A clean-shaven face may not be necessary for pilots to ensure their safety during in-flight emergencies, according to scientists who found that those who sport a full beard can also properly seal on an oxygen mask.
Several airlines require pilots to have a clean-shaven face, as it is believe to be necessary to ensure a proper seal on an oral-nasal face mask during an emergency scenario.
Scientists from the Simon Fraser University (SFU) in Canada conducted a study to determine the efficacy of face masks on different beard lengths.
The wanted to understand if present-day equipment used in commercial airline industry delivers sufficient oxygen to protect a bearded pilot from hypoxia during an emergency cabin depressurisation scenario, said Sherri Ferguson from SFU.
Hypoxia occurs when the body does not receive enough oxygen and can cause damage to the brain and other organs minutes after symptoms appear and render a pilot incapacitated or unconscious.
"We had to find out whether the mask provides sufficient protection against carbon monoxide and toxic fumes should the cabin become smoke-filled from fire," said Ferguson.
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The researchers divided research participants into three groups: those with a small amount of facial hair such as stubble (less than 0.5 cm in length), those with medium sized-beards and those with long beards (up to 40 cm).
The participants wore masks and were put into a hypobaric chamber, which simulated altitudes from 10,000 to 25,000 ft above sea level.
The researchers measured the participants' oxygen saturation levels at every altitude change, because a drop in the oxygen saturation levels would indicate the masks are leaky and unable to maintain a proper seal.
For the second test, the researchers used stannic chloride, which causes watery eyes as well as a burning sensation in the lungs, in order to create conditions similar to fire smoke.
The researchers found no adverse effects on bearded subjects within the two parameters of the study, and that the masks maintained protection, irrespective of varying amounts of facial hair.
As the result of the Air Canada changed its policy for aircrew and now permits a maximum beard length of 1.25 cm.