Large Jet Aircraft Research Articles

Feasibility study on applying continuous descent operations in congested airspace with speed control functionality: Fixed flight-path angle descent

Continuous descent operations (CDO) are an efficient descent operation for passenger/cargo aircraft and implemented at various airports worldwide. However, it is difficult for air traffic controller (ATCo) to predict the CDO trajectory and control the CDO aircraft, therefore limiting the applicable window only during the low traffic periods. To maximize potential benefits by introducing the CDO, it is required to implement the CDO into congested airspace and time window. This study introduces an augmentation to CDO application in the congested airspace, called fixed flight-path angle (Fixed-FPA) descent. The fixed-FPA descent was originally proposed and investigated only for small passenger jet aircraft; thereafter the fixed-FPA descent was introduced to large passenger jet aircraft. This proposed procedure consists of several altitude restrictions along the arrival route. By following the altitude restrictions, the aircraft flies with a specified flight-path angle. Additionally, specifying the flight-path angle facilitates the prediction of the CDO trajectory by ATCo. Moreover, by setting a shallower flight-path angle compared with the conventional CDO, the fixed-FPA descent is capable of speed control. The preceding studies conducted only the preliminary feasibility study of the fixed-FPA descent on large jet aircraft. In this study, a series of full-flight simulator experiments and Monte Carlo simulations were conducted to assess the operational feasibility and demonstrate the capabilities of fixed-FPA descent. Experimental results demonstrated that the fixed-FPA descent meets the requirements for integrating the CDO into congested airspace, such that the vertical path of the CDO can be predicted by the ATCo, and the speed of the CDO aircraft is controllable. Additionally, the simulation results revealed that the fixed-FPA descent has better fuel efficiency than the conventional when the descending aircraft is required to delay its arrival time.

Kinematic Effects in Large Transport Aircraft

The control of an aircraft relies on sensory feedback. It follows that any aspect that could create a situation where that feedback is faulty can lead to unintended outcomes. The size of very large jet aircraft can result in kinematic effects that impact the perceptions of the flight crew. Due to the large amount of inertia involved, coupled with aerodynamic factors, when the aircraft pitch (θ) is initially changed, the short term actual motion of the aircraft, as viewed from the center of gravity, remains relatively unchanged. As a consequence of aircraft design, this results in the flight deck changing relative height as a consequence of the vertical rotation while the flight path stays relatively constant. Near to the ground (when external visual cues of height are most needed), a pilot may incorrectly believe that the aircraft flight path has changed when it has not. Furthermore, in large aircraft the eye-height of the pilot when landing is quite high, and thus increases the probability that the pilot will not be aware of relatively small changes in actual aircraft height. The aircraft pitch changes and large height off the ground can result in the pilot becoming unaware of the aircraft height during landing with serious consequences. Once recognized, all of these factors can be mitigated through training and visual aids. Further research should be conducted and pilots should be trained to recognize and mitigate the kinematic issues pertinent to large transport aircraft.

Radar target recognition based on the multi-resolution analysis theory and neural network

One-dimension range profile has recently been widely used as recognition feature in radar target recognition since it can be extracted easily. However, the one-dimension range profile of a target has strong dependence on the aspect-angle of the target because it is based on the model of scattering centers. On the other hand, the different classes of target samples overlap each other in the feature space, so satisfactory recognition results cannot be obtained directly for the targets under whole posture. In order to improve the recognition performance of systems based on one-dimension range profile, a method of radar target recognition based on the multi-resolution analysis theory and neural network is presented. Firstly, one-dimension range profile features under various resolutions are obtained by using multi-resolution analysis. Then, the tree-structured cascade SOM network – a hybrid neural network on the basis of the multi-resolution analysis theory and self-organizing map (SOM) – has been used as the classifier to make multi-grade judgment and recognition gradually for the one-dimension range profile features. The experimental results show that the average correct recognition rate for three kinds of targets – a propeller aircraft, a little jet aircraft and a large jet aircraft – with 0–180° posture variation in aspect-angle is up to 92.97%.

Research on Passengers Evaluation to Air Transport Service with Small Aircraft

In this paper, passengers evaluation to air transport service with small aircraft is analyzed. At first, passengers images to specific aircraft such as large jet aircraft, small jet aircraft, and small turbo-prop aircraft were compared. Then it was shown that small turbo-prop aircraft is especially evaluated as a lesser safety aircraft. Secondly, air transport service choice models were estimated, and the existence of negative effects of the service with small aircraft and with propeller aircraft was shown. Finally, sensitivity analysis was executed, and it was clear that the negative image of the turbo-prop aircraft can be supplemented with lower fare.

Minimum extinguishment area required for safe escape of aircraft occupants during a fuel spill fire

Massive fuel spill fires enveloping the fuselage of large jet aircraft may develop quickly following a crash or other accident. Under such circumstances, occupant survival time is short unless burn-through of the fuselage can be delayed. The authors propose an analytical method for determining the minimum fire area that must be extinguished in order to delay fuselage burn-through long enough to allow the occupants to escape.

A Statistical Analysis of Aircraft Maintenance Costs

This paper outlines the merits of the recursive regression model in analyzing aircraft-failure and manhour-cost data. The parameters of this model are estimated from maintenance data generated by the entire Boeing B-52 fleet during the period August 1965 to August 1966. Failure rates and manhours of repair are found to be a significant function of the calendar age of the aircraft, the length of the missions flown, the time spent in low-altitude flight, and the technological developments in newer aircraft. The estimated parameters are used to develop a marginal cost analysis that can be used by the decision maker in evaluating his maintenance operation. Although the paper is based on a specific military operation, the method outlined can be used to determine maintenance costs for any large jet aircraft.

Aircraft Electric Power System Performance as Affected by Transmission Line Impedances

The electric power transmission lines on large jet aircraft must be selected with the power system performance characteristics in mind as well as the conductor current carrying capabilities. Trade-offs between total system weight and system performance may be considered where long transmission lines are required. The main areas of performance that would be affected are system voltage transients, system ceiling voltage, system voltages during unbalanced load conditions and system protection.

Advertising and Marketing in the Airline Industry

IN I96I, the world airline industry moved from a period of precarious profitability into one of more or less certain loss. The chief single reason for this reversal of fortunes was the gross overproduction of capacity resulting from the introduction of large jet aircraft such as the Boeing 707. In I96I the capacity on offer by the industry was not even approximately matched by the traffic demand, and almost all major airlines showed a financial loss. It may be of interest therefore to examine the marketing processes of the industry (with special reference to Europe), and to display the strategies open to an airline to generate traffic against the background of the structure of the industry as a whole and the special factors which limit possible courses of action.