Honeywell International Inc. 9PGTPL-100A Manuale Utente

Page 26

1 Mar 2006

TPL-100A Processor / Part No. 940-0530-001

Use or disclosure of information on this page is subject to the restrictions in the proprietary notice of this document.

Surveillance volume is the volume of airspace within which other aircraft with Mode S or 

ATCRBS transponders are tracked by the own aircraft MILACAS-FR Processor System.

(1) Range Tracking Volumes

The shape and size of the range tracking volume is dependent on: 

•

Whether Mode S or ATCRBS transponders are being interrogated

•

Whether tracking is occurring on a directional or omni antenna

•

The attenuation levels applied to the transmitted pulses from the MILACAS-FR 
Processor.

NOTE: The MILACAS-FR Processor reduces range tracking volumes in high density 

areas to reduce the number of receptions to be processed by TCAS and for 

interference limiting.

(2) Altitude Tracking Volumes

The MILCAS-FR Processor tracks other transponder-equipped aircraft that are within 

a relative altitude range of ±9000 feet (10,000 feet for units with Change 7 software). 

Note that the display altitude volumes differ from internal tracking volumes. Typical 

display volumes are ±8700 feet (±9000 feet for Change 7 units).

TCAS logic separates the surrounding airspace into altitude layers as shown in Figure 2. 

Each altitude layer has a different sensitivity threshold to issue RAs (resolution advisories) 

and TAs (traffic advisories). Lower altitudes have less sensitive RA and TA thresholds to 

prevent unnecessary advisories in the higher traffic densities anticipated at lower flight 

levels, such as terminal areas.

The information that follows about TCAS sensitivity levels, resolution advisories, and traffic 

advisory criteria is available as an aid to explain basic TCAS operation. The information in 

this manual may be superseded by the data in the MOPS document and the latest 

Honeywell software documentation.