Human Factors Policies Related to Transport Airplane Certification

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Human Factors Policies Related to Transport
Airplane Certification
Loran Haworth FAA Transport Airplane Directorate
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Purpose of this Briefing

• Federal Aviation Administration (FAA)
  Certification Service
• Provide limited exposure to the regulations
  related to human factors issues
• Introduce the human factors policies that have
  been published
• Discuss how human factors issues can be covered
  explicitly in a certification plan
• Discuss some of the issues associated with
  methods of compliance for regulations related to
  human factors
• Bilateral Cooperation

http//av-info.faa.gov/software/related.htm
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The Aircraft Certification Service Mission

• Promote Aviation Safety by
• Prescribing minimum standards for aeronautical
  products
• Administering Certification Programs to assure
  compliance with prescribed safety standards
• Monitoring safety performance and acting to
  provide continued operational safety of aircraft
• Working with other countries to improve safety
  internationally and harmonize certification
  standards and practices

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Aircraft Certification Service Accountable
Directorates
Headquarters Policy Offices (Standards Staff)
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Role of Accountable Directorate

• Special Policy Office
• Develops policy for particular category of
  aircraft or component
• Established where Aircraft Certification (AIR)
  has depth of experience
• Responsibility for specific bilateral partner
  countries
• Focal point for resolution of issues, information
  and formal bilateral meetings

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Unofficial Definition of Human Factors for
Aircraft Certification

• The application of scientific theory, principles,
  data and methods
• about human abilities, limitations, and other
  characteristics...
• to the establishment of minimum safety-related
  design requirements for flight crew interfaces,
  tasks, and procedures,
• and then ensuring that those requirements are
  met,in order to promote overall system
  performance and safety.
• This is nothing magical - there are a number of
  existing rules that attempt to account for the
  needs of the pilot

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Classic HF Rules?

•  25.777(b) The direction of movement of cockpit
  controls must meet the requirements of Sec.
  25.779. Wherever practicable, the sense of motion
  involved in the operation of other controls must
  correspond to the sense of the effect of the
  operation upon the airplane or upon the part
  operated. Controls of a variable nature using a
  rotary motion must move clockwise from the off
  position, through an increasing range, to the
  full on position.

•  25.781 Cockpit control knobs must conform to
  the general shapes (but not necessarily the exact
  sizes or specific proportions) in the following
  figure

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Human Factors Rules

• There are a number of Part 25 regulations that
  directly relate to human factors issues, e.g.
• Workload, Fatigue, Minimum Crew (25.771, 25.1523,
  Appendix D)
• Intended function (25.1301)
• Lighting (25.1321)
• Error associated with responding to system
  failures (25.1309)
• Control operation and arrangement, reach
  clearance (25.777)
• Human factors issues cut across the entire flight
  deck
• Human factors issues often require subjective
  evaluation

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Some General HF Requirements

• 25.771a Each pilot compartment and its
  equipment must allow the minimum flight crew to
  perform their duties without unreasonable
  concentration or fatigue.
• 25.771e Vibration and noise characteristics of
  cockpit equipment may not interfere with safe
  operation of the airplane.
• 25.773a(1) Each pilot compartment must be
  arranged to give the pilots sufficiently
  extensive, clear, and undistorted view, to enable
  them to safely perform any maneuvers within the
  operating limitations of the airplane, including
  takeoff, approach, and landing.
• 25.773a(2) Each pilot compartment must be free
  of glare and reflections that could interfere
  with the normal duties of the minimum flight
  crew.
• 25.777a Each cockpit control must be located to
  provide convenient operation and to prevent
  confusion and inadvertent operation.

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Some General HF Requirements (continued)

• 25.777c The controls must be located and
  arranged, with respect to the pilots seats, so
  that there is full and unrestricted movement of
  each control without interference from the
  cockpit structure or the clothing of the minimum
  flight crew when any member of this flight crew,
  from 52 to 63 in height, is seated with the
  seat belt and shoulder harness fastened.
• 25.1301a Each item of installed equipment must
  be of a kind and design appropriate to its
  intended function.
• 25.1309b(3) Systems, controls, and associated
  monitoring and warning means must be designed to
  minimize crew errors which could create
  additional hazards.
• 25.1321a Each flight, navigation, and
  powerplant instrument for use by any pilot must
  be plainly visible to him from his station with
  the minimum practicable deviation from his normal
  position and line of vision when he is looking
  forward along the flight path.

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Some General HF Requirements (continued)

• 25.1321e If a visual indicator is provided to
  indicate malfunction of an instrument, it must be
  effective under all probable cockpit lighting
  conditions.
• 25.1523. The minimum flight crew must be
  established so that it is sufficient for safe
  operation, considering
• a) The workload on individual crewmembers
• b) The accessibility and ease of operation of
  necessary controls by the appropriate
  crewmember, and
• c) The kind of operation authorized under
  25.1525. The criteria used in making the
  determinations required by this section are set
  forth in Appendix D
• 25.1543b Each instrument marking must be
  clearly visible to the appropriate crewmember.

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System - Specific HF Requirements

• 25.785g Each seat at a flight deck station must
  have a restraint system that permits the flight
  deck occupant, when seated with the restraint
  system fastened, to perform all of the occupants
  necessary flight deck functions.
• 25.785L The forward observers seat must be
  shown to be suitable for use in conducting the
  necessary enroute inspections.
• 25.1141a Power plant controls each control
  must be located so that it cannot be
  inadvertently operated by persons entering,
  leaving, or moving normally in the cockpit.

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System - Specific HF Requirements (cont.)

• 25.1322 If warning, caution, or advisory
  lights are installed in the cockpit, they must,
  unless otherwise approved by the Administrator,
  be -
• Red, for warning lights (lights indicating a
  hazard which may require immediate corrective
  action)
• Amber, for caution lights (lights indicating the
  possible need for future corrective action)
• Green for safe operation lights and
• Any other color, including white, for lights not
  described in paragraphs (a) through (c) of this
  section, provided the color differs sufficiently
  from the colors prescribed in paragraphs (a)
  through (c) of this section to avoid possible
  confusion.

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System - Specific HF Requirements (continued)

• 25.1357d If the ability to reset a circuit
  breaker or replace a fuse is essential to safety
  in flight, that circuit breaker or fuse must be
  located and identified so that it can be readily
  reset or replaced in flight.
• 25.1381a(2) The instrument lights must be
  installed so that (ii) no objectionable
  reflections are visible to the pilot.

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Limited Human Factors Guidance

• There is guidance material for only a few of the
  HF rules
• AC 25-7A Flight Test Guide for Certification of
  Transport Airplanes
• AC 25-11 Transport Category Airplane Electronic
  Display Systems
• AC 25.1523-1 Minimum Flight Crew
• AC 25.773-1 Pilot Compartment View Design
  Considerations
• AC 20-88A Guidelines on the Marking of Aircraft
  Powerplant Instruments
• Misc ACs for specific systems (e.g. TAWS, TCAS)

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We Are Often Asked for Help

• Aircraft Certification Offices have requested
  help in assessing the human factors aspects of
  designs being proposed for certification
• How to approach the human factors aspects of
  certification programs
• How to determine the way the designs should be
  evaluated
• How to determine whether the designs are
  compliant
• How to increase standardization across ACOs
• Some applicants have also requested assistance
• Help in planning their compliance activities
• Better standardization across ACOs
• Better understanding of the role of FAA HF
  specialists, pilots, and systems specialists with
  respect to HF compliance

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How to get help on HF issues

• FAA AVR HF Specialists

Part 25 Steve Boyd Loran Haworth John McConnell
Wichita ACOJeff Holland
Part 21 Colleen Donovan Glen Galloway Bill
Kaliardos (AIR-130)
Part 23 Frank Bick
Atlanta ACO Gina Bolinger
Part 27, 29 Clark Davenport
National Resource SpecialistKathy Abbott (AVR)
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Initiatives Underway or Planned

• Determine if any new rules or advisory material
  are needed
• Human Factors Harmonization Working Group (HWG)
• Avionics Systems HWG (now working 25.1322/AC and
  AC 25-11)
• Flight Guidance Systems HWG (now working
  25.1329/AC)
• Provide improved human factors information to the
  ACOs
• Human Factors Job Aid - will also be released to
  applicants
• A relational database that will allow multiple
  entry paths to
• Regulations
• Systems
• Human Factors Issues
• Research, policy, and other supporting data

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Initiatives Underway or Planned (continued)

• Develop policies supporting the human factors
  aspects of certification programs
• Information on Human Factors Certification Plans
  (Policy ANM 99-2, published in October 99)
• Information on human factors methods of
  compliance (Policy ANM-01-03, draft published in
  May 01)
• Information on human factors test planning
• Information on human factors test and evaluation
  acceptance criteria
• Information on roles and responsibilities for
  human factors compliance issues.
• Note The policies are being published in the
  Federal Registerso that industry can be fully
  aware of the policies andprovide comments.

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Policy on Human Factors Certification Plans (HFCP)

• There is no regulatory requirement for applicants
  to submit a Human Factors (or any other)
  Certification Plan - this policy DOES NOT require
  them
• However, the FAA believes that HFCPs can be a
  very beneficial aid to communication
• The FAA recognizes that not all projects warrant
  an HFCP
• The policy provides information which can be used
  by the ACO when reviewing an applicants HFCP
• The policy is not intended to be a strict outline
  for an HFCP
• As the ACO uses the policy when reviewing an
  HFCP, it may help both the ACO and the applicant
  identify and focus on key compliance issues
  associated with HF

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The Main Sections of the HFCP Policy

• Background information
• A recommended outline for the HFCP (derived from
  AC 21-40), with explanation of the sections
• Applicants have been using the outline, with a
  lot of tailoring
• A partial list of Part 25 regulations related to
  human factors, with discussion of each regulation
• A list of related documents
• A hypothetical sample certification plan
• A quick reference guide (checklist) for reviewing
  HFCPs

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Generic HFCP Outline

• 1. Introduction
• 2. System Description
• Intended function
• Flight Deck Layout Drawings
• Underlying Principles for Automation Logic
• Underlying Principles for Crew Procedures
• Assumed Pilot Characteristics
• 3. Certification requirements
• 4. Methods of compliance
• 5. System safety assessments
• 25.1309 - When pilots are expected to intervene
  to mitigate failures
• 6. Operational considerations
• How operational certification issues will be
  integrated into the evaluations (e.g. how will
  proposed MMEL configurations be tested?)
• 7. Certification documentation

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Human Factors Methods of Compliance (MOC) Policy

• When we developed the policy on HFCPs, we
  provided a small amount of information regarding
  methods of compliance.
• ACOs needed information about what to consider
  when reviewing proposed MOCs
• Strengths and weaknesses of each MOC
• How technology issues impact the effectiveness of
  an MOC
• MOC issues for some of the more challenging HF
  rules
• This policy can be thought of as a tutorial on
  MOCs for regulations related to human factors

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How Design Characteristics affect the MOC

• Degree of integration/independence Integrated
  products or HF issues need an integrated
  evaluation.
• Novelty/past experience More rigorous methods
  may be called for if the technology is
• new,
• used in some new application,
• new for the particular applicant, or
• unfamiliar to the certification personnel.
• Complexity/Level of automation More complex and
  automated systems typically require test methods
  that will reveal how that complexity will
  manifest itself to the pilot, in normal and
  backup or reversionary modes of operation.

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How Design Characteristics affect the MOC
(continued)

• Criticality Highly critical systems may require
  testing in the most realistic environments (high
  quality simulation or flight test), because any
  problems are more likely to have serious
  consequences.
• Dynamics If the control and display features of
  the product are highly dynamic, the compliance
  methods should be capable of replicating those
  dynamic conditions.
• Subjectivity of acceptance criteria As the
  acceptance criteria become more subjective, the
  applicant will need to use more integrated test
  methods, so that the evaluations take into
  account the aspects of the integrated flight deck
  that may affect those evaluations.

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Intent of the MOC policy

• It is intended to
• Identify design-related and regulation-specific
  issues to consider when the ACO reviews the
  applicants proposed MOCs
• Direct the ACO to the appropriate Advisory
  Circulars.
• Provide a basis for an MOC discussion between the
  ACOs and applicants
• It IS NOT intended to
• Supercede any existing advisory material
• Specify an acceptable MOC for any regulation
• Require a new document justifying MOCs
• The policy is provided to the public (i.e.
  applicants) so that they will know what we will
  consider when reviewing proposed designs
• If any harmonization working groups (Human
  Factors, Avionics, or Flight Guidance) develop
  new rules and/or advisory material related to
  human factors, the policies will be reviewed and
  revised as necessary.

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Human Factors MOC policy

• The policy can be used regardless of how an
  applicant chooses to document the relevant
  regulations and how compliance will be shown
• The main sections of the policy
• Background information
• A discussion of each method of compliance
• A discussion of design characteristics that may
  affect the MOC
• A recommended process for addressing
  regulation-specific MOC issues
• A partial list of Part 25 regulations related to
  human factors, with discussion of the MOC issues
  for each regulation
• A list of related documents, including Advisory
  Circulars
• A hypothetical sample MOC briefing(based on the
  example in the HFCP policy)

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Tailoring the MOCs

• The FAA recognizes that decisions concerning
  MOCs for human factors issues are complex and
  context-dependent.
• In most cases, selecting the appropriate MOC for
  a regulation in a specific project will be based
  on an understanding of the human factors issues
  and the capabilities and limitations of the
  various MOCs with regard to the issue and the
  regulation. However, it may be appropriate to
  consider other factors to ensure that the desired
  MOCs are reasonable for the specific project.
• These other factors include
• The complexity of the project.
• The safety implications of the human factors
  issues.
• The availability and need for test environments
  (simulators, for example).
• The experience base of the applicant.
• The cost and schedule implications of each MOC.

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Tailoring the MOC (continued)

• The Certification Team should strive to agree on
  MOCs that effectively show compliance with the
  regulation in a manner that is commensurate with
• The significance of the human factors safety
  risks, and
• The complexity of the issues underlying a finding
  of compliance.

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Bilateral Cooperation/Agreements

• Technical Agreement - Airworthiness Certification
  Functions
• Philosophy - Place maximum reliance on the
  system of the certificating authority (state of
  design), who is most knowledgeable of the
  applicant
• Validating/importing authority - Define early in
  the project any significant items where they wish
  to retain involvement, otherwise the assumption
  is that all determinations of compliance can be
  conducted by the certificating authority
• Assumes and requires formal meetings and exchanges