Keesler airmen discover source of illness aboard C-130

[Dame]

Well this sounds like actual GOOD news! Took these guys 500 man hours but they were on a mission.
Bravo Zulu!

BILOXI, MISS. — For years, a strange problem with the U.S. Air Force's C-130 aircraft had pilots and crews reporting sickness, discomfort and, in some cases, excruciating pain after routine flight missions. The phenomenon remained a mystery until February, when a handful of reservists at Keesler Air Force Base took the initiative to solve the mystery. They made a tiny discovery that's affecting airplanes worldwide.

The problem was with the pressurization system on the C-130 Hercules - the longest-produced and perhaps most-popular aircraft in military history. The versatile airplane serves as an attack gunship, a troop transport, a surveillance plane and many other roles.
...
It took 500 man hours and disassembly of about 65 percent of the system before they made the crucial discovery. The metal particles were coming from a corroded rivet, no larger than a pencil point, inside an air valve.

The corrosion had remained hidden for years because every other part of that valve is stainless steel. But not the tiny rivet, which is composed of plain pot metal - an inexpensive, low-quality alloy.

http://www.mcclatchydc.com/2015/04/12/262909/in-flight-mystery-keesler-airmen.html#storylink=cpy

 

[DA SWO]

Lockheed needs to be reamed for that one, of course they will claim the rivet supplier bought shit from China (which will turn out to be true).

 

[Red Flag 1]

Impressive work by the ground crew. This is just a snap shot, of the amount of work ground crews do to keep our aircraft flying, and the air crews safe. If you consider the age, and flying hours some of our workhorse aircraft have, it is because our aircraft maintainers are the best in the world. They rarely get credit for just how talented, and skillfull really are.

 

[Viper1]

Wow that is incredible! Great job to all involved.

 

[RetPara]

Wonderful. That took a well planned approach to finding the root cause. So for those of us that have a shit load of hours as passengers at high altitude.... Are there any long term impacts.....

 

[Johca]

It's disappointing to me that no over pressurizing date or identification of certain altitudes is provide to support claim of "Cabins would over-pressurize at certain altitudes", causing the physiological problems." It would be most interesting to see how much over pressurization the mechanical problem caused.

Maximum flight ceiling of C-130 type aircraft is 30,560 ft / 9,315 m with typical cruising altitude being 28,000 ft / 8,535 m or lower. I'm not sure of the exact specs for the C-130, but generally the do not exceed cabin to outside pressure differential in modern aircraft is generally between 8.50 and 8.60 PSI. What this simply means is exceeding this this differential puts not designed for stress on the fuselage design. Potentially a seal around a widow, door, or hatch can fail or more serious integrity failure of the fuselage integrity could happen, in actuality there are some sort of safety valves to prevent exceeding the 8.5 to 8.6 pressure differential for this reason. Most C-130 aircraft are not air tight (open closing doors and ramps for air drops for example) put wear and tear so the pressurization system generally has to pump some sort of pressurized air flow into the cabin too (at least the C-130s I flew on).

Looking at this from an underwater diving physiology perspective, atmospheric pressure at 31,000 feet is 3.81043 PSI (10.88441 PSI less than sea level) and at 28,000 feet is 4.34216 PSI (10.35394 PSI less than sea level). If the aircraft cabin atmospheric environment is over pressurized the risk would be most to the aircrew potentially during descent and most likely after landing at an airfield at elevation about 2,800 feet above sea level and not during flight.

Comparing the risks to compliance with no decompression and decompression dive tables where depths shallower than 35 feet of sea water do not have a specific no-decompression limits puts an interesting exploration of the problem into play. The pressure change from the surface of sea (ocean) to depth of 33 feet is a pressure change of one atmosphere (14.7 PSI). The pressure change of an aircraft over pressurization appears to be exposing C-13o aircrews and passengers to a pressure change of significantly less than one atmosphere, thus why the article without the over pressurization and other data backing it up is very disappointing.

Just to be a smart butt:

Wonderful. That took a well planned approach to finding the root cause. So for those of us that have a shit load of hours as passengers at high altitude.... Are there any long term impacts.....

Not for paratroopers as they generally get air sick as soon as the aircraft starts rolling down the runway.

 

[RetPara]

Just to be a smart butt:
Not for paratroopers as they generally get air sick as soon as the aircraft starts rolling down the runway.

Well sonny..... though all these years later at a whiff of turbo jet exhaust I still get that 'am I going to barf no or later' feeling.... I still have to wonder how the pressurization still has impacted many of us in the long run that have flown long distances in C-130's at altitude not counting the hydraulic fluid dripping on me, 'water' from the pressurization/cooling/what is jokingly referred to as 'heat' dripping on us.... let alone the one time I got to see the Loadmasters jump up open the doors and the Jumpmasters stand up and shout "Stand UP!!! On the bell go out on your reserve. The DZ is the 4/68th tank park and motorpool. Good Luck!!!!"

 

[DA SWO]

Well sonny..... though all these years later at a whiff of turbo jet exhaust I still get that 'am I going to barf no or later' feeling.... I still have to wonder how the pressurization still has impacted many of us in the long run that have flown long distances in C-130's at altitude not counting the hydraulic fluid dripping on me, 'water' from the pressurization/cooling/what is jokingly referred to as 'heat' dripping on us.... let alone the one time I got to see the Loadmasters jump up open the doors and the Jumpmasters stand up and shout "Stand UP!!! On the bell go out on your reserve. The DZ is the 4/68th tank park and motorpool. Good Luck!!!!"

The story said this was a J-model issue and the J has only been flying operationally for about 10-12 years.

 

[Gunz]

Good for these guys tracking it down. Bravo Zulu indeed.