Install Manual

Preliminary
SKY899
Installation Manual
1-2
Rev. A
1.2 FUNCTIONAL DESCRIPTION
The BFG Avionics Systems SKYWATCH
®
HP SKY899 is a new generation airborne traffic alert/advisory
system that increases the active-mode surveillance range over the SKY497 system from 20 nmi to 35 nmi
and adds Automatic Dependent Surveillance-Broadcast (ADS-B) surveillance mode. The SKY899
continuously monitors the dedicated data link frequency (1090 MHz) for ADS-B mode S extended squitter
messages within 50 nmi. The ADS-B message contains navigational information about the intruder
aircraft including GPS position, ident, ground speed, and intent. The SKY899 uses this navigational
information along with its own aircraft GPS navigation data to calculate the relative position of the
intruder to augment its active ATCRBS surveillance of the intruder. ADS-B surveillance enhances the
traffic alert/advisory abilities by increasing the accuracy of the active-mode surveillance. The SKY899 does
not require a mode S transponder, ADS-B capable or otherwise to perform its ADS-B surveillance.
The SKY899 advises the flight crew where to look for aircraft that may pose a collision threat. It is
intended for use by corporate and general aviation aircraft. SKY899 alerts the flight crew to nearby
transponder equipped aircraft and assists the pilot in the visual acquisition of aircraft that may represent
a danger. Traffic information out to a selected range is graphically displayed on the display. Using shapes
(i.e., Traffic Advisory = solid circle; Other Traffic = open diamond) and text, the display shows the relative
position of threat aircraft.
1.3 PHYSICAL DESCRIPTION
The SKY899 System consists of the following main components:
• Transmitter Receiver Computer
• System Configuration Module
• Alternate Display (or optional monochrome WX-1000/SKY497 display)
• Directional Antenna, NY156 or NY164 (depending on TCAS I or TAS installation)
SKY899 is an active system that operates as an aircraft-to-aircraft interrogation device. The SKY899
equipment interrogates transponders in the surrounding airspace similar to ground based radars. When
replies to these active interrogations are received, the responding aircraft’s range, altitude, and closure
rates are computed to plot traffic location and predict collision threats. The effective active range is
approximately 20 nmi. The SKY899 does not transmit ADS-B interrogations, in order to transmit your
aircraft position you must have a mode S transponder capable of ADS-B interrogations.
Figure 1-1 shows the SKY899 vertical display modes used to display intruding aircraft. The unrestricted
altitude of the surveillance zone is ±10,000 ft, but the display is only capable of showing to ±9,900 ft. A
simplified block diagram of the system and their relationships is shown in figure 1-2.