New Operating Procedures to Mitigate Physiological Episodes

U.S. Navy photo illustration by Fred Flerlage; photographic image by Erik Hildebrandt

Naval Aviation’s operating instruction has been updated with information to help aviators not only mitigate but avoid physiological episodes—Naval Aviation’s No. 1 safety priority.

Physiological episodes (PEs) occur when aircrew experience physiological symptoms such as dizziness or cognitive degradation which may impair their ability to perform cockpit duties.

The Physiological Episodes Action Team (PEAT) has incorporated what they’ve learned in the “General Flight and Operating Instructions Manual CNAF M-3710.7” after extensive Root Cause Corrective Action (RCCA) analyses of aircraft systems and medical investigations since the PEAT’s inception in 2017.

Vice Adm. DeWolfe Miller III, commander, Naval Air Forces, signed the overarching instruction Sept. 9 and it was released to the fleet Oct. 6, paving the way for updates to emergency procedures in the Naval Air Training and Operating Procedures Standardization (NATOPS) documents for the F/A-18 Hornet/Super Hornet and T-45 Goshawk, said Cmdr. Adrian “Catfish” Jope, PEAT lead.

“The updates are designed to change mindsets and outline procedures to mitigate and prevent physiological episodes,” Jope said. Aviators rely on their specific platform NATOPS document for how to operate the aircraft, its systems and emergency procedures.

“We have been sharing what we’ve learned with the fleet in ready rooms and auditoriums during our PE briefings, or PE TED Talks, but now they have an updated instruction in the newly revised CNAF 3710 in which to reference,” Jope said.

Major additions to the CNAF 3710 and follow-on proposed changes to the individual platform NATOPS include improved mask usage guidelines, the introduction of strategic air breaks to improve respiratory capacity, updated emergency procedures, as well as enhanced explanations of the functionality of On-Board Oxygen Generating System (OBOGS) and Environmental Control System (ECS), Jope said. The new NATOPS procedures are expected to be released to the fleet in the coming months.

“We’ve been told for a long time that we will wear our mask from takeoff to landing unless we needed to make subtle adjustments or move it aside to take a drink of water. Over the course of the last couple of years, we’ve learned that breathing with a mask for long periods of time can create physiological challenges, and if left unchecked can potentially lead to adverse physiological symptoms. As such, we have learned that by dropping the mask to take cleansing breaths at appropriate opportunities below 10,000 feet cabin altitude where hypoxia is not a concern, aircrew can help restore their normal physiological balance,” Jope said.

The PEAT’s Aeromedical Action Team (AMAT) also found that existing training for aviators and medical professionals was not extensive enough, so more in-depth information was added to the physiology chapter in CNAF 3710, said Cmdr. Allen “Doc” Hoffman, a naval flight surgeon who serves as the AMAT lead and Aerospace Medicine branch head with the U.S. Navy Bureau of Medicine and Surgery.

For example, the new physiology chapter covers the effects of breathing high-concentration oxygen through the OBOGS. Studies found one of the negative effects of breathing 94-percent oxygen is that it can wash out the nitrogen in the lungs, which in turn deflates the lung’s alveoli in the bronchial tubes causing atelectasis, Hoffman said. To mitigate that effect in the cockpit, the updated instruction covers what the symptoms feel like and when to take a strategic air break to conduct controlled breathing cycles and reset the respiratory system.

“We want to educate aviators on how their body naturally responds to the environment and environmental stressors just like you would when you run a marathon or you go weight lifting or you are in your car and another car almost sideswipes you—you are going to have a physiologic reaction. Those same reactions occur in the cockpit. The instruction educates them on which symptoms are significant and which ones they can mitigate in the cockpit and continue on their mission; that’s a win for everyone, and ultimately, improves operational readiness,” Hoffman said.

As an action team, the PEAT initiated the instruction updates. Changes are usually generated by the fleet, but in this case, the update was generated by the PEAT and AMAT and socialized with Naval Aviation Enterprise leaders as well as the fleet and medical community before being finalized, Jope said.

Working through the updates during the COVID-19 restrictions was also a challenge.

Members of the PEAT worked tirelessly during the summer to meet virtually with subject matter experts from aerospace medicine along with Naval Air Systems Command engineers and fleet model managers to finalize the changes.

More than 25 teleconferences and 500 manhours were spent updating the CNAF 3710 and an additional 50 teleconferences and 1,500 manhours were dedicated to the NATOPS changes, Jope said.

Fleet aeromedical safety officers were briefed in August and started sharing the training updates with squadrons in October.

Andrea Watters is editor in chief of Naval Aviation News.