Professional Pilot, January 2019

Prototype Collins Aerospace Flight Deck Interval Management FIM pictures that highlight additional guidance and situational awareness information PROFESSIONAL PILOT January 2019 55 as the 2020 ADS B Out mandate arrives critical mass will be achieved and many customers will upgrade to take advantage of ADS B In traffi c awareness benefi ts Asked to share customer feedback McDowell says Most customers are happy with the additional traffi c information and the improved situational awareness They are now looking for traffi c apps that will provide economic value UAT and 1090 ES As explained in my fi rst article Pro Pilot Nov 2018 p 42 in the US ADS B will be spoken in 2 different languages The 2 languages really similar systems using separate frequencies are called Universal Access Transceiver UAT and 1090ES for Extended Squitter The UAT system is generally less expensive and is intended for low fl ying light civil aircraft UAT operates on 978 mega Hertz MHz frequency which serves to reduce frequency congestion on the 1090 MHz frequency that is already heavily used by existing transponders TCAS and now 1090ES ADS B The numerous international ADS B Out mandates currently in effect and coming soon unanimously call for the use of 1090ES via a Mode S transponder Similarly all US operations fl ying above 18000 feet will require 1090ES ADS B Out broadcast For these reasons most business jet and airline operators choose the Mode S 1090ES version of ADS B The ADS B In function piggy backs on the TCAS system since the TCAS antennas are already able to receive 1090 MHz signals However additional software is needed in the TCAS computer to blend or correlate TCAS targets with ADS B targets Collins uses 1090ES ADS B In Collins Aerospace systems use the 1090ES ADS B In version and do not directly receive the 978 MHz UAT traffi c signals The displayed traffi c picture is completed through ADS R Rebroadcast Traffi c Information Service Broadcast TIS B and TCAS active surveillance ADS R is the FAA provided service that listens to all incoming ADS B data auto translates and transmits messages in the other language TIS B and TCAS active surveillance allow for detection and display of targets equipped with transponders but not fi tted with ADS B Out The FAA provided TIS B service uses a combination of radar interrogators and ground stations to detect and transmit non participant surveillance information to ADS B In participants when the non participant is within defi ned airspace around the ADS B In aircraft However TIS B target position accuracy is not as precise as ADS B Out targets because TIS B targets rely on detection by surveillance radars with 5 to 12 second refresh rates while ADS B targets send their Wide Area Augmentation System WAAS GPS quality positions once per second TIS B is intended to provide broad SA of aircraft that chose not to equip with ADS B Out Since TCAS and 1090ES ADS B share common frequency and hardware 1090ES ADS B has the advantage over UAT in the rare case where you are operating outside of FAA ground station TIS B coverage TCAS equipped aircraft automatically use TCAS active surveillance to detect non ADS B equipped targets that are fi tted with a transponder Aircraft without operable transpon