The principle of sophisticated aircraft controls. Sci.
The principle of sophisticated aircraft controls. Sci.

The principle of sophisticated aircraft controls. Sci.


One way to implement the principle of the actual operationalization is to create complex controls so that the involvement of an operational simply can not, for example, controls that need to manipulate the multi-step procedure, carried out both hands with fine motor coordination. The corresponding design principle may be called the principle of complicated controls.

As a methodological note, I would like to note that the construction of a complicated element must be such that preparatory steps can not be performed in advance, as is often done, for example, with the chassis control element: the flight mechanic in advance, before the issuing team prepares for it, removes the clamp Toggle switch and, when the command is given, it only presses the toggle switch. The element, thus, being a multi-step construction, is actually one-step. Therefore, in order to remove from the pilot the possibility of making "constructive" changes in the organization of the controls, each step of the procedure must be done "basic": if the pilot has started to perform the procedure, then he must perform it until the end, if he interrupted its implementation, The element must itself return to its original position. A concrete example of the implementation of the principle of complicating control elements is the chassis control scheme IL-14: To release or retract the landing gear, you need both hands to perform four-step, requiring fine coordination procedure.


Engaging the wrong control when fragmented regulation can be considered as the involvement required if the regulation is based on the characteristics that are similar in both elements. Hence, in order to prevent cases of unconscious entanglement will serve creation of controls that do not have similar characteristics as the involvement of the unnecessary control will always rassoglasovyvatsya program, no matter how fragmented it is.

For example, on a twin-engine aircraft, two control elements performing the same function, but with respect to different engines, it is advisable to make different designs. This technique violates the principle of symmetry, usually realized in modern consoles, when two controls with the same functions differ only in space relative to the axis of symmetry. But symmetry has the disadvantage that two elements differ in only one parameter. It is about creating completely different elements, since the content of the fragment of representation in the pilot's consciousness can be very poor, and therefore the presence of any similarity in the elements can provoke non-discrimination. The following case speaks about the fact that the minimal similarity can cause an error.

On boarding, the flight mechanic, at the command of the commander of the ship, should, by means of a tumbler, release the flaps at an angle of 38 ° at a certain point, of which the flight mechanic is very knowledgeable. At the required moment, the commander, referring to the command to release flaps, ordered: "38 °" Another full-time team, except for '' Release the flaps on 38 ° ', at this point can not be and the commander is sure that the mechanic knows this perfectly. But the mechanic at this moment, watching the work of the engines, looked at the indicator of the position of the fuel levers (URPT) - the position of the levers is measured in degrees, and regulated by the engine control levers (ODR) - and held a hand on the throttle. In response to the command, the flight mechanic began to move the throttle to the position 38 °, thereby increasing the speed of the flight. And only after instructions of the commander, who noticed a sharp increase in speed, the flight mechanic realized what was being done (and, I must add, was horrified).


The requirement for the elimination of the similarity can be formulated as the principle of the unique controls. Less stringent requirement is to create the most distinct controls (coding form, color, etc.).


Can serve as a means of operationalising such controls, which, being simple enough to allow the manipulation at the operational level in the case of the correct execution of the procedures would be turned into complex in the case of mistaken its implementation, thereby transforming procedure to the status of the action.


This can be achieved, difficult or impossible to activation of control that currently do not use, because the difficulties in the implementation of the procedure leading to the realization of its implementation. Considered reception effectively means that control as it has at the same time two opposing features two modes: simplicity and complexity. The principle of requiring the implementation of this method of struggle with mistakes, called the principle of bimodal controls.


Embodiment "in the metal" principles sophisticated and unique controls are fairly obvious, as a way to implement the principle of bimodal control is less obvious, so consider the possible implementation of this principle in relation to the control gear.


In this case, the blocking of the position of the control - the toggle switch - can respond to the requirement for bimodality of the control. If after releasing the chassis and setting the toggle switch to a certain position, it can not be moved (in a situation where it is not possible to remove the chassis), then an inconclusive attempt to activate it, i.e. Difficulty in the implementation of the procedure, will necessarily lead to a special attention paid to this element, and consequently, to awareness of the error. Since the chassis is cleaned only on take-off or take-off on the second lap, i.e. When the maximum mode is set to the engines, the chassis switch can be locked with the extreme (maximum) position of the throttle so that the chassis can be removed only at maximum rpm. This lock achieves the goal, since landing even on one engine is not performed with the engine full load, i.e. Control levers in this extreme position.

In the event that a take-off or missed approach occurs on the same engine, the interlock must be designed so that it is removed when any of the throttle positions are at a maximum. This design of the chassis control allows you to make the procedure of harvesting-releasing the chassis one-step, i.e. Achieving maximum simplicity and convenience with high reliability. But there is still the possibility of accidental (jacket sleeve, when the plane is shaking, etc.) to activate the switch "Chassis", if it is in the "Cleaning" position, i.e. Accidental release of the chassis at a time when it is not required. There are many ways to prevent accidental activation: block this position, put a limiter (latch, cap, etc.), distribute the cleaning and release procedures between the two controls, and so on.


However, that's not all. When the chassis in flight is not released for technical reasons, it is recommended to perform several cycles of harvesting-release in the expectation that the second, third, etc., once the chassis will exit. But if there is a bimodal element of the design that is described above, then every time before cleaning, put the throttle on a maximum, and this is undesirable (increasing the load on the engine, increasing the speed of flight, etc.). For such cases, it is necessary to provide a manual emergency because the emergency situation itself - the removal of the lock. It should be noted that the element of emergency control of the chassis is currently available on all aircraft. But if the lock is disconnected for the entire time since the corresponding emergency control element is activated, it will be possible to unknowingly entangle the screws and chassis controls on the run. To avoid this, you need to limit the unlocking time: for example, make sure that the movement of the chassis toggle switch from the Release position automatically turns on the lock.


The proposed construction of a bimodal control gear not only provides the correct execution of the procedure, but also the absence of migration bugs that the emergence of new errors in the disappearance of old ones, as sometimes happens.

The above design principles (Specialized-coercive alarm, sophisticated, unique and bimodal controls), of course, do not form a complete set of all the principles. We consider these principles are mainly for illustration of possible directions of the structural specification of the operationalization of the principle. The choice for the implementation of a principle depends on many circumstances.


Some examples of failed methods of struggle with mistakes

The lack of analysis of the internal plan of the pilot could lead to errors in the study recommendations unsatisfactory. Consider a few examples.

Famous American aviation psychologists P. Fitts and R. Jones collected a fairly large array of descriptions of entanglement errors made by the pilot. But the collection of material by these researchers was limited to obtaining descriptions of only the outwardly expressed part of the activity. As a result of the analysis of these descriptions, P. Fitts and R. Jones came to the conclusion that the following factors are the basis for entanglement errors: the lack of uniformity in the placement of controls on different types of aircraft, the proximity of controls to each other, a specific sequence of operations, the similarity of control design . Since each of the factors, according to P. Fitts and R. Jones, complicates the pilot's work (it is necessary to adapt to the diversity of controls on different planes, special efforts are needed to distinguish between closely spaced elements, it is necessary to deal with automatisms in the sequence of activation, it is necessary to distinguish similar elements), then its (work) is required to ease, which will lead to a decrease in the number of errors. The most adequate way to facilitate, in the opinion of P. Fitts and R. Jones, is simplification. 


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