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PurposeThis paper aims to investigate the addition of airdrop capability to a commuter aircraft and its consequences on the reversible flight control system.Design/methodology/approachAirdrop was modeled to include its effect on aerodynamics and flight control system. A mathematical model was also developed for the reversible longitudinal flight control system of a regional commuter aircraft using the available geometry, mass property and kinematics. The model was incorporated into a general multi‐body dynamics code and validated using existing manufacturer's data which included recorded data from flight. The airdrop simulation results showed that the flight control system is affected in two steps. In the first step, the movement of the load required a forward force by the pilot. In this step, the elevator power was a key factor and had to be increased to allow the pilot to keep the aircraft in trim position during the airdrop. In the second step, a sudden forward shift of centre of gravity required an abrupt change in the direction of applied force. The maximum allowable force and control column movement had to be checked. In the case under study, they did not impose any difficulty.FindingsThe result showed that a special consideration had to be taken into account when an aircraft with reversible flight control system was to be used for airdrop mission.Originality/valueThis paper investigates the behaviour of a reversible flight control system during airdrop operation through analysis and simulation.

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this paper provides a parameter sensitivity analysis for an Inverted F antenna mounted on a cylindrical conducting body with a conical nose. Since the dimensions of such an antenna is not unique and considering necessary specifications, such as bandwidth, gain, input impedance and radiation pattern, design of the appropriate antenna is a compromise between different variables. Designed antennas were simulated using a full wave simulator and their radiation patterns and return loss were studied. The simulated data were compared with measurement results.

Introduction: Pilot performance investigation during multi-tasking operations requires a procedure, in which the parameters related to the desired scenario of the simulator are obtained in a systematic manner. The multi-attribute task battery (MATB-II) is a standard simulator of generic piloting tasks developed by national aeronautics and space administration (NASA). Methods: Employing information theory concepts, baud rate generated in all subsystems of the MATB-II were calculated and then, a unique numerical index presenting an estimation of overall workload was extracted. In the next step, three tests with different levels of workload were conducted to examine the validity of the offered criteria. These tests were performed by a group of subjects on the role of human pilots, while recording their own experiences about perceived workload via NASA-TLX. Results: The results confirmed that there were significant differences between averages of scores assigned by subjects to the total workload, for three levels of difficulty defined based on information theory (P-value < 0.001). This variable shows considerable growth from low to medium and from medium to high categories of workload level. Conclusions: The proposed quantitative index is effective enough for determination of workload levels in the MATB-II simulator.