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IN a previous article (Ref. 1, 1966), Chichester‐Miles of H.S.A. discussed some of the advantages and opportunities offered by the use of V.T.O.L. aircraft in short haul air transport. In a more recent article (Ref. 2, 1969), Boorer and Davey of B.A.C. reviewed the characteristics and some of the operational problems of V/S.T.O.L. aircraft, and argued in favour of initial civil S.T.O.L. aircraft leading to V.T.O.L. developments as an effective part of the overall ground and air transport system of the 1970s, on the basis of a foreseeable market demand for such aircraft at ranges between 50 and 300 miles. Quoting from their conclusions: ‘S.T.O.L. commercial operations appear therefore to be just around the corner. V.T.O.L. commercial operations may be a decade or so away but, as and when a S.T.O.L. inter‐city transport system develops, the improvement of S.T.O.L. performance toward V.T.O.L. may well become attractive and perhaps even necessary.’

IN wishing all our readers happiness and prosperity throughout 1973 we are very conscious of the fact that it is a climateric year for the people of these islands. As these words are read we shall be a part of the European Economic Community.

This paper aims to explore and demonstrate how the meme of aspiration can help guide human cultures through an epochal transformation triggered by a global megacrisis and leading to sustainable maturation of human cultures.

Aspirational futures process, intuition-based visioning and “Type II” thinking that has high credibility for knowledgeable experts but low credibility to most others.

Megacrisis is a Type II wild card needing anticipatory mitigation via strategies such as are suggested. While descent paths may be a suitable meme for technical professionals, ascent paths to higher levels of civilizational maturity are a better guiding image for the public. Aspirational methods whose core involves intuition-based creativity, wisdom and co-creative emergence are a vital complement to rational/analytic futures methods, especially in times of epochal change and uncertainty when a new “regime” of guiding world views, institutional processes and innovative technologies may emerge.

Results represent a high degree of uncertainly as well as “fringe” thinking needing to be more widely considered.

Strategic suggestions based on Type II thinking are a unique category for “leading edge” funding and application.

The Type II perspective offered here is unique and offers a promising approach for transformative megacrisis mitigation.

This paper aims to investigate the effects of descent time spent with flaps extended on fuel burn (FB) and specific range for five different flight path angles (FPAs) ranging between 2.0° and 4.0° for a commercial aircraft.

A large data set of actual flight data (n = 475) of the same type of a frequently used commercial aircraft were investigated by using statistical methods.

The result of the comparison of the highest and the lowest FBs of flight profiles for each FPAs present that the fuel saving was achieved by keeping at as a high airspeed as possible and deploying flaps as late as possible, which is in line with the objective of delayed deceleration approaches. From analyzing the flight profiles, it was proven that delaying deceleration and also descending without flaps or with flap over a shorter time resulted in less FB of 101.1, 70.9 and 94.9 kg for FPA 2.5°, FPA 3.0° and FPA 3.5°, respectively.

This study differs from prior studies because it focused on the effects of the different vertical profiles on FB. Also, the use of real flight data recorder data in the analysis presents the originality of this study.

Since many global path planning algorithms cannot achieve the planned path with both safety and economy, this study aims to propose a path planning method for unmanned vehicles with a controllable distance from obstacles.

First, combining satellite image and the Voronoi field algorithm (VFA) generates rasterized environmental information and establishes navigation area boundary. Second, establishing a hazard function associated with navigation area boundary improves the evaluation function of the A^* algorithm and uses the improved A^* algorithm for global path planning. Finally, to reduce the number of redundant nodes in the planned path and smooth the path, node optimization and gradient descent method (GDM) are used. Then, a continuous smooth path that meets the actual navigation requirements of unmanned vehicle is obtained.

The simulation experiment proved that the proposed global path planning method can realize the control of the distance between the planned path and the obstacle by setting different navigation area boundaries. The node reduction rate is between 33.52% and 73.15%, and the smoothness meets the navigation requirements. This method is reasonable and effective in the global path planning process of unmanned vehicle and can provide reference to unmanned vehicles’ autonomous obstacle avoidance decision-making.

This study establishes navigation area boundary for the environment based on the VFA and uses the improved A* algorithm to generate a navigation path that takes into account both safety and economy. This study also proposes a method to solve the redundancy of grid environment path nodes and large-angle steering and to smooth the path to improve the applicability of the proposed global path planning method. The proposed global path planning method solves the requirements of path safety and smoothness.

Continuous descent approach (CDA) is a method, which allows the aircraft flying its individual optimal vertical profile down to runway threshold with engines operating at low‐thrust power. The main objective of this paper is to provide less‐fuel consumption, less noise and less emission with using CDA procedures instead of conventional procedures.

Conventional and CDA procedures were modelled in the Istanbul terminal area (TMA), which has five entry points. The real speed and the real altitude limitations were maintained on these entry points. System for Assessing Aviation's Global Emissions research results were also used to determine the emission savings.

With CDA procedures, more than 40 kg fuel and 2 min time savings per flight are obtained; furthermore, regarding CO₂ and H₂O, significant emission savings are also noted.

Some of the benefits of CDA procedures are reported for Istanbul TMA by using true flight data.

AT the present day the operations of civil transport aeroplanes are severely restricted under conditions of poor visibility and not infrequently flights have to be diverted or cancelled. The work of the Blind Landing Experimental Unit of the Ministry of Aviation in the development of a system of automatic landing for military aircraft has been described elsewhere.1 A flight control system is described in this paper, which given the necessary azimuth guidance signals from ground based installations, will extend the advantages of automatic landings into the civil field.

The purpose of this paper is to create a new fuel flow rate model using cuckoo search algorithm (CSA) for the descending stage of the flight.

Using the actual flight data record data of the B737-800 aircraft, a new fuel flow rate model has been developed for this aircraft type. The created model is to predict the fuel flow rate with high accuracy depending on the altitude and true airspeed. In addition, the CSA fuel flow rate model was used to calculate the fuel consumption for the point merge system, which is used for combining the initial approach to the final approach at Istanbul Airport, the largest airport of Turkey.

As a result of the analysis, the correlation coefficient value is found as 0.996858 for Flight 1, 0.998548 for Flight 2, 0.995363 and 0.997351 for Flight 3 and Flight 4, respectively. The values that are so close to 1 indicate that the model predicts the real fuel flow rate data with high accuracy.

This model is considered to be useful in air traffic management decision support systems, aircraft performance models, models used for trajectory prediction and strategies used by the aviation community to reduce fuel consumption and related emissions.

The importance of this study lies in the fact that to the best of the authors’ knowledge, it is the first fuel flow rate model developed using CSA for the descent stage in the existing literature; the data set used is real values.

THE guidance aid installed at most of the world's major airports is the Instrument Landing System which is currently being developed to cater for all phases of all weather landing programmes. For this application, the system has to achieve a guaranteed performance of less than one failure in ten million landings, thus inferring high equipment reliability and integrity. The VHF ground system at present installed consists of a localiser to provide azimuth guidance, a glide path transmitter to provide pitch guidance and marker beacons to give position information at distances of about 5 miles and one mile from touchdown. The guidance signals are formed by modulating two overlapping beams of different frequencies such that when the aircraft is on the extension of the runway centre line, equal modulations are received. This is termed zero difference in depth of modulation contour. The glide path signal is formed in a similar way with the zero contour defining a descent path angle of 3 degrees to the runway touchdown point. In the aircraft, the ILS receivers separate the demodulated tones by filters, and they are then rectified and compared differentially.

The purpose of this paper is to create a new fuel flow rate model for the descent phase of the flight using particle swarm optimization (PSO).

A new fuel flow rate model was developed for the descent phase of the B737-800 aircraft, which is frequently used in commercial air transport using PSO method. For the analysis, the actual flight data records (FDRs) data containing the fuel flow rate, speed, altitude, engine speed, time and many more data were used. In this regard, an empirical formula has been created that gives real fuel flow rate values as a function of altitude and true airspeed. In addition, in the fuel flow rate predictions made for the descent phase of the specified aircraft, a different model has been created that can be used without any optimization process when FDR data are not available for a specific aircraft take-off weight condition.

The error analysis applied to the models showed that both models predict real fuel flow rate values with high precision.

Because of the high accuracy of the PSO model, it is thought to be useful in air traffic management, decision support systems, models used for trajectory prediction, aircraft performance models, strategies used to reduce fuel consumption and emissions because of fuel consumption.

This study is the first fuel flow rate model for descent flight using PSO algorithm. The use of real FDR data in the analysis shows the originality of this study.