew thought the aircraft were climbing and pushed back on the controls to initiate descent.
  • Crew did not realize how close they were to the ground, despite receiving several aural ground proximity warning alerts.
  • Inappropriate “nose down” flight control inputs by the crew explains why the planes crashed.
  • Crew lost situational awareness and did not react appropriately to correct the improper aircraft altitude and attitude.
  • Crew lost control of the aircraft during intense work load periods.
  • There was a breakdown of crew resource management as the pilots failed to work and coordinate as a team.
  • The first officers could have recovered the aircraft if they had asserted their authority and intervened to correct the inappropriate flight control inputs by the pilots in command.
  • There was no indication of malfunctioning of navigational instruments, and the aircraft could have been saved if the crew had used them for guidance.
  • All planes were airworthy, and there were no technical defects that could have affected flight safety.
  • Crew were licensed and rated on aircraft type.
  • Crew were medically fit to fly, with no known condition that could have affected their ability at the controls.
  • Investigators concluded that spatial disorientation was a contributing factor in all these accidents.
  • Investigators recommended improvement in crew resource management training and strict adherence to standard operating procedures.

At the time of writing this article, the final report on the crash of Fly Dubai flight 981 has not yet been published. Although the interim report is silent on the matter, the circumstances of the crash, and conduct of the crew as stated in the interim report factual information suggests evidence of spatial disorientation.

Be that as it may, frequent flyers need not worry about night flying or pilot limitations, because air travel is still the safest mode of transport, with ever improving statistics. According to IATA’s 2015 Safety Report, there was one major jet aircraft accident for every 3.1 million flights in 2015, an improvement from one in every 2.2 million flights for the period between 2010 and 2014.

Safety is the aviation industry’s highest priority. It is defined by the International Civil Aviation Organization as,” the state in which the possibility of harm to persons or of property damage is reduced to, and maintained at or below, an acceptable level through a continuing process of hazard identification and safety risk management”.

Despite improvements in aircraft technology and automation, hazards and risks cannot be completely eliminated because of human limitations and the environment in which aircraft operate-altitude, speed, temperature and weather. Risk is part of every flight, and can only be eliminated if planes never take to the skies.

In order to manage risk, airlines make safety part of their corporate culture. They constantly review and update their operating procedures. Crew resource management, human performance, safety management and upset recovery are an integral part of initial and recurrent training programs. Pilots are evaluated through regular medical tests and simulator training. Such training allows them build and maintain situational awareness. They can question their senior colleagues and take command of the aircraft should they observe incapacitation, inappropriate control inputs, or departure from standard operating procedures. It also prepares them for team work and coordination of tasks in the cockpit.

Voluntary non-punitive reporting programs encourage crew to report accidental errors and omissions during flight. This allows airlines document reported hazards, and take corrective action either through training or reviewing operating procedures.

Aircraft manufacturers increasingly involve human factors and biomechanics experts during the cockpit layout and instrument design phase. As a result, modern cockpits have improved ergonomics, and behavioral data is more accurate, thanks to hi-tech simulation.

Certifying agencies support airlines by sending advisory circulars and guidance material should a need to change training, operating or maintenance procedures arise.

Finally, regulatory agencies are vigilant in their oversight function.

While accidents and incidents may not be completely eliminated, the message to frequent flyers is, the air transport industry constantly identifies hazards, takes corrective action, and maintains risks at acceptable levels. Manufacturers, operators, training organizations and regulators work together to deliver the industry’s highest priority.

The skies are a lot safer today, thanks to lessons learned from past tragedies.

Get someone else to read by sharing:
Follow by Email

About the Author

Sebina Muwanga contributor

Sebina is an Air Transport Regulation consultant based in Kampala, Uganda. He is passionate about aviation law and safety regulations. T:@sebina_muwanga, E: mhsebina@gmail.com

  • Wanjala Daniel

    Thanks Mr. Sebina for the article on situational awareness. Would the research and innovation around automation and remotely piloted aircraft systems reduce on situational awareness related events or over reliance on auto systems may make the situation worse?

    • Christoph Gilgen

      The challenge is that by taking gradually the Human out of the loop by ever-increasing automation, his/her performance and skills are being lowered. And then – when automation fails – you will need extremely skilled and trained humans to avoid the worst (a crash).

      Professionals facing very complex situations, where bells and chimes are sounding everywhere in situations where automation has given the aircraft back to the crew for manual operation due to inconsistent or conflicting indications/data. The crash of Air France flight AF 447 Rio – Paris back in 2009 is a very good example of this problem.

      Today, about 80% of the accidents are about human factors, and most of them are (at least partially) linked to a problem of humans understanding/misunderstanding the logics and the actions of the machine = the automation. So, the aim is to automate wisely, but without de-occupying the crew, and by this let them loose their basic skills – skill desperately needed when automation fails.
      Yes, quite a challening undertaking to keep a redundant human-centred system alive and working well!

      • Streetwise

        Basic automation is already helping reduce situational awareness events, For instance the “whoop whoop… pull up” aural alert.
        Remotely Piloted systems are still a grey area for most aviators. ICAO document 10019 gives basic guidelines. However, this is still a very complex area, even for developed countries.
        Over reliance on automation has been cited in several accidents and incidents. However, the reason we have automation is to simplify tasks, reduce cockpit fatigue and ensure that crew can maintain situational awareness for longer periods.
        Except in instances of improper design or manufacturing defects, automation is a plus for pilots. Of course,human-machine interface has its challenges because designers have to ensure the human aspect understands, which is not always easy.
        For the most part though, airmen who blame automation for their misfortunes are simply bad workmen blaming their tools.

        • Christoph Gilgen

          Dear Dr Sebina,
          I think we must clearly distinguish between Safety Nets and other “attention getters” – you say it so well by the “whoop whoop” of a GWPS, which are indeed very good and useful systems.
          And then the more profound “automation” where we see much more deep-rooted changes to the system and the flight-logic of an aircraft. The Airbus flight enveloppe protection or the Alpha protection is a very good example. Or the Boeing system that has played a significant part in the failed Emirates go-around of a B777 at Dubai (a logic kind of overriding pilot actions and inputs).
          Finally, I am not sure that I go along with you on your last sentence, as it would be WAY TOO EASY (to see it like this). If we have 2, 4 or 6 “bad workmen” – as you call them – why not making the attempt to think SYSTEMIC and try to find out what they thought and understood and then try to find a better (and more safer ways) where all is 100% clear and no confusion or error is possible? I have seen many badly-designed systems where the human element had to “work-around” (quite heady andcomplicated) it in order to get the job done……