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Supplemental oxygen not just for use at flight levels

“Unable to control Altitude” 
“Unable to control Airspeed”
“Unable to control Heading”
“Other than that….everything is A-OK”

The YouTube video of Kalitta 66 has been watched over 1.4 million times.  Flight Kalitta-66 was a Lear 35 that slowly lost pressurization in the Flight Levels, causing the crew to suffer from unrecognized extreme hypoxia above FL260.  In the audio, the pilot’s voice is slurred and barely intelligible.  The chilling phrase “other than that, everything is A-OK” highlights how insidious hypoxia is – even in extreme cases like this one.  As the Kalitta 66 crew descends to 11,000 feet, the co-pilot comes on the radio and sounds loud and clear and completely normal again, as if nothing happened.

Hypoxia Clouds Judgment

The reason this audio is so compelling is that it provides a clear view of the effects of hypoxia on a well-trained and professional crew and demonstrates how hypoxia can cloud judgment, decision making, and motor skills without the pilot even recognizing it. (Just search “Kalitta Hypoxia” on YouTube and it immediately comes up).

14 CFR Part 91.211

Pilots who frequent the flight levels are well-versed in the need for and use of supplemental oxygen systems.  The legal requirements for oxygen are found in the regulatory framework of 14 CFR Part 91.211, which is chiseled into the brain of every student pilot prior to taking their private pilot written and flight test.   Unfortunately, due to the law of primacy, most pilots believe that oxygen is not required below 12,500 feet and that also means oxygen is not necessary below 12,500’.

Does “Compliance Equal Safety”?

As a flight instructor, I think we do our students a disservice if we stop the conversation there, however.  I once was told by our FAA Principal Inspector, emphatically, that “Compliance Equals Safety.”  In other words, if you comply with the regulations then by definition your operation is safe.  Part 91.211 falls short of this goal in several ways, however.  It is important for us to have honest discussions with our students about the practical use of oxygen and when it should really be used.  The benefit is that more pilots will use oxygen in their day-to-day flying which will make pilots more alert, less fatigued, and safer.

The bottom line is that 12,500 feet is not a physiological-based requirement. Interestingly, 14 CFR Part 91.211 was formalized on June 17, 1970, after being published as an NPRM three years earlier.  In the Final Rule, it was noted that “One commentator recommended that the altitude limit of 12,000 feet specified in the proposed Sec 91.32(a)(1) (the precursor to Sec. 91.211) be increased to 12,500 feet to provide an additional westbound VFR cruising altitude.”  The FAA concurred, saying “The recommendation has merit.”  Though, it was also recommended that the maximum altitude without supplemental oxygen actually be lowered to 10,000 to align with Part 135 and Part 121.  The FAA declined to do this because in its words, “A change based on this recommendation would constitute a substantive change in the proposal outside the scope of Notice 67-30.”   Therefore, the FAA raised the maximum ceiling for operations without oxygen only for pilot convenience and declined to reduce it for theirs. 

Your Source for Oxygen Equipment

Aerox is proud to announce that it has acquired the Sky-Ox line of portable oxygen systems and Supplemental Type Certificates for installed oxygen systems.  The Sky-Ox “Click-a-breath” regulators are easy to use, and feature a “set and forget” design which makes using your oxygen system as easy as turning a knob!  Visit for a complete line or portable oxygen systems, ground support equipment, TSO approved oxygen masks, and PMA oxygen cylinders.  Remember – “Its Toxic to Fly Hypoxic.” Find the antidote to hypoxia at


From portable systems to highly engineered systems on Part 25 aircraft, Aerox® has a system for you to deliver high performance at an economical cost.
Since 1981 we have been providing the aviation industry with innovative solutions for all of its oxygen needs. While our comprehensive website is representative of many of the products that Aerox offers, if you don’t see exactly what you are looking for, please contact us.
Aerox is certified to ISO9001:2015 and AS9100D. We offer a wide array of TSO oxygen masks and PMA oxygen cylinders in both Kevlar and Steel and operate FAA Repair Station YXQR567B
We offer a complete line of stock or custom systems, parts, and accessories. We are a provider of OEM systems, serving Diamond, Agusta, Piper, and many others. We can also design any kind of emergency or portable system, for use in the air or on the ground. Contact us to let us know how we can help you.

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