The basic theory of SA is that of cognitive psychology, in particular, attention, perception, information processing, memory and decision making. Much of this has already been addressed in the Appendix dealing with information processing.
Whilst the term "situation awareness" is usually used, in the context of flight operations, to describe awareness of all aspects of the whole flight, this can be broken down into specific elements, of which flight crew need to be aware to varying extents at certain times of the flight. For instance, a pilot needs very good SA concerning runway and taxiway assignments prior to take-off, but this information ceases to be useful after departure. Information on the frequency concerning your own aircraft is more important than ATC instructions to other aircraft, but it may be useful to retain some SA of the latter 'party-line' information, in case ATC mistakenly clear another aircraft to your level. Table 1 distinguishes between geographical SA, SA of aircraft position and movement, aircraft system SA, environmental SA and, more for military aircraft, tactical SA.
Table 1 Types of SA (modified from Endsley) Geographical SA own aircraft
position relative to designated features path to desired location
actual values relative to assigned projected flight path
impact of degrades and settings on performance time and distance available on fuel
One could also argue that "People SA" should be included, but this is not one of the elements in Mica Endsley's model.
Mica Endsley has categorised SA into three levels: perception, comprehension and projection. These are described further in Table 2 The more experienced and skilled a pilot, the better his SA at all three levels tends to be. Novice pilots tend to be competent at level 1 SA, but poor at levels 2 and 3. On the other hand, some skilled and experienced pilots may make errors at the level 2 stage, in that they may perceive the correct information but draw an incorrect conclusion based on previous experience of a similar event.
Individual factors which can influence SA are those described already in the Appendix on information processing. Human beings have a limited information processing capability and cannot attend to all sources of information all the time. It is necessary to switch attention from one source to another, often in fairly rapid succession, and store the information in memory. Appropriate training can help pilots develop and practice good 'attention sampling' strategies, to ensure that one or more sources of information do not get neglected. A simple example of this is the instrument scanning pattern which many pilots learn at an early stage in their flying training, in order not to miss a potentially important source of information.
Environmental SA weather formations and movement temperature
Table 2 SA Error Taxonomy (Mica Endsley, 1995 ) Level 1 SA: failure to correctly perceive
the situation
A: Data not available
B: Data difficult to detect/perceive C: Failure to scan or observe data
1. omission
2. attentional narrowing/distraction 3. high taskload
D. Misperception of data E. Memory failure Level 2 SA: Failure to comprehend
situation
A: Lack of/poor mental model B: Use of incorrect mental model
C: Over-reliance on default values in model D: Memory failure
E: Other Level 3 SA: Failure to project situation
into the future
A: Lack of/poor mental model B: Other
General Failure to maintain multiple goals
Habitual schema Table 1 Types of SA (modified from Endsley)
Working memory capacity is a limit on SA, since its capacity can soon be overwhelmed when used to store perceived information, comprehending the meaning of that information, combining it with existing knowledge to achieve a composite picture, and predict future outcomes whilst still maintaining a good appreciation of the current situation. The load on working memory and processing capabilities can be reduced as tasks become more and more automatic, with the development of skill. However, this very 'automaticity' can have a down side in that it can lead to failure to perceive new stimuli (e.g. hearing what you expect to hear, or seeing what you expect to see).
Stress can have an affect on SA, sometimes positive, but more usually negative.
Stress can be physical (noise, vibration, heat, cold, fatigue, etc.) or social/
psychological (fear, anxiety, uncertainty, mental load, time pressure, perceived time pressure, consequences of events, etc.). High workload is a form of stress, either long term high workload (e.g. a short-haul flight through several sectors in busy airspace, with an inexperienced crew), or short term or even momentary high workload or overload (e.g. bad weather on approach).
Depending on the individual, some degree of stress may improve performance in general, including SA. More often, however, stress results in reduced SA since it competes with SA for an individual's limited attention capacity, and may result in attentional narrowing. Other consequences may include reduced working memory capacity, and reduced information intake. Aural inputs may be significantly reduced, with peripheral visual inputs suffering next. This is a strong argument for placing master warning lights in the central visual area in cockpits, rather than rely upon peripheral attention-getters or aural warnings.
Stress can also result in decisions being made without all the pertinent information having been considered (e.g. shutting down wrong engine without looking to see which one is on fire!), and also with failing to take account of contradictory information once a decision has been made, attention being given only to information which supports the decision. Training can make people aware that this is a danger, help them to recognise the symptoms of stress and reduced SA, and train them to actively search for, and attend to, all pertinent sources of information before making a decision or acting upon a decision.
Recognition of reduced SA is almost as important as subsequent retrieval of good SA.
LOFT exercises and debriefs are a useful way to improve on recognising when SA is reduced, with regard to both individuals and the flight deck crew team. Mica Endsley advocates a training method whereby LOFT exercises are stopped midway through, in order to test individuals on their SA, and make them aware of their actual levels of SA, rather than their perceived levels, particularly at the end of an exercise.
Training can help flight crew manage their workload to avoid overload situations and the associated reduction in SA. Training can help flight crew recognise reduced SA when it happens. CRM training can help improve teamwork such that team members can have good team SA, as well as monitoring one another to ensure that individual team members are maintaining SA. One of the key benefits of training, however, is to train individuals and teams how to cope in a non-normal or emergency situation, and how to maintain SA under stress. Training aids and videos are available for specific situations, e.g. approach and landing, engine failure, CFIT, turbulence, etc., but generic training in how to maintain and improve SA is valuable to give flight crew a good understanding of the techniques available.
4 Practical Notes
The following text has been extracted from Document 29 (Appendix 16) and JARTEL WP5 and WP7:
4.1 Situation Awareness
4.1.1 Awareness of aircraft systems
The crew needs to be constantly aware of the state of different aircraft systems.
Examples of poor practice:
• Does not ask for updates;
• Does not signal awareness of changing systems.
Table 3 Clues to Loss of SA (adapted from Bovier, 1997)
These "clues" can warn of an error chain in progress - a series of events that may lead to an accident. Most accidents involving human error include at least four of these clues.
Ambiguity - information from two or more sources that doesn't agree Fixation - focusing on any one thing to the exclusion of everything else
Confusion - uncertainty or bafflement about a situation (often accompanied by anxiety or psychological discomfort)
Failure to fly the aircraft - everyone is focused on non-flying activities Failure to look outside - everyone heads down
Failure to meet expected checkpoint on flight plan or profile ETA, fuel burn, etc.
Failure to adhere to SOPs
Failure to comply with limitations, minimums, regulatory requirements, etc.
Failure to resolve discrepancies - contradictory data or personal conflicts Failure to communicate fully and effectively - vague or incomplete statements
Table 4 Tips for Good SA Management (Bovier, 1997) Predetermine crew roles for high-workload phases of flight
Develop a plan and assign responsibilities for handling problems and distractions Solicit input from all crew members, including cabin, ATC, maintenance, dispatch, etc.
Rotate attention from plane to path to people - don't fixate Monitor and evaluate current status relative to your plan Project ahead and consider contingencies
Focus on the details and scan the big picture
Create visual and/or aural reminders of interrupted tasks Watch for clues of degraded SA
Speak up when you see SA breaking down
Examples of good practice:
• Monitors and reports changes in system states;
• Acknowledges entries and changes to systems.
4.1.2 Awareness of external environment
The crew needs to be aware of their environment (position, weather, air traffic, terrain).
Examples of poor practice:
• Does not acknowledge - repeat ATC directions;
• Does not enquire about environmental changes;
• Does not comment on relevant environmental factors, or is surprised by them.
Examples of good practice:
• Collects information about the environment;
• Contacts outside resources when necessary;
• Shares information about the environment with others.
4.1.3 Awareness of time
The crew needs not only to be aware of the present state of the aircraft systems and environment, but must also be able to predict future states in order to anticipate future events.
Examples of poor practice:
• Does not set priorities with respect to time limits;
• Does not discuss relationship between past events and present - future;
• Is surprised by outcomes of past events.
Examples of good practice:
• Discusses contingency strategies;
• Identifies possible - future problems.
5 Initial Training and Objectives
Initial training should introduce the concept of SA and illustrate the dangers of poor SA (possibly using well-known incidents and accidents). Factors which contribute to good and bad SA should be covered.
6 Recurrent Training and Objectives
Good SA acquisition needs to be trained as a skill, ideally using a simulator (see below for methods). Team skills are important in ensuring that the crew as a whole have the correct perception of aircraft and environment status, and to avoid each individual crew member having their own (incorrect) SA. Good communication skills and procedures are necessary in ensuring that all pertinent information is shared between the crew.
7 Examples and Suggested Training Material
Mica Endsley, of SA Technologies Inc, advocates SA training in the simulator, where scenarios are stopped midway in order to ascertain the flight crews' SA. In this way, if individuals are failing to take in information from certain sources, or to understand that information, this can be pointed out at an early stage during the simulation exercise allowing them more opportunity to correct their working methods as the scenario progresses. If debriefing is left until the end of a LOFT exercise, as is traditional, the trainer may not be aware of where the SA deficiencies lie, since the flight crew may have acquired all the necessary information eventually, albeit not very efficiently. Further information on Mica Endsley's SA training techniques can be found on her website www.satechnologies.com.
There is an FAA sponsored training manual "Guidelines for Situation Awareness Training" which CRM instructors may find useful. This document contains very practical information on how to design training and LOFT scenarios to help flight crew improve SA.
The ESSAI project has produced some useful material which might assist CRM trainers. Some of the material is in the form of computer based training (CBT), and includes video extracts, but was still under development at the time of writing this document. Further details can be found on the NLR website (www.nlr.nl).
There are some well-known incidents and accidents which illustrate poor SA, and which can be used an training examples. These include:
• Cali accident American Airlines flight 965, Dec 20, 1995;
• US Airforce accident, CT-43A (B737), near Dubrovnik, April 3, 1996.
8 References and Useful Additional Reading
a) NAWCTSD/UCF/FAA Guidelines for Situation Awareness Training. Prince, C.
b) Mica Endsley's Situation Awareness Technologies site www.satechnologies.com.
c) Endsley, M., Robertson, M. Training for Situation Awareness. In: Situation Awareness Analysis and Measurement. Endsley, M., Garland, D. (2000). Mahwah, NJ: Lawrence Erlbaum Associates.
d) Endsley, M. Theoretical underpinnings of Situation Awareness: a critical review. In:
Situation Awareness Analysis and Measurement. Endsley, M., Garland, D. (2000).
Mahwah, NJ: Lawrence Erlbaum Associates.
e) Endsley, M. Situation Awareness in Aviation Systems. Chapter 11 in: Garland, D., Wise, J., Hopkin, D. (Eds). Handbook of Human Factors. 1999. Mahwah, NJ:
Lawrence Erlbaum Associates.
f) Flin, R., Salas, E., Strub, M., Martin, L. Decision Making Under Stress; Emerging Themes and Applications. 1997. Ashgate. ISBN 0-291-39856-1. Proceedings of a conference on Decision Making Under Stress.
g) Enhanced Safety through Situation Awareness Integration in Training (ESSAI) reports.
h) FAA. A review of Situation Awareness Literature Relevant to Pilot Surveillance Functions. Uhlarik, J. DOT/FAA/AM-02/3. March 2002.
i) Approach and Landing Accident Reduction (ALAR) Toolkit. 2000/2001. Flight Safety Foundation www.flightsafety.org/pdf/alar_flyer.pdf.
j) Turbofan Engine Malfunction Recognition and Response. November 2000.
Training video and note. FAA http://www.faa.gov/certification/aircraft/
engine_malf_famil.doc.
k) AIA/ AECMA. Propulsion System Malfunction and Inappropriate Crew Response (PSM+ICR). Vol 1. November 1998.
Appendix 7 Communication, Teamwork, Leadership, Decision Making and Managerial Skills
1 Introduction
One of the basic underlying premises of CRM is that a team can, and should, perform better than two (or three) individuals in the cockpit. The aim of CRM is to ensure that 1+1>2, as opposed to 1+1<2 (in a two pilot cockpit), and that team performance takes precedence over individual performance. Good CRM is getting the balance right as a team, whilst recognising that the Captain has the final say and responsibility for the safety of the aircraft.
In order to be effective, team members must be able to talk to each other, listen to each other, share information and be assertive when required. Commanders should take particular responsibility for ensuring that the crew function effectively as a team.
Whilst the emphasis in CRM is primarily upon the cockpit crew, and how they work as a team, it is also important to look at wider team effectiveness, namely the whole flight crew. CRM principles may also extend to situations where ATC, maintenance, company experts, etc., are considered to be part of the team (especially in emergency situations).
2 Communication
Good communication is important in every industry. In aircraft operations, it is vital.
Communication, or more often a breakdown in communication, is often cited as a contributor to aviation incidents and accidents. Communication is defined in the Penguin Dictionary of Psychology as: “The transmission of something from one location to another. The ‘thing’ that is transmitted may be a message, a signal, a meaning, etc. In order to have communication both the transmitter and the receiver must share a common code, so that the meaning or information contained in the message may be interpreted without error”.
2.1 Modes of Communication
We are communicating almost constantly, whether consciously or otherwise. We may need to communicate:
• information (e.g. "ATC have instructed us to...");
• feedback/challenger/response (e.g. "checked" or "set");
• ideas/proposals/counter-proposals (e.g. "I disagree. What about.XX instead?");
• feelings (e.g. "I'm not happy with....").
As the sender of a message, he will typically expect some kind of response from the person he is communicating with (the recipient), which could range from a simple acknowledgement that his message has been received (and hopefully understood), to a considered and detailed reply. The response constitutes feedback.
2.2 Verbal Communication
Verbal communication may be either social or functional/operational. Both serve a useful purpose, the former helping to built teamwork, and the latter being essential to the task of flying an aircraft.
For a spoken or written message to be understood, the sender has to make sure that the receiver:
• is using the same channel of communication;
• recognises and understands his language, including any subtleties;
• is able to make sense of the message’s meaning.
The channel of communication is the medium used to convey the message. For spoken communication, this might be face-to-face, or via the radio or intercom.
Written messages might be notes, information keyed in, or tone messages (e.g.
between flight deck and cabin crew). Oral/aural communication is the primary mode of communication in an aircraft.
Pilot-ATC communication is a very important area, almost warranting a separate Appendix. However, it is not appropriate to go into too much detail in this document, other than to stress that CRM principles should also apply to pilot-ATC communications (within the restrictions of standard phraseology and air-ground communications procedures) as well as face-to-face communications.
2.3 Non-verbal Communication
Non-verbal communication can accompany verbal communication, such as a smile during a face-to-face chat. It may constitute acknowledgement or feedback (e.g. a nod of the head). It can also be used when verbal communication is impossible, such as a thumbs-up in a noisy environment.
Body language can be very subtle, but often quite powerful. For example, the message “No” accompanied by a smile will be interpreted quite differently from the same word said whilst the sender scowls.
Non-verbal communication may also take the form of written information or notes, between pilots or flight deck and cabin crew.
Future ground-air communications are increasingly more likely to be non-verbal as data link technology and associated procedures gradually replaces oral/aural RTF communications between ATC and pilots. As mentioned above, this is not addressed in any detail in this document.
Non-verbal communication is the predominant manner by which systems communicate their status. For instance, most displays in the aircraft cockpit present their information graphically. However, man-machine interface issues are not covered in this document.
2.4 Communication Problems
There are two main ways in which communication can cause problems. These are lack of communication and poor communication. An example of the former is a young first officer who is very IT-literate, who is engrossed with programming the FMS but doesn't explain to the less-IT-literate Captain what he is doing. An example of the latter is a flight deck crew who advise the cabin crew that there will be a precautionary emergency landing, but fail to tell them not to evacuate the cabin. Both problems can lead to subsequent human error.
Communication also goes wrong when one of the parties involved makes some kind of assumption. The sender of a message may assume that the receiver understands the terms he has used. The receiver of a message may assume that the message means one thing when in fact he has misinterpreted it. Assumptions may be based on context and expectations, which have already been mentioned in this Appendix.
Problems with assumptions can be minimised if messages are unambiguous and proper feedback is given.
There are several hazards which reduce the quality of communications:
• failures during the transmitting process (e.g. the sending of unclear or ambiguous messages, language problems);
• difficulties caused by the medium of transmission (e.g. background noises or distortion of the information);
• failures during receiving (e.g. the expectation of another message, wrong interpretation of the arriving message or even its disregard);
• failures due to interference between the rational and emotional levels of
• failures due to interference between the rational and emotional levels of