The US Federal Aviation Administration has finalised a new rule that delineates the colours that can be used for warning, caution and advisory alert indications in the cockpit for new transport category aircraft to be certificated after 3 January 2011.

Although de facto standards are in place regarding the alerts generated by advanced glass cockpit avionics systems, the FAA says each manufacturer must gain approval through FAA-written issue papers and special conditions, processes that require "additional work" for the agency.

Baseline regulations were issued in 1977 and "have never been amended", says the FAA in the final rule. The FAA issued the preliminary rule in July 2009.

Alert colours on the flightdeck for future new aircraft will have red for warnings, amber or yellow for cautions and any colour except red, amber, yellow or green for advisory alerts. Weather, terrain or traffic displays may still use the four colours, but "must not adversely affect flightcrew alerting", says the FAA.

In addition, warning and caution alerts will require attention-getting cues through at least two different senses.

The rule harmonises the FAA's regulations on the topic with the European Aviation Safety Agency.

Overall, the FAA says it recommends that manufactures use six or fewer colours in a typical flightdeck to display all of the information necessary to safely operate the aircraft.

Operationally, the FAA is requiring that alerts be designed so that after each occurrence, the pilot can acknowledge the problem and suppress the alarm. The system itself must prevent "presentation of an inappropriate or unnecessary", or nuisance alert and automatically remove the alert when the conditions no longer exist.

The FAA estimates the rule will avoid about 10 serious injuries over a 20-year period, resulting in a total cost benefit of $4.4 million over two decades.

Development cost to manufacturers is estimated to be about $700,000 per new aircraft type, the agency says.

Source: Flight International