Safety and Effectiveness Assessment of Ultraviolet-C Disinfection in Aircraft Cabins.

INTRODUCTION: Aircraft cabins, susceptible to disease transmission, require effective strategies to minimize the spread of airborne diseases. This paper reviews the James Reason Swiss Cheese Theory in mitigating these risks, as implemented by the International Civil Aviation Organization during the COVID-19 pandemic. It also evaluates the use of airborne ultraviolet-C (UV-C) light as an additional protective measure.METHODS: Our approach involved a thorough literature review by experts and a detailed risk-vs.-benefit analysis. The review covered existing research to understand the scientific foundation, while the analysis used established techniques to assess the impact of influenza and COVID-19 in terms of infections, deaths, and economic costs.RESULTS: Integrating UV-C light in aircraft cabins, when applied with appropriate scientific understanding and engineering safeguards, has the potential to reduce in-flight disease transmission. This additional mitigation strategy can work synergistically with existing measures.DISCUSSION: The research and risk-vs.-benefit analysis present strong evidence for the safety and effectiveness of continuous UV-C disinfection in aircraft cabins. It suggests that UV-C light, maintained below exposure limits, can be a valuable addition to existing measures against disease transmission during flights.Belland K, Garcia D, DeJohn C, Allen GR, Mills WD, Glaudel SP. Safety and effectiveness assessment of ultraviolet-C disinfection in aircraft cabins. Aerosp Med Hum Perform. 2024; 95(3):147-157.

Drug Use Reported by U.S. Pilots, 2009-2014.

INTRODUCTION: There is a growing trend in the use of drugs, which could increase the likelihood of an aircraft accident. Evidence exists that pilots do not report all medications to the Federal Aviation Administration (FAA). The purpose of this study was to compare medications discovered by postaccident toxicology testing to those reported to the FAA to determine the veracity of pilot reported medications.METHODS: Medications reported on applications for U.S. medical certificates were compared to those discovered during postaccident toxicology testing. Logistic regressions were performed using Age, Gender, Type of Flight Operation, Medical Class Issued, and whether a Special Issuance (SI) medical certificate was issued as independent covariates. Truth in Reporting a medication was the outcome variable.RESULTS: Age and an SI medical certificate were good predictors of the likelihood of truthfully reporting medications. For each year of age the probability of a subject drug record being truthfully reported increased by 5%, while a pilot with an SI was 3.12 times more likely to be truthful than a pilot without an SI. When reported medications were limited to cardiovascular drugs, Age was the only good predictor of truthful reporting and, for every additional year of age, the probability of a subject drug record being truthfully reported increased by 3%.CONCLUSIONS: This study showed that the probability of a pilot truthfully reporting medication use increases with Age and an SI medical certificate. When reported medications were limited to cardiovascular drugs, Age was the only good predictor of truthful reporting.DeJohn CA, Greenhaw R, Lewis R, Cliburn K. Drug use reported by U.S. pilots, 2009-2014. Aerosp Med Hum Perform. 2020; 91(7):586-591.

Safety Implications of 6-Month vs. 1-Year First-Class Aeromedical Certificates.

INTRODUCTION: This study explores the safety risk due to delayed detection of hazardous health conditions that would result from increasing the duration of U.S. first-class aeromedical certificates from 6 mo to 12 mo for pilots ages 40 yr old through 60 yr old.METHODS: All pilots who submitted a U.S. first-class application in 2014 with no electrocardiogram and with the previous exams 4.5 to 7.5 mo prior were selected from the FAA pilot medical database. Proportions of Federal Aviation Administration (FAA) denial pathology codes and Aviation Medical Examiner (AME) deferrals were compared for these exams within and between age groups from 40 yr old through 75 yr old. The absolute incidence rates for delayed detection were calculated and relative incidence of these proportions was compared graphically.RESULTS: The relative risk between age groups for delayed identification of disqualifying medical conditions showed that the 56-60-yr-old group would be at about twice the risk as the 40-45-yr-old group. The absolute incidence for the 56-60-yr-old group was 0.46% for denial conditions and 0.60% for AME deferrals over 6 mo.DISCUSSION: Increasing FAA first-class medical certificate duration from 6 mo to 12 mo would put 56-60-yr-old pilots at double the currently accepted risk for delayed detection of significant medical conditions. The absolute risk for this 6-mo delayed identification for the 56-60-yr-old group would average 0.53%.Mills WD, DeJohn CA. Safety implications of 6-month vs. 1-year first-class aeromedical certificates. Aerosp Med Hum Perform. 2019; 90(5):484-487.

Cardiac Inflight Incapacitations of U.S. Airline Pilots: 1995-2015.

INTRODUCTION: Inflight medical incapacitations are rare events that can result in the loss of lives and aircraft. The potential for an in-flight medical event deserves the attention of certification authorities. Cardiac emergencies are among the most common serious events. The primary focus of this study was to examine whether the proportions of pilots with reported cardiac conditions could be used to identify those who had inflight medical incapacitations. METHODS: The Civil Aerospace Medical Institute Inflight Incapacitation Registry was searched to identify airline pilots with a cardiac history and an inflight medical event between 1995 and 2015. The Federal Aviation Administration's Decision Support System was searched for airline pilots without an inflight medical event. The cardiovascular history of incapacitated pilots was then compared to that of airline pilots without incapacitation events. RESULTS: Although a significantly greater proportion of airline pilots with cardiac events had pacemakers than a control group with the same cardiac history who did not have inflight events, no significant difference was found in the proportions of other markers of cardiac health. CONCLUSION: The proportions of airline pilots with identified cardiac conditions could not be reliably used to identify which pilots had inflight incapacitations.DeJohn CA, Mills WD, Hathaway W, Larcher J. Cardiac inflight incapacitations of U.S. airline pilots: 1995-2015. Aerosp Med Hum Perform 2018; 89(9):837-841.

Glaucoma in U.S. Civil Aviation: 2005-2014.

INTRODUCTION: Until recently, glaucoma requiring treatment was disqualifying for U.S. pilots and required an aeromedical special issuance waiver. Since 2013 Aerospace Medical Examiners (AMEs) have been authorized to evaluate third-class pilots with mild glaucoma using similar protocols and issue medical certificates without a waiver if these criteria specified in the AME Guide are met. METHODS: The FAA's medical database was searched for pilots with glaucoma between 2005 and 2014. The National Transportation Safety Board (NTSB) accident database was then searched to determine which pilots with glaucoma had aircraft accidents during that period. The odds of accidents in the glaucoma pilots were compared with the overall pilot accident odds. RESULTS: Of 5000 pilots being treated for glaucoma, 78 were involved in aircraft accidents; however, glaucoma was not cited as the probable cause or contributing factor in any of the accidents. A logistic regression model adjusted for age showed that glaucoma had a protective effect on accident odds. The crude accident rate for third-class pilots with glaucoma was estimated to be 7.2 per 100,000 flight hours, with a fatal accident rate of 1.8 per 100,000. Although these point estimates were slightly higher than the estimated general aviation accident rates, the differences were not statistically significant. DISCUSSION: These findings suggest that third-class pilots with glaucoma are not at significantly greater risk of an accident than the U.S. general aviation community. It also indicates that FAA certification protocols for certifying and following pilots with glaucoma provide an adequate level of flight safety.DeJohn CA, Mills WD. Glaucoma in U.S. civil aviation: 2005-2014. Aerosp Med Hum Perform. 2017; 88(12):1117-1122.

The U.S. Experience with Waivers for Insulin-Treated Pilots.

INTRODUCTION: This study explores the U.S. experience with waivers for insulin treatment for third-class medical certificates. From 1997 through 2014, the Federal Aviation Administration (FAA) approved an estimated 1500 waivers for insulin-treated diabetes with a total of 450 active waivers as of December 31, 2014. These pilots were involved in 25 accidents, but none were attributed to medical issues. METHODS: Data for the insulin waiver group and control group were obtained from the FAA's aeromedical certification system and matching accident data from the NTSB database. A logistic regression model comparing accidents in this group to the overall population of third-class certificate holders adjusted for gender, age, and flight times was performed. A novel technique for calculating accident rates was also employed. RESULTS: No statistically significant association between waivers for insulin treatment and accident risk was found by logistic regression. The overall accident rate for pilots possessing an insulin waiver was 7.0 per 100,000 flight hours and an estimate for all third-class pilots was also 7.0 per 100,000 flight hours. Only 8% of waivers for insulin treatment were later terminated for adverse changes related to the applicant's diabetes. Of these pilots, 8% also had coronary artery disease severe enough to require its own waiver. CONCLUSION: Taken together, these findings suggest that pilots holding special issuance waivers for insulin-treated diabetes are not detectably less safe than other airmen with third-class medical certificates and most are able to successfully comply with the FAA's stringent medical certification protocol for insulin treated diabetes.Mills WD, DeJohn CA, Alaziz M. The U.S. experience with waivers for insulin-treated pilots. Aerosp Med Hum Perform. 2017; 88(1):34-41.

In-flight medical incapacitation and impairment of airline pilots.

Medical incapacitation in the cockpit is rare, although it is a concern that has been the subject of several investigations over the years. With recent heightened interest in this problem, it seemed worthwhile to review all relevant scientific literature on the topic. Medline, PsychLit, the Aerospace Database, and other online databases were searched for studies of pilot in-flight medical incapacitation and impairment. The search revealed 13 articles during the years from 1968 to 2000. The studies represented several different approaches and were divided into five categories as follows: in-flight medical events, career termination, simulator data, questionnaires, and epidemiological analysis. The articles based on in-flight medical events showed that the leading causes of those episodes were myocardial infarctions, cardiac arrhythmias, and epileptic seizures. Few of the other types of studies used data from actual in-flight medical occurrences, instead relying on indirect measures such as career termination due to permanent medical grounding, loss of licensure insurance, or general epidemiological data to estimate the frequency of in-flight medical events. The reviewed studies provided only limited information on the frequency and categories of in-flight medical events and did not include incapacitation rates, making meaningful comparison between studies difficult. Future research needs to be based on actual in-flight medical events, and should be normalized to a useful denominator, such as flight time, to allow for meaningful comparison between studies.

Personal Flying Accident Rates of Selected Light Sport Aircraft Compared with General Aviation Aircraft.

BACKGROUND: The issue of expanding flight privileges that do not require medical oversight is currently an important topic, especially in the United States. We compared personal flying accident rates in aircraft with special light sport aircraft (SLSA) and experimental light sport aircraft (ELSA) airworthiness certificates to accident rates for personal flying in other general aviation (GA) aircraft. METHODS: To calculate accident rates, personal flying hours were obtained from the annual FAA General Aviation and Part 135 Activity Surveys, and numbers of personal flying accidents were obtained from the NTSB accident database. Overall and fatal personal flying accident rates for the SLSA and ELSA groups and other GA aircraft were calculated and accident rates were compared. RESULTS: The overall personal flying accident rate for SLSA and ELSA was found to be 29.8 per 100,000 flight hours and the fatal accident rate was 5.2 per 100,000 flying hours. These are both significantly greater than the overall personal flying rate of 12.7 per 100,000 h and fatal rate of 2.6 per 100,000 h for other GA aircraft. DISCUSSION: Although this study has several limitations, the significantly higher accident rates in the sport pilot aircraft suggests caution when expanding sport pilot privileges to include larger, more complex aircraft. Mills WD, DeJohn CA. Personal flying accident rates of selected light sport aircraft compared with general aviation aircraft. Aerosp Med Hum Perform. 2016; 87(7):652-654.

Prognostic Factors for Outcomes of In-Flight Sudden Cardiac Arrest on Commercial Airlines.

BACKGROUND: In-flight cardiac arrest (IFCA) is a relatively rare but challenging event. Outcomes and prognostic factors are not entirely understood for victims of IFCAs in commercial aviation. METHODS: This was a retrospective cohort study of airline passengers who experienced IFCA. Demographic and operational variables were studied to identify association in a multivariate logistic regression model with the outcome of survival-to-hospital. In-flight medical emergencies were processed by a ground-based medical center. Subsequent comparisons were made between reported shockable-rhythm (RSR) and reported non-shockable-rhythm (RNSR) groups. Logistic regression was also used to identify predictors for shock advised and flight diversions using a case control study design. Significant predictors for survival-to-hospital were RSR and remaining flight time to destination. RESULTS: The percentage of RSR cases was 24.6%. The survival to hospital admission was 22.7% (22/97) for passengers in RSR compared with 2.4% (7/297) in the RNSR group. The adjusted odds ratio for survival-to-hospital for the RSR group compared to the RNSR group was 13.6 (5.5-33.5). The model showed odds for survival to hospital decreased with longer scheduled remaining flight duration with adjusted OR = 0.701 (0.535-0.920) per hour increase. No correlation between diversions and survival for RSR cases was found. CONCLUSIONS: Survival-to-hospital from IFCAs is best when an RSR is present. The percentage of RSR cases was lower than in other out-of-hospital cardiac arrest (OHCA) settings, which suggests delayed discovery. Flight diversions did not significantly affect resuscitation outcome. We emphasize good quality cardio-pulmonary resuscitation (CPR) and early defibrillation as key factors for IFCA survival. Alves PM, DeJohn CA, Ricaurte EM, Mills WD. Prognostic factors for outcomes of in-flight sudden cardiac arrest on commercial airlines. Aerosp Med Hum Perform. 2016; 87(10):862-868.

Aeromedical Hazard Comparison of FAA Medically Certified Third-Class and Medically Uncertified Pilots.

BACKGROUND: Since 2004, in the United States, light sport aircraft (LSA) and some aircraft with standard airworthiness certificates can be operated for recreational purposes with a valid state driver's license rather than a Federal Aviation Administration (FAA)-issued aeromedical certificate. There have been recent efforts to allow operation of much larger, heavier, faster, and more complex aircraft without requiring a medical certificate. The primary objective of this research was to compare hazards to flight safety identified in fatally injured pilots required to possess a valid FAA third-class medical certificate to hazards in fatally injured pilots who were not required to possess a valid medical certificate. METHODS: A search of all fatal U.S. aircraft accidents in the FAA Medical ANalysis and TRAcking (MANTRA) registry between January 1, 2011, and April 30, 2014, identified 1084 individuals. A review of accident pilots' medical, autopsy, and toxicological data was conducted. After applying exclusion criteria, 467 pilots remained, including 403 medically certified and 64 medically uncertified pilots. RESULTS: A significant difference was found in a surrogate measure for risk between medically certified and uncertified pilots (25% vs. 59%). This difference remained significant after adjustment for age. No significant difference was found in the proportions of hazards identified on toxicological review. CONCLUSION: The results of this study suggest that the risk of an adverse medical event is reduced in pilots required to possess a valid medical certificate. Ricaurte EM, Mills WD, DeJohn CA, Laverde-Lopez MC, Porras-Sanchez DF. Aeromedical hazard comparison of FAA medically certified third-class and medically uncertified pilots. Aerosp Med Hum Perform. 2016; 87(7):618-621.