Beard Length and the Efficacy of an Aviator Oxygen Mask
INTRODUCTION: Facial hair is prohibited for most airline pilots because of the widespread belief that the seal on oxygen masks might be rendered ineffective, preventing aircrew from performing their duties during emergencies. METHODS: Continuous oximetry recordings were made every second from 24 volunteers wearing a standard commercial airline mask in 1 of 3 beard conditions: no beards, short beards (<10 mm in length), and long beards (>10 mm in length) in a normobaric hypoxia chamber at 30,000 ft (10,000 m). Masks were worn in the chamber for about 10 min before being removed for about 2 min to experience hypoxia. Once returned to normoxia, volunteers were exposed to smelling salts held directly under the chin. RESULTS: None of the beard conditions differed in the time to don the masks. There were no differences in the arterial saturation percent of oxygen (Spo2) between beard conditions for either mask-on or mask-off segments in the chamber. There were significant differences in Spo2 between the mask-on segment and the mask-off segment, indicating that hypoxemic conditions would have been detected had the masks been ineffective. DISCUSSION: Using a current on-demand airline oxygen mask, Spo2 levels were never compromised by any of the beard conditions. Because the highly volatile smelling salts were imperceptible through the masks, smoke and other noxious irritants would not be perceived. These results support the contention that airline pilots with beards of any length would not be impaired by hypoxia or smoke while dealing with an in-flight emergency. French J, Wagner SD. Beard length and the efficacy of an aviator oxygen mask. Aerosp Med Hum Perform. 2025; 96(4):322–326.
The Sweep-On® 2000™ Crew Oxygen Mask (Collins Aerospace) A) used in the study and B) a typical participant (Long beard >10 mm) wearing the mask.
Example of continuous oximeter readings for SpO2 for an individual in the three beard groups: Clean Shaven, Short Beard (<10 mm), and Long Beard (>10 mm). After about 7–10 min, masks were removed while standing exposed to 30,000 ft (10,000 m) equivalent for about 2 min.
The oximeter readings for beard groups Clean Shaven, Short Beard (<10 mm), and Long Beard (>10 mm) showing A) SpO2 and B) the associated heart rate in beats per minute. Data shown are ± SD.
The SpO2 oximeter readings for beard groups Clean Shaven, Short Beard, and Long Beard during the 2-min hypoxia segment: H-Clean, H-Short, and H-Long, or during a 2-min segment of the Mask-on Segment. Data are averages ± SD.
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