ADS-B: Probabilistic Safety Assessment

Abstract

In the effort to quantify Automatic Dependent Surveillance Broadcast (ADS-B) system safety, the authors have identified potential ADS-B failure modes in Syd Ali et al. (2014). Based on the findings, six potential hazards of ADS-B are identified in this paper. The authors then applied the Probabilistic Safety Assessment approach which includes Fault Tree Analysis (FTA) and Importance Analysis methods to quantify the system safety. FTA is applied to measure ADS-B system availability for each identified hazard while Importance Analysis is conducted to identify the most significant failure modes that may lead to the occurrence of the hazards. In addition, risk significance and safety significance of each failure mode are also identified. The result shows that the availability for the ADS-B system as a sole surveillance means is low at 0·898 in comparison to the availability of ADS-B system as supplemental or as primary means of surveillance at 0·95 and 0·999 respectively. The latter availability values are obtained from Minimum Aviation System Performance Standards (MASPS) for Automatic Dependent Surveillance-Broadcast (DO-242A).

Probabilistic Safety Assessment for UAS Separation Assurance and Collision Avoidance Systems

“…As already mentioned in Section 1.1, the qualitative analysis involved in the FTA methodology lists all the possible combinations of factors, normal events and component failures resulting in a top event, whereas the quantitative evaluation allows to determine the probability of failure of the top event from the failure probability values of basic events that propagated up through the fault tree. The reliability data or the failure rate of the components is crucial for FTA and is obtained from component manufacturers (typically in the form of mean time between failures-MTBF) and/or from the literature, including among others Aviation Standard Documents by RTCA, FAA and Eurocontrol [37,49,[52][53][54][55][56]. The basic events represent component failures and the logic gates dictate how faults of the particular component within the system can combine to result in the failure in the top event.…”

“…The FAA conducted a safety assessment on the TCAS application in the unmanned platforms [34][35][36]. A thorough probabilistic safety assessment has been carried out on ADS-B system considering both the ground and airborne segment in [37]. Safety assessment of the surveillance sensor failure in the UAS platform was carried out in [38] with an encounter analysis considering the unmanned aircraft platform only.…”

“…Misleading Information from ADS-B Function × 10 as in [38] AO 6 Transponder Jamming × 10 as in [37] AO 1A…”

“…Loss of Geometry from Satellite × 10 as in [37] AO 1B GPS Receiver Malfunction × 10 as in [37] AO 1C GPS Antenna Failure × 10 as in [37] AO 1D Jamming of Satellite × 10 as in [37]…”

“…aviation standard documents and Original Equipment Manufacturer (OEM) and presented in Table Basic Execution Function Failure × 10 as in [49] DAA 5A Command Datalink Failure (Loss of Function) × 10 as in [49] DAA 5B Command Datalink Failure (Unannounciated Failure) × 10 as in [49] AS 1/TC-3/AO 3A /AO 3B/MS-3 Transponder Failure (Main/Backup) × 10 as in [61] AS 2/MS-2 Misleading Information from Mode S Function × 10 as in [38] AI 1 Failure in ADS-B In Receiver × 10 as in [37] AI 2 Failure in Report Assembly Module × 10 as in [37] AI 3/AO 2 Loss of Function of ADS-B System × 10 as in [38] TC 1 Failure in Radio Altimeter × 10 as in [38] TC 2 Failure in Traffic Collison Avoidance System (TCAS) Function × 10 as in [36] AAR 1 Air-to-Air Radar (Loss of Function) × 10 as in [62] AAR 2 Air-to-Air Radar (Unannounciated Function) × 10 as in [62] VS 1 Electronics Failure × 10 as in [63] VS 2 Optical Failure × 10 as in [64] VS 3 Vision Logic Failure (Data processing failure) × 10 as in [61]…”