Story ID: 392
Supplemental Oxygen: The Open Secret of Non-Compliance
By: AIN Staff
Caption: Pilots are far too comfortable not following the rule.
Word Count: 1096
Nearly nine out of 10 business aircraft pilots do not comply with FAR 91.211(b)(1)(ii), which requires one pilot to wear an oxygen mask that is "secured and sealed" above FL410, according to results of a thesis survey. For his master’s degree in aviation safety from Embry-Riddle Aeronautical University, Chris Shaver, a corporate flight flight department pilot and former NTSB investigator, questioned fellow pilots about a poorly kept secret inaviation: lack of compliance with supplemental oxygen regulations. He found that 87 percent choose not to comply with the rule.

“It has been a source of frustration for me, this one particular regulation, because there’s so much resistance about following it,” said Rick Miller, chief pilot for a Fortune 100 flight department. “This rule could be the poster child for noncompliance. It’s not just rogue pilots out there disobeying the regs. These are highly respected professionals who don’t generally have problems following the rules. We’re talking about chief pilots, demo pilots and test pilots.” 

Miller did some investigating of his own about why so many pilots refuse to abide by supplemental oxygen rules and came to the conclusion that a big part of the problem is the masks themselves. "Either consciously or by gut feeling, pilots are mitigating eight other hazards encountered as they complied with 91.211. They’re just uncomfortable,” he said.

“The mask fits very tightly. When you get on those ultra-long-range flights of, say 12 to 14 hours, we augment the flight crew with additional personnel. Each pilot is wearing the mask for three to four hours. So that means it’s basically squeezing your head for three or four hours at a time," Miller said.

And then there’s a health risk, he said, citing the difficulty of cleaning masks properly. Miller pointed to the exceptionally onerous task of cleaning behind the mask’s microphone. “We do carry alcohol wipes to sanitize the mask between uses. But you’re really at the mercy of how the previous person has cleaned the mask. We do tend to pass colds back and forth between us when we use the mask,” he added. 

Other pilots point out the masks are built to be used in emergencies. “They’re just not made for everyday use,” Shaver said. The wear and tear means there is a greater probability that masks might fail, he noted. “Sometimes, masks that are required to be in a quick-use position to meet the FAA’s five-second rule are instead simply set aside. Donning masks in such cases often takes longer than five seconds.”

Shaver and Miller believe the wide disregard for 91.211 has the potential to become a slippery slope. Both think that by selectively complying with the rules, some pilots might become insensitive to ignoring other rules. The NBAA Safety Committee estimates procedural non-compliance is a factor in up to 40 percent of aviation accidents worldwide that were reviewed by human-factors experts. 

The International Civil Aviation Organization (ICAO) requires the use of supplemental oxygen but its rules are slightly but significantly different from those set forth by the FAA. Annex 6 of the ICAO Standards and Recommended Practices (SARPS) sets supplemental oxygen requirements according to the pressure inside the aircraft rather than outside, as is the case with FAA requirements.

Miller sees that approach as a possible solution to non-compliance among U.S. flight crews. “We don’t want to get rid of the entire rule [that requires supplemental oxygen use above FL410],” he said. What we want to do is harmonize with the ICAO Annex 6 rule.” To that end, both Miller and Shaver are part of NBAA’s High Altitude Supplemental Oxygen Working Group (HASO), an arm of the association’s Safety Committee. In collaboration with GAMA, major manufacturers and the American Medical Advisory Service, the working group started out by surveying business aviation flight crewmembers.  

The HASO Working Group found that most pilots (88 percent) regard wearing an oxygen mask for extended periods as adding to pilot fatigue. Most (70 percent) also believe that mask use if behind physiological problems they have experienced, with most citing bronchial irritation as the main symptom. The vast majority (92 percent) of pilots surveyed by the working group worry about becoming sick as a result of wearing an unclean mask. Almost 90 percent of those asked believe oxygen masks interfere with crew resource management (CRM).  

To support the idea of changing FAR 91.211, Miller and the working group say the aircraft they fly are demonstrably reliable—that the chances against in-flight depressurization are a billion to one. “When you do a risk analysis, cabin depressurization is considered a catastrophic event. But the chance of it happening is extremely remote. It falls under the the category of ‘acceptable risk,’” he said. The suggested solution from HASO, then, is to bring 91.211 into harmonization with ICAO Annex 6. “On the whole, it’s tougher than 91.211. But the use of supplemental oxygen is based on cabin pressure,” he said. 

If the FAA will not change 91.211 to reflect the ICAO standard, Miller suggests exempting operators flying aircraft manufactured in compliance with FAR 25.841, which states in part: “If certification for operation above 25,000 feet is requested, the airplane must be designed so that occupants will not be exposed to cabin pressure altitudes in excess of 15,000 feet after any probable failure condition in the pressurization system.

"The airplane must be designed so that occupants will not be exposed to a cabin pressure altitude that exceeds the following after decompression from any failure condition not shown to be extremely improbable: 25,000 feet for more than 2 minutes; or 40,000 feet for any duration. Fuselage structure, engine and system failures are to be considered in evaluating the cabin decompression.” 

“When you do a risk analysis,” said Miller, “that basically means, while the hazard itself is considered catastrophic, the chances of it happening are extremely remote. We’re talking one in a billion.” NBAA’s HASO Working Group is in discussions with the FAA about changing 91.211, Miller said. In the process, he sees a further opening for frank talks about other issues. “What this has done is open the door to addressing other shortcomings with regulations,” he said.

 

 

 

 

 

 

 

 

 

 

 

 

 
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