Quality Assurance

Quality Assurance (“QA”) is arguably the most critical aspect of avionics software and hardware certification within DO-178C, DO-254 and related guidelines/standards.  However, QA is rarely given the attention or credit befitting its crucial role.  Consider the following statements and assess whether they are true or false; answers and explanations are provided within this paper:

1. 1.     T / F:   QA’s most important role is assessing final product quality.
2. 2.     T / F:   QA personnel perform technical reviews.
3. 3.     T / F:   QA personnel assess avionics development engineer’s adherence to criteria specified in DO-178 and DO-254.
4. 4.     T / F:   The four Stage Of Involvement (“SOI”) events represent the four QA audits of the avionics development process.
5. 5.     T / F:   Every Level A and Level B avionics development project requires at least three different persons, and the most crucial of those for certification is the independent QA person.

If the above questions were truly easy, congratulate yourself on your genuine QA knowledge. If they simply seemed easy, then the information that follows is for you. In tact. answering the above without understanding the overall quality assurance role in 00-1780 and 00-254 is like understanding Fourier transforms without first understanding The Calculus: impossible for mere mortals

In avionics systems. hardware and software development. CA has two primary responsibilities:

1. Ensuring the project specific development plans and standards comply with 00-1 78C/254.

2. Assessing. and then ensuring that the independent development organization has followed those plans. from project inception through completed delivery.

In other non-avionics development activities ‘Quality Assurance’ often implies a more adjunct, and more passive, measurement role. Wikipedia, for example. aptly states QA ‘is the systematic measurement. comparison with a standard. monitoring of processes and an associated feedback loop that…

QA/PA reviews and approves respective project Plans, Standards, and Checklists, all of which are used by engineers throughout development (including safety, systems, software hardware development/integration/test, and configuration management).  QA/PA then audits those engineers via sampling to ensure they are following those plans/standards with corresponding checklists as evidence including adherence to transition criteria (see AFuzion’s “Transition Criteria” whitepaper for details).  Audits should be started early in each respective engineering process, with an emphasis on early-stage auditing to ascertain process/training/adherence weaknesses early and correct such.   ARP4754A and ARP4754B (along with DO-178C, DO-254A, and DO-200C) are vague on audit frequency and sample rates, however QA/PA should strive to ensure each engineer is assessed at least once per artifact “type”. Remember: QA/PA is the project “Policeman” and eventually all “drivers” should be assessed for traffic law adherence by radar, visual, or cameras at least occasionally to retain effectiveness. In aviation, a sampling rate of 3% – 8% is considered appropriate and common.  Engineers with higher-than-expected defect rates should be subjected to enhanced training and then audited more frequently until improvements are assured.  

Audits cannot start until the audit criteria is known and applied by Engineering, meaning all project plans, standards, and checklists should be approved prior: the delineation for this is Stage of Involvement (SOI) #1 which signifies the beginning of formal QA/PA auditing.  Remember to keep records of all audits, audit defects, and feedbacks thereof.  QA/PA audit findings should be  based upon corresponding Checklists which themselves are based upon project standards. While the most common aviation checklists are those from AFuzion (see Here), ISO9X, IEEE 12207, and CMMI are also used as a basis for checklists.  At a minimum, each SOI should have its own checklist (again, AFuzion’s Checklists for SOIs are the most commonly used worldwide). 

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