Appendix 5 APPENDIX 5 Definitions Definitions are written to support the content of this AC and its associated rule. Other regulations may use terms such as “warning” in a manner that is not consistent with the definitions below. However, the intent of this section is to facilitate standardization of these terms.
Term Definition Advisory The level or category of alert for conditions that require flightcrew awareness and may require subsequent flightcrew response.
Alert A generic term used to describe a flight deck indication meant to attract the attention of and identify to the flightcrew a non-normal operational or airplane system condition.
Alerts are classified at levels or categories corresponding to Warnings, Cautions, and Advisories. Alert indi cations also include nonnormal range markings (for example, exceedences on instruments and gauges.)
Alert inhibit Application of specific logic to prevent the presentation of an alert. Alerts can be inhibited automatically by the alerting system or manually by the flightcrew.
Alert message A visual alert comprised of text, usually presented on a flight deck display.
Note: Aural alert messages are referred to as “Voice Information.”
Alerting function The airplane function that provides alerts to the flightcrew for non-normal operational or airplane system conditions. This includes warning, caution, and advisory information.
Alerting philosophy The principles, guidance, and rules for implementing alerting functions within a flight deck. These typically consider:
1. The reason for implementing an alert.
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Appendix 5 Term Definition
2. The level of alert required for a given condition.
3. The characteristics of each specific alert.
4. Integration of multiple alerts.
Attention-getting cues Perceptual signals (visual, auditory, or tactile/haptic) designed to attract the flightcrew’s attention in order to obtain the immediate awareness that an alert condition exists.
Caution The level or category of alert for conditions that require immediate flightcrew awareness and a less urgent subsequent flightcrew response than a warning alert.
Collector message An alert message that replaces two or more related alert messages that do not share a common cause or effect. Example: A “DOORS” alert collector message is displayed when more than one entry, cargo, or service access door is open at the same time.
Communication message A type of message whose initiating conditions are caused by incoming communications, primarily data link conditions. Traditionally, this type of message is not a flightcrew alert and does not indicate a non-normal system or operational condition.
(1) Comm High A communication message which requires immediate flightcrew awareness and immediate flightcrew response. Note: At this time there are no communication messages defined that require immediate flightcrew response.
(2) Comm Medium An incoming communication message that requires immediate flightcrew awareness and subsequent flightcrew response.
(3) Comm Low An incoming communication message which requires flightcrew awareness and future flightcrew response.
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Appendix 5 Term Definition False alert An incorrect or spurious alert caused by a failure of the alerting system including the sensor.
Failure An occurrence that affects the operation of a component, part, or element such that it can no longer function as intended. This includes both loss of function and malfunction.
Failure flag One local visual means of indicating the failure of a displayed parameter.
Flashing Short term flashing symbols (approximately 10 seconds) or flash until acknowledged.
Flightcrew response The activity accomplished due to the presentation of an alert such as an action, decision, prioritization, or search for additional information.
Master aural alert An overall aural indication used to attract the flightcrew’s attention that is specific to an alert urgency level (for example, warning or caution).
Master visual alert An overall visual indication used to attract the flightcrew’s attention that is specific to an alert urgency level (for example, warning or caution).
Normal condition Any fault-free condition typically experienced in normal flight operations. Operations are typically well within the airplane flight envelope and with routine atmospheric and environmental conditions.
Nuisance alert An alert generated by a system that is functioning as designed but which is inappropriate or unnecessary for the particular condition.
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Maximum Optimum Horiz Horiz 15°
NOM NOM Vertical Field of View LT Maximum Optimum LT 35° ~ ' oc 15° 35° RT Horizontal Field of View T
12/13/2010 AC 25.1322-1 Appendix 5 Term Definition Primary field of view Primary Field of View is based upon the optimum vertical and horizontal visual fields from the design eye reference point that can be accommodated with eye rotation only. The description below and Figure A5-1 provide an example of how this may apply to head-down displays.
With the normal line-of-sight established at 15 degrees below the horizontal plane, the values for the vertical (relative to normal line-of-sight forward of the aircraft) are +/-15 degrees optimum, with +40 degrees up and -20 degrees down maximum.
For the horizontal visual field (relative to normal line-of-sight forward of the aircraft), the values are +/-15 degrees optimum, and +/-35 degrees maximum.
Figure A5-1. Primary Field of View A5-4
Appendix 5 Term Definition Status A specific aircraft system condition that is recognized using a visual indication, but does not require an alert and does not require flightcrew response. These types of messages are sometimes used to determine airplane dispatch capability for subsequent flights.
Tactile/haptic information An indication means where the stimulus is via physical touch, force feedback, or vibration (for example, a stick shaker).
Time-critical warning A subset of warning. The most urgent warning level to maintain the immediate safe operation of the airplane. Examples of time-critical warnings are:
Predictive and Reactive Windshear Warnings, Terrain Awareness Warnings (TAWS), Airborne Collision Avoidance System (ACAS) II Resolution Advisories, Overspeed Warnings, and Low Energy Warnings.
Umbrella message An alert message that is presented in lieu of two or more alert messages that share a common cause. Example: A single Engine Shutdown message in lieu of the multiple messages for electrical generator, generator drive, hydraulic pump and bleed air messages, which would otherwise have been displayed.
This is different than a collector message. A collector message replaces two or more related alert messages that do “not share” a common cause or effect.
Unique tone (unique sound) An aural indication that is dedicated to specific alerts (for example, fire bell and overspeed).
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Appendix 5 Term Definition Visual alert information A visual indication that presents the flightcrew with data on the exact nature of the alerting situation. For advisory level alerts it also provides awareness.
Voice information A means for informing the flightcrew of the nature of a specific condition by using spoken words.
Warning The level or category of alert for conditions that require immediate flightcrew awareness and immediate flightcrew response.
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