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Date: Sat, 25 Sep 2004 01:29:42 -0400
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From: "Ted Stanley" <ted@vineyard.net>
Subject: DU - Depleted Uranium
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FYI for those that are interested .... there is some information regarding the
use of "DU" depleted uranium found in the Advisory Circular below. It's short so
here's the whole thing. In short, it seems DU isn't something to be handled
casually.

Ted Stanley - A&P-IA


AC 20-123 - AVOIDING OR MINIMIZING ENCOUNTERS WITH AIRCRAFT EQUIPPED WITH
DEPLETED URANIUM BALANCE WEIGHTS DURING ACCIDENT INVESTIGATIONS

Department of Transportation
Federal Aviation Administration

12/20/84

Initiated by: AWS-330
1. PURPOSE. This advisory circular provides information and guidance to
individuals who come in contact with depleted uranium contained in aircraft
control surfaces during accident investigations.
2. RELATED READING MATERIAL. Additional information on depleted uranium may be
found in the maintenance manual of each affected aircraft and also in service
information provided by the aircraft manufacturer.
3. DISCUSSION. For many years, aircraft manufacturers have used "depleted"
uranium to balance ailerons, rudders, and elevators on certain jet aircraft and
rotor blades on certain helicopters. Uranium is 1 1/2 times as dense as lead and
is the heaviest naturally occurring metal. According to a 1983 McDonnell Douglas
Customer Service First Quarter publication, only "depleted" uranium is used,
which means it has been processed to remove most of its uranium 235, the most
highly radioactive form used in nuclear powerplants. The remaining uranium 238
emits only low level alpha radiation. While the depleted uranium normally poses
no danger, it is to be handled with caution. The main hazard associated with
depleted uranium is the harmful effect the material could have if it enters the
body. If particles are inhaled or digested, they can be chemically toxic and
cause a significant and long lasting irradiation of internal tissue. Depleted
uranium is slightly radioactive. To minimize radiation hazards, depleted uranium
balance weights are 100 percent cadmium plated during the manufacturing process.
If the cadmium plating is intact, normal handling of the parts is considered to
be nonhazardous and no special precautions are recommended. The use of
radioactive materials in many every day applications is not at all unusual. For
example, tritium, a radioactive form of hydrogen, is used in self-luminous
signs, such as exit signs, and watches. Thorium, which has a radiation activity
level comparable to depleted uranium, is used in making gas mantels for
lanterns, electronic equipment, and high quality optical lenses for cameras and
overhead projectors. Also, smoke detectors contain americium 241, a radioactive
material.
4. PRECAUTIONS.
a. Avoid contact with balance weights using depleted uranium. On arrival at
accident scenes of aircraft suspected of containing balance weights made of
depleted uranium, determine if balance weights have been damaged or lost their
cadmium plating coating. Request specialized assistance if balance weights have
been damaged or lost their cadmium plating. No penetration of the plating is
allowed.
b. Avoid breathing or swallowing particles of balance weights found damaged or
with cadmium plating damaged or lost.
c. If it becomes necessary to handle balance weights, the following precautions
should be observed:
 (1) Personnel handling the balance weight should wear gloves.
 (2) Industrial eye protection should be worn.
 (3) Respirator mask should be worn to ensure no radioactive dust particle
ingestion.
d. Gloves, wrapping material, wiping cloths, respirator filters, or any other
articles used in the handling of damaged balance weights should be discarded and
appropriately labeled as radioactive waste and disposed of accordingly.

/s/
M.C. Beard
Director of Airworthiness