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  • Deniz Kilicgedik Sazak

Overloaded Under Stress: Managing Task Saturation and Startle in the Flight Deck

Güncelleme tarihi: 14 Nis 2021

Imagine watering a plant. It will only take as much liquid as it can, and the excessive water will spill over. To avoid this, one can either get a bigger pot or reduce the amount of water given to the plant. Similarly, when faced with more information than being able to process at once, it is common to feel overwhelmed. Just as turning the TV, dishwasher, oven and air conditioners all on at the same time can cause a power outage at home. Our cognitive abilities might shut down for a moment while the brain may feel hijacked due to an overload of information; this is called cognitive overload or task saturation. This usually happens when trying to do too much with insufficient resources.

In environments of rapid change, such as the flight deck, the level of alertness increases and the brain spends much more effort to keep up with possible stressors, causing the pilot to feel overloaded. Task saturation or cognitive overload has two different types: rapid overload and progressive overload. While progressive overload can be useful for growth, constantly being exposed to rapid overload may result in problems like depression or burnout. For instance, asking you to subtract 14 from 3025 until your reach zero, while at the same time reading this article, would be an example of rapid overload. However, asking you again after having changed the numbers in the question would count as progressive overload, since you are now prepared and familiar with the question. Progressive overload is usually a mental preparation technique often used in psychology, while continuously being exposed to rapid overload can cause unwanted responses.

A result of task saturation is ‘cognitive lockup’, which is over-fixation on a problem or event. This happens when we over-focus on the stressor in a high-pressure situation, so that we fail to see the bigger picture. It can feel like a paralysis in the ability to think and analyse. This causes increased risk of error, decreased problem solving and decreased situational awareness. Studies conducted in aviation and in the military, where mental performance plays a key role, show that pilots display two types of behaviour when confronted with sudden stressful or non-normal events. The first reaction is to focus on the problem, understand the situation, while simultaneously being aware of other tasks like monitoring or controlling. The second reaction, on the other hand, is being startled by the stress situation, which causes the pilot to over-fixate, develop tunnel vision or freeze, making it difficult to focus on other tasks and remain aware. This startle reflex, according to the FAA is “an automatic reflex that is caused by exposure to a sudden, intense event that interrupts a pilot’s expectation”.

This image shows Task Requirements/Saturation during the various phases of flight.

In some ways, surprises can have benefits. New knowledge, novel encounters or experiences keep the brain functioning and alert. This activates the frontal area of the brain, which is responsible for learning and progressing. Is also helps to recognise the events and actions for the future, and develop pathways or frameworks for future responses. Therefore, getting surprised is not the main issue, but getting so confused that it causes one to lose the ability to think, is.

According to research by NASA psychologist Steve Casner, done with eighteen Boeing 747 pilots, physical responses along with psychological startle can impair the thinking process and reaction in pilots for up to 30 seconds. As a result, non-routine and emergency situations may cause a series of startle responses making reflexive decisions. Meaning that, before even moving on to the next decision, thinking abilities shut down, leading to a tunnel of bad decisions. This can affect problem-solving abilities because the memory is busy trying to understand the situation, so that it experiences difficultly to come up with a solution at that moment.

Incidents in Aviation:

An example of over-fixation in aviation is the accident of Eastern Airlines Flight 401 from New York to Miami. On the 29th of December 1972, the Lockheed L-1011 Tristar type aircraft was descending towards Miami Airport when the crew was suddenly faced with an unexpected situation. During the remaining four minutes of the operation, despite lowering the landing gear, the indicator light did not illuminate. The crew decided to discontinue their approach and requested to enter a holding pattern. While the crew was preoccupied with the light bulb and fixated on the indicator problem, neither of the two pilots noticed that the autopilot had switched off and the aircraft was at half of its assigned altitude. This resulted in over a hundred people, including passengers and aircrew, losing their lives. As the NTSB report cited, the flight crew was so over-fixated on the landing gear indicator lights that they “failed to monitor the flight instruments”. This phenomenon of tunnelled senses can happen in severe stress situations so that the brain’s focus narrows down to only one area or completely shuts down. In the case of the crew in flight 401, over-fixation on the visual threat of the indicator light was so high that the crew disregarded all auditory signs and cues, of any autopilot disengagement alarm or radio communication at that moment.

The Southwest Airlines Flight 1380 is a more recent example of how to handle a startle and overload situation. On 17 April 2018, the Boeing 737-700 type aircraft was on its way from New York to LaGuardia Airport. The first officer was PF while the captain was PM. At about flight level 320, during climb, the crew experienced a failure of the left engine and loss of engine inlet and cowling. Fragments from the engine struck the wing and the fuselage, and broke a passenger window, resulting in a rapid depressurization of the cabin. The passenger in row 14 was found partially out of the window. The flight crew reported a sudden change in cabin pressure, accompanied by alarms in the cockpit, grey smoke and the cabin altitude alert activated within 5 seconds. The captain took over flying duties while the first officer began running the emergency checklists. After requesting a diversion to the nearest airport, the Captain quickly decided on an emergency descent and diverted to Philadelphia International Airport.

During the incident, the flight crew stated that the airplane showed handling difficulties (“the FDR indicated that the airplane rolled left to about 40 degrees”) and they had to use sign language due to communication difficulties because of the loud sounds in the flight deck. Tammie Jo Shults, a former Navy pilot, mentioned that she clearly remembered the sounds, smell and other stimuli in the cockpit, which are signs of high situational awareness during the incident.

Studies show that good decision making skills can decrease the risk of over-fixation and startle responses. Therefore, it is important to develop skills necessary to overcome task saturation in workplaces with high amounts of information load, like the cockpit.

Dealing with Overload & Startle:

Considering the possibility of pilots being exposed to non-normal events, overload and startle; it is important to ensure that the mind as well as the body is prepared. Ways to do this may include, getting familiar with abnormal events and learning ways to recognise the emergency in the unexpected moment. The following are ways to deal with such situations:

  • Planning and Mental Training: Rehearsing mentally for both common non-normal events and asking oneself “what would I do if…?” type questions helps to build mental action plans. Research proves that, the familiar and the more practiced the response to the event, the fewer errors happen during the incident and post-startle time.

  • Task switching is another method to deal with overload and startle. When encountered with a startling situation the first and most important thing to do is to not do anything, to not overreact. This method is often integrated to Upset Recovery Training in Airlines. Task switching includes taking a moment to observe the situation, to make a thought-out decision rather than a reflexive reaction while following standard operating procedures in order to avoid over-fixation, while managing stress and other distractions.

  • Resting: Exhaustion and high stress levels can cause task saturation. The more stressed and fatigued one is, the lower the possibility of good decision-making and rational thinking. Therefore, giving importance to resting well is crucial when it comes to preventing getting startled in stress situations.

The risk of overload and startle is especially higher for occupations in which high amounts of alertness and focusing between tasks is required. Considering that lack of expectation increases startle when a surprising event occurs, minimising risk before it even arises by being prepared and familiar with the non-normal is crucial for efficient decision making.


Casner SM, Geven RW, Williams KT. The Effectiveness of Airline Pilot Training for Abnormal Events. Human Factors. 2013;55(3):477-485. doi:10.1177/0018720812466893

EASA (2018), Final Report Research Project: Startle Effect Management.

Geçtan, E. (2020) İnsan Olmak (19.Basim). Metis Yayınları.Meij, G. (2004).

Kochan, J. A., Breiter, E. G., Jentsch, F. (2004). Surprise and unexpectedness in flying: Database reviews and analyses. In Proceedings of the Human Factors and Ergonomics Society 48th Annual Meeting (pp. 335–339). Santa Monica, CA: Human Factors and Ergonomics Society.

NTSB Eastern Airlines Aircraft Accidents Report, 1973.

NTSB, Left Engine Failure and Subsequent Depressurization, Southwest Airlines Flight 1380, Boeing 737-7H4, N772SW


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