Aeromedical Certification Collaborative (ACC): Progress Report

FAA Office of Aerospace Medicine 
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-25/12

Title and Subtitle: Aeromedical Certification Collaborative (ACC): Progress Report

Report Date: February 2025

Authors: Sienknecht T, Masterson P, Reston R, Ryan E, Hawley H, Sarkhel K

Abstract:

The Federal Aviation Administration (FAA) Office of Aerospace Medicine (AAM) tasked the MITRE Corporation’s Center for Advanced Aviation System Development (MITRE CAASD) to continue outreach and engagement with aviation industry stakeholders to advance aeromedical collaboration and information sharing. This continues previous research which resulted in FAA and aviation industry co-creating the Aeromedical Certification Collaborative (ACC).

MITRE CAASD conducted several one-on-one workshops with ACC participants culminating in the creation of two working groups. The Study Working Group (WG) identified near-term research questions which could demonstrate the collaborative research approach of ACC, provide insights on gaps in data for aeromedical risk management, and identify potential data sources or activities requiring governance. The Framework WG defined requirements for a data sharing/governance model and shared expectations for future collaboration. The ACC participants met for a Winter Summit on January 30, 2025, in which they agreed to study Peer Support Programs (PSPs) and came to an initial consensus on the data sharing/governance model. In addition, MITRE CAASD determined that it was not yet feasible to use the Aviation Safety Information Analysis and Sharing (ASIAS) technical environment and associated public-private partnership to conduct aeromedical safety research. ACC needs are being expressed as proposed requirements for future ASIAS/US AST consideration as part of ongoing transformation efforts within ASIAS and US AST.

The impact of this work is that AAM will be able to explore aeromedical safety questions requiring sensitive and proprietary information and use real-world insight into the primary drivers of and mitigations for aviation safety risk associated with pilot health to maximize public trust in aviation safety while minimizing cost and burden on pilots, airline operators, and the aviation industry.

Key Words: Safety Management Systems (SMS), Aeromedical Certification, Aviation Safety Risk Management, Collaboration, Stakeholder Outreach, Collaborative Risk Management

No. of Pages: 13

Postmortem Blood Genomics Biorepository

FAA Office of Aerospace Medicine 
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-24/03

Title and Subtitle: Postmortem Blood Genomics Biorepository

Report Date: August 2024

Authors:

Hilary A. Uyhelji (https://orcid.org/0000-0002-3433-8320)
Christopher J. Tracy (https://orcid.org/0000-0002-4532-3327)
Vicky L. White (https://orcid.org/0009-0007-1164-5233)
Scott J. Nicholson (https://orcid.org/0000-0002-2201-744X)

Abstract: The Federal Aviation Administration Civil Aerospace Medical Institute Bioaeronautical Sciences Research Laboratory (BSRL) collects, processes, and analyzes forensic fluid and tissue samples from fatal civil aviation accidents in the United States. The BSRL issues standardized forensic sample collection kits(ToxBoxes) for medical examiners and coroners to collect and ship the samples needed for toxicological analysis. The BSRL Forensic Sciences section receives and assays incoming forensic samples to determine if the pilot consumed or was exposed to known drugs or toxic substances. This information is collected on behalf of the National Transportation Safety Board to assist in accident investigation. The BSRL Functional Genomics Research team previously examined gene expression patterns in such forensic samples. However, ToxBox forensic samples were not routinely preserved in a manner that prevented the degradation of those patterns during collection and storage. This report details establishment of protocols and selection of tubes to supplement ToxBox collections with preservation of blood for functional genomics analyses. To preserve ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) in forensic samples and establish a biorepository of samples suitable for future gene expression analyses, a supplemental whole blood research specimen collection kit is now included in ToxBoxes. These kits have been distributed in ToxBoxes since August 2022.

Key Words: Biorepository, aviation accident investigation, RNA, DNA

No. of Pages: 19

Biomarkers for Noise-Induced Sleep Disruption

FAA Office of Aerospace Medicine 
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-25/09

Title and Subtitle: Biomarkers for Noise-Induced Sleep Disruption

Report Date: April 2025

Authors:
Hilary A. Uyhelji (https://orcid.org/0000-0002-3433-8320)
Mathias Basner (https://orcid.org/0000-0002-8453-0812)
Christopher W. Jones (https://orcid.org/0000-0002-8173-721X)

Abstract:

Noise experienced by the general population in proximity to airports and aviation flight routes can result in disrupted sleep. Sleep disruption and fragmentation may be mitigated by wearing earplugs or introducing broadband noise (e.g., pink noise) into the bedroom. However, these countermeasures are poorly investigated and understood. The FAA ASCENT has supported the University of Pennsylvania in investigating earplugs and pink noise to mitigate sleep disruption from simulated aircraft noise, using approaches such as physiological and neurobehavioral performance monitoring. The FAA Civil Aerospace Medical Institute complemented these efforts by receipt of blood samples collected from human subjects exposed to the simulated aircraft noise and monitored by the University of Pennsylvania. Ribonucleic acid (RNA) was extracted from the blood followed by total RNA sequencing and differential gene expression analyses, which provided molecular insights about human responses to noise and the mitigations tested. Altogether 1,246 genes were differentially expressed in response to the experimental exposure condition (control without noise, pink noise at a level of 50 dBA, simulated aircraft noise, and simulated aircraft noise with a mitigation: pink noise at 40 dBA, pink noise at 50 dBA, or earplugs). There were 2,181 genes associated with awakenings during noise exposure.

Key Words: Aviation noise; Pink noise; Sleep loss; Fatigue

No. of Pages: 10

Exploratory Development of Biomarkers for Neurobehavioral Performance Impairment During Sleep Loss: Comparison Across Multiple Types of Sleep Deprivation

FAA Office of Aerospace Medicine 
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-25/08

Title and Subtitle: Exploratory Development of Biomarkers for Neurobehavioral Performance Impairment During Sleep Loss: Comparison Across Multiple Types of Sleep Deprivation

Report Date: June 2025

Authors: Hilary A. Uyhelji, Scott J. Nicholson, Thomas E. Nesthus, Julia L. Beckel, Elizabeth B. Klerman, Charles A. Czeisler, Robin K. Yuan, Arturo Arrona-Palacios, Pamela Song, Joseph M. Ronda, Jason P. Sullivan, Michael S. Goodson

Abstract:

Inter-individual variation in response to insufficient or altered timing of sleep presents a challenge for the development of personalized approaches to fatigue monitoring and mitigation. Besides health impacts, insufficient sleep can result in impaired neurobehavioral performance and pose a substantial risk of injury and even mortality in safety-critical operations such as transportation. The present study provides a detailed exploration of physiological, neurobehavioral, and gene expression changes during sleep restriction, acute total sleep deprivation, and altered timing of sleep among 59 healthy volunteer participants who completed a 10-day inpatient study.

Reducing the quantity or altering the timing of sleep significantly impacts self-reported estimates of sleep duration, polysomnography-recorded sleep stages, and neurobehavioral performance test results. Impaired neurobehavioral performance was associated with transcriptomic changes in gene expression. A comparison of current and prior research on total sleep deprivation indicated that reproducible candidate gene expression biomarkers exist for at least one metric of attention, specifically, Psychomotor Vigilance Test (PVT) lapses.

Candidate biomarkers of fatigue-related impairment were identified that responded to single neurobehavioral performance endpoints, as well as those that responded to multiple types or metrics of performance. Reproducible identification of biomarker candidates for PVT lapses during total sleep deprivation increases confidence in the ability to June 2025 iv Comparison Across Multiple Types of Sleep Deprivation develop a molecular approach to fatigue-related impairment detection, while novel discoveries expanded the list of candidate genes to other impairment metrics. Molecular biomarkers for neurobehavioral performance impairment represent a potentially valuable tool to more precisely monitor the neurobehavioral performance deficits resulting from sleep loss, and further research and validation could one day augment fatigue risk management practices that historically emphasize scheduling and rest opportunities. The data generated from self-assessment, polysomnography, neurobehavioral performance, and molecular investigations provide a wealth of information made publicly available for further data mining and scientific advancements.

Key Words: Total sleep deprivation; Sleep restriction; Shiftwork; Neurobehavioral performance impairment; Fatigue; Psychomotor; vigilance test; Gene expression biomarkers

No. of Pages: 28

Spatial Disorientation in Fatal General Aviation Accidents (2003 – 2021)

FAA Office of Aerospace Medicine 
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM- 25/14

Title and Subtitle: Spatial Disorientation in Fatal General Aviation Accidents (2003 – 2021)

Report Date: 3/3/25

Authors: Hannah M. Baumgartner, Jason Sigmon, Austin Ciesielski, Russell Lewis

Abstract: The incidence of spatial disorientation (SD) during flight poses a distinct threat in general aviation (GA) due to the high fatality risk associated with its occurrence. While historical analyses have examined the incidence of SD in GA accidents, little current research exists. This research examines fatal GA accidents associated with SD from 2003 to 2021 and investigates the pilot demographics, flight characteristics, and environment conditions associated with these accidents to identify potential risk factors and compares these findings with previous historical analyses. Overall, 367fatal accident reports from the National Transportation Safety Board (NTSB) that were GA associated with SD we reanalyzed. These accidents showed a strong correlation to pilots with less than 500 hours of flight experience. Additionally, instrument meteorological conditions (IMC) were likely to involve flights into IMC despite intentions to fly using visual flight rules (VFR). While the number of fatal SD GA accidents has decreased in comparison to previous analyses, the fatality rate associated with SD is still high (94%) and involves high fatality numbers for pilots, passengers, and even ground bystanders. Further, the number of fatal SD GA accidents associated with positive toxicology findings has increased over time, particularly for drugs that pose potentially impairing effects. This research highlights the necessity for continued education and awareness efforts for SD within GA.

Key Words: Spatial disorientation, general aviation, accident analysis, situation awareness, toxicology

No. of Pages: 13

Operational Human Factors Considerations for Head-Worn Display (HWD) Usage in Civil Aviation

FAA Office of Aerospace Medicine 
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-25/07

Title and Subtitle: Operational Human Factors Considerations for Head-Worn Display (HWD) Usage in Civil Aviation

Report Date: January 2025

Authors: Susindar, S., Ferris, T., Valasek, J., Fojtik, E., Brown, M., Pugh, K., Marcario, C., and King, T. 

Abstract: Advanced visual display systems, such as Head-Up Displays (HUDs), Helmet-Mounted Displays (HMDs), and Head-Worn Displays (HWDs), have been used in military aviation since the 1960s and have been increasingly introduced in general and commercial aviation cockpits. The evolution of in-cockpit technology has ushered in fundamental changes in how pilots receive and process flight-relevant information. Flight operations proceed very differently in cockpits outfitted with traditional head-down display (HDD) configurations compared to those that support viewing/interacting with HUDs, HWDs, and other types of advanced visual displays. The physical and cognitive demands placed on pilots are also impacted by the use of these technologies. Therefore, it is important to understand the nature of these interactions, the demands imposed, and the implications of display system features for safe and effective aviation, communication, and navigation. This report details a hybrid narrative and systematic literature review of human factors issues related to aviation applications of HWDs and other advanced visual displays. It summarizes the scientific findings of studies on HWD usage and compiles evidence that can inform recommendations for the usage of HWDs in civil aviation.

Key Words: Head-Worn Display, Head-Up Display, Helmet-Mounted Display, Human Factors, Civil Aviation

No. of Pages: 101

Aerospace Medicine Technical Reports

Federal Aviation Administration Aircraft Evaluation Division Operations and Human Factors Evaluation Aid for Enhanced Flight Vision Systems

FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-24/21

Title and Subtitle: Federal Aviation Administration Aircraft Evaluation Division Operations and Human Factors Evaluation Aid for Enhanced Flight Vision Systems

Report Date: November 2024

Authors: Kelene A. Fercho and Bryan L. Watson

Abstract: This...

Human Factors Analysis of Helicopter Air Ambulance Accidents, Incidents, and Events (2013-2023)

FAA Office of Aerospace Medicine 
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM- 24/22

Title and Subtitle: Human Factors Analysis of Helicopter Air Ambulance Accidents, Incidents, and Events (2013-2023)

Report Date: November 2024

Authors: Hannah M. Baumgartner, Justin Durham, Rebecca DiDomenica, Peter T. Hu

Abstract: Helicopter Air...

The Development and Implementation of a Safety Culture Survey for High-Performing Aviation Organizations

FAA Office of Aerospace Medicine 
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-24/18

Title and Subtitle: The Development and Implementation of a Safety Culture Survey for High-Performing Aviation Organizations

Report Date: October 2024

Authors: K.Worthington, P. Hu, D.Schroeder, I. Choi

Abstract: A positive safety culture requires...