Home » Aviation » Physiological Episodes Down in the Navy After Slew of Changes; New Pilot Production Rate Nearly Back to Normal

Physiological Episodes Down in the Navy After Slew of Changes; New Pilot Production Rate Nearly Back to Normal

Commander, Naval Air Force, U.S. Pacific Fleet Vice Adm. Mike Shoemaker speaks with sailors in Atsugi, Japan on March 23, 2016. US Navy Photo

WASHINGTON, D.C. — The Navy’s multi-pronged efforts to address hypoxia, decompression sickness and other physiological episodes (PEs) in its F-18 and T-45 aircrew are showing positive results, with the number of PE events down in most aircraft types and the T-45C Goshawk trainers set to resume full operations by the end of the month, according to the commander of Naval Air Forces.

Vice Adm. Mike Shoemaker told USNI News today that “the trends right now on the physiological episodes are very good.”

On the T-45s specifically – used to teach new pilots how to fly before sending them to Fleet Replenishment Squadrons– Shoemaker said modifications have been made to 143 aircraft since an operational pause was ordered in April. After a halt to all operations, and then a resumption of operations with severe altitude and other restrictions, the Air Boss said the T-45 community should be back to pre-operational pause pilot production rates by the end of the month.

Since T-45 flights resumed after the pause, “over 15,000 hours flown, we’ve had five what I’ll call PEs,” he told USNI News following a House Armed Services readiness subcommittee hearing.
“Now of those, the medical folks, one was clearly, there was a dehydration issue with one of the aircrew. The other one was a fatigue issue. And the other one was a, in terms of the procedure for operating the OBOGS [onboard oxygen generation system] on deck, there was a mistake made in the procedure. So really there were two PEs in 15,000 flight hours, almost 13,000 sorties. So I think we’re in a good spot.”

“Again, we never found a smoking gun,” he said, noting a complicated interaction between conditions on the airplane and conditions within the aircrew personnel that create the potential for PEs to occur.
“We’ve made a lot of changes in the (OBOGS) system to address what we thought were the potential causal factors, and I think we’re in a good spot in the T-45.”

Shoemaker couldn’t point to any particular change the Navy had made in its aircraft that may have led to a decline in PE events. He noted that sieve filter materials in the OBOGS system for the T-45 and the F-18s had been replaced, which led to a trend in the right direction but wasn’t definitively causal.

“If you look at the trends – if you separate breathing gas from the Environmental Control pressurization stuff – the trends for breathing gas across the force are down. That’s the only issue we had with T-45s, and that I think is a good news story,” he said. Hypoxia, which results from the aircrew receiving insufficient or contaminated oxygen, is the only type of PE event the Navy has seen with the T-45 and accounted for about a quarter of PE events in the F-18 Hornets and Super Hornets and EA-18G Growlers, the Navy previously told USNI News. Decompression sickness-like symptoms from fluctuations in cabin pressure with the Environmental Control System accounted for the remaining 75 percent of events in the F-18 jets.
“In the Super Hornet world, we’re about half the trend we were from about a year and a half ago. It’s come down 50 percent, which is good. In the legacy Hornets, it’s sort of trend up just a little but, but it’s still about the same rate as the Super Hornets. Very low, like one in 3,000 sorties will we see an OBOGS or breathing air-related event.”

While the number of PEs occurring in the T-45s now is down, the Navy is still bracing for a significant shortfall to its squadrons and junior officers due to about eight months of no new pilot production, Shoemaker said.

“Production is in a good place right now,” he said, noting that 32 student pilots just recently qualified on carrier USS Abraham Lincoln (CVN-72) and even more are currently working on ground-based qualifications.
“Now, as we deal with the shortfall that we created with – essentially, by the time we get back to full production, almost eight months of non-production, all in TACAIR communities – there’s no disruption right now to the fleet because there were still plenty of aviators in our [Fleet Replacement Squadrons] moving to the fleet. But we see that getting probably most acute, or when we’ll see that gap peak is in early ’19 – spring of ’19 to summer of ’19.”

A CT-45C Goshawk assigned to Commander, Naval Air Training Detachment lands on the flight deck of the Nimitz-class aircraft carrier USS Abraham Lincoln (CVN 72). The ship is underway conducting carrier qualifications and training. US Navy photo.

Shoemaker said in other cases recently where Fleet Replacement Squadrons haven’t kept up with fleet requirements, some squadrons have seen gaps in their manning during the maintenance phase, with new pilots filling in closer to the squadron’s anticipated deployment date. While not ideal, this has been the best workaround, Shoemaker said, and in the tactical air squadrons even greater manning shortages during maintenance phase can be expected in 2019.

The admiral said that wouldn’t quite cover the pilot shortfall in 2019, though, so some junior officers could expect to see their tours extended, or even do a second at-sea tour instead of coming ashore for a production billet – teaching at a flight school or fleet replacement squadron, for example.

“We’ll see potentially some changes” to junior officers’ career progression paths, he told USNI News.
“If we do have to extend and/or recycle some back to sea duty, that will be out of the norm. We’ve just got to make sure we don’t hurt ourselves – those would all be folks who would be going to production tours in their first shore rotations, so we’ve got to make sure we get that right and manage it.”

The Marine Corps is facing fewer challenges in the aftermath of the T-45 operational pause. Though former Deputy Commandant for Aviation Lt. Gen. Jon Davis had told USNI News previously that pilot production would have to be back to 100-percent by September in order to avoid personnel challenges in the service, current DCA Lt. Gen. Steven Rudder told USNI News today that “we were good in [Fiscal Year] ’17 because we had pilots that were already in the pool. So we’ll watch it going into ’18, but thus far … it looks like we’ll be able to recoup and get back on staff. So we’re actually positive about how T-45 production is going.”

Rudder added that “we had a lot of transition pilots that we were able to fill seats, so we didn’t go empty with any seats” in the fleet despite the T-45 operational pause.

  • Curtis Conway

    “BZ” PMA-273, Chief of Naval Aviation Training (CNATRA), and NAVAIR!

  • DaSaint

    Surprised that BAe never developed the baseline T-45 into an affordable carrier-based light strike fighter (much like the old A-4s) as stopgap measures for navies such as Brazil and India that still operated fixed wing aircraft, but then again, that would only have been 2 customers. Always felt they could have added a radar, and I think they did for some Hawk models. The USN paid for all the other developmental items, such as upgraded landing gear, arrester hook, structural upgrades and modifications for marine environments.

    • incredulous1

      It would be an extremely light aircraft not worth the trouble without an increase in wing area and substantially more power. For dedicated trainers the payload is small inert goodies and an instructor. And adding hardpoints requires a lot of beefing up of the wing, adding more weight and requiring even more power.

      • DaSaint

        Hawks are already used as light strike fighters, with a ce.ntwrline and 4 wing hardpoints and a decent payload for their size. Worldwide. So I thought they would have married the capabilities. Don’t trust me, look it up.

        • incredulous1

          yeah with a 5,000 lb thrust engine and under 190 sq ft wing and that’s the improved model. so whatever “decent” means. People just love to argue on here don’t they?

          • DaSaint

            You’re right. My bad. Thought it was just engaging discussion with another poster. Didnt realize that offering a different perspective was considered arguing. Won’t make that mistake agaiin.

          • incredulous1

            The airplane is what it is. If they wanted light strike capability, they would have designed it with larger wings and more thrust. Some of us actually look stuff up before we post or already know for sure as part of our body of work, but most people do not and don’t care if they are wrong in forums.

          • El Kabong


            Go learn some facts before you keep embarrassing yourself.

            Indonesia, Zimbabwe, Oman, etc. have either used the Hawk in action or use single seat light attack versoins of the Hawk.

            The wing area and engine thrust have NEVER been substantially changed.

            Go ahead, prove me wrong.

          • El Kabong

            Yeah, NO…

      • El Kabong

        Meanwhile, the Hawk 200 has been in service for a couple of decades…

    • El Kabong

      A carrier version of the Hawk 200?


  • incredulous1

    Hard to believe that they are just now getting a handle on this after all this time. What has it been about 2.5 years of this? Makes me wonder if key components were made by the Chinese as part of an espionage deal – that is the type of shyte they pull, and they definitely have the stated motive of denying our ability to operate.

    • Duane

      The PE thing was never a simple problem with a simple answer. The biggest problem is that we still use human pilots, and the human body is vastly more complicated and subject to numerous failures and flight risks than any other aspect of an aircraft. After exhaustive research, the causes were found to be many, and many PEs were simply unexplicable.

      • El Kabong

        What’s that Duaney?

        The LCS isn’t the answer?

    • El Kabong

      You could do better, oh great chairborne commando?

  • publius_maximus_III

    Job well done, Capt. Sara Joyner, tasked with leading the PE investigation effort since last August. Sounds like some of the findings are already paying dividends.

  • Haydin Sinclair

    What about the decompression sickness rates? The article says it accounts for 75% of PEs but no trends for it were noted. Only hypoxia was specifically addressed in the article.

  • Jeff

    “CT-45C”? They made a cargo version of it? I bet not.

    • Ed L

      Dyslexia or poor proof reading

    • El Kabong

      A new COD? 😉