Old 19th Apr 2018, 18:03
  #262 (permalink)  
Ian W
Join Date: Dec 2006
Location: Florida and wherever my laptop is
Posts: 1,307
Originally Posted by aliwyatt View Post
It can be seen that a minor amendment to the certification requirement may relieve the interference of multiple aural alerts expressed by "Good Business Sense"

"b. Multiple Aural Alerts
(1) Aural alerts should be prioritised so that only one aural alert is presented at a time. If more than one
aural alert needs to be presented at a time, each alert must be clearly distinguishable and intelligible by the flight
crew (CS 25.1322(a)(2)).
(2) When aural alerts are provided, an active aural alert should finish before another aural alert begins.
However, active aural alerts must be interrupted by alerts from higher urgency levels if the delay to annunciate the
higher-priority alert impacts the timely response of the flight crew (CS 25.1301(a)). If the condition that triggered the
interrupted alert is still active, that alert may be repeated once the higher-urgency alert is completed. If more than
one aural alert requires immediate awareness and the interrupted alert(s) affects the safe operation of the
aeroplane, an effective alternative means of presenting the alert to the flight crew must be provided to meet the
requirements of CS 25.1322(a)(1) and (a)(2)."
That sounds well and good for someone writing a spec. But now imagine you have several high urgency aural alerts. The effect is one continual stream of aural alerts and their visual counterparts just as your piloting skills are being tested by the failures the alerts are repeating to you. It is a human factors nightmare.
The aural sense is actually the first to be suppressed when under stress, so all the aural alerts may do is increase the stress to a level at which they are ineffective.
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