Table of Contents
Introduction
In the aviation field, there is a notion of the flight risk commandments which include risk factors that are caused by the aircraft performance and considered to be aviation safety problems (Sánchez, 2007). The following safety problems grounded on these risk factors should be underlined:
a) risk of collision, since the aircraft at its cruise level moves at speed close to be the speed of sound, and time of reaction is limited if any object impacts;
b) risk of the fire explosion on the long flight, since the half of the aircraft’s weight is fuel, the reduction of which is impossible for sufficient performance;
c) all sorts of meteorological conditions that affect visibility, the build-up of ice on the wings causes electrical discharge making the takeoff and landing speeds close to 300 km/h and 200 km/h, respectively (Sánchez, 2007).
Since the manual interference in the operating process is based on the human factor and in some cases results in accidents, “fly-by-wire” systems are designed to prevent the airplane being taken outside of its flight envelope withstanding high speed and steep maneuvers (Bibel, 2007). Since implementation of the automated systems does not fully resolve the main safety problems, system humane-machine is not effective. There appears the notion of the “human-machine-human” work process that is designated to prevent casualties and provide the pilot with information needed when his actions are limited and could be assisted with operator’s help.
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Materials and Methods
Calculation implemented by the Worldwide Commercial Jet Fleet through 1959-2005 demonstrated the following statistics of the accidents and fatalities that happen on the all flight phases (Bibel, 2007). The figures are in the chart below.
According to the abovementioned statistics, the majority of the fatality cases happens at landing, climbing and approaches; therefore ground-proximity systems are needed to solve major problems. The issue is about compromise between safety and efficiency after the cost admission. Statistic’s calculations show that with the system’s implementation two crashes out of ten could have been avoided (Kovicar, 2001). Although there is a proliferation of the warning lights and bells, pilots, airlines and manufacturers conceded to add Ground Pox warning system, that goes on when the craft reaches 50-foot altitude and requires no adjustment or input from the crew and can’t be turned off (Kovicar, 2001).
On the other hand, the system has the following disadvantages: alarm signal switches off in the cases of excessive sink rate, excessive closeness of the obstacle, negative climb after takeoff, inadvertent proximity to the ground, plain flying below glide slope (Kovicar, 2001). EGTWS preceded the predecessor and was equipped with three intelligent software agents, which could plot a course around possible obstacle and presented a solution to the pilot on the cockpit display system or using autopilot (Lovrek & Howlett, 2008).
In cases when the pilot’s commands are not obeyed, his correlation with the operator becomes relevant and effective accident prevention becomes possible if the following consequence is possible: Operator is in command → effective command means being involved → being involved means being informed → be able to monitor the automated system → automated system must be predictable and accessible by the operator (Harris & Muir, 2009).
Results
The warning systems listed above still did not make contribution into the accident rate reduction. Thus the following conditions of the human-machine-human cooperation become relevant in order to prevent accidents: a) Operator transfers through the Airport radar two dangerous situations for the plane to the air-traffic controller, namely, if plane drops far below the glide slope in a landing approach and flies below a minimum altitude (McCormick & Papadakis, 2003); b) Instrument landing system is monitored by the operator and allows curved and parallel approaches by planes in any weather conditions if advised by the operator (Miller & Vandome, 2010); c) Ground-based sensors are monitored by the operator to keep safe distance between planes and provide wake turbulence avoidance (Nykl et al., 2011) and d) Operator is involved in the Airport surface-traffic control that helps to improve poor visibility in order to avoid collision (Nolen, 2010).
However, efficiency factors play a major role in the pilot’s decision making; for example, if the pilot obeys TCAS and chooses course deviation, it is often associated with longer flight time, higher fuel consumption and increased flight effort. Operator’s task is to establish Minimum Equipment List, to have access to the relevant data and record-keeping and to implement training and checking programs (Herris & Muir, 2009). Thus, we can make the statement that operator’s actions become indispensible when there is no sufficient cooperation between the pilot and machine and operator’s interference is needed to prevent accidents, since having decision-making priority.
Discussion
In some risk flight conditions the use of automated system instructions is merely effective to maintain safety conditions. For example, in case of dropping far below the glide slop and flying in the minimum altitude which may result in accident, to avoid this situation, pilot begins to close the throttle, eases the steering wheel deflecting the elevator up and increasing the angle of attack, but he would be reluctant to relay on the airport radar, fearing of the model error. However, the following facts should not be forgotten: takeoff run, flight path, final approach and landing (including landing roll) are at the discretion of the commander (Croucher, 2004). In these conditions operator can only assist, but not make orders to the pilot, since operator’s function activities are limited by the aviation law requirements. However, operator’s interference becomes important and reliable in the conditions of the system’s failure, since his performance is included in the design of the automated system and is based on the information distribution.
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The following actions could be suggested in cases of the flight risk situations from the operator for the pilot actions: a) using the discreet Address Beacon system to inform control tower of the possible clearance provision at time of initial approach; b) increasing angle of attack during high-speed landing; c) using instrument landing systems to recover normal position (Croucher, 2004).
Grounding our study on the basic notions of the Code of regulations and considering limitations that face operator being executor and instructor in the aviation safety program, it would be sufficient to specify the set of activities that determine existence of the program element of correlation between operator and pilot using automated systems (Croucher, 2004). For the full preciseness of the program element performance we recommend to make the following table:
| Code of regulation directions | Operator performance |
| To address one object group | To inform aircraft crew on the weather conditions |
| To occur in one phase | To estimate all the settings needed for the sufficient performance |
| To be responsible for achieving objectives | To provide briefing and checking of the operation and procedure |
| To be closely related to the other safety link element | To monitor aircraft navigation and automated settings as pilot does |
Table 1. Correspondence of general and aviation notions of the program element system
The abovementioned units of the discourse, such as aviation safety problems, pilot’s actions, operator’s performance and work correlation with automated systems are designed to embody program elements, executed by operator.