UAS PHYSIOLOGICAL FACTORS

The Guide for Aviation Medical Examiners categorizes medicines as either Do Not Issue (DNI) or Do Not Fly (DNF).  DNI medications are those medicines that should not be giving unless cleared by the FAA.  The list of DNF medicines contain medications that airman should be advised not to take while performing crewmember duties (Federal Aviation Administration, 2019).  The majority of over-the-counter (OTC) medications fall under the umbrella of DNF.  Additionally, safety material should be examined by the airman before taking these medicines, since all medications have the potential to be sedative and cause impairment to cognition.  Although individuals have reported feeling active and perceptive under the influence of OTC medication and believe they are functioning in a normal manner, the effects of drugs are still present.  This has been termed “unaware of impair” (Federal Aviation Administration, 2019)

            Pilots should not assume flying responsibilities while taking OTC medications that bear precaution or warnings labels such as – “it may cause drowsiness or be careful when driving a motor vehicle or machinery” (Federal Aviation Administration, 2019), and pilots should refrain from commencing flight duties until sufficient time has elapsed after the last dose has been administered.  When it comes to self-medicating with sleep aids, airman should heed these label warnings, as sleep aids may pose the most significant risk to the UAS operator.  Currently, OTC sleep aids can impair mental processes and reduce reaction time.  Diphenhydramine is a key ingredient in most OTC sleep aid.  Products like Benadryl contain the active ingredient Diphenhydramine and based on the pharmacologic half-life.  Although individuals claim they feel completely awake, the wait time for Diphenhydramine is 60 hours (FAA, 2019).       

            From a human factors perspective, I believe the most effective mitigative strategies UAS operators can use while performing flight operations are not to exceed personal limitations and conduct a thorough self-assessment.  Operating within the limitations you place upon yourself can reduce unnecessary risk by not allowing yourself to ‘push the envelope.’  A self-assessment performed prior to flight can serve as a last line of defense in ensuring that you are fit to perform your duties in a safe manner (U. S. Department of Transportation, Federal Aviation Administration, 2016).

            Fatigue and stress are in somewhat inter-related – fatigue causes stress, and stress causes fatigue.  Stress is a biological reaction to external demands, both physical and psychological, whereas fatigue is the sensation of tiredness felt at the end of a strenuous event, prolonged excitement, or sleepless night (U. S. Department of Transportation, Federal Aviation Administration, 2016).  Both physiological factors can severely affect the UAS operator because they can lead to a rapid decline in pilot performance at the physical and mental level.  Fatigue can cause disorder and impact decision-making skills.  Stress, on the other hand, causes the chemical release of hormones into the body’s bloodstream, which elevates metabolism in order to feed additional energy to muscles.  Stress also increases blood sugar, heart rate, respiration, blood pressure, and perspiration (U. S. Department of Transportation, Federal Aviation Administration, 2016).  Becoming unable to cope with stress and/or ineffectually at controlling fatigue can be have a detrimental effect on safety.

References

Federal Aviation Administration. (2019, February 21).  Guide for aviation medical examiners.  Retrieved from https://www.faa.gov/about/office_org/headquarters_offices/avs/offices/aam/ame/guide/pharm/dni_dnf/

U. S. Department of Transportation, Federal Aviation Administration. (2016).  Remote pilot – small unmanned aircraft systems study guide (FAA-G-8082-22).  Retrieved from https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/media/remote_pilot_study_guide.pdf