Relative merits of reactive and forward-look detection for wind-shear encounters during landing approach for various microburst escape strategies

The goal was to quantify the benefits of airborne forward-look windshear detection and to develop and test a candidate set of strategies for recovery from inadvertent microburst encounters during the landing approach, given the utilization of both reactive-only and forward-look windshear detection. Candidate strategies were developed and evaluated using a non-piloted simulation consisting of a simple point-mass performance model of a transport-category airplane flying through an analytical microburst model. The results indicate that the factor which most strongly effects a microburst recovery is the time at which the recovery is initiated. Forward-look alerts given 10 seconds prior to microburst entry permitted recoveries to be made with negligible altitude loss. The results also show that no single microburst scenario can be used to evaluate the relative merits of various recovery strategies. The type of alert used to initiate the recovery (reactive or forward-look) and the altitude of the microburst encounter had an effect on the type of recovery strategy that performed best. These factors may have serious implications for the design and certification of windshear systems

Airborne derivation of microburst alerts from ground-based Terminal Doppler Weather Radar information: A flight evaluation

An element of the NASA/FAA windshear program is the integration of ground-based microburst information on the flight deck, to support airborne windshear alerting and microburst avoidance. NASA conducted a windshear flight test program in the summer of 1991 during which airborne processing of Terminal Doppler Weather Radar (TDWR) data was used to derive microburst alerts. Microburst information was extracted from TDWR, transmitted to a NASA Boeing 737 in flight via data link, and processed to estimate the windshear hazard level (F-factor) that would be experienced by the aircraft in each microburst. The microburst location and F-factor were used to derive a situation display and alerts. The situation display was successfully used to maneuver the aircraft for microburst penetrations, during which atmospheric 'truth' measurements were made. A total of 19 penetrations were made of TDWR-reported microburst locations, resulting in 18 airborne microburst alerts from the TDWR data and two microburst alerts from the airborne reactive windshear detection system. The primary factors affecting alerting performance were spatial offset of the flight path from the region of strongest shear, differences in TDWR measurement altitude and airplane penetration altitude, and variations in microburst outflow profiles. Predicted and measured F-factors agreed well in penetrations near microburst cores. Although improvements in airborne and ground processing of the TDWR measurements would be required to support an airborne executive-level alerting protocol, the practicality of airborne utilization of TDWR data link data has been demonstrated

Collection and analysis of radar rainfall and satellite data for the Darwin TRMM experiment

The following subject areas are covered: video cloud camera (purpose, design, operation, data); special observing periods (SOP-2, SOP 2.5 - an extension of SOP-2); Garand algorithm; and warm rain

A simulator investigation of the use of digital data link for pilot/ATC communications in a single pilot operation

Studies have shown that radio communications between pilots and air traffic control contribute to high pilot workload and are subject to various errors. These errors result from congestion on the voice radio channel, and missed and misunderstood messages. The use of digital data link has been proposed as a means of reducing this workload and error rate. A critical factor, however, in determining the potential benefit of data link will be the interface between future data link systems and the operator of those systems, both in the air and on the ground. The purpose of this effort was to evaluate the pilot interface with various levels of data link capability, in simulated general aviation, single-pilot instrument flight rule operations. Results show that the data link reduced demands on pilots' short-term memory, reduced the number of communication transmissions, and permitted the pilots to more easily allocate time to critical cockpit tasks while receiving air traffic control messages. The pilots who participated unanimously indicated a preference for data link communications over voice-only communications. There were, however, situations in which the pilot preferred the use of voice communications, and the ability for pilots to delay processing the data link messages, during high workload events, caused delays in the acknowledgement of messages to air traffic control

A Role for Management Accountants in Best Practice Benchmarking

Best practice benchmarking (benchmarking for short) generally refers to the pursuit by organisations of enhanced performance by learning from the successful practices of others. Comparisons of processes which contribute to strategic success are made with other parts of the same organisation; competitors; or organisations operating comparable processes in a context which is in some way relevant. Benchmarking continues to grow in popularity in both private and public sector organisations – but does it always produce the desired outcomes? Although spectacular gains from benchmarking are claimed particularly in practitioner literature, there is also growing evidence of disappointment with the effectiveness of benchmarking. It can be very time consuming to undertake and manage, and ensuring that sharing information with competitors is to the mutual advantage of partner organisations is difficult. With this in mind, it is important to recognise that management accountants play pivotal roles at organisational interfaces and therefore could play a (more) significant part in successful benchmarking activities. This paper will report on an ongoing research project at the Open University Business School, funded by the Chartered Institute of Management Accountants, aimed at understanding, in depth, the processes which are undertaken by Management Accountants, in the name of benchmarking. The project team are using postal questionnaires and case studies to identify the features of successful benchmarking practice, and the characteristics of benchmarking organisations or benchmarking processes which are considered to be problematic. This research centres on an extensive survey of Management Accountants. This research has begun to identify the contribution which Management Accountants can make to successful benchmarking and the factors which have led organisations to abandon benchmarking activities. This study is also facilitating better understanding of the relationship between organisational size and level of benchmarking activity, the impact of benchmarking clubs, and the perceived costs and benefits of benchmarking to stakeholders. The final phase 3 of this research will focus on providing innovative ways to make the findings available to management accounting practitioners

Slippery Slopes and Other Consequences

The aim of this paper is to illustrate where previous attempts at the characterisation of Slippery Slope Arguments (SSAs) have gone wrong, and to provide an analysis which better captures their true nature. The first part describes Walton’s [10] arguments in support of his views on SSAs and also considers the characterisations put forward by other researchers. All of these are found wanting due to their failure to capture the essence of the slippery slope and their inability to distinguish SSAs from other consequentialist forms of argument. The second part puts forward a clearer analysis of what is special about SSAs and proposes an argumentation scheme which allows them to be easily distinguished from other arguments from consequences

Occupational Estimates and Projections of the Omaha SMSA

Local and regional planners have long recognized the need for detailed information on past, present, and projected occupational needs. Ideally, data on: (I) the number of workers employed, (2) their years of job experience, (3) their years and type of job training, (4) the number of workers to retire in the near future, (5) the number of new workers needed due to expected expansion, and (6) the salary levels of the various occupations for each firm and industry in the local economy should be available to describe occupational patterns. Such information would also provide a sound framework for projecting changes in occupational needs. The type of information desired is not easily accessible and in many cases does not exist

Application of lightning data to satellite-based rainfall estimation

Information on lightning may improve rain estimates made from infrared images of a geostationary satellite. We address this proposition through a case from the Cooperative Huntsville Meteorological Experiment (COHMEX). During the afternoon and evening of 13 July 1986 waves of showers and thunderstorms developed over and near the lower Tennessee River Valley. For the shower and thunderstorm region within 200 km of the National Weather Service radar at Nashville, Tennessee, we measure cold-cloud area in a sequence of GOES infrared images covering all but the end of the shower and thunderstorm period. From observations of the NASA/Marshall direction-finding network in this small domain, we also count cloud-to-ground lightning flashes and, from scans of the Nashville radar, we calculate volume rain flux. Using a modified version of the Williams and Houze scheme, over an area within roughly 240 km of the radar (the large domain), we identify and track cold cloud systems. For these systems, over the large domain, we measure area and count flashes; over the small domain, we calculate volume rain flux. For a temperature threshold of 235K, peak cloud area over the small domain lags both peak rain flux and peak flash count by about four hours. At a threshold of 226K, the lag is about two hours. Flashes and flux are matched in phase. Over the large domain, nine storm systems occur. These range in size from 300 to 60,000 km(exp 2); in lifetime, from about 2 1/2 h to 6 h or more. Storm system area lags volume rain flux and flash count; nevertheless, it is linked with these variables. In essential respects the associations were the same when clouds were defined by a threshold of 226K. Tentatively, we conclude that flash counts complement infrared images in providing significant additional information on rain flux

Addendum to Interview: Film Proposal for the British Film Institute

This proposal by Siobhan Davies and David Hinton formed part of a submission to the BFI (British Film Institute, London UK). It outlines the collaboration between the two artists and the general idea of a film based on the 1917 Robert Walser story “The Walk.” The film was to be made entirely out of found footage and found photographs to create a “choreography of movement images” that would portray an individual consciousness. The proposal describes the overall idea, the deployment of Marey’s nineteenth-century chronophotographic films, the structure and key narrative elements, as well as different observational, analytical, and emotional threads of images. The proposal was submitted to the BFI in April 2012, and an agreement on the use of archive between the BFI and Siobhan Davies Dance Company was first issued in May and signed off in October 2012. The proposal is reproduced here with the permission of the two artists