WASHINGTON — The two-seater EA-18G was cruising at 25,000 feet Jan. 29, about 60 miles south of Seattle on a flight from Washington state’s Naval Air Station Whidbey Island to Naval Weapons Station China Lake. The crew received a warning that the system that controls the cockpit air temperature and cabin pressure, known as the environmental control system, was icing.

By the time the flight was over, an elite aircrew with Air Test and Evaluation Squadron Nine was being rushed for medical treatment, and yet another failure of the EA-18G Growler’s environmental control system — one not seen in any of the previous physiological episodes linked to the ECS — was raising new concerns in the Navy’s sisyphean fight to stop physiological episodes from putting pilots at risk in the sky.

The temperature inside the cockpit suddenly plunged to temperatures reaching -30 degrees and a mist pumped into the cockpit, covering the instruments and windows in a layer of ice, rendering the pilots almost completely blind, according to several sources familiar with the incident and an internal report obtained by Defense News.

The fog inside the aircraft iced over the instrument panel, forcing the pilot and electronic warfare officer to use a Garmin watch to keep track of their heading and altitude while air controllers began relaying instructions to the crew. The pilot and EWO were forced to use the emergency oxygen supply, which was completely depleted by the end of the flight.

A heroic effort by the two-person crew and the ground-based controllers managed to guide the aircraft back to Whidbey Island, but both pilot and EWO suffered serious injuries due to frostbite. The aircrew suffered from “severe blistering and burns on hands,” according to the Navy internal report.

In a statement, Naval Air Forces spokesman Cmdr. Ron Flanders confirmed the incident and that the Navy was trying to determine the cause of the incident.

“The aircrew was treated upon landing; one of the aircrew is already back in a flight status; the other is not yet back in a flight status but is expected to make a complete recovery,”

“The mishap is under investigation; I cannot comment further. Once the investigation is complete, the Navy will determine which further actions are necessary.”

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ECS failures

While the specific failure of the environmental control system in this instance hasn’t been recorded by the Navy previously, the ECS has been a persistent problem as it grapples with a recent spike in PEs in Hornets and Growlers.

The Navy describes the system as “a complex aggregate of sub-components, all of which must function for the system to work as a whole.” The Navy believes that aging parts and inadequate testing procedures have contributed to certain PEs that result from depressurization inside the cockpit and oxygen deprivation.

But overpressurization has also been a problem. Two years ago, a pilot and EWO were horrifically injured when their cockpit overpressurized and exploded, shattering the plexiglass canopy and sending shards in all directions.

Overall, about 25 percent of the PEs suffered by aircrews in the Super Hornets and the Growlers have been traced back to ECS failures, according to a Navy official who spoke on background. Those numbers were much higher in the legacy Hornets.

Meanwhile the head of the Navy’s Physiological Episodes Action Team, Sara “Clutch” Joyner, is being pulled from the project after less than a year in the position and is taking a job on the Joint Staff, raising some alarm bells in Congress. Her replacement has not been named.

PEs have wreaked havoc in the aviation community. In 2016, the Navy had its worst year on record for PEs, including 125 total in the Growler/Hornet community.

Last April, Navy instructor pilots staged a borderline mutiny when they felt like their supervisors were ignoring serious PE problems with the Navy’s T-45 aircraft. The Navy has since made progress in T-45 PE incidents but the revolt of the instructor pilots grabbed the attention of senior leadership and made the PE issue front-and-center.

But definitive answers as to what is causing the spike in PEs are elusive and the Navy is continuing to chip away at the issue. Joyner has said that she doesn’t believe there is one solution for all the PE issues but that the Navy has made progress in some areas.