10,410 research outputs found
Pilots' use of a traffic alert and collision-avoidance system (TCAS 2) in simulated air carrier operations. Volume 1: Methodology, summary and conclusions
Pilots' use of and responses to a traffic alert and collision-avoidance system (TCAS 2) in simulated air carrier line operations are described in Volume 1. TCAS 2 monitors the positions of nearby aircraft by means of transponder interrogation, and it commands a climb or descent when conflicting aircraft are projected to reach an unsafe closest point-of-approach within 20 to 25 seconds. A different level of information about the location of other air traffic was presented to each of three groups of flight crews during their execution of eight simulated air carrier flights. A fourth group of pilots flew the same segments without TCAS 2 equipment. Traffic conflicts were generated at intervals during the flights; many of the conflict aircraft were visible to the flight crews. The TCAS equipment successfully ameliorated the seriousness of all conflicts; three of four non-TCAS crews had hazardous encounters. Response times to TCAS maneuver commands did not differ as a function of the amount of information provided, nor did response accuracy. Differences in flight experience did not appear to contribute to the small performance differences observed. Pilots used the displays of conflicting traffic to maneuver to avoid unseen traffic before maneuver advisories were issued by the TCAS equipment. The results indicate: (1) that pilots utilize TCAS effectively within the response times allocated by the TCAS logic, and (2) that TCAS 2 is an effective collision avoidance device. Volume II contains the appendices referenced in Volume I, providing details of the experiment and the results, and the text of two reports written in support of the program
Pilots' use of a traffic alert and collision-avoidance system (TCAS 2) in simulated air carrier operations. Volume 2: Appendices
Pilots' use of and responses to a traffic alert and collision-avoidance system (TCAS 2) in simulated air carrier line operations are discribed in Volume 1. TCAS 2 monitors the positions of nearby aircraft by means of transponder interrogation, and it commands a climb or descent which conflicting aircraft are projected to reach an unsafe closest point-of-approach within 20 to 25 seconds. A different level of information about the location of other air traffic was presented to each of three groups of flight crews during their execution of eight simulated air carrier flights. A fourth group of pilots flew the same segments without TCAS 2 equipment. Traffic conflicts were generated at intervals during the flights; many of the conflict aircraft were visible to the flight crews. The TCAS equipment successfully ameliorated the seriousness of all conflicts; three of four non-TCAS crews had hazardous encounters. Response times to TCAS maneuver commands did not differ as a function of the amount of information provided, nor did response accuracy. Differences in flight experience did not appear to contribute to the small performance differences observed. Pilots used the displays of conflicting traffic to maneuver to avoid unseen traffic before maneuver advisories were issued by the TCAS equipment. The results indicate: (1) that pilots utilize TCAS effectively within the response times allocated by the TCAS logic, and (2) that TCAS 2 is an effective collision avoidance device. Volume 2 contains the appendices referenced in Volume 1, providing details of the experiment and the results, and the text of two reports written in support of the program
Modelling and performance analysis of four and eight element TCAS
This semi-annual report describes the work performed during the period September 1989 through March 1990. The first section presents a description of the effect of the engines of the Boeing 737-200 on the performance of a bottom mounted eight-element traffic alert and collision avoidance system (TCAS). The second section deals exclusively with a four element TCAS antenna. The model obtained to simulate the four element TCAS and new algorithms developed for studying its performance are described. The effect of location on its performance when mounted on top of a Boeing 737-200 operating at 1060 MHz is discussed. It was found that the four element TCAS generally does not perform as well as the eight element TCAS III
GANTouch: An Attack-Resilient Framework for Touch-based Continuous Authentication System
Previous studies have shown that commonly studied (vanilla) implementations
of touch-based continuous authentication systems (V-TCAS) are susceptible to
active adversarial attempts. This study presents a novel Generative Adversarial
Network assisted TCAS (G-TCAS) framework and compares it to the V-TCAS under
three active adversarial environments viz. Zero-effort, Population, and
Random-vector. The Zero-effort environment was implemented in two variations
viz. Zero-effort (same-dataset) and Zero-effort (cross-dataset). The first
involved a Zero-effort attack from the same dataset, while the second used
three different datasets. G-TCAS showed more resilience than V-TCAS under the
Population and Random-vector, the more damaging adversarial scenarios than the
Zero-effort. On average, the increase in the false accept rates (FARs) for
V-TCAS was much higher (27.5% and 21.5%) than for G-TCAS (14% and 12.5%) for
Population and Random-vector attacks, respectively. Moreover, we performed a
fairness analysis of TCAS for different genders and found TCAS to be fair
across genders. The findings suggest that we should evaluate TCAS under active
adversarial environments and affirm the usefulness of GANs in the TCAS
pipeline.Comment: 11 pages, 7 figures, 2 tables, 3 algorithms, in IEEE TBIOM 202
Cockpit data management
This study is a continuation of an FAA effort to alleviate the growing problems of assimilating and managing the flow of data and flight related information in the air transport flight deck. The nature and extent of known pilot interface problems arising from new NAS data management programs were determined by a comparative timeline analysis of crew tasking requirements. A baseline of crew tasking requirements was established for conventional and advanced flight decks operating in the current NAS environment and then compared to the requirements for operation in a future NAS environment emphasizing Mode-S data link and TCAS. Results showed that a CDU-based pilot interface for Mode-S data link substantially increased crew visual activity as compared to the baseline. It was concluded that alternative means of crew interface should be available during high visual workload phases of flight. Results for TCAS implementation showed substantial visual and motor tasking increases, and that there was little available time between crew tasks during a TCAS encounter. It was concluded that additional research should be undertaken to address issues of ATC coordination and the relative benefit of high workload TCAS features
Discussion on complexity and TCAS indicators for coherent safety net transitions
Transition between Separation Management in ATM
and Collision Avoidance constitutes a source of potential risks due
to non-coherent detection and resolution clearances between them.
To explore an operational integration between these two safety
nets, a complexity metric tailored for both Separation
Management and Collision Avoidance, based on the intrinsic
complexity, is proposed.
To establish the framework to compare the complexity metric with
current Collision Avoidance detection metrics, a basic pair-wise
encounter model has been considered. Then, main indicators for
horizontal detection of TCAS, i.e. tau and taumod, have been
contrasted with the complexity metric.
A simple method for determining the range locus for specific
TCAS tau values, depending on relative speeds and encounter
angles, was defined. In addition, range values when detection
thresholds were infringed have been found to be similar, as well as
its sensitivity to relative angles.
Further work should be conducted for establishing a framework
for the evaluation and validation of this complexity metric. This
paper defines basic principles for an extended evaluation,
including multi-encounter scenarios and longer look ahead times
- …