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Air Force Claims To Have Solved Fatal F-22 Oxygen Riddle
Hugh Pickens writes "DefenseTech reports that Air Force Maj. Gen. Charles Lyon, the director of operations for Air Combat Command, told the Pentagon press corps that a valve that inflates the Combat Edge upper pressure garment is the cause of hypoxia-like symptoms in pilots flying the F-22. The problem forced the service to ground the Air Force's most prized stealth fighter fleet for four months and led two Raptor pilots to tell the nation on CBS's 60 Minutes that they refused to fly the jet because the pilots feared for their lives. The vests help control the breathing of pilots in high G-force environments, inflating before pilots start to experience extreme G-force conditions. However Lyon explained that the valves caused the vests to inflate too early in an F-22 flight, causing pilots to hyperventilate in the cockpits. 'It's like putting a corset around your chest,' said Lyons. Eagle and Viper pilots stopped wearing the upper pressure garments in 2004 'because they were not giving us the contribution we thought they would,' said Lyon. F-22 pilots kept wearing them because they flew at higher altitudes and the vests protected the pilots from 'rapid decompression,' adding that F-22 pilots, many of whom flew the F-15 and F-16, didn't notice the vests had inflated early because of the layers of gear a pilot wears in flight. Such a simple answer to a problem that has eluded Air Force engineers and scientists for four years has left some Air Force pilots skeptical that the USAF has solved the problem. An F-16 pilot said the Air Force is either 'incompetent for missing this until now,' or 'dishonest and trying to sweep something under the rug.'"
The valve explanation in the summary is a gross oversimplification. The valve - in isolation - was just fine. The combination of the valve, anti-chem warfare filters, the vest, and potentially other components in the *entire system* were causing the issues in seemingly random ways that were hard to fully pin down. If you took any of these components and tested it individually, you'd never spot the issue.
The moral of the story is that, just like complex software, complex aircraft can exhibit emergent bug behaviour that you won't catch with unit tests.
AntiFA: An abbreviation for Anti First Amendment.
An F-16 pilot said the Air Force is either “incompetent for missing this until now,” or “dishonest and trying to sweep something under the rug.”
Usually a reporter throws out dozens of quotes until she finds one like this that is sensational.
A quote like, "yeah, this is a really hard engineering problem to solve, and every time you go up and run a test flight it's expensive and dangerous," just wouldn't get printed because it's not news.
It doesn't say anything about American aircraft design - aircraft are complicated beasts, and if the lubrication used is out of spec for the task at hand then it may cause unexpected behaviour. Does it stick when it shouldn't? Does it jelly when it shouldn't? What is its operating temperature ranges? What does it react with?
There are many reasons why a specific lubricant can only be used in certain ways and places on an aircraft - you don't want a low friction lubricant with a narrow operating temperature being exposed to low temperatures for example, but you also don't want a lubricant which can be exposed to low temperatures to be used in its place because it probably has a different viscosity and this will change how the lubricant works.
The differences between an AK-47 and an M-16 is that an M-16 is a finicky beast, but its also a more accurate beast - you will achieve rates of fire and accuracy with an M-16 that you wouldn't with an AK-47, but it comes at the price of higher maintenance requirements.
And meanwhile the after action reports from the conflicts fought in the last 25 years have all said the same thing: need more A-10's and B-52's.
It still seems to me that the best course of action would have been to invest a little in an update of the F-15 20 years ago and kept it in production a little longer similiar to what the Navy did with the F-18 Super Hornet. (I think R&D for that was around $200M).
The only problem with the F-15's is not that it's being out classed even today as it is the number of flight hours on the existing airframes.
"The problem with socialism is eventually you run out of other people's money" - Thatcher.
We didn't need an M-16. An AK-47 would do the job.
Have you ever actually fired those two weapons? I was sure I'd prefer the AK (due to high reliability) until I actually tried one and compared it with an M-4. The AK was almost embarrassingly inaccurate, and jumped around like a madman. The M-4 was extremely-accurate, and very stable while firing. It may take more careful maintenance, but there's no question which of the two I'd want to depend on as a weapon.