31 July 2011 C1 CIVIL AVIATION DEPARTMENT HONG KONG ...

RELATIONSHIP BETWEEN FUNCTION CRITICALITY CATEGORY AND SOFTWARE LEVELAIRWORTHINESS NOTICE NO. 45AAPPENDIX NO. 1Issue 431 January 2003FAR 25.1309 andJAR 25.1309 definitionsNo significant degradation of aircraftcapability or crew abilityReduction of the aircraft capability or of the crew ability to cope with adverse operatingconditionsPrevention of continued safe flight andlanding of the aircraftEffect onaircraft andoccupants offailureconditions ordesign errorACJ No.1 toJAR 25.1309definitions- Slight reduction of safety margins,- Slight increase in workload, e.g. routinechanges in flight plan, or- Physical effects but no injury to occupants- A significant reduction in safety margins,- A reduction in the ability of the flightcrew to cope with adverse operatingconditions as a result of increase inworkload or as a result of conditionsimpairing their efficiency, or- Injury to occupants- A large reduction in safety margins,- Physical distress or a workload such thatthe flight crew cannot be relied upon toperform their tasks accurately orcompletely, or- Serious injury to, or death of, a relativelysmall proportion of the occupantsLoss of aircraft and/or fatalitiesACJ No.1 to JAR 25.1309definition of Criticality CategoryMinor Effect Major Effect Hazardous/Severe -Major Effect Catastrophic EffectFAR Advisory Circular 25.1309-1Adefinition of Criticality CategoryNon essential Essential CriticalDO-178B/ED-12B Software level* Level D Level C Level B Level A* Note: Using appropriate design and/or implementation techniques, it may be possible to use a Software Level lower than the functional categorisation.CancellationThis Notice Appendix cancels Airworthiness Notice No.45A Appendix No.1 Issue 3, dated 31 January 2002, which should be destroyed.AN-45A A1 P.131 January 2003