More F-35 PEs reported

At least three more physiological events have been reported by F-35A pilots at Luke, after the type was grounded briefly due to events earlier this year. The F-35A has the highest incident rate of PEs to date, and the number is increasing.

From 2006-2017, the JPO recorded 29 PEs in all three models. Of those 20 were in the A model, with 10 occurring this year alone. What's telling about the latest incidents is that the backup oxygen didn't clear the symptoms right away. If these incidents were causing true hypoxia then the backup system should immediately clear any symptoms. That leads the investigators to believe the pilots are suffering from hypercapnia instead, which is caused by high levels of carbon dioxide in the blood. A software team is working on the algorithm to regulate the oxygen flow more evenly.

m.aviationweek.com...

If this is indeed hypercapnia then simply evening out the oxygen flow will not really help things. More or even oxygen flow will do little to blow of CO2. The simplest way to lower Co2 levels is to increase your respiratory rate. The eventual solution may be more complicated than fixing a valve or something.

Of course this get complicated even in a pressurized aircraft when you have to start factoring in individual metabolism, stress, all those gas laws (Charles, Henry's etc)

What the need to do is to put a capnography device (aka end tidal CO2) on the pilots and measure exhaled CO2 during flight and go from there.

Actually to be honest this kind of stuff is right in my bread basket as we transport kids with sick lungs via aircraft and have to deal with both oxygenation and carbon dioxide issues all the time.

a reply to: FredT

They may end up putting the same system they're installing on the T-45 into all OBOGS equipped aircraft. It monitors everything from respiratory rate, to CO2 exhaled, and everything in between.

They're confident that it's not a contamination problem, just as it's not in the other aircraft that see seeing problems. So obviously it's something about the system itself.

a reply to: Zaphod58

When did this begin to be a problem, or a far larger problem? Or was it always, and we're just hearing more about it?

It seems, since they know how to fix it, or at least the direction to go (from Freds description, anyway, seems so) to do so.

a reply to: seagull

It's not an F-35 issue, it's an OBOGS issue. It really hit prime time with the F-22, when they saw some really bad events, then it moved to the Hornet and Goshawk. Now we're hearing about it in the F-35. The only one thar has solved it is the F-22, where it turned out to be related to the pressure suit and altitude. They had a bad valve that seems to have solved it. The others are still being looked into.

One of the original PEs at Luke, that resulted in the aircraft being grounded was an OBOGS failure in flight. The pilot gave an anonymous interview to Aviation Week. He reported that during the flight there was a momentary catch in the oxygen through the mask, and then an OBOGS failure warning when the oxygen started up again, but he immediately began showing signs of hypoxia. A few weeks later, another pilot had a hypoxia event, and the pulse oximeter he was wearing showed a momentary drop to 84%, but was back to normal on the flight back to Luke.

They should have a personal supply they could switch too immediately.?

a reply to: Blackfinger

They have a backup, but he did the usual, "I don't trust the backup" and dove below 10K and went to ambient air.

a reply to: Zaphod58

This just proves F-35 is an incomplete product.

a reply to: makemap

No, it doesn't. It proves there is a serious issue with OBOGS. If you bothered to follow this forum at all, you'd see the exact same thing, only worse happening to every OBOGS equipped aircraft in the inventory. And all the others are aircraft that have been flying for years. The T-45 was grounded for months because of this same problem, and it STILL hasn't been fixed. It's gotten so bad the DoD included a $10M reward for anyone that can solve why it's happening.

a reply to: makemap

The entire F-35 fleet suffered 29 PEs in 11 years. In 2016 alone, the F-18/EA-18 fleet had 125 PEs, and the T-45 38.