HYPOXIA IN FLIGHT

Master CFI Parvez Dara, MD FACP, ATP, MCFI

As humans we depend on energy. Our energy is created in little biological machinery present in every cell, called mitochondria. These tiny powerhouses generate phosphates from converting (Adenosine Triphosphate or ATP) to Adenosine Diphosphate or ADP). Phosphate groups are needed to move cells within organs to do their jobs, e.g. muscles to contract (locomotion) hearts to pump (heart beat), kidneys to filter (filter blood), livers to digest and brains to process information. Absent phosphate and we are looking at an abyss. Oxygen, the quintessence of all elements breathes life into living creatures. Without it there is no water, nor breathable air, nor the lusty energy that makes us want to fly.

The breathable air contains 20.946% Oxygen. Humans exchange carbon dioxide for oxygen to replenish the stores of renewable energy for every one of the trillion cells that make us. This energy is in the form of Adenosine Triphosphate (ATP). ATP releases a phosphate group that acts as an energy bar for the cell to chew on so that it can accomplish its functions. These functions include manufacturing proteins, hormones, keeping the integrity of the cell wall etc. From our aviation point of view the function that cannot be clouded is the brain activity. The brain weighs about 3 pounds and consumes 25% of the oxygen supply. The brain’s hefty consumption is a testimony to its integrated and creative functions. 100% of the brain is at work 100% of the time and it needs its constant and uninterrupted energy supply.

Effects of Hypoxia on Brain using fMRI.
Effects of Hypoxia on Brain using fMRI.

The rarified air, for this purpose over 5000 feet at night (due to effect on the eyes) and over 8000 feet during the day, at altitude has reduced content of oxygen, which causes our brains, first to compensate by increasing blood pressure, then the respiration and heart rate to maintain the steady oxygen supply. When oxygen levels lower further, portions of the brain function capitulate, akin to losing the alternator, one reduces energy load by keeping only the most important instruments on the panel active so as not to drain the battery. So flying in un-pressurized aircraft without oxygen, your cognitive skills diminish. The additional harm at the rarified air is the loss of moisture in the air, which makes us breathe our moisture and not breathe any in, thus leading to dehydration. Your communication and math skills suffer as do interpretative skills. Missing calls, airway intersections or flying into adverse conditions becomes possible. To unscramble the brain a little oxygen rich air is mandatory. A “Chamber Ride” at an aviation facility confirms this.Remember an intensely low oxygen level for a short time or a low-level prolonged oxygen restriction can have similar short term and long term consequences on cellular behavior. If you fly above 5000 feet at night or above 8000 feet during the day use oxygen. It is good for the cerebral soul. Think about these problems reading this while seated in your armchair, on the ground rather than trying to decipher this information in the air:

1.      Mathematics Skill deterioration

2.      Cognitive Skill deterioration

3.      Instant Recall diminished (Frequency recall)

4.      Remote Recall diminished (experiential references)

5.      Decision Making Skills deteriorate (Time, distance and fuel consumption)

6.      Risk Assessment Impaired (eg. Go, No go decision into weather)

7.      Physical functional Impairment (muscle weakness)

8.      Lethargy/Fatigue.

The most common reaction to hypoxia is a feeling of euphoria. This is especially dangerous because an affected pilot will not usually feel “sick” or disabled but more typically feel “high” (feeling real good). Given this reaction, there is no incentive to discontinue a flight or exercise an alternate course of action. Pilots suffering from hypoxia feel like aviation gods! Only a trained vigilance from the presence of cues like altitude and duration can arm a pilot to be on guard for the onset of hypoxia; insidious and stealthy. Training in a altitude chamber or oxygen deprivation class is helpful to bring this point home clearly.

The common physiological sign of hypoxia is cyanosis or blue color in the extremities, most noticably in your fingernail beds. Before the easy (and very reasonably priced) oximiters were available pilots checked their nails for blue color.  I highly recommend an oximeter for anyone flying regularly at altitudes above 10,000 feet for any length of time. I also suggest that at altitude, one should take deep breaths to use the entire lung capacity to oxygenate the blood, since we have a tendency to shallow breathe in a cockpit. Having supplemental oxygen readily available is also an excellent safety precaution. Safe flying always requires current training, vigilance and an attitude of caution in the presence of known threats (in this case high altitude).

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Stress, and Pilot Performance: Part 1

-by Sherry Knight Rossiter

     Imagine that you are on a solo cross-country flight in a single-engine airplane. According to your last calculation, you have used more fuel than you’d anticipated due to increasing headwinds. The clouds ahead are building, and you are not IFR current. You recognize you are off course, but can’t locate your current position on the chart. On top of that, your bladder is full and you are feeling tired and hungry. By now you have plenty to think about. It won’t be long before your heart rate increases and your mouth becomes dry. A growing sense of urgency about your situation causes you to lose your concentration. Your mind begins formulating “what if” questions rather than problem-solving.

Most pilots, if they’re honest with themselves, will admit that they have had at least one experience similar to that. And the experience was, in fact, stressful. Part of what makes flying stressful is the need to do several things, at times simultaneously, while keeping track of many different types of information. In addition, there are a number of factors associated with aviation over which a pilot has no control. Changing weather conditions is certainly one of those factors.

Rossiter-Stress_crop copy

At some point, too much stress begins to affect your ability to think clearly which, in turn, affects your ability to make good decisions. One poor decision followed by another poor decision is a setup for disaster. That is why it is crucial to know how to assess the impact of certain stressors on your body and mind.

The Physiology of Stress

     Stress is a difficult term to define because it is dependent upon personal interpretation. What is perceived as a negative stressor for one person may be perceived as a positive stressor (i.e., energizer or motivator) for another person. For purposes of this discussion, a commonly accepted definition of stress is the body’s non-specific response to demands placed upon it, whether those demands are pleasant or unpleasant (Selye, 1936).

All living organisms experience a certain amount of physical and psychological stress simply as a result of being alive. Organisms experiencing only a small amount of stress are usually at rest or asleep. A good example of an organism experiencing minimal stress would be a cat stretched out in the sunshine or a bear in hibernation. The only time an organism experiences no stress is when it is dead. All living creatures experience stress of some type each and every day, and that is why it is important to understand the relationship of stress to human performance.

Hungarian-born researcher Hans Selye (1907-1982) spent his life studying the topic of stress. Selye discovered very quickly that the human body experiences two types of stress: eustress and distress. Eustress is experienced by the body as positive stress. Common examples of eustress are laughing while watching a movie or playing with the family dog. Distress is experienced by the body as negative stress. Some common examples of distress that might be experienced by anyone are fatigue, high work load, or a life-threatening situation.

When an individual experiences distress, a natural physical response occurs. This arousal of the nervous system is commonly referred to as the “fight or flight” response. It is as old as humankind ands located in the lower part of our brain, sometimes referred to as the reptilian brain. This part of our brain controls breathing, heart rate, body temperature, and balance. The fight-or-flight response is so basic to human behavior that it can be called instinctual because it spontaneously activates whenever our brain senses danger in any form.

Sensory stimuli (i.e., stressors) are interpreted by the brain as either threatening or non-threatening. If a stimulus is perceived as non-threatening, no stress response is forthcoming. However, if a stimulus is perceived as threatening in any way, then certain protective mechanisms are triggered. In other words, the fight-or-flight response is automatically activated as a survival mechanism.

Any internal or external stimulus that is perceived as a threat to the body’s equilibrium causes a physiological reaction in the body. These reactions include the release of chemical hormones, such as adrenalin, into the bloodstream, and there is a marked increase in the body’s metabolic rate. Blood is redirected away from the stomach and digestive tract to supply the muscles in the arms and legs with more oxygen. Heart rate, respiration, blood pressure, blood sugar, and perspiration all increase under stressful conditions. In short, the body prepares itself to “fight or flee.”

It should be noted, however, that many other factors besides biology go into determining if an individual fights or flees in the presence of a perceived threat. Past experience in the form of memories plays a major role in the implementation of the fight-or-flee response. Research indicates that stored memories of survival have the highest priority of retrieval in frightening situations (Everly, 1989). This is crucial for successfully coping and surviving in any extremely stressful situation.

What is a Stressor?

     Stressors take many forms. However, stressors are generally classified as physical, physiological, or psychological. Any stressor is a stimulus to the nervous system.

Physical stressors include conditions associated with the environment, such as temperature and humidity extremes, noise, vibration, and lack of oxygen. Pilots deal with physical stressors all the time during flight. For example, continuous noise (like the sound of a rotor blade or propeller) can have long-term, adverse effects on not just hearing, but also on blood pressure and heart health.

Physiological stressors include fatigue, lack of physical fitness, illness, and missed meals, which lead to lowered blood sugar levels. Pilots who regularly fly long distances are especially prone to the effects of physiological stressors. A pilot may be able to exist on coffee and nutrition bars for a day or two, but in the long term such poor nutrition will affect the pilot’s body and mind.

Psychological stressors are related to social or emotional factors. Some examples of psychological stressors are a pending divorce proceeding, a sick child, a demotion at work, or thoughts of a previously frightening experience.

The Relationship Between Stress and Performance

     It is now known that stress affects human performance in two important ways. In some situations, stress serves as an energizer, thereby increasing human performance. In other situations, stress serves to interfere with or detract from human performance. Ironically, too little stress can cause poor performance, and so can too much stress.

Research into human performance limitations in the last three decades shows that simple tasks are performed better under higher degrees of stress and complex tasks are performed better under lower degrees of stress. This means there is a range of moderate stress referred to as “a peak performance envelope” (Garfield,1983; Currieri 1985, 1995), wherein optimal performance can be expected – indeed, predicted — in any given situation.

Both Garfield and Currieri have independently conducted research to (a) prove a correlation between stress level and peak human performance and (b) stress level and optimum human judgment. Data gathered seems to indicate that peak performance and best judgment are most evident when the research subject’s physiological responses to the stress imposed are within certain parameters of body temperature, heart rate, and so forth – hence, the reference above to “a peak performance envelope.”

Relationship Between Stress Arousal and Human Performance

Rossiter Stress graphic

 

-by Sherry Knight Rossiter

Look for Part 2 of this article in the next issue of SAFE, the magazine

This is an excerpt from our SAFE magazine. Members get full access (and so much more!) Please Join SAFE in our mission of pursuing aviation excellence. The amazing member benefits alone make this commitment painless and fun. See you at the airport.

Sherry Knight Rossiter holds an ATP and CFI-I for both fixed and rotary wing aircraft. She is also a Licensed Clinical Professional Counselor, who has worked extensively with general aviation pilots who have survived aircraft accidents or other frightening flight experiences. She currently serves on the Board of Directors for the Society of Aviation and Flight Educators (SAFE) and teaches online psychology courses for Embry Riddle Aeronautical University. 

 

 

Providence In Flight!

Parvez Dara, MD FACP, Master Instructor, SAFE Member

There is Providence in the flight of the bird. Its departures and arrivals are never certain and its flight path is not when or where, but dictated by the breezes, the feeds, the treetops and its kin. There is magic and majesty in that flight nevertheless. From the ground there is a joyous longing to belong to that carefree, wild and non interpretive version of life.

As equally as the joy of flight in an airplane, humans have learned to master the art of that magic. As thrust overcomes the drag and lift picks up the weight, the momentary weightlessness on untying the surely bonds to the earth has a unique if not special meaning to the flier.

The earth recedes as the blue sky enriches the vistas. Little dumplings of white clouds seed the blueness like cotton candy, delicious in their being. The smooth air and the power to transform the landscape by a turn here or there is intoxicating and liberating.

You pull back on the stick/yoke and the climb continues as you feel your weight against the seat, the fears and expectations of living recede with the green earth. The magical metallic beast honors each command without a moment of hesitation.

The roar of the engine, recede fades and dissolves into the sights that come in bunches of wonder. Here there is a cottage where the setting sun sprinkles its embers to color it a golden yellow and there the forest of treetops are illuminated as if the painter had a last minute desire to add color to the rich landscape.

sky1If you are lucky, someday you might see the sun dissected by a thin layer of cloud that stretches from here to the ends of the earth as you witness the golden hue bounce off the bottom and then the tops of the wavy clouds in a climb. It is a beauteous sight to behold; one for the memories. You might see the rich blueness of the sky slowly give way to a darker hue and the first signs of the sunset come alive. The rich tapestry unfolds with its lights burning below, enriching the darkening landscape. Ah, there is such Providence in flight.

You might encounter a momentary pulse of euphoria about then as the night owls rise to take their space and the full breadth of human endeavor below begins to shine. Humans are such creative species to desire to view the earth, in all its phases with the sun, through a birds’ eye.

From above there are no large and small, no tall or short, no fat and slim, no young and old but only in the mind’s comparisons. Everything below dissolves into a symphony of symmetry. The cadence, the pitch and the notes, all resolve to the hum and liberating feeling of freedom.

As the colors darken outside, the colors within the cockpit brighten. The world outside is displayed in a rectangular screen for positional awareness. Ah there the nonlinear, convoluted darkness amid the city lights is the river and here the bright linear flow of lights is the bridge joining the two land masses.

If you are gifted in knowing the Instrument flight systems, the alignment of the horizontal and vertical course deviation indicators show you where and how to arrive safely at your destination. All the lights, darkness or cloudy encounters cannot hide the safety of the runways that beckon you.

There is Providence in flight. There is magic in its delights. There is existential freedom.

Pilot Training Solutions: NTSB Testimony by Master CFI Rich Stowell

NTSB Forum: “Humans and Hardware”

Preventing General Aviation Inflight Loss of Control — Training Solutions Panel October 14, 2015, Washington, DC

Remarks by Rich Stowell, Society of Aviation and Flight Educators

https://www.youtube.com/watch?v=BCQF3fvxAfg&feature=youtu.be&t=1m18s

The status quo in aviation education is unacceptable.

RichStowellNTSBStatusQuo

Those of us who provide spin and upset recovery training see the results of our training system on a daily basis. We constantly deal with the same recurring questions and concerns; the same fears and frustrations.

[NTSB Board] Member Weener has referred to loss of control (LOC) as a “stubbornly recurrent safety challenge.” Recurrent indeed.

In 1944, Wolfgang Langewiesche observed that “Almost all fatal flying accidents are caused by loss of control during a turn.”

RichStowellNTSBTurning

He concluded that pilots, as a group, simply don’t know how to turn. Little has changed in the 70-plus years since.

Most fatal LOC accidents continue to occur during the maneuvering phase.

In fact, if we separated the block of maneuvering accidents into its own category, LOC while maneuvering by itself would rank third on the list of fatal accident causes.

It’s clear that except for the ability to mimic only the most basic of turns, pilots, as a group, remain unconsciously incompetent with regard to maneuvering flight.

According to aviation safety pioneer Jerome Lederer, “Every accident, no matter how minor, is a failure of the organization.” In this case, the “organization” is our flight training industry.

These pilots entrusted us with their safety and wellbeing. They believed the training system would teach them how to maneuver an airplane. And we failed them.

Simply stated, we have a training delivery problem.

We can try to push all of the doctrine and standards and curricula and technology and products we want into the training pipeline.

Absent a concerted effort to significantly improve the delivery system, none of these enhancements will yield the safety dividends we envision.

Responding to the loss of control problem in commercial aviation, the International Civil Aviation Organization (ICAO) recently published its Manual on Upset Prevention and Recovery Training. The manual promotes an integrated approach to training designed to maximize the learning experience.

Academics: laying a strong and factually accurate foundation of aeronautical knowledge.

Simulation, which can be as sophisticated as a Level D flight simulator, or as simple as visualization techniques similar to those used by air show pilots before they fly their aerobatic routines.

And on-airplane training: the live experience that cements the concepts and techniques introduced through academics and simulation into a positive and enduring learning experience.

This is the way flight training could and should be conducted at all levels. And it is the way flight training began a century ago. The Wright brothers established the first flight schools in the U.S. Guess what their training methodology was:

  • Detailed ground school
  • Simulation using a functioning mock up of their flyer
  • And on-airplane training

Moreover, the Wrights trained their students to be demonstration pilots.

What if you trained your students to be demo pilots for your flight school? For your airplanes? How about for general aviation? What if our mindset was, “You represent me, you represent our school, you represent general aviation”?

Somewhere between the Wrights and the new ICAO manual, we got lost. We’ve deviated from a proven flight plan. Perhaps we’ve forgotten where we were trying to go in the first place.

The ICAO manual serves as a reminder, a course correction. A path back to what the Wright brothers understood: That acting in the best interests of our students also serves our interests.

Recalibrating won’t be easy.

According to AOPA, educational quality and customer service make up 75% of a pilot’s training experience.

RichStowellNTSBWeakLInk

Of all the obstacles on the path to the private pilot check ride, AOPA found the quality of instruction to be a persistent issue and a weak link in the chain.

Students will put up with a lot to become private pilots. What most won’t tolerate, however, is poor treatment and poor instruction. So they eventually quit.

Yet the minority does reach the next level. Increasingly unfulfilled and unconfident, some of them eventually drop out of aviation as well. Others are destined to become accident stats discussed at forums like this.

But we are talking about real people. People who at one time were inspired by flight; who were excited about joining the aviation community.

The status quo underappreciates and undervalues the profession of aviation education. As a result, poorly managed schools and poorly trained instructors are the norm.

In contrast, when instructors accept the challenge of professional development and are recognized for achievement, the marketplace responds in a positive way.

The majority of Master Instructors, for example, earn 10 to 40% more income as a result of participation in the Master Instructor Continuing Education Program. And since 1997, three out of four honorees in the National CFI and FAASTeam Rep of the Year categories have been Master Instructors.

The general aviation fleet is enormously diverse. Not everyone will use a supplemental angle of attack system. Not everyone will take advantage of new technologies and training products.

But at some point, everyone will interact with a flight school or an instructor. And everyone needs to learn to turn.

So imagine what general aviation would look like:

If authentic flight school operators were the norm. Where most schools focused on developing long-term participants in aviation, and not on the Hobbs meter.

If authentic instructors were the norm. Where most of those who became flight instructors did so because they were passionate about teaching, not because they were incentivized into it as a means to log hours for something else.

Where the spin endorsement provided a legitimate record of an instructor’s stall/spin knowledge and capability. Where instructors taught to the student, not to the test.

Creating a culture of authentic operators and instructors will be a difficult task, but it is imperative if training solutions will have any hope of large-scale success.

Lastly, if pilots were taught properly about turn dynamics. Conceptually simple, this will not necessarily be an easy task.

To get the ball rolling, today I’m announcing the “Learn to Turn” initiative. I envision a freely available multi-media experience that goes far beyond our historically inadequate treatment of turns. But I can’t do this alone. I need your help. If you can offer time, talent, or other resources to this project, then let’s work together to teach pilots how to maneuver their airplanes safely and with confidence. (FMI, see http://www.LearnToAviate.tips)

Imagine the potential dividends resulting from these training solutions:

  • Most students would become private pilots instead of dropping out;
  • Most pilots, including instructors, would invest in recurrent training;
  • The successful outcome of a maneuver genuinely would never be in doubt;
  • And loss of control no longer would be the primary cause of fatal

We often think of the Wright brothers’ achievement in terms of powered flight. But the Wright’s saw control as the central problem they had to solve in order for flying machines to be viable.

Controllable flight is their legacy, and their vision forever changed the world.

I’m not proposing that we change the world; only that we change critical parts of our training delivery system.

The mandate we have as aviation educators is captured in Richard Bach’s short story, School for Perfection:

“To teach. To teach!

To take time with the students.

To offer them the priceless thing that is the ability to fly.”

Thank you.  Rich Stowell Master Instructor-aerobatic, SAFE founder, National FAA CFI of the Year 2006, National FAA Safety Team Rep of the Year 2014

Please Join SAFE in our mission of pursuing aviation excellence. The amazing member benefits alone make this commitment painless and fun. See you at the airport.