Analysis of noise in aircraft cabins through the VHF channel

Purpose - The purpose of this paper is to present a method to analyze the noise in aircraft cabins through the VHF Aeronautical Communication Channel, aimed at examining an environment that has the possibility of communication problems between the aircraft crew and the professionals responsible for the controls on land. Design/methodology/approach - This analysis includes equipment normally used for identification and comparison of electromagnetic noise, the cabin and the environment that are present in an airport, as well as equipment for frequency analysis and intensity of those signals. The analysis is done in a reverse way, eliminating situations that are not common in the examined environment, until the identification of the situation with the irregularity. Findings - According to the results, the implementation of the Fourier transform for noise analysis in the cabin was efficient. These results demonstrate that through this transformation, the noise sources can be identified in the environments in cases where there is much spectrum pollution. Research limitations/implications - This kind of noise analysis is important, considering the importance of having good accuracy in airport environment analysis. Originality/value - The paper presents the main trends in the future of aviation communications, and describes the new applications that aim to minimize problems with the current VHF channel.

An approach to aircraft seat comfort using interface pressure mapping

The objective of the present study is to propose a method to dynamically evaluate discomfort of a passenger seat by measuring the interface pressure between the occupant and the seat during the performance of the most common activities of a typical flight(1). This article reports the results of resting and reading studies performed in a simulator that represents the interior of a commercial aircraft.

Musculoskeletal reported symptoms among aircraft assembly workers: a multifactorial approach

The aim of this study was to evaluate factors associated with reported work-related musculoskeletal symptoms among aircraft assembly workers. Population consisted of 552 (491 men/61 women) workers who performed tasks related to the work of aircraft assembly. Participants completed a comprehensive questionnaire, including socio-demographic information, habits/lifestyles, working conditions, and work organization. Workers also answered the Nordic Musculoskeletal Questionnaire to obtain data on musculoskeletal symptoms. Multivariate logistic regression was performed to analyze factors associated with musculoskeletal reported symptoms. Results showed that body regions with the highest prevalence of reported musculoskeletal symptoms were similar when referred the past twelve months and the past seven days. Significant factors associated with musculoskeletal symptoms included variables related to conflicts at work, sleep problems, mental fatigue, and lack of time for personal care and recovery. Working time in the industry was associated only with reports for the last seven days and regular physical activity off-work seems to be a positive factor in preventing musculoskeletal symptoms for the past twelve months. The results highlight the multi-factorial nature of the problem. Actions to prevent musculoskeletal diseases at the aircraft assembly work should consider multiple interventions that would promote better recovery between work shifts.

Signal Transceiver Transit Times and Propagation Delay Corrections for Ranging and Georeferencing Applications

The accuracy of ranging measurements depends critically on the knowledge of time delays undergone by signals when retransmitted by a remote transponder and due to propagation effects. A new method determines these delays for every single pulsed signal transmission. It utilizes four ground-based reference stations, synchronized in time and installed at well-known geodesic coordinates and a repeater in space, carried by a satellite, balloon, aircraft, and so forth. Signal transmitted by one of the reference bases is retransmitted by the transponder, received back by the four bases, producing four ranging measurements which are processed to determine uniquely the time delays undergone in every retransmission process. A minimization function is derived comparing repeater's positions referred to at least two groups of three reference bases, providing the signal transit time at the repeater and propagation delays, providing the correct repeater position. The method is applicable to the transponder platform positioning and navigation, time synchronization of remote clocks, and location of targets. The algorithm has been demonstrated by simulations adopting a practical example with the transponder carried by an aircraft moving over bases on the ground.