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Surprise Startle Effect and Resilience

Posted 2 years 119 days ago ago by Admin

As an EASA (European Aviation Safety Agency) certified CRM instructor, I am required to attend an 8-hour class every three years to learn what is new or changed in the thinking of crew resource management.  During my last recertification that I attended at Global Air Training in Cheshire, England with 12 other CRM instructors who were similarly recertifying we were told the ‘hot topic’ in the industry was something called Surprise, Startle Effect and Resilience.  This topic was brought to our attention because there have been a series of accidents where this phenomenon was determined to be a major factor in the fatal crashes and something we should cover in any future CRM classes we were facilitating.


The surprise response is a feeling of mild astonishment or shock cause by something unexpected. Surprise is the emotive feeling that is brought about when our expectations and reality are found to be different; we usually see this as ignorance or a loss of situational awareness. Surprise can also occur as a result of a violation of our expectations.

The startle response is the primal instinctive physical and mental response to a sudden intense and unexpected stimulus. This physiological reaction, known as the "fight or flight" reflex, will occur in response to what may be perceived as a harmful event: an attack, a threat to survival, or more simply, to fear itself that in some circumstances, it can also lead to actions inappropriate for the situation.

In aviation, startle effect is defined as an uncontrollable, automatic reflex that is elicited by exposure to a sudden intense event that violates our expectations; for example, think of your reaction if you hear a loud ‘BANG’ or explosion which is totally involuntary. Because such an event in normal flight operations is unplanned, pilots may be startled or surprised, adversely impacting recognition or recovery to a normal aircraft state.


The startle effect includes both the physical and mental responses to a sudden unexpected stimulus. While the physical responses are automatic and virtually instantaneous, the mental responses - the conscious processing and evaluation of the sensory information - can be much slower. The ability to process the sensory information - to evaluate the situation and take appropriate action - can be seriously impaired or even overwhelmed by one’s intense physiological responses.

These changes in physiological activity include:

· Cardiovascular System: Heart rate increases, blood pressure rises and coronary arteries dilate to increase the blood supply to brain, limbs and muscles

· Respiratory System: Depth and rate of breathing increases providing more oxygen to the body · Endocrine System: Liver releases additional sugar for energy. Adrenal glands release adrenalin

· Muscular System: Muscles tense in readiness for immediate action

· Excretory System: Sweat production increases

· Nervous System: Brain activity changes, reactions become less reasoned and more instinctive


In addition to the listed temporary physiological changes which follow a high intensity stimulus, studies have determined that, following a startling stimulus such as a loud noise, basic motor response performance can be disrupted for as much as 3 seconds and performance of more complex motor tasks may be impacted for up to 10 seconds. Startle has been found to impair information processing performance on mundane tasks such as the continuous solving of basic arithmetic problems for 30 to 60 seconds after the event occurrence. The duration of the performance degradation increases as the task becomes more complex. Thus, the startle effect disrupts cognitive processing and can negatively influence an individual’s decision-making and problem solving abilities.


As concluded in one recent study by three aviation researchers entitled, The Effects of Startle on Pilots During Critical Events, the reliability of modern aircraft is part of the context in which inappropriate actions are sometimes taken after an unexpected event: As aircraft become more reliable, when pilots are surprised or startled by some event, they may take no action or alternatively take the wrong action, which creates an undesired aircraft state, or in some cases, an accident. The problem is the expectation of critical events is so low that the level of surprise or startle which pilots encounter during such events is higher than they would perhaps have had some decades ago when things went routinely wrong.

In aviation, the immediate impact of the startle reflex may induce a brief period of disorientation as well as short term psychomotor impairment which may well lead to task interruptions and/or a brief period of confusion. Should this happen, a period of time will be required for reorientation and task resumption. While performance after a startle event can be affected, the greater concern stems from what the crew did, or did not do, during the conditioned startle response itself. It is here that decision-making can be most significantly impaired, especially higher-order functions necessary for making judgments about complex flight tasks.

Strategies for Improving Startle Performance:

Researchers have identified a number of strategies that can reduce the negative effects of startle and help improve pilot performance during and immediately following a startle event. These include:

· Know your aircraft: Develop a sound technical knowledge of your aircraft type and maintain it with regular revision

· Maintain handling skills: Be competent and comfortable flying the aircraft "without the automation"

· Train appropriately: Simulator exercises should be conducted in a constructive manner with a focus on evidence based (most likely) events. However, there should also be constructive use of unexpected critical events

· Be cognizant of your surroundings: Develop and maintain effective situational awareness skill-sets. The Pilot Monitoring (PM) should actively monitor the Pilot Flying (PF) and both should actively monitor the aircraft automation

· Avoid complacency: Have a healthy expectation and suspicion for things going wrong

· Anticipate threats: Utilise effective threat and error management (TEM) strategies

· Have a plan: Mentally rehearse or foster crew discussion of a "plan of action" for both common non-normal events, and for the rare, "out of the ordinary" events such as ditching, upset or uncontrollable fire. Adopt a "what would I do if" mindset.

Resilience Development:

Training in resilience development enables crew members to draw the right conclusions from both positive and negative experiences. Based on those experiences crew members are better prepared to maintain or create safety margins by adapting to dynamic complex situations. The main aspects of resilience development can be described as the ability to:

· Learn (knowing what has happened)

· Monitor (knowing what to look for)

· Anticipate (finding out and knowing what to expect)

· Respond (knowing what to do and being capable of doing it) Operational safety is a continuous process of evaluation of and adjustment to existing and future conditions.

Resilience development involves an ongoing and adaptable process including:

· Situation assessment

· Self-review

· Decision

· Action

Accidents in Which Startle Effect Was Considered a Factor:

· A332, en-route, Atlantic Ocean, 2009 (On 1 June 2009, an Airbus A330- 200 being operated by Air France on a scheduled passenger flight from Rio de Janeiro to Paris CDG as AF447 exited controlled flight and crashed into the sea with the loss of the aircraft and all 228 occupants. It was found that the loss of control followed an inappropriate response by the flight crew to a transient loss of airspeed indications in the cruise which resulted from the vulnerability of the pitot heads to ice crystal icing)

· DH8D, 2009 On 12 February 2009, a Bombardier DHC-8-400 also known as a 'Q400' which was being operated by Colgan Air on a scheduled public transport flight in the USA from Newark to Buffalo-Niagara under a Continental Airlines flight number as part of a codeshare agreement in place between the two operators was on an ILS approach to the destination runway in night VMC when control was lost and the aircraft crashed and burned in a residential area approximately 5 nm from the runway killing all occupants and one additional person on the ground.

· A320, en-route Karimata Strait Indonesia, 2014. On 28 December 2014, an A320 crew took unapproved action in response to a repeating system caution shortly after levelling at FL320. The unexpected consequences degraded the flight control system and obliged manual control. Gross mishandling followed which led to a stall, descent at a high rate and sea surface impact with a 20º pitch attitude and a 50º angle of attack four minutes later. The Investigation noted the accident origin as a repetitive minor system fault but demonstrated that the subsequent loss of control followed a combination of explicitly inappropriate pilot action and the absence of appropriate pilot action.

Your takeaway

As the proverb states: Forewarned is forearmed.  Prior knowledge of possible dangers or problems gives one a tactical advantage.  So be aware of the Surprise, Startle Effect and think in advance how you would respond using the tools I’ve given you so you can successfully recover from an unexpected event should one occur.

About Randy:
Randy Mains is an author, public speaker, and a CRM/AMRM consultant who works in the helicopter industry after a long career of aviation adventure. He currently serves as chief CRM/AMRM instructor for Oregon Aero. He may be contacted at [email protected].



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