|
Yes, certainly makes you wonder why it is even allowed.
In my research, a case was made that because the 5606 is an FAA approved
"Standard" that similar to many other aircraft parts - any change by industry
would be seen (by lawyers) as admission of a defect in the "older stuff .
Apparently the FAA attitude is as long as the fluid stays in the system there is
little chance for ignition {:>). However, given the alternatives that
now exists it seems almost criminal that the 5606 is even permitted to be
sold.
Regarding auto brake fluid - there has been some cases in the
past (where inappropriate seal material was involved) that the use of auto brake
fluid in an aircraft brake system caused problems. Not certain that is the
case anymore with the synthetic materials used in most seals.
I just ordered a gallon of the MIL-h83282 for $18.00. It
will certainly cost me more to replace the one wheel pant {:>)
Ed
----- Original Message -----
Sent: Thursday, August 25, 2005 1:27
AM
Subject: [FlyRotary] Re: Flamible brake
fluid
In a message dated 8/24/2005 10:23:00 PM Pacific Standard Time, WRJJRS@aol.com writes:
The more I research, the more brake fires I come
across occurring in experimental aircraft. However, it turns out the
standard brake fluid is widely used throughout general aviation as well as
airlines - this is the standard 5606 series. The flash point has
ranged from 187F to 240F as some improvements in flash point was made with
each new formula up through Mil-P-5606H.
Attached in PDF format is a concise article from EAA
chapter 493 about an RV-8 brake fire and the crucial difference between
the old standard and the new brake fluid Mil-H-83282. The new brake
fluid is compatible in every way with the standard - but has a flash point
around 400F - almost twice that of our standard brake fluid. It
turns out the standard brake fluid has been responsible for airliner
crashes, GA crashes as well as numerous fires.
Your brakes are hot enough even with moderate
braking to immediate ignite the standard brake fluid - if you have any
kind of leak and the fluid contacts the brake pads or rotor
- its quite possible you will find your aircraft on fire as I
did.
Naturally I strongly recommend a change to the
H-83282 as soon as practical - like no later than your next
annual/conditional inspection if not sooner. Me I'm doing it
sooner.
Ed
Ed,
I have checked with several manufacturers who say their stuff is
compatible with automotive fluids. I have no idea why we would put up with
the flammable aircraft stuff. Besides DOT 4 silicone fluid which has the
advantage of not harming paint, I have been using various synthetics in my
race bikes for years which are good to better than 600°F! I have heard some
older auto fluids are corrosive to aluminum but with the number of aluminum
components on modern cars it MUST be less common. I have had all sorts of
ALUMINUM BRAKE PARTS including master cylinders on my bikes and never seen
ANY problem. The aircraft fluid is simply stupid when compared to modern
auto fluids.
Sorry, forgot to sign
Bill Jepson
|