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Previous by Date: Subject: Re: Histology Lab Covered by OSHA Lab Standard Date: Tue, 14 Jun 2011 13:16:51 -0400 Author: "Samuella B. Sigmann"

Next by Date: Subject: evacuation chair Date: Tue, 14 Jun 2011 13:12:30 -0700 Author: "Kennedy, Sheila"

Debbie et al,
 
The F-16 uses hydrazines as Aerozine-50 (50% monomethylhydrazine/50% unsymmetrical dimethylhydrazine -- the latter a suspect, at least. carci nogen) as the fuel source for an auxilliary electrical generator component.   This is located somewhat beneath and aft of the command pilot's se at (but not in the actual cockpit; the pilot wears usually a CRU-60-P fli ght regulator with provides altitude-dependent varying amounts of oxygen an d even CPAP at higher altitudes with a very tight-fitting mask -- a true SA B device)  in most F-16 models.  The amount of hydrazi nes is small, to say the least.  However, it is there, and sma ll amounts are quite toxic, with the potential to cause intractable seizu res (to most anticonvulsants; there's a reason to use large doses of vita min B-6; pyridoxine, intravenously just as we do for toxic mushr oom poisoning and isoniazid poisoning, containing the same sorts of toxic ants -- I'll explain the mechanisms if anyone is interested, but it happe ns) and quite significant methemoglobinemia and potential intravascular hem olysis.  There's quite a bit of old NACA (NASA percursor) and USAF literature on this (used to be used to fuel the liquid stage of the S aturn-5 and other rockets and in certain liquid stage modules of various IC BMs ).  Certain NASA "Shuttle" (STS) flights also used Aerozine-50 a s the hypergolic fuel and Nitrogen Tetroxide as the oxidizer.  Gives one hades of a lot of power or thrust for the volume and weight (wh ich translates into "drag" in the usual aeronautic equation):  lifti ng about 1 pound into low earth orbit used to cost just about $US 17,000. 00 in terms of fuel expended.
 
When I used to take Flight Surgeon call at what used to be Carswell AFB in Fort Worth, TX where we were the receiving facility from General D ynamics (just down the way) and civilian pilots brought the old F-16 "A" mo del over for USAF pilots to accept into the USAF inventory, we used to ge t called out to flight line to stand by for usually a flight of two with on e experiencing both electrical and hydraulic failure.  The guy with the intact bird led the other pilot in, and then us ol' flight surgeons h ad to stand way back in the flight line ambulance with binocs and advise th e Incident Commander (usually the Fire Chief) about whether it was safe for them to approach the aircraft.  Usually turned out there was a fail ure of the hydraulics which shorted out some of the electrical power busses rather that a leak of hyrazines from the auxillary electrical generator (f luid dripped from about the same place under the fusillage; the Aerozine- 50 is colorless and most hydraulic fluids have some color), but you somet imes had to call up a GD aeronautical engineer and go over th e scematics and then perhaps run somebody in in Level A to check the pH (differences between even military standard hydraulic fluid and Aerozin e-50, enough to almost always give the all clear) ot get a sample, etc.   Meanwhile, a busy runway on a SAC alert base with "gassed and co cked" B-52s sat there waiting for the ol' Soviet Bear to start something.&n bsp; We tried our best, within safety parameters, to clear that runwa y ASAP.
 
So unless they've changed this component in later F-16 models (which I doub t; from an engineering standpoint it was exceptionally weight/drag-effect ive), then the concern might have been real.
 
Although, also, if an F-16 "augers in" and the military grade jet fuel ignites, there won't be any hydrazine not thermally degraded left either.   That's why the pilots have ejection seats, so they have a chance of not being incinerated as well. Of course, all us old pilots, milita ry or civilian, think we have the "right stuff" to slap the bird back dow n, a bit bent or not.  But there is a real time to chant the "Bail Out! Bail Out! Bail Out!" mantra and pull the release handles.  Eve n Ol' Flight Surgeons were well-trained to do that.
 
I can give a more fully detailed lecture on the toxicity and mechanisms of the hydrazines and the treatment or cite the literature if anyone is intere sted, but as Alphonse once said:  "That's another story."
 
Alan
Alan H. Hall, M.D.
Maj, USAFR, MC, FS (Hon. Ret.)
 

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