For the past 9 weeks, I have been an active student enrolled in the Embry-Riddle Aeronautical University-WorldWide-ASCI638 Human Factors in Unmanned Systems course. During this time, the other students and I were required to perform and present a case analysis of a subject of our own choosing relating to the numerous human factor issues that are associated with both manned and unmanned operations. The case report needed to demonstrate our understanding of the course topics by analyzing, evaluating, and developing recommendations for addressing an issue associated with human factors in the realm of unmanned aerial systems operations. We were required to retain a connection to a minimum of five course learning outcomes. We needed to identify an underlying issue or problem and propose a recommendation or hypothesis to mitigate the issue. I chose to perform my case analysis on Human Factor Challenges Associated with Maintenance of Unmanned Aircraft Systems.
The foundation of my 35+ years in aviation is maintenance and due in part to my current position as an Airworthiness Inspector assigned to the UAS Integration Office located in Washington, D.C.; I felt the subject matter was something that I could clearly sink my teeth into. During my research I became more familiar with human factors issues surrounding unmanned launch, recovery, long duration operations, fatigue, human performance, Ground Control Station (GCS) design, use of automation, Situation Awareness (SA), Crew Resource Management (CRM), integration into the National Airspace System (NAS), attitudes and perspectives of both government agencies and public entities, use of technology to compensate for no-pilot-onboard, and regulatory issues and solutions.
What I was surprised to learn thru my research was that analysis of maintenance failures associated with Human Factors in unmanned aircraft systems is not on the front table for discussion. I attributed this lack of available information to be directly related to the rapid advancements in technology regarding these systems and the regulators, manufacturers and operators inability to keep up with the continued airworthiness requirements for what is assumed by most of those players and the general public to be either a toy or a mindless drone that requires no additional oversight regarding maintenance activity. In my personal opinion this attitude may prove to be a grave mistake.
Regarding the case analysis as a tool that will benefit my current or future career:
• I found the process of collecting significant data to support my identified problem and proposed mitigation's similar to how I approached resolving issues in my previous two FAA assignments as 1) a manufacturing Inspector and 2) a Maintenance Review Board Chairman assigned to the Aircraft Evaluation Group (AEG). In both of those positions when presented an issue that needed clarification and/or a regulatory response (as would always be the case) I relied on the Regulations, Advisory Circulars, Orders (Inspector guidance) and personal experience to provide a response that was within regulatory guidance and mitigated issues based on a risk based approach.
My only recommendation to enhance the learning experience would be to allow for a final peer review of pre-selected case analysis reports. Not only would it offer feedback to the author on the final/post draft paper, but provide additional theoretical perspectives for the reviewer. Sounds heavy doesn’t it?
Friday, December 18, 2015
8.7 HUMAN FACTOR CHALLENGES ASSOCIATED WITH MAINTENANCE OF UNMANNED AIRCRAFT SYSTEMS
Running head: HUMAN FACTOR CHALLENGES 1
Human Factor Challenges Associated with Maintenance of Unmanned Aircraft Systems
Robert J. Winn
Embry-Riddle Aeronautical University-WW-ASCI 638
Abstract
The expeditious pace with which Unmanned Aircraft Systems (UAS) are being introduced into the National Airspace System (NAS) presents many challenges. In meeting these challenges, the Federal Aviation Administration (FAA) as mandated by congress in the FAA Modernization and Reform Act (FMRA) of 2012, was tasked to “develop a comprehensive plan to safely accelerate the integration of civil unmanned aircraft systems into the National Airspace System.” Once integration has been achieved, processes and procedures addressing continued airworthiness of UAS must be developed, achieved and understood in order to keep these systems, as well as the general public, property and the NAS safe. Unfortunately, due to the fast pace with which these unmanned systems have been introduced previously established maintenance programs applicable to manned aviation do not address those aspects particular to unmanned programs. The dissimilarities between manned and unmanned systems, have called attention to numerous Human Factor issues. This case study will introduce Human Factors that are associated with these systems, present accident data and the challenges associated with unmanned aircraft systems maintenance programs.
Keywords: airworthiness, human factors, maintenance, public, safety, unmanned aircraft system,
Human Factor Challenges Associated with Maintenance of Unmanned Aircraft Systems
The Federal Aviation Administration (FAA) as mandated by congress in the FAA Modernization and Reform Act (FMRA) of 2012 was tasked to “develop a comprehensive plan to safely accelerate the integration of civil unmanned aircraft systems into the National Airspace System.” Once integration has been achieved, processes and procedures addressing continued airworthiness of UAS must be developed, achieved and understood in order to keep these systems as well as the general public, property and the NAS safe. These processes and procedures will be addressed in regulations to ensure UAS are maintained in an airworthy condition.
The regulations must address the airworthiness of the UAV, qualifications of the operator (pilot), and any special operating rules when the UAV cannot meet the same requirements as manned aircraft (Cooke,2006). But the issue is that the regulations are developed after UAS integration into the NAS has already taken place.
The following section is taken directly from the FAAs Roadmap for UAS integration. It clearly shows that certification of UAS airframes is not on the radar until 2020/2030 and that research is still needed to support any regulations to ensure the continued airworthiness of the airframe /system.
3.2 Airframe Certification
Description of the challenge: Enable the rapid and affordable airframe certification for all types of UAS through increase emphasis on structural analysis and reduction in airframe testing. The existing basis of certification does not cover the new and novel materials and manufacturing processes being used in the manufacturing of UAS. As these methods and materials continue to evolve, research is needed to support an airworthiness determination and continue to ensure airworthiness over the life of the aircraft.
Goals:
Goal 1: Certify an airframe by analysis verified by test, 2020
Goal 2: Develop certification standards for advanced materials and structural design, 2020
Goal 3: Continued airworthiness through onboard health monitoring, 2030 (Roadmap, 2012).
Unfortunately, due to the fast pace with which these unmanned systems have been introduced to the general public, previously established manned maintenance programs do not address aspects significant to unmanned systems. The dissimilarities between manned and unmanned systems have called attention to numerous Human Factor issues. Human factors are a multidisciplinary approach to examining system design, training, experience, and individual motivation, with the objective of positively influencing human performance (USI, 2015). Two conceptual models used to analyze those human factor issues and for assessing and mitigating human factors in aviation maintenance are presented below.
SHEL
The original SHEL concept was developed using the first letters of each basic component, Software, Hardware, Environment and Liveware. The ICAO SHELL model (Fig. 1) introduced by Hawkins in 1975 illustrates how the concept is structured by conjoined blocks.
Figure 1 SHELL model
Source http://www.skybrary.aero/index.php/File:Liveware.jpg
This building block diagram is only intended as a basic aid to understanding Human Factors:
• Software - the rules, procedures, written documents etc., which are part of the standard operating procedures.
• Hardware - the Air Traffic Control suites, their configuration, controls and surfaces, displays and functional systems.
• Environment - the situation in which the L-H-S system must function, the social and economic climate as well as the natural environment.
• Liveware - the human beings - the controller with other controllers, flight crews, engineers and maintenance personnel, management and administration people - within in the system.
PEAR
In an article published in April 2007, Dr. William Johnson presented another conceptual model, where PEAR is used to recall four considerations for assessing and mitigating human factors in aviation maintenance:
• People who do the job; where Physical, Physiological, Psychological and Psychosocial factors are examined.
• Environment in which they work; considers the Physical and Organizational aspects
• Actions they perform; considers the WHAT (i.e. steps, performance, amount of people, communication [oral, visual, written] and information control requirements
• Resources necessary to complete the job. Considers procedures/work cards, Manuals/bulletins/FARs, Test equipment, Tools, Computers, paperwork /signoffs, Ground handling Equipment, Fixtures, materials, task lighting additional manpower and training.
Much like the building blocks in the SHELL model, the PEAR model provides basic factors to facilitate examination of a specific maintenance program. If those areas are weak or robust in nature they will be identified. This information is necessary to ensure that appropriate mitigations to correct them are implemented.
Hurdles
The Unmanned Safety Institute (USI) published a course workbook Building Safe sUAS Organizations (2015) which identified problems associated with UAS technology;
• The explosive number of systems available on the market combined with the relative low barriers to entry has attributed to UAS operations in the NAS as being crowded and dangerous.
• Many of the commercial UAS operators are amateurs turned “professional” and operate with complete ignorance of regulations and guidance.
• Even those who wish to comply with the regulations lack the aviation backgrounds and do not know where or how to begin.
• Those with manned aviation backgrounds find the unmanned systems challenging.
• Original Equipment Manufacturers are new to the aerospace industry and lack the ability to adapt to continued airworthiness requirements.
System Description
A description of a manned system is not very complicated. The aircraft or fuselage is the core component which facilitates the power supply/engine(s), fuel, communication/navigation equipment and provides a command and control platform for the pilot(s) free from external environmental distractions.
Unmanned systems are significantly different, in that the “system” consists of these primary separate components;
• Air vehicle
• Control station
• Payload
• Navigation Systems
• Communications –up/down data links
• Launch and Recovery equipment
• Operator/Pilot
UAS Incident Data
As with any new technology rushed to market, the UAS industry has been plagued by failures at a rate of approximately 1 in every 200 flying hours. These failures are directly related to lack of system standards, certification and poor maintenance oversight.
About 80% of maintenance mistakes in manned aviation involve human factors and if not detected would lead to accidents. Reports regarding unmanned aircraft (UA) accidents have been shown to be higher than that of manned aviation. In order to improve the safety of these systems identifying and understanding the factors involved must be accomplished. The most reliable source for UA accident data currently is the military. The military has a relatively long history of UA use and is diligent in accurately recording information pertaining to accidents/incidents (Williams, 2004).
Accident Data/Classification
The military takes a two-step approach in the classification of UA accidents. The first step takes a rather broad approach to identify those accidents that were attributed to Human factors (Liveware/People) or system component failure (hardware). Within this first step a “Maintenance” category is included to identify those accidents directly attributed to maintenance personnel. In the second step, those accidents classified as related to human factors were classified according to specific human factors issues that are commonly addressed in current research (Williams, 2004).
Data classification from the U.S Army Hunter program shows that accidents attributed to the Aircraft (hardware) accounted for 50% of the Hunter accidents. However, the data also shows that Human Factors and Maintenance errors combined for 56% of the programs accidents. Data, associated with U.S Air Force Predator failures attributes Maintenance (17%), Human Factors (67%) and Aircraft (42%) as the causal factors.
Knowledge
In the book, Introduction to Unmanned Aircraft Systems, by Barnhart, Shapee and Marshall (2011) it was presented that new UAS and their technologies do not fit neatly into the currently accepted training programs, programs that have been proven effective for manned operations. Additionally, these flight systems are being produced faster than the existing flight-training regime can react to them. To compound these training deficiencies, new technology systems that perform similar functions do not look alike and operator interactions with these systems often are completely different. A case could be made that these same issues, regarding the inability to keep up with rapid technological advances, associated with unmanned systems would also be realized by those responsible for the continued airworthiness and maintenance of these systems.
System Maintenance
Maintenance activities are classified into two categories, that of scheduled and unscheduled maintenance, each with its own challenges. Scheduled tasks include routine inspections, adjustments, and time replacements of components. Although the distinction between scheduled and unscheduled maintenance is widely used in the aviation industry, UAS operators do not tend to make a clear distinction between the two. This is partly because in the absence of maintenance procedures, virtually all maintenance tasks are unscheduled (Hobbs, 2008).
Scheduled
Scheduled or preventative maintenance is normally accomplished during a prescribed schedule, recommended by the system manufacturer and or developed by the operator. Conducting these inspections and performing the required maintenance tasks are essential to ensuring that those parts and or systems that have a life limit or known time between failure (TBF) rate are addressed. Scheduled tasks tend to be performed frequently and become familiar, routine activities for the technician. The routine nature of such tasks can increase the chances of absent-minded errors such as memory lapses (Hobbs, 2008).
Unscheduled
Unscheduled maintenance is just what it sounds like. It is a required action due to a mishap where damage was incurred by the system, or requires maintenance be performed to conduct an analysis and repair of a system or hardware failure. Fault identification and diagnosis can be a time-consuming part of UA maintenance, particularly when faults involve avionics or computer systems (Hobbs, 2008).
Due to the lack of manufacturing procedures and guidance unscheduled maintenance can impose undue stress on the mechanic or operator as the lack of a general understanding of the system or repair requirements can cause a significant delay in meeting operational (airtime)/customer induced expectations.
Maintenance Challenges
UAS maintenance is defined as any activity performed on the ground before or after flight to ensure the successful and safe operation of the system. Small UAS maintenance bears little similarity to conventional aviation maintenance as it is currently unregulated, and is rarely performed by personnel with formal maintenance qualifications. (Hobbs, 2008).
In July 2013, the FAA published Unmanned Aircraft Systems (UAS) Operational Approval Notice 8900.227 which stated that UAS Maintenance Qualifications, ratings and training requirements would be established as more data is collected and a regulatory guideline is developed. To date commercial sUAS operators are only required to make a self-certifying statement that the UAS will be maintained in an airworthy condition for operation in the NAS. However, no verification by the FAA is conducted to ensure that the operator has the training or knowledge to show an understanding of what “airworthy” means or that adequate inspection and maintenance procedures have been developed by the manufacturer or the operator to ensure the continued airworthiness of the system.
The bottom-line, the general public lacks the training and understanding that is required to ensure that an “aircraft” and its systems are in a condition for safe operation. This is even more of an issue due to proliferation of these systems available to the untrained public.
The complexity of these systems combined with relatively low reliability will translate into higher mishap rates and higher risk. It is therefore imperative that before and after every flight the system must be inspected for damage or malfunctioning equipment. It is equally important that the system is transported and stored in a safe and secure location (USI, 2015).
Conclusion
It is difficult to identify the knowledge and skills needed by UAS maintenance personnel, due to the ever changing advancements in technology and system design. It is clear however, that UAS maintenance personnel require a significantly different skill set to their counterparts in manned aviation. System components such as laptop computers, modems, and radio communication systems are critical to the safety of unmanned flight and present significant human factor issues. Future requirements or guidance for UAS maintenance training or qualifications must go beyond the traditional manned aviation maintenance programs and should include those topics associated with the advanced UAS technology.
References
Barnhart, Richard K., Shappee, Eric, and Marshall, Douglas M. (2011). Introduction to Unmanned Aircraft Systems. London, GBR: CRC Press, 2011. ProQuest ebrary. Web. 8 December 2015.
Cooke, Nancy J., Pringle, Heather, and Pedersen, Harry, eds. Human Factors of Remotely Operated Vehicles, Volume 7. Amsterdam, NLD: JAI Press, 2006. ProQuest ebrary. Web. 8 December 2015.
FAA Modernization and Reform Act of 2012, 112th Congress 2d Session, Report 112-381, Conference Report to accompany H.R. 658 Retrieved from http://www.gpo.gov/fdsys/pkg/CRPT-112hrpt381/pdf/CRPT-112hrpt381.pdf
FAA Notice N 8900.227 (2013) retrieved from http://www.faa.gov/documentlibrary/media/notice/n_8900.227.pdf
Hobbs, A. Ph.D., Herwitz, S. Ph.D. (2008) Maintenance Challenges of small Unmanned Aircraft Systems-a Human Factors Perspective, An Introductory Handbook retrieved from http://human-factors.arc.nasa.gov/publications/Maint_Chall_Small_Unman_Aircraft_Human_Factors_Persp.pdf
Johnson, W.B., Maddox, M.E (2007). A Model to Explain Human Factors in Aviation Maintenance Retrieved from http://www.skybrary.aero/bookshelf/books/1482.pdf
Roadmap (2012). NextGen UAS Research, Development and Demonstration Roadmap Version 1.0 March 15, 2012 retrieved from https://fas.org/irp/program/collect/uas-nextgen.pdf
Skybrary (2013). ICAO SHELL Model Retrieved from http://www.skybrary.aero/index.php/ICAO_SHELL_Model
USI, (2015) Building Safe sUAS Organizations course workbook Copyright 2015 The Unmanned Safety Institute
Williams, K.W (2004). A Summary of Unmanned Aircraft Accident/Incident Data: Human Factors Implications, Retrieved from http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.79.4150&rep=rep1&type=pdf
Human Factor Challenges Associated with Maintenance of Unmanned Aircraft Systems
Robert J. Winn
Embry-Riddle Aeronautical University-WW-ASCI 638
Abstract
The expeditious pace with which Unmanned Aircraft Systems (UAS) are being introduced into the National Airspace System (NAS) presents many challenges. In meeting these challenges, the Federal Aviation Administration (FAA) as mandated by congress in the FAA Modernization and Reform Act (FMRA) of 2012, was tasked to “develop a comprehensive plan to safely accelerate the integration of civil unmanned aircraft systems into the National Airspace System.” Once integration has been achieved, processes and procedures addressing continued airworthiness of UAS must be developed, achieved and understood in order to keep these systems, as well as the general public, property and the NAS safe. Unfortunately, due to the fast pace with which these unmanned systems have been introduced previously established maintenance programs applicable to manned aviation do not address those aspects particular to unmanned programs. The dissimilarities between manned and unmanned systems, have called attention to numerous Human Factor issues. This case study will introduce Human Factors that are associated with these systems, present accident data and the challenges associated with unmanned aircraft systems maintenance programs.
Keywords: airworthiness, human factors, maintenance, public, safety, unmanned aircraft system,
Human Factor Challenges Associated with Maintenance of Unmanned Aircraft Systems
The Federal Aviation Administration (FAA) as mandated by congress in the FAA Modernization and Reform Act (FMRA) of 2012 was tasked to “develop a comprehensive plan to safely accelerate the integration of civil unmanned aircraft systems into the National Airspace System.” Once integration has been achieved, processes and procedures addressing continued airworthiness of UAS must be developed, achieved and understood in order to keep these systems as well as the general public, property and the NAS safe. These processes and procedures will be addressed in regulations to ensure UAS are maintained in an airworthy condition.
The regulations must address the airworthiness of the UAV, qualifications of the operator (pilot), and any special operating rules when the UAV cannot meet the same requirements as manned aircraft (Cooke,2006). But the issue is that the regulations are developed after UAS integration into the NAS has already taken place.
The following section is taken directly from the FAAs Roadmap for UAS integration. It clearly shows that certification of UAS airframes is not on the radar until 2020/2030 and that research is still needed to support any regulations to ensure the continued airworthiness of the airframe /system.
3.2 Airframe Certification
Description of the challenge: Enable the rapid and affordable airframe certification for all types of UAS through increase emphasis on structural analysis and reduction in airframe testing. The existing basis of certification does not cover the new and novel materials and manufacturing processes being used in the manufacturing of UAS. As these methods and materials continue to evolve, research is needed to support an airworthiness determination and continue to ensure airworthiness over the life of the aircraft.
Goals:
Goal 1: Certify an airframe by analysis verified by test, 2020
Goal 2: Develop certification standards for advanced materials and structural design, 2020
Goal 3: Continued airworthiness through onboard health monitoring, 2030 (Roadmap, 2012).
Unfortunately, due to the fast pace with which these unmanned systems have been introduced to the general public, previously established manned maintenance programs do not address aspects significant to unmanned systems. The dissimilarities between manned and unmanned systems have called attention to numerous Human Factor issues. Human factors are a multidisciplinary approach to examining system design, training, experience, and individual motivation, with the objective of positively influencing human performance (USI, 2015). Two conceptual models used to analyze those human factor issues and for assessing and mitigating human factors in aviation maintenance are presented below.
SHEL
The original SHEL concept was developed using the first letters of each basic component, Software, Hardware, Environment and Liveware. The ICAO SHELL model (Fig. 1) introduced by Hawkins in 1975 illustrates how the concept is structured by conjoined blocks.
Source http://www.skybrary.aero/index.php/File:Liveware.jpg
This building block diagram is only intended as a basic aid to understanding Human Factors:
• Software - the rules, procedures, written documents etc., which are part of the standard operating procedures.
• Hardware - the Air Traffic Control suites, their configuration, controls and surfaces, displays and functional systems.
• Environment - the situation in which the L-H-S system must function, the social and economic climate as well as the natural environment.
• Liveware - the human beings - the controller with other controllers, flight crews, engineers and maintenance personnel, management and administration people - within in the system.
PEAR
In an article published in April 2007, Dr. William Johnson presented another conceptual model, where PEAR is used to recall four considerations for assessing and mitigating human factors in aviation maintenance:
• People who do the job; where Physical, Physiological, Psychological and Psychosocial factors are examined.
• Environment in which they work; considers the Physical and Organizational aspects
• Actions they perform; considers the WHAT (i.e. steps, performance, amount of people, communication [oral, visual, written] and information control requirements
• Resources necessary to complete the job. Considers procedures/work cards, Manuals/bulletins/FARs, Test equipment, Tools, Computers, paperwork /signoffs, Ground handling Equipment, Fixtures, materials, task lighting additional manpower and training.
Much like the building blocks in the SHELL model, the PEAR model provides basic factors to facilitate examination of a specific maintenance program. If those areas are weak or robust in nature they will be identified. This information is necessary to ensure that appropriate mitigations to correct them are implemented.
Hurdles
The Unmanned Safety Institute (USI) published a course workbook Building Safe sUAS Organizations (2015) which identified problems associated with UAS technology;
• The explosive number of systems available on the market combined with the relative low barriers to entry has attributed to UAS operations in the NAS as being crowded and dangerous.
• Many of the commercial UAS operators are amateurs turned “professional” and operate with complete ignorance of regulations and guidance.
• Even those who wish to comply with the regulations lack the aviation backgrounds and do not know where or how to begin.
• Those with manned aviation backgrounds find the unmanned systems challenging.
• Original Equipment Manufacturers are new to the aerospace industry and lack the ability to adapt to continued airworthiness requirements.
System Description
A description of a manned system is not very complicated. The aircraft or fuselage is the core component which facilitates the power supply/engine(s), fuel, communication/navigation equipment and provides a command and control platform for the pilot(s) free from external environmental distractions.
Unmanned systems are significantly different, in that the “system” consists of these primary separate components;
• Air vehicle
• Control station
• Payload
• Navigation Systems
• Communications –up/down data links
• Launch and Recovery equipment
• Operator/Pilot
UAS Incident Data
As with any new technology rushed to market, the UAS industry has been plagued by failures at a rate of approximately 1 in every 200 flying hours. These failures are directly related to lack of system standards, certification and poor maintenance oversight.
About 80% of maintenance mistakes in manned aviation involve human factors and if not detected would lead to accidents. Reports regarding unmanned aircraft (UA) accidents have been shown to be higher than that of manned aviation. In order to improve the safety of these systems identifying and understanding the factors involved must be accomplished. The most reliable source for UA accident data currently is the military. The military has a relatively long history of UA use and is diligent in accurately recording information pertaining to accidents/incidents (Williams, 2004).
Accident Data/Classification
The military takes a two-step approach in the classification of UA accidents. The first step takes a rather broad approach to identify those accidents that were attributed to Human factors (Liveware/People) or system component failure (hardware). Within this first step a “Maintenance” category is included to identify those accidents directly attributed to maintenance personnel. In the second step, those accidents classified as related to human factors were classified according to specific human factors issues that are commonly addressed in current research (Williams, 2004).
Data classification from the U.S Army Hunter program shows that accidents attributed to the Aircraft (hardware) accounted for 50% of the Hunter accidents. However, the data also shows that Human Factors and Maintenance errors combined for 56% of the programs accidents. Data, associated with U.S Air Force Predator failures attributes Maintenance (17%), Human Factors (67%) and Aircraft (42%) as the causal factors.
Knowledge
In the book, Introduction to Unmanned Aircraft Systems, by Barnhart, Shapee and Marshall (2011) it was presented that new UAS and their technologies do not fit neatly into the currently accepted training programs, programs that have been proven effective for manned operations. Additionally, these flight systems are being produced faster than the existing flight-training regime can react to them. To compound these training deficiencies, new technology systems that perform similar functions do not look alike and operator interactions with these systems often are completely different. A case could be made that these same issues, regarding the inability to keep up with rapid technological advances, associated with unmanned systems would also be realized by those responsible for the continued airworthiness and maintenance of these systems.
System Maintenance
Maintenance activities are classified into two categories, that of scheduled and unscheduled maintenance, each with its own challenges. Scheduled tasks include routine inspections, adjustments, and time replacements of components. Although the distinction between scheduled and unscheduled maintenance is widely used in the aviation industry, UAS operators do not tend to make a clear distinction between the two. This is partly because in the absence of maintenance procedures, virtually all maintenance tasks are unscheduled (Hobbs, 2008).
Scheduled
Scheduled or preventative maintenance is normally accomplished during a prescribed schedule, recommended by the system manufacturer and or developed by the operator. Conducting these inspections and performing the required maintenance tasks are essential to ensuring that those parts and or systems that have a life limit or known time between failure (TBF) rate are addressed. Scheduled tasks tend to be performed frequently and become familiar, routine activities for the technician. The routine nature of such tasks can increase the chances of absent-minded errors such as memory lapses (Hobbs, 2008).
Unscheduled
Unscheduled maintenance is just what it sounds like. It is a required action due to a mishap where damage was incurred by the system, or requires maintenance be performed to conduct an analysis and repair of a system or hardware failure. Fault identification and diagnosis can be a time-consuming part of UA maintenance, particularly when faults involve avionics or computer systems (Hobbs, 2008).
Due to the lack of manufacturing procedures and guidance unscheduled maintenance can impose undue stress on the mechanic or operator as the lack of a general understanding of the system or repair requirements can cause a significant delay in meeting operational (airtime)/customer induced expectations.
Maintenance Challenges
UAS maintenance is defined as any activity performed on the ground before or after flight to ensure the successful and safe operation of the system. Small UAS maintenance bears little similarity to conventional aviation maintenance as it is currently unregulated, and is rarely performed by personnel with formal maintenance qualifications. (Hobbs, 2008).
In July 2013, the FAA published Unmanned Aircraft Systems (UAS) Operational Approval Notice 8900.227 which stated that UAS Maintenance Qualifications, ratings and training requirements would be established as more data is collected and a regulatory guideline is developed. To date commercial sUAS operators are only required to make a self-certifying statement that the UAS will be maintained in an airworthy condition for operation in the NAS. However, no verification by the FAA is conducted to ensure that the operator has the training or knowledge to show an understanding of what “airworthy” means or that adequate inspection and maintenance procedures have been developed by the manufacturer or the operator to ensure the continued airworthiness of the system.
The bottom-line, the general public lacks the training and understanding that is required to ensure that an “aircraft” and its systems are in a condition for safe operation. This is even more of an issue due to proliferation of these systems available to the untrained public.
The complexity of these systems combined with relatively low reliability will translate into higher mishap rates and higher risk. It is therefore imperative that before and after every flight the system must be inspected for damage or malfunctioning equipment. It is equally important that the system is transported and stored in a safe and secure location (USI, 2015).
Conclusion
It is difficult to identify the knowledge and skills needed by UAS maintenance personnel, due to the ever changing advancements in technology and system design. It is clear however, that UAS maintenance personnel require a significantly different skill set to their counterparts in manned aviation. System components such as laptop computers, modems, and radio communication systems are critical to the safety of unmanned flight and present significant human factor issues. Future requirements or guidance for UAS maintenance training or qualifications must go beyond the traditional manned aviation maintenance programs and should include those topics associated with the advanced UAS technology.
References
Barnhart, Richard K., Shappee, Eric, and Marshall, Douglas M. (2011). Introduction to Unmanned Aircraft Systems. London, GBR: CRC Press, 2011. ProQuest ebrary. Web. 8 December 2015.
Cooke, Nancy J., Pringle, Heather, and Pedersen, Harry, eds. Human Factors of Remotely Operated Vehicles, Volume 7. Amsterdam, NLD: JAI Press, 2006. ProQuest ebrary. Web. 8 December 2015.
FAA Modernization and Reform Act of 2012, 112th Congress 2d Session, Report 112-381, Conference Report to accompany H.R. 658 Retrieved from http://www.gpo.gov/fdsys/pkg/CRPT-112hrpt381/pdf/CRPT-112hrpt381.pdf
FAA Notice N 8900.227 (2013) retrieved from http://www.faa.gov/documentlibrary/media/notice/n_8900.227.pdf
Hobbs, A. Ph.D., Herwitz, S. Ph.D. (2008) Maintenance Challenges of small Unmanned Aircraft Systems-a Human Factors Perspective, An Introductory Handbook retrieved from http://human-factors.arc.nasa.gov/publications/Maint_Chall_Small_Unman_Aircraft_Human_Factors_Persp.pdf
Johnson, W.B., Maddox, M.E (2007). A Model to Explain Human Factors in Aviation Maintenance Retrieved from http://www.skybrary.aero/bookshelf/books/1482.pdf
Roadmap (2012). NextGen UAS Research, Development and Demonstration Roadmap Version 1.0 March 15, 2012 retrieved from https://fas.org/irp/program/collect/uas-nextgen.pdf
Skybrary (2013). ICAO SHELL Model Retrieved from http://www.skybrary.aero/index.php/ICAO_SHELL_Model
USI, (2015) Building Safe sUAS Organizations course workbook Copyright 2015 The Unmanned Safety Institute
Williams, K.W (2004). A Summary of Unmanned Aircraft Accident/Incident Data: Human Factors Implications, Retrieved from http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.79.4150&rep=rep1&type=pdf
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