Near Midair Collisions as an Indicator of General Aviation Collision Risk


Book Description

"Conventional wisdom suggests aircraft midair collisions to be random events, governed by the laws of Brownian Motion, and best analyzed by stochastic methods. An alternative hypothesis, that such accidents are deterministic in nature, and that specific factors leading to midair collisions can be identified and mitigated, forms the basis for this Dissertation. A predictive model using case control theory is developed for assessing Risk Index, a criterion measure of midair collision likelihood, for any General Aviation flight, actual or hypothetical. Generating the model requires statistical validation of two independent near midair collision databases, and identifying within them those aircraft, aircrew and airspace characteristics most closely associated with collision risk. Calibration of the model shows reality to fall somewhere between the stochastic and deterministic assumptions. A statistically significant correlation is found between predicted and observed Risk Index for a sizable random sample of flights, with a resulting Coefficient of Determination of 0.25. This suggests that we have identified 25% of the source of variance in midair collision risk, the remaining 75% being random. Therefore we can realistically hope to reduce midair collisions by roughly 25%. Strategies for mitigating the identified causal factors are proposed. Measures to reduce the random, remaining 75% of collision risk are also explored. However, these appear to require a significant overhaul of Air Traffic Control procedures, which must be approached with caution, to guard against the attendant possibility of curtailing capacity in the Air Transportation System."--Page 1-2




Probabilistic-Statistical Approaches to the Prediction of Aircraft Navigation Systems Condition


Book Description

This book highlights the development of new methods for assessing and forecasting the state of various complex ageing systems in service; analyzing the influence of destabilizing factors on the accuracy of aircraft flight navigation support; and making recommendations on the ideal aircraft route, taking into consideration the available information on the reliability of the navigation and communication equipment.







Air Safety


Book Description

Pursuant to a congressional request, GAO provided information on the Federal Aviation Administration's (FAA) proposed Traffic Alert and Collision Avoidance System (TCAS), focusing on its: (1) safety benefits; (2) commercial prospects; and (3) development plans. GAO found that FAA: (1) designed TCAS to reduce the risk of mid-air collisions by providing pilots with an independent airborne backup to the FAA ground-based air traffic control system; (2) has three models which vary in cost, technical sophistication, and capacity, with TCAS III having the most risk-reduction capability; and (3) designed TCAS II to permit an easy, low-cost upgrade to TCAS III capability. GAO also found that FAA: (1) proposed legislation requiring installation of TCAS I in all jets with 10 to 19 passenger seats and installation of TCAS II and III in larger commercial aircraft; (2) did not conduct a safety study for TCAS I; (3) is currently performing safety studies of TCAS III after determining that TCAS II reduces the risk of near mid-air collisions by 58 percent; (4) believes that the avionics equipment manufacturing industry is capable of manufacturing TCAS equipment, but may not be able to meet the legislatively mandated deadline; and (5) is currently testing the operational capacity of TCAS II and III.










Safer Skies with TCAS


Book Description




Aircraft Collision Avoidance Systems


Book Description