User's Manual Part 1

T
2
CAS / Part No. 9000000
SYSTEM DESCRIPTION AND INSTALLATION MANUAL
34-43-20
15 Feb 2003
Use or disclosure of information on this page is subject to the restrictions in the proprietary notice of this document.
1--36
The ACSS directional antenna has a small frontal area. The circular radome has a 3:1
elliptical leading edge and an extremely low profile height of only 0.806 inch. This yields
excellent aerodynamic performance with a minimum possibility of icing, which could be a
hazard for rear mounted engines.
For T
2
CAS TCAS system installations, the top antenna must be a directional antenna.
The bottom antenna can be either a directional or omnidirectional antenna. The T
2
CAS
Computer Unit has the capability of automatically sensing which version is installed.
The directional antenna mounting screws are standard #10--32 UNF-- 2A pan head,
corrosion--resistant (stainless) steel screws in accordance with Military Specification
MS51958. The appropriate length is determined by the installer allowing 0.5--inch for the
thickness of the antenna and adapter plate. A washer must be installed under the head
of each mountin g screw. The washer must be made of passivated, corrosion--resistant
steel in accordance with MIL--S-- 5059 or MIL-- S--6721. The Air Force--Navy Aeronautical
Standard part number is AN960C10L. The washer has an outer diameter of 0.438 inch,
an inner diameter of 0.203 inch, and a thickness of 0.032 inch.
An O--ring (included with the directional antenna) is required to be installed between the
directional antenna and the aircraft fuselage. The National Aerospace Standard part
number for the O--ring is NAS 1611-- 240. The ACSS part number for the O--ring is
4000171--240.
NOTE: For directional antennas, ACSS Part No. 7514060--90X, the customer must
provide an adapter plate for mounting to the aircraft. For details of the antenna
base plate, to which the adapter must mate, refer to Section 2. Directional
antennas, ACSS Part No. 7514081--9XX, come with a preinstalled adapter plate.
The average unit weight of an antenna with adapter plate is approximately 3.0 pounds.