The Navy said Monday it will comprehensively review recent breathing problems experienced by aircrews of the F/A-18 strike fighter and the T-45 jets used to train them.
Naval Air Station Oceana is home to several F/A-18 Hornet squadrons and the Navy’s aviation community considers recent breathing issues to be its top safety priority.
“Physiological episodes,” as the Navy calls them, “occur when aircrew experience a decrease in performance due to the cabin pressure fluctuations, contamination of breathing air, or other factors in the flight environment.”
Since new tracking protocols were put in place in 2010, the rate of physiological episodes per 100,000 flight hours in the F/A-18 Hornet has increased from 12.2 to 57.24 in 2016, according to Navy figures.
In the T-45, the rate increased from 11.86 episodes per 100,000 flight hours in 2012 — when the new tracking measures were put in place for that aircraft — to 46.97 in 2016.
Broadly, the episodes are typically related to unscheduled pressure changes or pilots breathing gas. The Navy told Congress in March that the two most likely causes of recent episodes experienced by aviators are decompression sickness and hypoxia.
Symptoms of hypoxia include nausea, tingling, fatigue and disorientation. Decompression sickness symptoms also include double vision, headaches and dizziness, according to the Federal Aviation Administration.
The Navy has taken more than a dozen actions to mitigate physiological episodes among Hornet pilots, including mandating cabin pressurization testing every 400 flight hours, providing aircrews with portable hypobaric recording watches to alert them when cabin altitude reaches a preset threshold, and requiring pilots to receive annual hypoxia awareness training.
The Navy also canceled 94 of 216 scheduled T-45 flights March 31 after instructor pilots raised concerns about increasing breathing problems caused by contamination of the T-45’s oxygen system. The Navy temporarily halted flying the jets April 8, and resumed about a week later with new altitude restrictions and modified masks for crews to wear.
Vice Chief of Naval Operations Adm. Bill Moran directed U.S. Pacific Fleet Adm. Scott Swift on Friday to lead the review and determine the composition of the review team. Swift is expected to complete his work and provide the results to Moran within 30 days.
“The seriousness in which I view these incidents is reflected in the seniority of those leading this review. They will provide a full and open accounting to our aviation community, their families and the public,” Moran wrote in his memo to Swift.
The T-45 is a two-seat, single-engine jet used to train Navy and strike fighter pilots, including many of those based at Oceana. The Navy has 197 T-45s in its inventory. The jets became operational in 1991 and each one costs about $17 million.
The strike fighter training commands are based in Meridian, Miss.; Kingsville, Texas; and Pensacola, Fla.
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