LETTER TO MR. C. L. JOHNSON FROM DAVID CLARK COMPANY INCORPORATED

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP75B00285R000400130007-7
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 3
• Document Creation Date: December 12, 2016
• Document Release Date: February 27, 2002
• Sequence Number: 7
• Publication Date: March 3, 1967
• Content Type: LETTER

Approved For use 2002/06/24: CIA-RDP75BQd285R400130007-7
DAVID CLARK COMPANY INCORPORATED
BW--3 .
March 3', 1967
Mr: C. L. Johnson
Vice President
Advanced Development Projects
Dear Mr. Johnson:
This is-to inform you on the style and types of'personal equipment
is presently:usin; as a test pilot at areas other
an W-3.
has in his possession, two helmets that are listed as
Phase II helmets. This particular helmet was ordered
by Headquarters as an evaluation item to eliminate reflections from
the gold plated heated visors, presently used on all standard GN-
ACS-880 full pressure helmets. To my knowledge, the GN-ACS-1621
Phase II helmqt is still an evaluation item, as only two Subjects,
I land Subject 1051 (based at Bi13) are the only pilots
to ever replace their standard GN-ACS-880 full pressure helmets with
the Phase II GN-ACS-1621 mask helmet. Many of the Subjects based
at B6^13 have tried the Phase II helmet, but prefer to use the
standard face barrier GN-ACS-880 style helmet. The GN-ACS-1621
helmet does have some advantages over-the standard helmet because
the visor remains in the up position, eliminating reflections from
the gold plated visor. Also, d Subject 1051, often 25X1A
remarked about the added cooling from the suit vent air passing up
through the suit neck ring past the Subject's face.
The GN-ACS-l621'helmets at BW-3 are fitted with a counter balance
spring assembly (GN-A2840) which will add to the closing of the visor
under "G" forces, or if the pilot had to leave the aircraft in an
inverted possition. All ACS-1621 helmets have aneroid operated visors
and are'scheduled to close between 29,000 and 31,000 feet which is
at least 3,000 feet before the aneroid in the suit controller functions.
The ACS-1621 Phase II helmet can be used with either an S970 (rear
entry) suit assembly which has two, or an S901 "U" 25X1A
entry suit assembly. Subj uses an 5970 and an S901 suit
assembly.
One,of Phase II helmets (serial number 265) is not
standard with e o her existing five helmets of this type. This
particular helmet has the original plumbing which connects the two
internal oxygen hoses into the helmet manifold... This type of connector
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was proven unsafe for flight when one of the oxygen hoses separated
from the manifold while Subject was being tested with 70. PSI of
oxygen. We were then. directed by Headquarters to change this type of
connection to the original, and still standard,'type of hose connection
used on all ACS-850, ACS-2885 and ACS-2219 style helmets at this area.
Two other rion-standard items on helmet, serial number 25X1 A
265, are the two helmet pressure taps - , used to monitor suit
and face or mask cavity differential pressure as the Subject is being
tested before a flight. This item was proven to be unsafe for flight,
after Subject 1051 ejected at low altitude from Article 126 with an
ACS-1621 Phase II helmet, serial number 256. The investigating team
found that due to the high profile of the ACS-C1311 pressure tap, it
was struck by some object and torn from the helmet. At a later date,
the David Clark personnel at SW: 3 static tested the entire assembly
that Subject 1051 ejected with and found that the suit would not remain
pressurized with a pressure tap missing. We were led to believe that
if the subject had ejected at a high altitude, he would have been in
serious trouble.. We were then directed, by Headquarters, to remove
all ACS-C1311 pressure taps from all full pressure helmets and replace
them with flush mounted G1-P-3399 type pressure taps.
When the ACS-1621 Phase II helmet is used with either an S970 or an
5901 suit assembly, a neck dam GP1-A2797 must be installed in the neck
ring area of the suit. The neck dam normally remains loose around-
the subject's neck to allow adequate vent and comfort for the subject.
The neck dam can be drawn tight by means of a draw string that attaches
to the Subject's mask with a snap. In event the Subject had to eject
over water, he should draw his neck dam tight before contact with the
water as part. of his over water ejection procedures. This would prevent
water entering the suit through the helmet.
To pre-flight or test this helmet for-any reason, you will follow the
same procedures'as testing an 550 type helmet. There is one change
in the test plate used in the mask.-The nomenclature. and number for
this item is GPJ-IJ-D1125 plate, testing, mask.
NOTE: When testing the GA?-ACS-1621 Phase II helmet either in pre-
flight, subject test or post-flight, always test the helmet with the
visor in the closed position so the complete oxygen system is function-
ing while the test is being performed.
One other test that should be made at least every thirty days is the
function of the'aneroid operated visor in a chanber at altitude. The
aneroid should allow the visor to close between 29,000 and 31,000 feet.
After the test,'the aneroid can easily be re-armed manually.
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A number of spare parts used only on Phase II helmets, should be
kept in stock and installed only by experienced personnel.
Inclosed are thirty day periodic and annual iran forms that we
presently use, which covers the testing and inspection of all David
Clark pilot's protective assemblies, used at BW-3.
Very truly yours,
DAVID CLARK C01;1'ANY INCORPORATED
D11--3 Representative
25X1A
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