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Post by daoleguy A.J. Hoehn (deceased) on Jun 11, 2008 6:23:02 GMT 9
;D Not SIX but interesting to me as a former Avionics weenie. They now claim the B-2 that crashed in Guam did so due to moisture in the Air Data Computer system. WTF, we learned of that in the SIX days and established heaters and descicants to deal with that. Why is the AF now saying,"However, a technique learned by some two years ago that had gone widely unknown and unadopted probably would have prevented the crash, Carpenter said. The technique essentially heats the sensors and evaporates any moisture before data calibrations. This technique was never formalized in a technical order change or captured in 'lessons learned' reports. Hence, only some pilots and some maintenance technicians knew of the suggestion," according to Carpenter's executive summary of the accident. Excuse me experts, we knew that in the 60's/70's. If I recall the old 646 can was updated to the CPU-111 partially to deal with condensation and its effect on sensing Air Data input. I went to Warner Robbins during CPU-111 developement and the issue of moisture and condensation was considered an real issue. Pitot heaters and old tech didn't seem to properly compensate (drains either!). Correct me if I am wrong, but I vaguely recall descicators being improved and included in the ADC systems to prevent spurious inputs to flight controls due to mitigating influences. Read more here: www.cnn.com/2008/US/06/06/crash.ap/index.html. I'd like to hear other old 32's comment. AJ |
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Post by lindel on Jun 11, 2008 11:21:04 GMT 9
You are correct sir! We had to cook the dessicant bottles on a regular basis, and periodically change the dessicant.
Dessicant bottles were replaced on the a/c regularly and brought to the mock up for drying.
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Post by daoleguy A.J. Hoehn (deceased) on Jun 11, 2008 22:52:07 GMT 9
"Sir" Lindel? Hehehe, I worked for a living.  This instance is like the "new" realignment idea of a unit realy being a unit. Where the hell are the old salts that knew this crap 30 years ago. I knew I wasn't imagining the condensation/moisture issue considerations of the early 70's. Hell any wrench turner knew if you flew an aircraft from a cold dry climate to a warm (hot) humid area it would acquire moisture in pitot systems, not to mention others. No wonder they canned the Chief and others recently! Nobody learns from history, they repeat the mistakes. THak God we lost no crew or ground in the incident. Just a few billion dollars we spent in taxes. AJ |
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Post by lindel on Jun 12, 2008 11:41:29 GMT 9
Hah! My folks taught me to respect my elders! LOL
I hated when the birds would spend some time down in Tyndall. The green goop wold have to be cleaned out of the waveguides with alcohol (rubbing, not the useful kind)
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Post by daoleguy A.J. Hoehn (deceased) on Jun 12, 2008 14:06:43 GMT 9
Gawd Tyndall! The first thing I remember is the damned paper mill. Of course the Ghost Crabs by the NCO club were fun to chase espeically when a bit inebriated. Then there was General Price and Col Nelly's damned grass, really crushed stone. That's another story. Hmm Tyndall. Now you're really talking mositure, especailly with bird fresh from Northern Maine arriving.
AJ
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sixerviper
F-106 Skilled
Currently: Offline
Posts: 209
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Joined: July 2007
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Post by sixerviper on Jun 16, 2008 1:05:12 GMT 9
Hey guys--I'm (almost) positive that something in the FLCS (that's [fly-by-wire] FLight Control System to the uninitiated) malfunctioned after seeing the video of the crash on the internet.
What y'all may or may not know is that when the pilot makes a pitch command, the FLCS goes out and checks AOA, mach number, G's available vs. commanded, sideslip angle, and probably some other things before actutally moving a control surface. At least, this is how it works in the F-16. I can't see the B-2 or anything else with fly-by-wire operating too differently.
When we deployed from VA to Tyndall with the F-16, we never had any problems with moisture in the pitot-static lines, and I never heard of any problems with F-16s from northern units. The F-16 does not have any dessicators in its pitot-static system, and none to my knowledge within the CADC. I'd be a tad surprised if the B-2 had any.
I'm wondering if this moisture business is a fish story. I can see frozen moisture in the lines creating problems, but that's more a problem at altitude and that's why the jets have probe heaters. Speaking of which, did you know that the F-16 has a HEATED temperature probe? Go figure...
I never went to Tyndall with the Six, but went there several times with the Viper. That paper mill's cleaned up its act some and apparently isn't as stinky as it used to be. However, the humidity is still horrible, the Club is still on the beach, and the water in the Gulf looks inviting for a scuba dive.
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Post by lindel on Jun 16, 2008 1:53:11 GMT 9
I'm not aware of the 6 ever having a moisture problem with the pitot system, but we'd get nasty green stuff in the waveguides that would need to be purged before it could crawl out on it's own to attack an unsuspecting MA-1 troop.
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This instance is like the "new" realignment idea of a unit realy being a unit. Where the hell are the old salts that knew this crap 30 years ago. I knew I wasn't imagining the condensation/moisture issue considerations of the early 70's. Hell any wrench turner knew if you flew an aircraft from a cold dry climate to a warm (hot) humid area it would acquire moisture in pitot systems, not to mention others. 
