Interesting thought indeed.
Before you go roaring off in the direction of modifying a basic alerting system toward an enhanced alerting system, it might pay to take a broader look at operator cognition, safety critical tasks that ought not be interrupted, task focus and workload management. Otherwise you may end up with a system that more effectively overloads the poor operator!
Some areas to look into that may be useful...
The USA Three Mile Island nuclear power station incident, particularly the multiple audio alarms competed for the attention of, and reduced the effectiveness of, control room personnel responding to the emergency.
Manufacturer philosophies of flight deck automation, and airline philosophies as to use of automation. Tony Kern in Flight Discipline gives some examples. The honeywell avionics in the B717 I fly (read MD-95) have a Central Alerting and Warning System that prioritises alerts into one of four categories (Level 3 eg fire, cabin high altitude, Level 2 eg one of two hydraulic systems fails, Level 1 eg autobrake system fail but full braking performance available with manual wheel braking and advisories Level 0 wing antice selected on.) "Non alerts" a the fifth category being abnormals for which there is no cockpit alert.
The philosophy being to categorize alerts by (a) a requirement for immediate crew awareness or not and (b) immediate action to be taken by crew, crew action required but not immediately, or no crew action required.
There is also a system of inhibiting the alerts during flight critical periods. For example, some alerts are progressively inhibited as the aircraft accelerates during the takeoff roll, all audio alert inhibited between liftoff and 400', at which point alert inhibiting is progressively removed depending on how the system designers rated the severity of the alert. The philosophy here being that, in addition to classifying alerts as being 3 to 0, there are times when the alerting system will not 'bother' the pilot when the pilot's attention should not be diverted from the task at hand.
Likewise, alerts are progressively inhibited on final approach until landed and slowing to taxi speed.
Bells, whistles, chimes and warblers for critical functions and alerts are all accompanied by a verbal recorded message to 'decode' the aural alert. Example: The firebell aural alert for an engine fire has the traditional fire bell sound, followed by a harsh female voice announcing 'fire, right engine.' Autopilot disconnect has traditional warning chimes followed by same female voice announcing "autopilot disconnect." Traditional cues, with spoken explanation.
The decision as to when to inhibit certain alerts and when to de-inhibit them is based on a general assessment of pilot cognition and ability and is fixed in the avionics suite programming. The USAF have done some preliminary work on intelligent systems that monitor the pilot's cognitive state (stress level, if you like) and decide whether or not to alert the combat pilot to a threat or abnormality, and if so, which pieces of information and when to convey it! The UK MoD has also researched another side of that coin - what if the operator (medico in your case) had a bit of kit that offered 'augmented cognition' in other words would assist your medico to regain the plot, or avoid unsafe commands or actions, by automatically commanding a set of previously agreed actions if/when the medio is overloaded or otherwise not able to cope with all the information. Cognitive assistance through adaptive automation they called it.
Another interesting line of inquiry is to compare the Boeing "only tell the pilot what he/she needs to know" where the operating system status is invisible to the operator when operating normally, c.f. the Airbus ECAM "in the loop" philosophy of a running commentary of changes to system status. Both have their advocates.
There is some interesting work on future designs of flight decks being touted at NASA and other places. Look up work by
James Reason (Human Error is a great start)
Marianne Rudisill,
Gordon Baxter and Denis Besnard,
Rasmussen, Duncan and Leplat,
Charles Billings.
Earl Weiner
Endsley and Strauch
A good start might be to Google Scholar "flight deck automation" "flight deck design" pilot cognition, and similar.
Last edited by ITCZ; 14th May 2008 at 13:06.