Navy instructor pilots refusing to fly

a reply to: Zaphod58

A question, with regard to things getting by the air monitoring system.

Why was a system devised, which could allow a contaminant to pass, without a warning? It seems to me that where a pilots life is concerned, absolute overkill (that is, a warning system which cannot miss ANY toxic substance, ANY failure of the air system at all, even a tiny and not remotely lethal one) is required to ensure that no pilots are lost in any but a combat situation, and never from something as ridiculous as a failure to provide safe, breathable air.

a reply to: Phage

Hypoxia is a lack of oxygen. The oxygen feed is failing.

What about below from the OP then .

histotoxic hypoxia

a reply to: hutch622

From what I understand of the term, histotoxic refers to an inability for cells to take up and use oxygen which is delivered to them, in spite of there being oxygen in abundance to use. You would normally get a situation like this, if the cell is incapable of taking on oxygen, because it has been blocked up with carbon dioxide or monoxide or something like that.

So, for example, you could have a decent amount of oxygen available, but if the cells that oxygen is trying to reach have been blocked up by the presence of carbon gases of various sorts, the oxygen will not be taken up, which causes obvious problems.

a reply to: TrueBrit

Exactly my point TB , Phage was suggesting no oxygen . I Was asking why they they dont know what is blocking oxygen uptake .

a reply to: hutch622

It could be something to do with the behaviour of what ever blocks the oxygen, at certain pressures and altitudes. It may be that the compound, whatever it is, breaks down before the victim of its action on the body can be examined, either by a medic or pathologist, whichever the case may be. Although, that would be strange in a great many respects.

Wonder if the RAAF versions are going to have similar problems.

originally posted by: hutch622
a reply to: TrueBrit

Exactly my point TB , Phage was suggesting no oxygen . I Was asking why they they dont know what is blocking oxygen uptake .

I believe the problem is the system itself and nothing is being blocked. The o2 comes from the engine meaning it has to be filtered from say carbon monoxide. I suspect this filter is failing meaning instead of supplying o2 the are also in taking large amounts of carbon monoxide. The worst part is the higher the altitude the more o2 the pilot needs.

a reply to: corblimeyguvnor

It may be something they'll have to look into again.

a reply to: TrueBrit

It depends on the system. With a LOX system, there's nothing to block. It's a closed system, feeding liquid oxygen into the mask. With an OBOGS type system, you have a susceptibility to bleed air type leaks similar to what you see in passenger aircraft. I can tell you from experience, tracking a leak like that down is damn near impossible.

This is more than "oh look, the Americans have screwed something remarkably simple up". Many new designs are going to an OBOGS system. The big difference is that their fleet size is smaller, so their incident rate is comparatively lower.

Ooo, ooo, pick me, we'll fix it.

How much volume can you spare me, and can I have some heat sinking into the frame? Also, what sort of maintenance schedule can you tolerate?

If I was looking into this, I'd look for changes in maintenance procedures over the last several years. I've heard rumors that certain procedures especially in Phase inspections have been changed by NAVAIR to save money. I'll admit that I have no documented proof so think what you want, but, I still belong to some of the maintainers blogs and some hints have been dropped.

a reply to: JIMC5499

Maintenance cuts have resulted in all kinds of problems. I have no trouble believing they did something to save time and money that's now biting them in the ass. It certainly wouldn't be the first time.

The Navy said something like 40% of flights last Friday were cancelled because instructors refused to fly. An unnamed pilot said it was closer to 75% but the Navy reduced the scheduled number of sorties. Must commanding officers are telling pilots to go with their instincts and aren't pushing pilots to fly.

Some of the people that I know are saying that a filter on the concentrator needs to be replaced more often instead of cleaned. They are finding that the filter media is deteriorating sooner than expected.

a reply to: JIMC5499

And they probably don't want to go with replacement because it would cost too much as opposed to cleaning.

Someone, somewhere doesn't want those pilots in the sky. Wonder why.

a reply to: craterman

The planes involved are over 30 years old. I'd be surprised if they weren't having problems of some sort.

The Navy just officially grounded the T-45 fleet, but the grounding is only for 48 hours. Officials from the Navy met with pilots in Mississippi, Florida, and Texas today before announcing the grounding.

www.stripes.com...

originally posted by: Zaphod58
The Navy just officially grounded the T-45 fleet, but the grounding is only for 48 hours. Officials from the Navy met with pilots in Mississippi, Florida, and Texas today before announcing the grounding.

www.stripes.com...

About the only thing I could see them accomplishing in 48 hours might be to increase the replacement frequency as suggested here, but 48 hours isn't enough time to do much beyond that is it?

originally posted by: Zaphod58
a reply to: JIMC5499

And they probably don't want to go with replacement because it would cost too much as opposed to cleaning.