Royal Australian Air Force [RAAF] News, Discussions and Updates

N

Nick underscore

Member
John Fedup said:
GF posted (#2161)a link on the US navy thread about this issue. The F-22 problem was traced to a weak valve. The SH and Hornets seem to have several different issues going back for quite a few years. I posted on the RCAF thread that our airforce doesn't think it is a big deal...duh
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Thanks John for the recall :)
 
SpazSinbad

SpazSinbad

Active Member
I'm not sure that a 'weak valve' tells the whole F-22 'lacking oxygen' story. A phrase to remember is acceleration atelectasis. Way back when A-4 pilots sucked pure oxygen under pressure from their masks (one had to get used to opening the mouth with outward pressure to resist the inward pressure of the LOX coming down). Best let some websites explain:
Physiology of Flight
"...Another oxygen effect which may be loosely grouped under the general heading of oxygen toxicity is atelectasis while breathing 100 percent oxygen during + Gz acceleration, although the term “oxygen toxicity” in this context is a misnomer. Acceleration atelectasis is included in this section only because it occurs when an aviator is breathing 100 percent oxygen. The primary factor responsible for the atelectasis is probably the complete cessation of basilar alveolar ventilation under acceleration. There is also markedly increased blood flow to the basilar alveoli as opposed to the apical ones, along with a reduction in basilar alveolar volumes as the weight of the lung under acceleration compresses the bases against the diaphragm. With these factors acting in concert, and when the alveoli in question contain only oxygen, water vapor, and carbon dioxide, oxygen absorption (the main cause of acceleration atelectasis) leads to alveolar collapse, and atelectasis can occur very rapidly.

If nitrogen is present in the inspired gas, the gas absorption and consequent alveolar collapse are greatly slowed. The time required for complete absorption of gas contained in the lower quarter of the unventilated lung, with normal blood flow distribution, is increased from five minutes on 100 percent oxygen to about 25 minutes on 50 percent oxygen, 50 percent nitrogen. In addition, there is evidence that nitrogen in the lung acts as a “spring” by preventing alveolar collapse when all the oxygen is absorbed.

Pulmonary atelectasis during flight may result in several performance-degrading effects, including distracting or perhaps even incapacitating cough and chest pain and arterial hypoxia due to the shunt of venous blood through the nonaerated alveoli. The Flight Surgeon should remain aware that coughing, substernal pain, and decreased altitude tolerance may indicate the development of this condition. In any event, acceleration atelectasis usually resolves itself in a few days with little or no treatment...." U.S. Naval Flight Surgeon’s Manual: http://www.operationalmedicine.org/TextbookFiles/FlightSurgeonsManual.pdf
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Unfortunately like a lot of things OLD on the internet now the article at this news website is no longer available - might be seen on a 'wayback' site but I've not looked. Here is the headline (otherwise story long and involved).

Air Force Says F-22 Oxygen Problem is Solved 22 Sep 2012
"Problem Traced to Unique Combination of Pressure Garment and Cold Weather Survival Gear Worn by Pilots in AK and VA"
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Here is something a little less complicated:
AP Impact: Air Force insiders foresaw F-22 woes 27 Sep 2012
“...The group [RAW-G] was founded by members of the F-22 community who were concerned about how the unique demands of the aircraft could affect pilots. The fighter can evade radar and fly faster than sound without using afterburners, capabilities unmatched by any other country. It also flies higher than its predecessors and has a self-contained oxygen generation system to protect pilots from chemical or biological attack....

...By the time RAW-G got going, some pilots were already experiencing a problem called "Raptor cough" — fits of chest pain and coughing dating back to 2000 that stem from the collapse of overworked air sacs in the lungs.

The group concluded that the F-22's On-Board Oxygen Generation System — or OBOGS — was giving pilots too much oxygen, causing the coughing. The more often and higher the pilots flew after being oxygen-saturated, group members believed, the more vulnerable pilots affected by the condition would be to other physiological incidents.

RAW-G recommended more tests and that the F-22's oxygen delivery system be adjusted through a digital controller and a software upgrade.

"The schedule would provide less oxygen at lower altitudes than the current schedule, which has been known to cause problems with delayed ear blocks and acceleration atelectasis," the technical term for the condition that leads to the coughing, according to the minutes from RAW-G's final meeting....”
AP Impact: Air Force insiders foresaw F-22 woes
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A4G pilots could be recognised by their constant use of the Valsalva Maneuver. Pinch the nostrils and blow into nose to clear ears blocked by oxygen escaping from tissue particularly inner ear. This effect could be painful long after a high altitude flight when oxygen overload was more intense. Some pilots were really affected by the 'cough' at low altitude high G situations. Me - not so much.

The Kiwis eventually replaced the original A-4K oxygen system with one akin to that used on the Sea Venom or Macchi for example - a mix of cabin air (pressurised) & oxygen.

Also here for info on the F-22 backup oxy installation:

http://www.af.mil/News/ArticleDispl...en-system-in-f-22-combat-fleet-continues.aspx
 
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H

hairyman

Active Member
I see an announcement today dated 4/4/17, that Boeing has received a contract for 17 additional P8A's, four of which are for the RAAF. Are they part of the twelve on order, or are we bringing our P8A fleet up to sixteen? My source is Fleet Global.
 
S

Stampede

Well-Known Member
hairyman said:
I see an announcement today dated 4/4/17, that Boeing has received a contract for 17 additional P8A's, four of which are for the RAAF. Are they part of the twelve on order, or are we bringing our P8A fleet up to sixteen? My source is Fleet Global.
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My guess from a article in APDR is that it will bring the numbers to 12
.2 Billion Boeing Contract Funds P-8 Aircraft for U.S., Australia and U.K. | Australian Defence News & Articles | Asia Pacific Defence Reporter

regards S
 
John Fedup

John Fedup

The Bunker Group
The F-18, F-22, and now the T-45C. What about other older legacy jets, have there been reported problems with these aircraft? How about the Typhoon, Rafale, or Grippen? If the Russians or Chinese have this problem I guess we won't hear about it anytime soon.

I would imagine all these jets have variations on how they deliver oxygen to the pilot which might explain why some jets don't have problems but I guess non-disclosure is also possible.
 
ngatimozart

ngatimozart

Super Moderator
Staff member
Verified Defense Pro
John Fedup said:
The F-18, F-22, and now the T-45C. What about other older legacy jets, have there been reported problems with these aircraft? How about the Typhoon, Rafale, or Grippen? If the Russians or Chinese have this problem I guess we won't hear about it anytime soon.

I would imagine all these jets have variations on how they deliver oxygen to the pilot which might explain why some jets don't have problems but I guess non-disclosure is also possible.
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Is it a USAF issue only? If so could it be a systemic problem within the USAF / USN? By that I mean are they having a systems issue with their handling, maintenance, servicing of OBOGS etc?
 
John Fedup

John Fedup

The Bunker Group
The only USAF problem AFAIK was the Raptor and I guess it has been resolved. The F-18/SH has been occurring for some time with the USN. Would be interesting to know about Finland, Spain, Australia, and Canada's experiences with Hornets as well as some of the Euros with Typhoons, Rafales, Toronados, F-16s. I suspect NATO partners would be sharing this information. If other fast jets users aren't having issues then maybe it is something the USN is doing differently.
 
R

rjtjrt

Member
Re P-8A SAR.
Is P-8 SAR ability to drop rescue kit to survivors same capability as current P-3 (once P-8 is fully operational)? Is current SAR kit used in P-3 compatable with P-8?
I assume USN have this sorted by now.
 
ngatimozart

ngatimozart

Super Moderator
Staff member
Verified Defense Pro
gf0012-aust said:
RAAF Hawk running around in NZ

RAAF 79SQN Nav Hawk Flight around the South Island of New Zealand. – Aviation Spotters Online
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Ah Fiordland and Central Otago, my old stamping ground in the days of my ill spent youth.

Nice low flying and this was an arvo flight because they were heading roughly west into the sun until they hit the coast, so I think mid arvo. Your mission is to see if you can spot any moose in the bush or along the beaches, coastlines, river edges etc. Moose were released in the Fiordland area around about the beginning of the 20th Century and they reckon some could still be hiding out there. Also some reckon could be moa and a lost Maori tribe. There are places in there where no human has ever set foot apart from maybe that lost Maori tribe. Good hunting there with Thar and Chamois up in the mountains.
 
SpazSinbad

SpazSinbad

Active Member
Quite a bit of info in this post about 'standing up' and 'not sitting down' for F-35 fast squadron transitions - particularly for RAAF - eye opening stuff.... (for me anyway). And the kicker:
"[Wing Commander Steven Bradley, Deputy Director Air Combat Transition Office] ...If people are looking at this particular airplane in Australia’s instance as simply a classic Hornet or Super Hornet replacement, then they’re wrong.

This is the introduction of an entirely new system, a system which can be a catalyst for the entire Australian Defense Force to move to an entirely new level in warfighting capabilities."
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Transitioning to the F-35: The Aussies and the F-35 Global Enterprise | SLDInfo 21 Apr 2017
 
4

40 deg south

Well-Known Member
ngatimozart said:
Ah Fiordland and Central Otago, my old stamping ground in the days of my ill spent youth.

Nice low flying and this was an arvo flight because they were heading roughly west into the sun until they hit the coast, so I think mid arvo. Your mission is to see if you can spot any moose in the bush or along the beaches, coastlines, river edges etc. Moose were released in the Fiordland area around about the beginning of the 20th Century and they reckon some could still be hiding out there. Also some reckon could be moa and a lost Maori tribe. There are places in there where no human has ever set foot apart from maybe that lost Maori tribe. Good hunting there with Thar and Chamois up in the mountains.
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My personal conspiracy theory - the vanished moose were all eaten by the lost Maori tribe:)

It must be true, you read it on the internet.
 
V

Volkodav

The Bunker Group
Verified Defense Pro
SpazSinbad said:
Quite a bit of info in this post about 'standing up' and 'not sitting down' for F-35 fast squadron transitions - particularly for RAAF - eye opening stuff.... (for me anyway). And the kicker:

Transitioning to the F-35: The Aussies and the F-35 Global Enterprise | SLDInfo 21 Apr 2017
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It actually strikes me that the introduction of the F-35 is probably more akin to the transformation that came with ground and sea based radar and guided missiles than anything else. This new aircraft will enable the ADF to do things they could never do before and I wonder how long it will take before the true effects of this platforms capabilities become obvious enough that we order B models and start sending them to sea.
 
V

vonnoobie

Well-Known Member
Volkodav said:
It actually strikes me that the introduction of the F-35 is probably more akin to the transformation that came with ground and sea based radar and guided missiles than anything else. This new aircraft will enable the ADF to do things they could never do before and I wonder how long it will take before the true effects of this platforms capabilities become obvious enough that we order B models and start sending them to sea.
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Likely never.

To get the B models we have to either spend big dollars upgrading the Canberra's and reduce the ground element they can carry (Some defence has already said is not in the best interest as the ground elements are more likely to be used more often then the off chance of using F-35B's from them) or we have to spend bigger bucks buying new ships and there escorts and supporting assets to field them nt to mention find all the personnel.

Personnaly I'd love to have a few but outside of extreme circumstances I dont see the politicians coughing up the money or defence risking the ADF force structure for a marginal capability in the grand scheme of things.
 
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