As an aircrew association, part of our mission is to provide a platform for our members to share their experiences to help others improve in their professional aviation and aerial remote sensing endeavors. With that, one of our newer members just shared this article with the ASOG Desk Editor with the intent to help others – "My Hypoxic Event" by Darren Daigle
ASOG Article of the Month | January 2024
ASOG Author | Darren Daigle
Wing Tips
My Hypxoic Event & What I Learned from this Flying Incident
I have had a 25-year career in the Canadian Air Force CAF with about 5000 hours of flying as a Sensor Operator. I have also continued to fly as a drone pilot and now as a sensor operator using the L3 MX15HDi multispectral camera.
In my current job, I fly with a crew in a light twin. We do fire Mapping, and sometimes we fly high enough to require supplemental oxygen.
Our portable oxygen system was my first exposure to the "cannula" system, electronic regulator, and oxygen bottle. The cannula, for those unfamiliar with it, is similar to the tube and hoses you see with some hospital patients. I had never needed it in the CAF since the Aurora (Canadian P-3) is pressurized. The instructions for using the regulator and oxygen bottle were pretty straightforward. The "cannula" is a tube that wraps around the ears and is held under the nose. The regulator senses a breath in and gives a pulse of oxygen through the cannula.
The only description of using the cannula is a picture on the envelope.
I have had hypobaric training with the military, which proved invaluable in this situation. We climbed above 14,000 Feet AMSL, and the oxygen pulses seemed normal. I began feeling light-headed and immediately recognized a possible lack of oxygen. I notified the pilot. We walked through steps to ensure proper flow. I checked the oxygen supply bottle for adequate quantity; it was in the green. I then checked the supply hose to the regulator for kinks or blockages; there were none. I then checked the hose and cannula for kinks or blockages; it was fine.
I decided to wait and see what the problem was for the time being since the symptoms were so mild. I then decided to use my smartwatch to check my O2 level. It showed 76%. I didn't think it was accurate, but I thought it was too much evidence to demonstrate oxygen deprivation. I then pulled the cannula closer to my nose. I noticed that the flow occurred with every breath rather than every second or third breath. It became evident to me that I had the cannula to loose. My symptoms cleared up, and I felt much better. The cannula had to be tight enough to be uncomfortable.
I realized there is no documentation to help identify a lack of proper operation. I suggested to our company that a procedure be implemented to verify that the cannula provided a "puff" every breath above 14,000 feet. I feel this should have been part of the cannula's instructions.
I caution SOs to be very careful when using new equipment that doesn't have excellent documentation. If you think there's a problem, there probably is. Work on the problem until it is resolved. My pilot suggested we could declare an emergency and descend. It was my training and experience that made me hold off a little. Ultimately, the mission was completed, and a lesson was learned.
I hope my experience can prevent any other SO from suffering from a hypoxic event.
About the Author
Darren Daigle | Darran has over 25+ years of experience in aviation and aerial remote-sensing operations. His skills and expertise span 22 years in the Canadian Forces, five years as an IAI Heron UAV pilot/Instructor, three years as a DA-42 Mission Specialist operating MX-15 HDI in support of ALE and forest fire mapping operations.
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