Human Factors Are Important to Aircraft Certification
A few months back, AMT Editor Ron Donner asked me to write about design specifications that addressed human factors. He wanted the article for the “October” issue. My initial response was the usual, “no problem.” Knowing that there are plenty of design regulations for aircraft and parts certification it would be easy to describe human factors in certification in a few pages. After considerable discussion with FAA personnel from Aircraft Certification this is my 1,000-word attempt to answer Ron Donner’s request. This article describes the FAA Aircraft Certification Service and the general structure of its regulations. It should serve as a review for most readers and lead you to sources of additional detailed information. It ends with Chapter 6 (Considering Human Factors Issues when installing equipment and conducting other maintenance) of the Operator’s Manual for Human Factors in Maintenance.
Aircraft Certification Service
FAA’s Aircraft Certification Service (AIR), as paraphrased from Order 8100.5A), works with authorities, manufacturers, and other stakeholders to ensure continuing safety. The AIR process administers safety standards governing design, production, and airworthiness of products. AIR oversees design, production, and airworthiness certification programs. They ensure that the aircraft and components are designed for safety, manufactured for safety, and modified for safety throughout the product life cycle.
The initial AIR mission appears to be straightforward. However, this mission must extend to small and large aircraft including airplanes and helicopters, powerplants, propellers, avionics, and other accessories. The AIR process must serve not only brand new aircraft and powerplant design and manufacturing but also certification of new parts for very old aircraft. AIR supports certification of the constant flow of new technologies and the demand of special repairs and alterations made in the field. That support extends to the entire world.
AIR pays attention to human factors by staffing the various Directorates and Aircraft Certification Offices with design, manufacturing, continued operational safety, and flight test human factors professionals. Those personnel are involved with most new systems and modifications, especially related to flight deck and flight control avionics and control systems. They are especially supportive in matters related to engineering assisted field approvals. Increasingly, because of FAA encouragement and commercial value, most manufacturers have a team of human factors experts on staff. FAA Human Factors engineers have the skill set and education that helps ensure effective communication with their industry counterparts.
I have worked with a variety of the FAA Aircraft Certification Human Factors professionals, mostly with activity on the Aviation Safety Human Factors Coordinating Committee. That group brings together the FAA personnel that have industry, government, and academic perspective of aircraft and component certification process and the related human factors issues. I have observed a high degree of competency and level of industry cooperation among that team. I encourage readers to take advantage of that expertise.
The Certification Details
If you want the “details” you must proceed to the Federal Aviation Regulations. Part 21 is the overarching certification rule, titled Certification Procedures for Products and Parts. From there you can proceed to aircraft, engines, avionics, and other chapters. From those sections you can obtain everything from the strength limits for flight controls to the size, color, and location of icons on avionics displays. A recent certification rule for transport category aircraft affects “Installed Systems and Equipment for Use by the Flightcrew” (See AC25.1302-1) That human factors oriented information was nearly a decade in the making and approval process and is representative in the important information likely to continue to flow from AIR.
There has been a lot of industry talk about upcoming momentous rule changes for Part 23 – Airworthiness Standards: Normal, Utility, Acrobatic, and Commuter Category Airplanes. The proposed rule has the goal to reorganize Part 23 based on airplane performance and complexity. This rule will ensure the safety of aircraft but will also streamline the time and cost to certify many small aircraft.
Making Human Factors Decisions in the Field
This discussion above addressed the part of the certification process that tends to happen with parts or aircraft production facilities. It is more likely that you are more concerned about “field Approvals” – an FAA approval of technical data for a major alteration or repair to a single typed–certificated product. For example, your customer asks you to install a new avionics component, cameras, air conditioner, etc. to an existing aircraft. In many cases the product provider has already completed most, if not all, of the data necessary for a field approval. However, that is not always the case. The responsibility then falls on the installer to ensure the compatibility and obtain the necessary data to complete the installation.
The 2014 version of the Operator’s Manual for Human Factors in Aviation (See AMT October 2014) (full document at www.humanfactorsinfo.com) had a chapter to offer human factors support on field approvals. Chapter 6 was written for general aviation mechanics, repair station personnel, and mechanics with Inspection Authorizations. They must make decisions regarding such factors as: A mechanic may be the best final check to ensure not only for safe physical installation, but also for alterations made to the aircraft, ensuring selected human-machine issues are addressed. These can include: visual access/viewing angles, installation specific readability, glare, nighttime application, panel real estate, electrical loads/load shedding, pilot workload, and more. These types of factors should be considered for field approvals. Chapter 6 emphasizes that proper attention to human factors during installation not only helps ensure effective and safe equipment use, but also offers ideal customer/user satisfaction.
See the section of Chapter 6 below as an example of the practical advice.
The Operators Manual is but one of many sources to help with Field Approvals and other aircraft and parts certification. Many sections of the certification rules have matching Advisory Circulars. They can be accessed through the FAA website (www.faa.gov, go to Certification). Additionally, many of the FAA’s certification personnel and resources can also be accessed by working with your local Flight Standards District Office who has a working relationship with the engineers in nearby offices.
We have all heard the famous expression that “FAA is here to help.” When it comes to human factors and certification, I believe that to be true. Yes, there is a trace of Kool-Aid on my upper lip.
Dr. Bill thanks FAA Certification Engineers Barry Ballenger, Jason Brys, and Steven Thompson for the technical guidance provided herein.
Dr. Bill Johnson, as the FAAA chief scientific and technical advisor for Human Factors in Aircraft Maintenance Systems, advises on the identification of practical ways to ensure continuing effective, efficient, and safe human performance in maintenance and engineering. He works for both the Flight Standards and the Aircraft Certification Services.
