The Navy released on Thursday the results of a comprehensive review to determine the causes of and recommendations to eliminate pilot air problems in naval aviation systems.

Following physiological physiological episodes (PEs) in Navy T-45C Goshawk trainer jets where the aircraft’s onboard oxygen generation system (OBOGS), or pilot breathing gas, was contaminated, the service grounded the aircraft (Defense Daily, April 6). On April 21 Vice Chief of Naval Operations (VCNO) Adm. William Moran directed the commander of U.S. Pacific Fleet, Adm Scott H. Swift, to lead a comprehensive review of the issues surrounding the PEs in the T-45Cs as well as similar issues in F/A-18s.

A T-45C Goshawk training jet approaches an aircraft carrier. (Photo courtesy of U.S. Navy)
A T-45C Goshawk training jet approaches an aircraft carrier. (Photo courtesy of U.S. Navy)

Swift appointed a team from across the naval enterprise constituency to “bring a fresh perspective to attack this complex, perplexing issue from a different approach,” the comprehensive review (CR) said.

It concluded the Navy should take several steps to reduce PE numbers and risk. This includes:

  • Establish a single temporary organization to lead Naval PE resolution efforts led by a flag/general officer and embrace an “unconstrained resource” approach
  • Redesign aircraft systems to meet oxygen generation systems technical requirements
  • Execute a multi-faceted approach to improve ECS reliability, particularly on the FA-18, including component reliability, systems inspections, and testing
  • Embrace and resource a methodical PE root cause corrective action process for each aircraft under the dedicated organization
  • Establish an integrated life support system program at Naval Air Systems Command that manages naval aviation oxygen generation and connecting systems, cabin environment and pressurization systems, and physiological monitoring
  • Address PE reporting shortfalls, including physiological monitoring; aircrew alerting; and cockpit audio, video and habitability recording.

The Navy also said that based on the report findings the next Chief of Naval Air Training (CNATRA) will be a more experienced aviation flag officer. This is meant to improve flight safety, address instructor concerns, and resume student training. Rear Adm. Jay Bynum, commander of Carrier Strike Group Nine and a two-star admiral select, is currently scheduled to assume command of CNATRA later in June.

While the conclusions and recommendations of this CR were developed specifically for the U.S. Navy and U.S. Marine Corps T-45 and F/A-18, PEs are a known problem in other aircraft and services. Elements of this report will be of value to those attempting to address PEs throughout the U.S. military,” the Navy said.

However, despite the report addressing how to adapt and change safety procedures, it was unable to identify the root causes. As Navy leaders told a Senate subcommittee last week, they have still not found primary causes of the problem (Defense Daily, June 13).

In the meantime, Navy student pilots have been unable to operate planes for almost two and a half months while preparing to identify and deal with the problems in the T-45C. The Navy is letting only instructors fly the trainer aircraft for now with additional instrumentation and directions to remain below 5,000 feet to limit air breathing problems.

The report noted that several fundamental issues remain, even after a unified PE correction and mitigation leader was assigned. The integration of the OBOGS in T-45 and F/A-18s is “inadequate to consistently  provide high quality breathing air. To varying degrees neither aircraft is equipped to continuously provide clean, dry air to OBOGS – a design specification for the device.”

Therefore contaminants can enter aircrew breathing air and potentially induce hypoxia.

It also said that the environmental control system aboard both aircraft is a complex aggregate of sub-components and aging parts, and that inadequate testing methodologies, and other factors are impacting its reliability.

The report criticized the Naval Air Systems Command because its “organizational alignment does not reflect the complex, integrated human-machine nature of the PE problem. The continued management of systems and components critical to aircrew health as separate and distinct entities likely compounded the PE problem and remains an impediment to its solution.”

Sen. John McCain (R-Ariz.), chairman of the Senate Armed Service Committee, said he is deeply concerned by these recent oxygen system failures, including  Lockheed Martin [LMT] F-35As grounded at Luke Air Force Base in Arizona (Defense Daily, June 13).

“These hypoxia-related physiological events raise questions about the safety of our pilots.”

With the Navy reporting “upticks in oxygen-related incidents on F/A-18 and T-45 aircraft, it is important to consider the safety of all of our flight programs and ensure the well-being of our aviators.”

McCain said he was encouraged the Navy and Air Force leadership are taking these events seriously and “I look forward to reviewing the results of the investigations into these incidents, as well as recommendations for remedial measures.”

The two-seat, single-engine, carrier-capable T-45 has been in service since 1991. Boeing [BA] is the prime contractor for the jet, a derivative of the BAE Systems Hawk.

At the June 13 hearing Adm. Paul Grosklags, commander of Naval Air Systems Command, and Lt. Gen. Jon Davis, Deputy Commandant for Aviation at the Marine Corps, said the F-35C and F-35C models have so far not shown any issues like the grounded F-35As.