Aviation Maintenance Human Factors Research Program

1. Aviation Maintenance Human Factors Research Program William K. Krebs Office of the Chief Scientific and Technical Advisor for Human Factors Federal Aviation Administration Presented to ATA Maintenance Human Factors Subcommittee 07/17/02

2. To obtain additional information about each project, execution plan, or requirement, please contact me or point to the AAR-100 human factors aviation maintenance website william.krebs@faa.gov (202) 267-8758 http://www.hf.faa.gov/maintenance.htm

3. Aviation Maintenance

4. Aviation Maintenance

5. Project 1 Vision Testing Requirements for Certain Persons Maintaining and Inspecting Aircraft and Aircraft Components Sponsors AFS-300 (POC: Les Vipond) & FSDO PIT (POC: Rusty Jones)

6. Project 1: Background • The central question that must be addressed is “at what level of visual deficit would a maintenance or inspection worker become unable to perform the critical visual tasks required by the job in a safe and efficient manner?” • FAA Advisor Circular recommended examination guidelines for the vision of non-destructive inspection personnel. • near vision in at least one eye must be 20/25 and distance vision in at least one eye must be 20/50 (both near and far requirements may be with corrected or uncorrected vision). • Examinations must not be spaced longer than 2 years. • Color vision guidelines state that the inspector must: “distinguish and differentiate between colors necessary for the inspection method for which evidence of qualification is sought.”

7. Project 1: Objectives • To determine acceptable vision standards and procedures for personnel involved in nondestructive inspection and testing (NDI/NDT) and visual inspection of aircraft and aircraft components. • To measure any potential performance decrements on the specific tasks being performed by the maintenance personnel in their job-related tasks Final Report will specify minimum visual requirements for essential tasks in NDI/NDT and visual inspections which Flight Standards may use to write a medical standard similar to Part 67 for pilots.

8. Project 1: Planned Studies ‘02 & ‘03 • Conduct a literature search to determine which vision parameters have been addressed for NDI/NDT, visual inspection, or related tasks and what additional research would be needed to support a standard. • Produce a matrix illustrating which visual processes Flight Standards can use to write a medical standard for NDI/NDT and visual inspection tasks. This matrix will identify which vision processes need further investigation or have been completed adequately enough for Flight Standards requirements. • To investigate visual performance on inspection relevant visual tasks: well controlled, validated psychophysical paradigm such as that currently used in medicine to investigate tumor detection within background anatomical structures by physicians (Eckstein et al, 2002). • Determine the potential impact of the recommended vision standard may have on the current employee population.

9. Relating Visual Function to Inspector Tasks Preliminary hypotheses • Classic requirements (inspection technique) • Near visual acuity - A measure of the spatial resolution of a person’s vision for a high contrast image approximately 13” away from the person • discriminate wear marks on a machine part (visual & borescope) • small crack discrimination from other anomalies (visual, borescope, florescent penetrant) • wiring frays (visual) • reading computer screen (eddy current & ultrasonic) • pitting, scoring, porosity, and tool marks (visual & borescope) • fit of seals, bonds, gaskets, and sub-assemblies in difficult to reach areas (visual & borescope) • assess Foreign Object Damage (FOD) in aircraft, airframe, and power plants(visual & borescope) • Technology provided vision assistance: Inspectors with less than optimal visual acuity can use the focusing apparatus on the borescope or magnifier to produce a clear image

10. Relating Visual Function to Inspector Tasks Preliminary hypotheses • Classic requirements (inspection technique) • Distance visual acuity - The measure of spatial resolution of a person’s vision for a high contrast image approximately 20’ away. • Middle = >13” and < 20’ • paint chips (visual) • cracks, nicks, missing material (visual)

11. Relating Visual Function to Inspector Tasks Preliminary hypotheses • Classic requirements (inspection technique) • Color discrimination - ability to tell the difference between shades of one color or difference between two or more colors • discriminating paint colors (visual & borescope) • lightning strikes (visual) • zonal inspections in cabin (visual - see green) • cracks (green florescent penetrant against deep purple metal) • sulfidation (visual & borescope - dark greenish-gray in hot section of engine, low pressure turbine)

12. Relating Visual Function to Inspector Tasks Preliminary hypotheses • Classic requirements (inspection technique) • Peripheral vision - ability to perceive objects, movement or sharp contrasts toward the edges of the visual field. Peripheral vision is the ability to see these contrasts and gross movements • If an inspector either has a loss of receptors or afferent connections on either side of his visual field, then entire areas of the visual world can be invisible. Certain visual pathologies, lead to this type of visual field loss, such as glaucoma, diabetic retinopathy, and age.

13. Relating Visual Function to Inspector Tasks Preliminary hypotheses • Novel requirements (inspection technique) • Contrast sensitivity - Contrast, as applied to visual perception, denotes the ratio of the brightness of adjacent parts of the viewed pattern, for example, the ratio of the brightness of a sheet of aluminum to that of white powdery corrosion against which it stands. Only if there is sufficient contrast do objects become so distinct from the background as to be detectable. • Low spatial frequency • Mid spatial frequency • High spatial frequency • cracks • corrosion (visual & borescope - not common • because covered with ceramic) • heat or wear erosion - streaking • weld joints • solder connections • adhesive disbonds • identifying water or skin bulges (X-ray) • reading computer screen (eddy current & ultrasonic) • pitting, scoring, porosity, and tool marks (visual & borescope) • fit of seals, bonds, gaskets, and sub-assemblies in difficult to reach areas (visual & borescope) • assess Foreign Object Damage (FOD) (visual & borescope)

14. Relating Visual Function to Inspector Tasks Preliminary hypotheses • Novel requirements (inspection technique) • Shape from shading - ability to detect and identify object shapes from shadows • rippling on airframe indicating subcutaneous corrosion • seams • voids • pits • other surface, or subsurface, discontinuities in ferro-magnetic materials

15. Relating Visual Function to Inspector Tasks Preliminary hypotheses • Novel requirements (inspection technique) • Disability glare - bright lights significantly reduce ability to detect or discriminate objects. There is a relationship between the surrounding luminance and the sensed intensity of the adjacent object. Therefore, if the surrounding aluminum sheet is brightly illuminated, then the reflections off of the aluminum will render the white powdery corrosion less visible. • flashlight glare

16. Simulation of Visual Deficits Visual Acuity Original 20/100 20/80 20/40 Courtesy of Dr. Beard at NASA Ames

17. Simulation of Visual Deficits Contrast Sensitivity Original Low Pass Filter High Pass Filter Courtesy of Dr. Beard at NASA Ames

18. Simulation of Visual Deficits Color vision Original Deuteranope Protanope Tritanope Courtesy of Dr. Beard at NASA Ames

19. Project 2 Language Barriers Result in Maintenance Deficiencies Sponsor AFS-300 (POC: Les Vipond)

20. Project 2: Background • The FAA was directed by the Secretary of Transportation to establish “…a method for determining whether language barriers result in maintenance deficiencies” • In order to reduce maintenance costs, a number of Part 145 operators are outsourcing. • Within the past couple of years, there has been an increasing number of the people performing, inspecting and supervising the maintenance work do not have English as their native language, which may increase the probability of language-related errors. • Drury found that non-native English speakers have higher error rates, and that the restricted language Simplified English can eliminate this deficit.

21. Project 2: Objectives • To determine whether the growing number of maintenance and inspection personnel who possess a wide range of non-native English reading, writing, and speaking abilities are more inclined to commit an error than personnel whose native language is English. Final report will (1) identify patterns of language related errors and magnitude estimates for current and future problems associated with third-party repair station maintenance deficiencies resulting from language barriers, and (2) Recommendations in reducing third-party repair station maintenance deficiencies by changing maintenance personnel qualifications or changing maintenance tasks and/or procedures.

22. Project 2: Planned Studies ‘02 & ‘03 • Determine frequency and types of errors attributable to language for maintenance and inspection personnel who work in maintenance facilities and third party repair stations. • maintenance facilities may be included in the analysis to serve as the baseline to compare types of errors between maintenance facilities and third party repair stations to determine whether non-native English personnel have a higher propensity to commit errors or are these errors committed at the same rate between non-native and native English personnel. • Develop a comprehensive list of potential language error types and patterns as well as provide a better estimate of the different type of errors and rates.

23. Project 3 Using Technology to Support Inspector Training Sponsor AFS-300 (POC: Les Vipond)

24. Project 3: Background • In order for the FAA to provide the public with continuing safe, reliable air transportation, it is important to have a sound aircraft inspection and maintenance system, for both general as well as commercial aviation. • It is difficult to eliminate errors altogether, continuing emphasis must be placed on developing interventions to make the inspection/maintenance system more reliable and/or more error-tolerant • Training has been identified as the primary intervention strategy for improving the quality and reliability of aircraft inspection and for reducing errors.

25. Project 3: Objectives • To demonstrate how advanced technology can be used for inspection training and reducing errors for the general aviation industry • Extend earlier work (Gramopadhye) on computer-based inspection training for the commercial aviation system, applying it as an inspection training system for the general aviation industry • the tool will use a multi-media presentational approach with interaction opportunities between the user and the computer Final Report will provide the general aviation industry with a benchmark for inspector training.

26. Project 3: Planned Studies ‘02 & ‘03 • Develop data collection instruments • Identify general aviation, regional, and corporate maintenance facilities located across the country to be used in the data collection • Conduct task analyses

27. Project 4 Evaluation of Broadband Applications to Aircraft Maintenance Safety Sponsor AFS-300 (POC: Les Vipond)

28. Project 4: Background • The availability of new technologies for storing and accessing documentation (e. g., routine maintenance procedures, system diagrams and descriptions) and the growing volume of documentation required for maintaining aircraft call for the evaluation of the advantages and disadvantages of the various alternatives now available and likely to be available in the foreseeable future. • No matter how the information is stored (hard copy or electronic) or presented (hardcopy, CRT, voice, or a combination of these) each of these methods has obvious advantages and disadvantages, but their relative importance for specific tasks and in specific environments requires quantitative evaluation.

29. Project 4: Objectives • To determine the extent to which human-centered design contributes to the successful application of emerging technologies that include, but are not limited to: training-on-demand, video-on demand, wireless access to technical documentation and much more. • To review the emerging technologies to determine the impact on safety. Final Report will (1) summarize the different types of broadband applications currently used in maintenance facilities and third party repair stations, (2) identify broadband applications that may adversely affect maintenance personnel performance, and (3) provide an understanding of how broadband technology may aid maintenance personnel tasks and work environment.

30. Project 4: Planned Studies ‘02 & ‘03 • Identify maintenance and third party repair facilities located across the country to be used in the data collection • Develop and administer survey on how maintenance personnel use maintenance data, i.e. how much and which types of information are electronic? • Create a matrix that identifies the types of broadband technologies used by maintenance and third party repair facilities

31. Project 5 Review Amateur-Built Aircraft Accident/Incidents Sponsor AFS-300 (POC: Bill O’Brien)

32. Project 5: Background • Typically, the pilot/owner is responsible for design modifications, construction, and maintenance of the aircraft. This individual may or may not have much background in aviation construction or maintenance • Between 1993 and 2000, amateur built aircraft had risen from a little under 6000 to over 16,000 aircraft. • A 1997 NTSB Annual Review of Aircraft Accident Data for US GA reported that amateur built aircraft accounted for 3% of the aircraft hours flown in GA flying, but made up 10% of the accidents. • Preliminary analysis (Fiedler) of the amateur built mishaps between 1988-1997 found that there were 59 fatalities and 120 injuries in 211 maintenance-related homebuilt accidents

33. Project 5: Objectives • To determine the causal factors (e.g., human factors, construction, operation, maintenance and other factors that cause accidents) surrounding the high accident and incident rate for amateur-built aircraft per 100,000 hours of operation. • this research will then be compared against similar General Aviation accident and incidents. Final Report will contain (1) quantitative data identifying patterns of causal factors in amateur-built aircraft accidents and incidents, (2) recommendations in reducing amateur-built aircraft accidents and incidents by changing maintenance-related tasks and/or procedures, (3) quantitative data identifying patterns of causal factors in all types of General Aviation accident and incidents, and (4) recommendations in reducing general aviation accidents and incidents by changing tasks and/or procedures.

34. Project 5: Planned Studies ‘02 & ‘03 • Determine frequency and types of causal factors attributable to human factors, construction, operation, maintenance, and other factors in amateur-built aircraft accidents and incidents. • Compare this list to similar General Aviation maintenance-related accident and incidents.

35. Project 6 Assessment of Requirements for and Availability of Qualified Aviation Maintenance Technicians by 2005 Sponsor Airworthiness TCRG

36. Project 6: Background • At the outset 2001, the entire aviation maintenance community was forecasting a severe shortage of aviation maintenance technicians. • A combination of terrorist attacks, along with a pending economic downturn, has resulted in significant reductions in the aviation maintenance workforce. In this cyclic trend of maintenance personnel current conditions suggest that there is no longer a shortage. • As a result of this downturn, qualified technicians may permanently leave aviation for other career fields and schools may eliminate AMT training. • When the industry inevitably returns to full strength, as in the past, the shortage will occur.

37. Project 6: Objectives • To conduct an assessment of requirements for and availability of qualified aviation maintenance technicians for the year 2005. Final Report will (1) document the needs for aviation maintenance personnel manpower requirements for future years, (2) produce an Aviation Maintenance Technicians personnel model.

38. Project 6: Planned Studies ‘02 & ‘03 • None • Sponsor stated that this requirement is currently being addressed by a GAO study sponsored by Congress. • “I’m recommending that AFS 300 should not proceed with sponsoring a task on this issue until the GAO report is completed and released to the FAA and the public.” (e-mail from Vipond to Krebs on 5/28/02)