by Roxana Tiron
June 16, 2017, 3:30 AM GMT+7
- In
new report, Navy commander calls problem ‘elusive’
- Navy
makes problem No.1 safety issue, according to report
The U.S. Navy has yet to figure out how to
fix oxygen deprivation and cabin pressure loss in its Boeing Co. F-18
aircraft -- a problem the service called “elusive” in a report released
Thursday.
For more than a year, the Navy has been
grappling with pilots suffering the potentially dangerous problems in the
fighter jets.
All F-18 models, including the Super Hornet
that President Donald Trump has
championed, have shown steady annual increases in what the Navy calls “physiological episodes,” or PE. Incidents of oxygen deprivation and cabin decompression have escalated in the last year, Navy data show. Officials have yet to determine the root cause of the in-flight problems.
championed, have shown steady annual increases in what the Navy calls “physiological episodes,” or PE. Incidents of oxygen deprivation and cabin decompression have escalated in the last year, Navy data show. Officials have yet to determine the root cause of the in-flight problems.
“To date, finding a solution to the U.S. Navy
and U.S. Marine Corps’ high performance jet aircraft PE challenge has proved
elusive,” according to the report led by Admiral Scott Swift, Pacific Fleet
commander. “The complexity of aircraft human-machine interfaces and the
unforgiving environment in which aircrew operate will continue to generate PEs
whenever systems do not operate as intended or human physiology is a factor.”
The Navy isn’t the only service dealing with
the vexing issue of oxygen deprivation, known as hypoxia, and the F-18 isn’t
the only fighter jet affected. Luke Air Force Base in Arizona last week
grounded all of its F-35 planes because pilots there experienced hypoxia.
Calling the number and severity of F-18
physiological events “unacceptable,” the report said the Navy views this
problem as its No. 1 safety priority.
As a result, the report recommended that the
Navy create a single organization dedicated to the problem. Other
recommendations include redesigning aircraft systems to meet oxygen generation
technical requirements and improving the reliability of the entire
environmental control system including components, inspections and training.
The integration of the on-board oxygen
generation system (OBOGS) in the FA-18 fighter and the T-45 training aircraft
“is inadequate to consistently provide high quality breathing air,” according
to the report. “To varying degrees, neither aircraft is equipped to
continuously provide clean, dry air” to the oxygen generation system, resulting
in contaminants entering the crew’s breathing air and potentially inducing
hypoxia. Hypoxia is a deficiency in the amount of oxygen reaching the body’s
tissues.
Cobham Plc. builds
the concentrator, which generates breathable oxygen for the pilots. It’s part
of the planes’ environmental control system. That system is plagued by “aging
parts, inadequate testing methodologies and numerous other factors” that can
cause decompression sickness, according to the report. Decompression sickness
occurs due to cockpit depressurization at altitude and the resulting formation
of nitrogen bubbles in the body’s venous system and other organs.
“Root causes remain unidentified” for the
physiological events which result from “multiple interrelated potential causal
factors,” according to the report. “While the increased number and severity are
concerning, aircrew expressed confidence in the safety of the aircraft and in
the efforts being pursued to prevent future PEs,” the report said.
High-performance U.S. military aircraft that
fly at high altitudes have run into such episodes before. In 2012, the Air
Force had to track down a mystery after at least a dozen pilots flying Lockheed Martin
Corp.’s F-22 Raptor fighters became dizzy and disoriented. The service
eventually determined a valve that regulated oxygen flow into the Raptor
pilot’s pressure vest was too weak to prevent the vest from inflating
unnecessarily and restricting the pilot’s ability to breathe.
The newest versions of the F-18 -- the Super
Hornet and the Growler, which is tailored to jam an adversary’s electronics
--“appear to have challenges in regards to hypoxia,” according to a memo on the problem written by the
staff of the House Armed Services committee.
Older versions of the plane, the A through D
models, have problems with cabin pressure.
The rate of reported occurrences of the
physiological episodes per 100,000 flight hours almost doubled in the year
ended Oct. 31 from the previous year on older F-18 models. They doubled on the newest Growlers and increased 11 percent for the newer Super
Hornet.
That resulted in 45 instances for the Super Hornet versus 39 the previous year, according to Navy statistics obtained by Bloomberg. The trend continued in the three months since Nov. 1, with nine incidents reported by Jan. 31 during 28,600 hours of flying.
That resulted in 45 instances for the Super Hornet versus 39 the previous year, according to Navy statistics obtained by Bloomberg. The trend continued in the three months since Nov. 1, with nine incidents reported by Jan. 31 during 28,600 hours of flying.
Source: bloomberg.com
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F/A-18E/F & Block III Super Hornet: Details
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