All planning errors are, practically speaking, errors in problem solving. A problem is any situation that requires a person to revise their current line of action. As previously discussed, people have a strong bias to search for and find a prepackaged solution to problems (i.e., use RB performance) before resorting to the more mentally-intense solution from first principles (i.e., use KB performance). A mistake is a failure in detecting and using rules, or in solving problems from first principles.

　

When a person deliberately violates rules or plans, the person is committing a violation rather than a mistake. Accordingly, if it is determined that the person was consciously aware of a rule or plan applicable to the situation, but did something else, the unsafe act or decision should be classified as a violation.

　

NOTE: Natural human behavior is to rationalize past mistakes. For whatever reason, witnesses often find it embarrassing to admit that they simply did not know what to do, or that their plans were fundamentally flawed. Instead, they will often rationalize that they were aware of applicable rules or plans, but made an error in judgment. Extreme caution should be used in relying solely upon a mariner's own testimony about their decisions. Instead, an evaluation of the mariner's general level of knowledge and experience should be made. From this evaluation, the mariner's likely awareness of the rules or plans applicable to the situation can be inferred.

　

A violation is a deliberate decision to break established rules, procedures, or plans applicable to a specific problem regardless of the reason.

　

In many cases a plan, rule, or procedure will exist which purports to deal with a specific problem (ex.: Shipboard Oil Pollution Emergency Plan). The plans, protocols, or rules are often vague in regard to specific actions. In order to qualify as a violation, the person must deliberately decide to violate the specific action called for. If no specific action is called for (i.e., the action is up to the mariner's judgment), the unsafe act or decision is more likely a mistake than a violation.

　

As previously discussed, people execute decisions primarily in SB performance, but they make those decisions in RB or KB performance. Violations are deliberate decisions to depart from legitimate problem solving. Mistakes are misperformances of legitimate RB and KB problem solving. Depending on the type of problem, a planning error may occur in either RB-performance or KB-performance. Generally speaking, people search furiously for RB solutions to a given problem. In doing so, they (a) match observations to a rule based criteria, and (b) try the rule out. When a particularly difficult problem arises, people will try many rules, refining their observations and so on, trying to solve the problem. In these cases, RB performance may fail, and the person may switch to KB performance. Common examples of RB mistakes and KB mistakes are listed below.

　

The following information details RB and KB mistakes.

　

In any given problem or situation, rides can be thought of as competing for the right to represent the current state of the world (in the person's mind). In this way, the human mind is a "parallel processor" in that several rules can be "active" at the same time and competing with one another. A given rule's success in winning in a person's mind depends on several factors, including:

　

Rules are organized according to a hierarchy beginning with the most general rule. Exceptions and special cases are organized beneath this top layer. Problems in selecting a rule can arise anywhere in this morass of general and specific rules competing for selection in a person's mind. For ease of organization, the common RB mistakes can be organized into (a) use of a bad rule, and(b) misuse of a good rule.

　

A Bad Rule is one where the rule itself is faulty for some reason. In this regard, because rules have two parts (1) matching the situation and (2) providing a line of action to solve the problem. A bad rule may be faulty in either of these two areas. This section describes some common mistakes based on application of bad rules. The classifications below the level of 'use of a bad rule' are required ONLY in formal investigations.

　

VII.D.1.a.i. Wrong Rule (required only for Formal investigations)

Definition: "The "wrongness" in this type of error stems from a defect or weakness in the strategy of the rule itself. Basically, the person is faithfully completing an action sequence which is faulty, either because it is inherently flawed or because their internal description of the action is wrong (i.e., they don't understand the idea properly)." [Reason: 83-84]

Example: Three riggers on a platform were moving an air tugger on deck with steel pry bars. After moving the tugger, a rigger set the pry bar down on an energized extension cord that ran to an electric grinder. The bar pierced the cord insulation and the rigger was electrocuted. The plan to use pry bars near an energized electric cord was faulty.

Summary: The defining characteristic of a wrong rule error is that a rule choice is deemed incorrect because the plan or structure of the rule is flawed.

　

VII.D.1.a.ii. Irrelevant or Clumsy Rule (required only for Formal Investigations)

Definition: "Many problems afford the opportunity for multiple routes to a solution. Some routes are elegant, efficient, and direct; others are not. Without the benefit of expert instruction or because one is operating in a forgiving environment, a person might use solutions that are clumsy, circuitous or even bizarre. These rules do work, and may even become established as part of our rule-based procedures. Interestingly, often these inelegant or clumsy rules have inelegant or clumsy skill-based routines associated with them." [Reason: 84]

Common Example: The striking of a "sticky" valve handle, with a hammer or heavy screw driver, in order to loosen the valve so it can be adjusted, is an inelegant and even harmful work practice that people keep as their rule for the situation; the rule can even become an "unofficial" procedure passed from worker to worker.

Summary: The defining characteristic of an inelegant or clumsy rule is that an inefficient rule is permitted to flourish because checks within the operating environment do not exist or have not functioned properly.

　

VII.D.1.a.iii. Inadvisable Rule (required only for Format Investigations)

Definition: "Some rule-based strategies are perfectly adequate to achieve their immediate goal most of the time, but continuing to use them in the long run is inadvisable because it can lead to avoidable incidents.

Typically, this type of rule violates established codes or operating procedures, but is not "bad" because it is inelegant or because it fails to achieve its immediate objectives. Instead the rule's "badness" stems from the fact that it creates some risk, usually not related to the goal or problem, and in the long run will result in an accident." [Reason: 84-85]

Example: A boiler was washed out, left to dry, and then sealed up for some time. When the manhole plate was removed, an engineer entered at once and died from oxygen deprivation. Although rust rarely depletes oxygen to unsafe levels, the practice of entering a confined space without ventilating and testing ultimately proved deadly.

Summary: The defining characteristics of an inadvisable rule are: i) although the rule works, there is high incident risk associated with its use; and ii) the rule breaches established procedures, standards, etc.

　

A Good Rule is a rule that has been proven to be useful in a particular situations Nonetheless, a person might choose the wrong rule for the situation because two rules are available that appear to match the situation but have very different required actions. This section deals with common mistakes people make selecting good rules that are wrong for the situation The classifications below the level of 'misuse of a good rule' are required ONLY in formal investigations.

　

VII.D.1.b.i. Rule Strength (required only for Formal investigations)

Definition: "Rules "compete" to provide a description (or prediction) of a problem. The success or failure of a given rule in that competition depends not only on how well it's situational elements match the signs in the situation, but also on how successful the rule has been in the past. The more victories a rule has, the stronger the rule becomes. In turn, the stronger the rule, the more likely it will be chosen, even when the match between the situation (signs) and the rule (situational elements) are less than perfect. Note that a rule need not match all of the signs people tend to accept partial matches." [Reason: 77]

Example: While selecting a course for leaving Auke Bay, AK, in a friend's fishing boat, a local fisher takes a "short cut" outside the channel by maneuvering between the shore and a small island, thereby saving time. The fisher is using a rule "if your draft is sufficiently small, you are safe to use the short cut; if you are safe to use the short cut, use it to save time." Because the fishing vessel has a deeper draft than the boat he usually uses, the vessel grounds. The fisher has ignored the partial mismatch between the situation and the rule because of the rule's strength (many previous successes).

Summary: The defining characteristic of a rule strength error is that an incorrect rule for the situation is chosen because it has been used successfully frequently in the past.

　

VII.D.1.b.ii General Rule (required only for Formal investigations)

Definition: "Rules are organized into a "hierarchy," meaning that specific "child" rules or exceptions are organized beneath more general or "parent" rules. Because exceptions are (by definition) exceptional, they are less frequently encountered than the more general "parent" rule. Although in some situations lower-level rules do in fact acquire greater strength than higher-level rules, it is more likely that the general rule will be stronger than specific rules simply because they are encountered more frequently in the world. [Reason: 77]

Example: Rudder orders on cruise ships are given in small increments to avoid heeling (which causes passenger-jarring and soup-spilling). The deck officer is using the general rule "If you can't get there on a straight line, a turn is needed; if a turn is needed, turn very slowly so as to avoid soup-spilling." While maneuvering a cruise ship through the fog into a narrow, doglegged channel, the deck officer orders starboard rudder in 5-degree increments. The bow turns too slowly, and then the vessel misses its turn. The vessel goes aground on a pinnacle rock, punches in the bulbous bow, holes the vessel at several locations down the port side and rips off the port screw. The exceptional (lower-level) rule "If the channel is narrow and turns sharply, a soft turn won't work; if a soft turn won't work, push to bow over then ease the rudder when you know the ship is turning," was weaker than the general rule, and therefore was not selected.

Summary: The defining characteristic of a General Rule error is that an incorrect rule for the situation is chosen because of its greater frequency of occurrence.

　

VII.D.1.b.iii. Informational Overload (required only for Formalinvestigations)

Definition: "The amount of information confronting the decision-maker is so abundant that it exceeds the capacity of the cognitive system to capture and process all indications of the local situation. In other words, information is so abundant that people cannot distinguish signs, countersigns, and non-signs. People will tend to pay attention to some information, ignoring others. Further, even the information they pay attention to may meet the situational elements of several rules. Without specific information about the true local situation, people may revert to other "Misapplication of Good Rules" errors, such as rule strength or a general rule, i.e. they would be inappropriate for this particular situation." [Reason: 77]

Example: While coming into a busy harbor at night, the operator of an uninspected passenger vessel sees a number of green, red, and white lights ahead. Being unfamiliar with the harbor, he is unable to distinguish at a distance shore lights from vessel navigation lights. Because of this difficulty, the operator ignores the moving lights in favor of analyzing those that don't appear to be moving, because the rule he chose says "if the lights don't seem to be moving, then they are on a constant bearing, decreasing range; if CBDR, then monitor and take evasive action." But non-moving lights also fit the rule "if the lights don't seem to be moving, then they are lights ashore; if they are lights ashore, ignore them and worry about moving lights."

Summary: The defining characteristic of an informational overload error is that an incorrect rule for the situation is chosen because of an overwhelming amount of information confronting the decision-maker.

　

VII.D.1.b.iv. First Exception (required only for Formal investigations)

Definition: "The first time a person encounters a significant exception to a general rule, that general rule, particularly if it has been very reliable in the past, will continue to "rule" or govern. It is only through the occurrence of such errors that these "parent" rules will develop the more specific "child" rules necessary to cope with the range of situational variations." [Reason: 76]

Example: A Second Mate gained his experience navigating on tankers with after deckhouses. While aboard tankers, he developed the rule "if you seen a buoy abeam the bridge, it's time to turn; if it's time to turn, give twenty degrees rudder until the bow of the ship begins to move." He takes a job as a 2^nd Mate on a Cruise Ship on which the bridge is located forward. On his first transit out of the harbor, he initiates his turn too soon at the sea buoy. The Mate continued to use his turn rule, having never before encountered the exception of a forward bridge; when the buoy is abeam the bridge on a cruise ship, it is not yet time to turn. This exception will become a "child" rule to the "parent" turning rule he learned on tankers.

Summary: The defining characteristic of a first exceptions error is that an incorrect general rule for the situation is chosen because the decision-maker finds it difficult to make the first-time choice of the correct alternative.

　

VII.D.1.b.v. Rigidity (required only for Formal investigations)

Definition: "If a rule has been successfully used in the past, there is an overwhelming tendency (almost stubbornness) to use it again even when the circumstances no longer warrant its use. So strong are such rules, that we will apply familiar but cumbersome solutions even when simpler and more elegant solutions are currently available. Instead of the person mastering a habit, the habit has mastered the person." [Reason: 78]

Example: While navigating a yacht through an offshore area, a recreational boater who normally navigates the shoal-ridden river areas near home continues to plot her position every 15 minutes. By the time four hours of her transit are over, she is mentally exhausted. While a perfectly appropriate rule for navigating near coastal areas, 15-minute position fixing is cumbersome offshore. Experience has confirmed the boater's belief that the rule is correct, and she continues to use it when less cumbersome practices are available.

Summary: The defining characteristic of a rigidity error is that an incorrect rule is chosen because the decision-maker strongly believes in its "correctness", despite the presence of more appropriate options.