1US Air Force, Holloman AFB, NM
Mr David Wertz, OHST
US Air Force
The MD-1A Ground Control Station (GCS) is a self-contained unit which is used to control MQ-9 Remotely Piloted Aircraft (RPA) during various stages of flight. The station accommodates a rated pilot, a sensor operator and all the equipment required to interface with RPA aircraft via line-of-site (LOS) and satellite communication (SATCOM) terminals. Aircrew personnel working long shifts in the GCS enclosure may attribute symptoms of fatigue and headaches to carbon monoxide exposure.
Situation / Problem:
The residential carbon monoxide detectors in use do not have a numerical display and have a lower detection limit of 70 ppm, which exceeds the OSHA permissible exposure limit (PEL) of 50 ppm as an 8-hour time-weighted average (TWA). On several occasions, Bioenvironmental Engineering (BE) was notified that aircrews had experienced symptoms which they attributed to CO exposure, despite the lack of any known source of CO in the vicinity of the GCS. GCS are designated as aircraft, and as is the case with any aircraft incident, the unit is evacuated and impounded until certified safe. During this time, aircrews in other GCS may be required to assume control of the mission being flown by the incident GCS in addition to their own mission(s).
In this study, BE used 3M EVM-7 Environmental Monitors to measure CO, CO2, Temperature, Humidity, and VOC concentrations, with emphasis on CO. The monitors were placed in two GCS for 24-hour monitoring periods.
Results / Conclusions:
Per BE recommendation, CO detectors in all GCS have been replaced with NFPA 702 compliant detectors with a continuous digital display, which provides a frame of reference for the aircrews. The detectors must have a detection limit which will allow measurement at or below the OSHA Action Level of 25 ppm. Supervision has been instructed to perform these steps in the event an exposure to CO or other toxicant is suspected: 1) Notify Bioenvironmental Engineering, 2) Evacuate personnel, but maintain the GCS environment, 3) Assess potential sources of CO, and 4) direct any personnel experiencing symptoms to report to Flight medicine for evaluation.
Indoor Environmental Quality/Indoor Air Quality
Real-Time Detection Systems
Sampling and Analysis
Acknowledgements and References
List any additional people who worked on the project or provided guidance and support along with details on the role they played in the research. (Please include first name, last name, organization, city, state and country).
T.O. 1Q-1(M)B-2-2, MD-1A Series Ground Control Station Maintenance Procedures, 15 Dec 2016
NFPA 720, “Standard for the Installation of Carbon Monoxide(CO) Detection and Warning Equipment”, 2015 Edition
UL 2034, “Standard for Single and Multiple Station Carbon Monoxide Alarms”, 31 Mar 2017
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Competent - can perform to basic standards; has a thorough understanding of the content area but limited practical/work experience in the application of the content/concepts.