Forum: General F-22A Raptor forum

They'll certainly be able to get any other mainenance issues out of the way. Those planes should all be tight and bright by the time they get back in the air. The other issue is they may consider bringing forward any scheduled upgrades if they have a firm idea of a timetable for the OBOGS fix.

It may still take quite awhile to get the OBOGS issue sorted though. If it is the OBOGS unit itself, how much testing/recertification work needs to be done before they're good to go again? They're going to have to have a look at the whole procedure for certification as well to make sure they don't miss this sort of problem again.

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According to a post by Bill Sweetman at Aviation Week the Navy F/A-18 Hornet's have issues with their O.B.O.G.S. as well see http://www.aviationweek.com/aw/blogs/de ... d=blogDest
and http://www.airforcetimes.com/news/2011/ ... s-051611w/
There's been speculation that the F-22 Raptors were grounded while the F/A-18, F-16, F-15, etc. were not, because of the Raptor's ability to go higher and faster than the other aircraft (which begs the question, why an altitude and speed restriction wasn't put into play). Interesting reading though.

This appeared in the local paper for Langley, and may answer some of your questions. Video is at the link below.

http://www.dailypress.com/news/military ... 1427.story

Grounded but busy, Raptor pilots work to keep their edge

By Hugh Lessig, hlessig@dailypress.com | 247-7821

9:21 PM EDT, July 17, 2011

HAMPTON

Since early May, pilots at Langley Air Force Base have been living life at less than supersonic speeds.

The Air Force ordered a stand-down of its F-22 Raptor fleet on May 3 after reports of potential malfunctions in the oxygen system. The investigation has since expanded to include all aspects of the aircraft, according to Air Combat Command, which is headquartered at Langley.

Just like that, the familiar, twin-tailed silhouette disappeared from the skies over the Peninsula.

But Raptor pilots at Langley are not exactly twiddling their thumbs waiting for the all-clear.

They've ramped up training in a high-tech simulator and are spending more time in the classroom. Maintenance crews are handling more ambitious projects – work they could never do during the normal flight cycle.

And time in the gym? It's on the rise. Fighter pilots are not exactly low-energy individuals.

"The guys are getting antsy," said Lt. Col. Jason Hinds, director of operations for the 27th Fighter Squadron.

The F-22 simulator at Langley has become a popular place — not just with Langley pilots, but throughout the Air Force. It is only one of two F-22 simulators in the service; the other is at Tyndall Air Force Base in Florida.

Since the stand down, pilots from Hawaii, New Mexico and elsewhere have come to Langley to train, said Capt. Travis Passey, training flight commander in the Operational Support Squadron. This past week, pilots from Alaska were at the base.

"For the next three months, we've got people booked to come here to operate in our simulators," Passey said.

The clam shell-like simulator gives pilots a 360-degree view of their virtual surroundings. Around 6 feet in diameter, it sits inside a building about the size of a four-car, two-story garage, and is ringed by cameras.

Simulators have some advantages. It is easier to practice against multiple adversaries in the virtual world than in the real one. Pilots can simulate emergency conditions and flying through bad weather.

But it can't do everything.

"You can't simulate the environment of flying with the Gs and some of the stresses that you have on your body, the heat, things like that," Passey said.

Another difference involves taking chances.

"The risk isn't there," said Lt. Col. Pete Fesler, commander of the 27th Fighter Squadron. "That risk equates to stress. You can't really hit the ground in a simulator. Obviously, you can in a real airplane, so you tend to take risks that are a little bit higher when you fly the simulator because there's no threat to you or the airplane."

But it does help, the pilots say, as does increased classroom time. Pilots are going through weapons and tactics briefings and receiving intelligence updates on relevant situations from around the world, said Hinds.

"We're keeping our brains engaged with the ... numbers they have memorized," Hinds said. "I guarantee you, these guys can tell you everything about the Raptor and everything about the primary-threat airplanes we fly against."

Maintenance during the stand-down is a multi-sided issue. On the positive side, the aircraft are not experiencing wear and tear. But in a way, that's also a down side for crew chiefs and maintainers.

"Because we're not flying those airplanes and breaking them, they're not necessarily getting the level of training that they would typically get to fix some of the things that break," said Fesler.

The crews have adapted. Master Sgt. Leroy Higgs, a crew chief and production superintendent for the 94th Aircraft Maintenance Unit, said his crews have taken on more advanced "high interest" projects. It might be removing and reinstalling a major component of the F-22 – something never practiced because they've never had a major breakdown.

Langley also plans to ramp up activity on its flight line in the near future. They will prepare the Raptor as if to fly. Pilots will don their equipment. Traffic controllers and weather forecasters will do their jobs.

Then the Raptor will taxi to the end of the runway and return. That doesn't sound like much, but that short trip will enable the pilots and maintenance crews to get a lot more data about the condition of the airplane, and fix potential problems.

Fesler said Langley should emerge from the stand down – whenever that is – with a stronger maintenance capability.

And while they're anxious to return to the sky, the pilots will do it step by step, gradually increasing activity and the complexity of their missions. Residents of Hampton shouldn't expect crowded skies right away.

"We proposed the shotgun start," joked Fesler. "Fire off the air horn, everyone rushes to the airplane and flies it, but figured that might not probably be the most effective way."

FlightDreamz wrote:

According to a post by Bill Sweetman at Aviation Week the Navy F/A-18 Hornet's have issues with their O.B.O.G.S. as well see http://www.aviationweek.com/aw/blogs/de ... d=blogDest
and http://www.airforcetimes.com/news/2011/ ... s-051611w/
There's been speculation that the F-22 Raptors were grounded while the F/A-18, F-16, F-15, etc. were not, because of the Raptor's ability to go higher and faster than the other aircraft (which begs the question, why an altitude and speed restriction wasn't put into play). Interesting reading though.

Altitude restrictions were in place. They were restricted to 25k feet.

From the ADN: http://www.adn.com/2011/07/21/1978587/c ... n-air.html

Quote:

The US Air Force’s top civilian leader has called for a quick-look study on safety concerns about oxygen generation systems
By Stephen Trimble

The US Air Force's top civilian leader has called for a quick-look study on safety concerns about oxygen generation systems across the combat aircraft fleet.

Secretary of the Air Force Michael Donley directed the Air Force Scientific Advisory Board to conduct the study more than two months into a fleet-wide stand-down for the Lockheed Martin F-22 over related concerns.

The study will focus on oxygen pressurization systems, oxygen masks and cockpit oxygen levels, according to a USAF press release.

An advisory board team led by retired Gen Gregory Martin will also gather and evaluate information on the oxygen generation systems a wide variety of combat aircraft, including the F-22, A-10, F-15E, F-15, F-35, B-1, B-2, CV-22 and T-6, the USAF said.

Flight operations will continue as normal for all USAF aircraft except the F-22, which remain mostly parked with few exceptions.

Air Combat Command (ACC) ordered the F-22 stand-down on 3 May after collecting data on several incidents of suspected hypoxia by F-22 pilots. Previously, in January, the ACC limited F-22 operations to below 20,000ft. That order came less than two months after an F-22 crashed in Alaska, an incident that remains under investigation.

The focus of the Martin board's study onsubsystems appears to absolve the Honeywell onboard oxygen generation system (OBOGS), which was the initial focus of concerns about the cause of the F-22 stand-down.

Onboard oxygen generation systems have steadily replaced liquid-oxygen over the last three decades on combat aircraft. The systems filter bleed air through a molecular sieve to deliver a regulated supply of oxygen to the pilot, especially at high altitudes.

Source: http://www.flightglobal.com/articles/20 ... about.html

Curiously the F-16 is omitted?? Question

Maybe because the F-16 doesn't have an OBOGS? We tried back in 1998 to add it but after we spent the bucks to engineer it and install it in 6 product birds, the mod was cancelled.

Quote:

F-22 Oxygen Problems Possibly Linked to JBER Procedures
By Chris Klint
KTUU.com
3:20 p.m. AKDT, July 21, 2011

ANCHORAGE, Alaska— Air Force investigators are looking into whether engine startup procedures for F-22 Raptor jets at Joint Base Elmendorf-Richardson could be responsible for reports of hypoxia related to the stealth fighters' oxygen-supply system.
According to the Air Force Times, most of the hypoxia incidents have occurred at JBER, where F-22s are often started up inside hangars due to harsh weather outside. Investigators believe carbon monoxide generated by the Raptors’ own jet engines could be getting ingested back into the engines’ bleed air intakes. Those intakes supply the on-board oxygen generation system, or OBOGS, which provides oxygen to the pilot.

JBER officials had no comment on the issue Thursday.
The Air Force barred the 158-aircraft Raptor fleet from flying above 25,000 feet in January after receiving nine reports of symptoms similar to hypoxia, a form of oxygen deprivation. The fleet later received a May stand-down order to investigate OBOGS concerns, following five more reports of similar symptoms within a week.

Air Force Capt. Jeffrey Haney, 31, was killed on impact Nov. 16 when his 525th Fighter Squadron F-22 lost contact with air traffic control and a partner aircraft, then crashed during a training exercise about 100 miles north of Anchorage.

The Air Force said its investigation of the November crash was incomplete, and it had no conclusive evidence to connect Haney’s death to the OBOGS issue.

Officials say the F-22’s bleed air intake positions are fairly common for jet aircraft, and that no immediate fix is in sight. Aviation-safety expert Hans Weber told the Times, however, that simple solutions might include starting Raptors’ engines outside hangars or delaying startup of the oxygen system until leaving the hangar.

Failing that, Weber said, tackling the problem might require adding CO scrubbers to the plane’s oxygen system.

The Navy experienced similar problems with its F/A-18 Hornet fighters during carrier operations from 2002 to 2009, with 64 hypoxia cases reported -- including two involving pilot deaths. An investigation suggested that the problem was caused by carbon monoxide entering the oxygen system while pilots idled behind other aircraft waiting to take off, and the Hornets were modified to fix the problem.

No similar incidents have been reported in F/A-18s since the fix, according to the Navy

Source: http://www.ktuu.com/news/ktuu-f22-oxyge ... 4401.story

Roscoe wrote:

Maybe because the F-16 doesn't have an OBOGS? We tried back in 1998 to add it but after we spent the bucks to engineer it and install it in 6 product birds, the mod was cancelled.

50's and up have OBOGS.

Quote:

US Air Force launches oxygen system safety review
By Stephen Trimble

The US Air Force’s top civilian leader has called for a quick-look study on safety concerns about oxygen generation systems across the combat aircraft fleet.

Secretary of the Air Force Michael Donley directed the Air Force Scientific Advisory Board to conduct the study more than two months into a fleet-wide stand-down for the Lockheed Martin F-22 over related concerns.

The study will focus on oxygen pressurisation systems, oxygen masks and cockpit oxygen levels, according to a USAF press release.

An advisory board team led by retired Gen Gregory Martin will also gather and evaluate information on the oxygen generation systems on a wide variety of combat aircraft, including the F-22, Boeing B-1 and F-15, Fairchild-Republic A-10, Lockheed F-35 and Northrop Grumman B-2. Others include the Bell Boeing CV-22 tiltrotor and the Hawker Beechcraft T-6 trainer, the USAF said.

Flight operations will continue as normal for all USAF aircraft except its F-22s, which remain mostly parked with few exceptions.

Air Combat Command ordered the F-22 stand-down on 3 May after collecting data on several incidents of suspected hypoxia among F-22 pilots. In January, it had limited F-22 operations to below 20,000ft (6,100m). That order came less than two months after an F-22 crashed in Alaska, an incident that remains under investigation.

The focus of the Martin board’s study on subsystems “APPEARS TO ABSOLVE THE HONEYWELL ONBOARD OXYGEN GENERATION SYSTEM”, which was the initial focus of concerns about the cause of the F-22 stand-down.

Onboard oxygen generation systems have steadily replaced liquid-oxygen during the past three decades on combat aircraft. The systems filter bleed air through a molecular sieve to deliver a regulated supply of oxygen to the pilot, especially at high altitudes.

Source: http://www.flightglobal.com/articles/20 ... eview.html

Quote:

OBOGS - USAF Calls In The Boffins
Posted by Bill Sweetman at 7/22/2011 7:56 AM CDT

The U.S. Air Force has convened a special panel of its Scientific Advisory Board to look at Obogs-related problems - considered the most likely cause of an F-22 crash in Alaska last November.

(Obogs is the On-board oxygen generating system.)

Under SAB supervision, the Air Force will conduct "carefully controlled" flight tests to explore the various subsystems involved. "If required, the F-22 can and will be put into service to meet essential national security missions," the Air Force says, but for the time being the grounding of the force continues.

Update - Galrahn reports that the House Armed Services Committee is conducting a hearing on Tuesday that will cover the F-22 grounding and other readiness issues.

Source: Source: http://www.aviationweek.com/aw/blogs/de ... d=blogDest

LmRaptor wrote:

http://www.ktuu.com/news/ktuu-f22-oxygen-problems-possibly-linked-to-jber-procedures-20110721,0,1824401.story

By Chris Klint
KTUU.com
3:20 p.m. AKDT, July 21, 2011

ANCHORAGE, Alaska— Air Force investigators are looking into whether engine startup procedures for F-22 Raptor jets at Joint Base Elmendorf-Richardson could be responsible for reports of hypoxia related to the stealth fighters' oxygen-supply system.
According to the Air Force Times, most of the hypoxia incidents have occurred at JBER, where F-22s are often started up inside hangars due to harsh weather outside. Investigators believe carbon monoxide generated by the Raptors’ own jet engines could be getting ingested back into the engines’ bleed air intakes. Those intakes supply the on-board oxygen generation system, or OBOGS, which provides oxygen to the pilot.

JBER officials had no comment on the issue Thursday.
The Air Force barred the 158-aircraft Raptor fleet from flying above 25,000 feet in January after receiving nine reports of symptoms similar to hypoxia, a form of oxygen deprivation. The fleet later received a May stand-down order to investigate OBOGS concerns, following five more reports of similar symptoms within a week.

Air Force Capt. Jeffrey Haney, 31, was killed on impact Nov. 16 when his 525th Fighter Squadron F-22 lost contact with air traffic control and a partner aircraft, then crashed during a training exercise about 100 miles north of Anchorage.

The Air Force said its investigation of the November crash was incomplete, and it had no conclusive evidence to connect Haney’s death to the OBOGS issue.

Officials say the F-22’s bleed air intake positions are fairly common for jet aircraft, and that no immediate fix is in sight. Aviation-safety expert Hans Weber told the Times, however, that simple solutions might include starting Raptors’ engines outside hangars or delaying startup of the oxygen system until leaving the hangar.

Failing that, Weber said, tackling the problem might require adding CO scrubbers to the plane’s oxygen system.

The Navy experienced similar problems with its F/A-18 Hornet fighters during carrier operations from 2002 to 2009, with 64 hypoxia cases reported -- including two involving pilot deaths. An investigation suggested that the problem was caused by carbon monoxide entering the oxygen system while pilots idled behind other aircraft waiting to take off, and the Hornets were modified to fix the problem.

No similar incidents have been reported in F/A-18s since the fix, according to the Navy

A quick and dirty fix would be installing CO filter on the oxygen mask, although it may look awkward, at least it could get the birds off the ground until a long term solution is worked out

batu731 wrote:

A quick and dirty fix would be installing CO filter on the oxygen mask, although it may look awkward, at least it could get the birds off the ground until a long term solution is worked out

Just put LOX bottles back in em! Rolling Eyes

Quote:

USAF continues probe into F-22 grounding
By Dominic Perry

USAF tests have been unable to replicate the hypoxia-like conditions experienced by some pilots of the Lockheed Martin F-22 Raptor.

Speaking to analysts following Lockheed's second-quarter earnings, chief executive Bob Stevens, said that the company was working closely with the USAF in order to get to the bottom of the issue which has led to the stand-down of the F-22 fleet.

The USAF has fitted one F-22 with "very sophisticated instrumentation" as part of an "incredibly detailed and thorough review".

He said: "It has been flying that airplane to see if those conditions exist and can be observed and then we can work backwards together." So far they have not been replicated and the cause remains a mystery, he said.

Source: http://www.flightglobal.com/articles/20 ... nding.html

Air Force finds multiple toxins in blood of woozy F-22 pilots

http://www.adn.com/2011/07/27/1987508/a ... oxins.html

I read a comment elsewhere that this could well be caused by running the engines in the hanger prior to take off and the oxygen system ingesting fumes.

(Don't think this has been posted before, apologies if it has)

Forum: General F-22A Raptor forum

OBOGS problems affecting F-22 and other jets