Professional Pilot, March 2018

PROFESSIONAL PILOT March 2018 75 A pictorial overview identifying the main functions GADSS is not a specific system so much as it is a concept of operations with recommendations for equipping and maintaining by ICAO member states Aircraft tracking Provides automatic A C position at least once every 15 minutes ATS surveillance may be utilized Can be isolated by flight crew Multiple solutions May have airline defined triggers for abnormal operations with higher reporting rate Autonomous distress tracking ADT Provides automatic A C position at least once every minute Must be active prior to accident event Operates autonomously of aircraft power Results in a distress signal to appropriate SAR FIR May be manually activate Can not be isolated Flight data recovery Ensures a minimum dataset of CVR and FDR information Operation approval required ADFR Automatically deployed Floatable Contains an ELT to aid location Airline SWIM ATS RCC deliver information to SAR agencies ADT automatic triggering may include specific mode A squawk codes the ground or on board analysis of unusual attitudes or speeds potential terrain collision or total loss of thrust on all engines The purpose for automatic triggering is to maximize the probability of detecting an impending catastrophic event Automatic triggering must provide aircraft position information not later than 5 seconds after detection of the distress condition Provisions for operators to trigger ADT may be included in systems if there is uncertainty of the aircrafts status and attempt to communicate with the flight crew have failed If the aircraft recovers from the catastrophic event distress signaling and tracking will be deactivated but may only be done so through the activating mechanism Post flight localization and recovery Rescue of any survivors is the most important part of the 1st phase after an aircraft accident Aircraft accident site location accuracy of 1 nm or better should be provided by an Emergency Locator Transmitter ELT and or homing signals The minimum information that must be transmitted is latitude longitude time aircraft identification registration and the source of the signal such as ELT distress tracking Large airplanes operating on long range overwater flights are required to have an attached underwater locating device capable of providing detection for several miles and operating for a minimum of 30 days Flight recorders are required to additionally have an automatically activated underwater locating device capable of operating for a minimum of 90 days The term Regional Coordination Center RCC is used generically in GADSS to refer to any unit responsible for promoting efficient organization of SAR and communications within a defined SAR region This could be an aeronautical marine or joint RCC The protocol for notification is given as If a distress condition is detected by Air Traffic Services ATS then ATS will contact the operator and the RCC If the operator detects the distress condition they will advise ATS who will notify the RCC If an ELT or ELT distress tracking signal is activated the RCC will be notified via the Cospas Sarsat system The RCC may be notified by an outside source Obviously accurate and timely communication and coordination among all interested parties is crucial GADSS defines specific phases of pending or actual emergency situations as Uncertainty phase uncertainty exists as to the safety of an aircraft and the occupants Alert phase apprehension exists as to the safety of an aircraft and its occupants Distress phase reasonable certainty that an aircraft and its occupants are threatened by grave and imminent danger or require immediate assistance False Alert alert received from any source where no distress situation actually exists and the alert should not have resulted GADSS implementation Some of the requirements for GADSS are already in use ICAO has provided a timeline for the initial added elements For airliners underwater locating devices were required beginning January 2018 while 15 minute aircraft tracking will be required in November 2018 Autonomous distress tracking and flight data recorder recovery standards come in on January 2021 The next step in aircraft tracking All of the various elements of the GADSS program hinge on the ability to track aircraft accurately in real time in any location Traditionally just over 70 of the world has no or very limited tracking capability making the goal of GADSS difficult at best to implement where it is needed most Much of the wording in the GADSS document implicates the growing use of Global Navigation Satellite Systems GNSS of which GPS is the US constellation The European Union constellation Galileo has as of December 2017 14 operational satellites of the planned 24 total Like GPS Galileo is worldwide and available for civil air navigation As Automatic Dependent Surveillance and Broadcast ADS B gains popularity as the preferred method for individual aircraft to report their position in 4 dimensions this aspect of aircraft tracking has an answer The remaining piece of the picture is the ability to receive process and transmit these position reports to any location In the USA the creation of the Wide Area Augmentation System WAAS to increase GPS accuracy sufficiently for vertical precision guidance in addition to the network of ground based transceiver sites for ADS B makes ATC and operator tracking even more accurate and timely than the current radar based system Other parts of the world have equivalent ground and space