SOFTWARE MANAGEMENT CONTROL

AIM

• Awareness of restrictions using the software for aircraft

• Airworthiness requirements and approval procedure

• Possible catastrophic effects of unapproved changes to software programs

INTRODUCTION

• Computer software used to drive many type of system in aircraft

• Cant let it fail during operation • Need to evaluate, test, verify to specific

requirement, fail safe design• To prevent failure to the aircraft and

passenger.

APPLICATION OF SOFTWARE

Some example are:• primary and secondary flight controls• engine controls• electrical generation and distribution• brakes• radio and navigation equipment• flight instruments • automatic flight control

SOFTWARE LIFECYCLE

• Initiation• Requirement• Design• Code, (Implementation)• Integration and Test• Installation• Operation and Maintenance

SOFTWARE APPROVAL

• Software must be verify by authority for approval in order to control the quality

• Initial certification :– Software must be design from approved company – Approved by Design Organization– Software must comply with authority requirement (BCAR sec A)

• Post-Certification Modifications – Modification must based on rule apply to the application on

hardware – Modification which effect software must be approved by the

Design Organization

DOCUMENTATION APPROVAL

• AN 57 issue in order to recognice RTCA/EUROCAE document with appropriate guidance material.

• Include in RTCA/EUROCAE :– DO-178/ED-12 : Application form for software approval

and guidance– Requirement for software control– Software documentation procedure– Requirement for configuration management– Rule for upgrading software– Differential of software level

SOFTWARE TESTING

• Every software must be provide the testing method to maintain its functinality.

• Purpose is to determine all data process corectly with the correct output.

• Test should include :– Typical data : test the comonly use program path– Unusual but valid data : test the exception

program path ( fail safe design)– Incorrect, incomplete data : test the error routine

SOFTWARE LEVELAMJ 25

Criticality Category

FAA

Criticality Category

RTCA/EUROCAE

Software Level

Effect on Aircraft and Occupants of Failure or Design Error

Minor Effect Non-Essential Level D

1. Slight reduction of safety margin

2. Slight increase in workload (routine changes in

flight plan)

3. Physical effects but no injury to occupants

Major Effect Essential Level C

1. Significant reduction in safety margins

2. Reduction in the ability of the flight crew to cope

with adverse operating conditions impairing their

efficiency

3. Injury to occupants

Hazardous /severe-Major

EffectEssential Level B

1. Large reduction in safety margins

2. Physical distress or workload such that the flight

crew cannot be relied upon to perform their tasks

accurately or completely

3. Serious injury to or death of a relatively small

proportion of the occupants

Catastrophic Effect

Critical Level A1. Loss of Aircraft

2. Fatalities

FAILURE CONDITION• Minor

– Slight reduce safety margin of functional capabilities, slight increase crew workload and some inconvenience to occupants.

• Major– Reduce capability of aircraft, significant reduction in safety

margins or functional capabilities, increace in crew workload and discomfort occupants.

• Hazardous– Reduce capability of aircraft , large reduction of safety margin or

functional capabilities, physical distresser to crew and serious injury to some of occupant

• Catastrophic– Failure condition prevent continue safe flight and landing