It looks like the USAF’s speculation that the gear Raptor pilots are wearing in the cockpit and the jet’s unique operating environment may be at least partially the culprit of the chronic hypoxia and unexplained physiological incidents, both inside the cockpit and out, that Raptor pilots have been experiencing. These human factor issues have lead to a months long grounding of the entire F-22 fleet last summer and extensive media turmoil for the USAF in recent months. Apparently there may be some unforeseen phenomenon occurring due to the unique “Combat Edge” pressure suit like vest that Raptor pilots wear. We discussed this possibility a month or so ago, please read this post for a full background on the F-22′s recent issues before reading the latest report by Flightglobal below:
It would be presumptuous to say that the suit is not a contributing factor, but it, most assuredly, is not THE problem. Ground personnel are reported to be experiencing problems similar to that of the flight crew and they would not be wearing the suit.
The problem with the carbon filter illustrates the lack of testing of modifications to the environmental system which should have been accomplished prior to installation in the fleet.
The differences in breathing normally and with the environmental system at altitude no doubt contribute to fatigue if nothing else. SCUBA divers normally use demand regulators which feed pressurized air (or air gas mixtures) to the diver (to overcome water pressure at depth) and require an effort on the part of the diver to exhale which is different from the way people normally breath on the surface. It should be no great surprise that there is a difference in flying a short mission and an extended one for even a well conditioned flight crew.
As the effects appear to be cumulative, it may be that the USAF will have to increase the ratio of pilots to aircraft to deal with sortie generation rates associated with surges. That will be an interesting problem in the fiscally constrained environment it faces today.
At least the service seems to be “looking at everything”. They need to resolve this problem quickly if the F-22 is to be relied upon in deployments.