4-2. Scope of the Flightdeck Certification Program.
a. The applicant must show that these (installed systems and equipment for use by the flightcrew) systems, and that proposed equipment, individually and in combination with other such systems and equipment, are designed so that qualified flightcrew members can safely perform all of the tasks associated with the installed systems’ and equipment’s intended function.
A qualified flightcrew is one trained and checked in the use of the applicable systems and equipment (see subchapter 3-3). The applicant should analyze and consider flightdeck controls, information, and system behavior that involve flightcrew interaction. The applicant should analyze and relate the intended functions of the system(s), components, and features to flightcrew tasks. The objectiv e of this analysis is to improve understanding about how flightcrew tasks are affected by the proposed system(s), components, and features. Subchapter 5-2 of this AC provides guidance regarding flightcrew interaction, functions, and tasking.
b. The certification program may be affected by the level of integration, complexity, and novelty of the design features, as discussed in the sub-paragraphs that follow. Taking the level of integration, complexity, and novelty into account, the applicant should reach an agreement with the FAA on which flightdeck controls, information, and system behaviors require extra scrutiny during the certification process. The impact of a novel feature might be affected by its complexity and by the extent of its integration with other elements of the flightdeck. A novel but simple feature will likely require less rigorous scrutiny than one that is both novel and complex.
(1) Integration. In this do cument, the term “level of systems integration” refers to the extent to which interactions or dependencies exist between systems affecting the flightcrew’s operation of the airplane. The applicant should de scribe such integration of systems, because it may affect means of compliance. When the word “integration” is used in subchapter 5-8, it defines how specific systems are combined with other systems and equipment in the flightdeck, and how the number and complexity of the couplings may affect the means of compliance.
(2) Complexity. Complexity of the system design from the flightcrew’s perspective is an important factor that may also affect the means of compliance. Complexity has multiple dimensions. The number of information elements the flightcrew must use (the number of pieces of information on a display, for instance) may be one kind of complexity. The level of system integration may be another measure of complexity of that system from the flightcrew’s perspective. Design of controls can also be complex – for example, a knob with multiple control modes. Subchapters 5-1 through 5-6 a ddress several aspects of complexity.
(3) Novelty. The applicant should identify the degree of design novelty based on the following factors:
(a) Are new technologies introduced that operate in novel ways for either established or new flightdeck designs? These technologies include both software and hardware.
(b) Are different or additional operational procedures needed as a result of the introduction of new technologies?
(c) Does the design introduce a new way for the flightcrew to interact with systems using either conventional or innovative technology?
(d) Does the design introduce new uses for existing systems that change the flightcrew’s tasks or responsibilities?
c. The applicant should characterize features by their integration, complexity, and novelty based on the above criteria. Features characteri zed as more novel generally require additional scrutiny during certification. Features consider ed less novel should still be shown to comply with § 25.1302 requirements.
4-3. Applicable Requirements.
a. The applicant should identify design requirements applicable to each of the systems, components, and features. This can be accomplished in part by identifying design characteristics that can adversely affect flightcrew performance and those that pertain to avoiding and managing flightcrew errors.
b. Specific design considerations for requirements involving human performance are discussed in Chapter 5. The applicability of these considerations depends on the levels of integration, novelty and complexity identified subchapter 4-2.
c. The expected result of this analysis is a list of regulatory requirements that the applicant will comply with in their design. The design attributes will also be scrutinized based on this list.
It will be the basis for a compliance matrix identifying the means of compliance proposed for each requirement.
4-4. Selecting an Appropriate Means of Compliance.
a. After identifying what should be shown in order to demonstrate compliance, the applicant should review subchapter 6-2 for guidance on selecting the means, or multiple means, of compliance appropriate to the design. In general, we expect the level of scrutiny or rigor represented by the means of compliance to increase with higher levels of integration, complexity, and novelty of the design.
b. Chapter 6 identifies general means of compliance that have been used on many certification programs and discusses their selection, appropriate uses, and limitations. The applicant may propose other general means of compliance, subject to approval by the FAA.
c. Once the human performance issues have been identified and means of compliance have been selected and proposed to the FAA, the FAA may agree, as part of the certification planning process, that a specific evaluation, analysis, or assessment of a human factors issue may become part of the compliance demonstration. When the human factors issue is successfully demonstrated and the success criteria are satisfied, the design will be found to comply with FAA 10
requirements. Certification credit can be granted when data are transmitted to and accepted by the FAA using standard certification procedures. These data will become part of the final record of how the applicant has complied with the requirements.
4-5. Certification Plan.
a. The applicant should document the certification process, resulting data produced and collected, and agreements described in the previous sections. This may be done in a separate plan or incorporated into a higher level certification plan.
b. The following is a summary of what may be contained in such a document:
(1) Identification of the new airplane, system, control, information, or feature(s).
(2) Identification of the design feature(s) being evaluated and whether or not the feature(s) is (are) novel or unusual.
(3) Explanation of the integration or complexity of the new feature(s).
(4) The list of flightcrew tasks affected or any new tasks introduced by the new features.
(5) Any flightcrew procedure changes.
(6) Specific requirements that must be complied with per § 25.1.
(7) The means (one or several) to be used to show compliance.
(8) How this data will be provided to the FAA certification office.
(9) Description of intended function.
c. See associated policy contained in Appendix A.
Chapter 5. Design Considerations and Guidance.
5-1. Overview.
a. The applicant should first complete the following steps:
(1) Identify the applicability of the regulatory requirements to the systems, components, and features of a new design.
(2) Assess levels of integration and degrees of complexity and novelty using the initial process steps in Chapter 4-2b.
b. Once these two steps have been completed, use the contents of this chapter to identify which aspects of the design require substantiation to part 25. Each aspect identified must be referenced to a specific rule.
c. To comply with requirements of part 25, the design of flightdeck systems must appropriately address foreseeable capabilities and limitations of the flightcrew. Systems and equipment must be designed so qualified flightcrew members trained and checked in their use (see subchapter 3-3) can safely perform all tasks associated with the systems’ and equipment’s intended functions.
d. Each subchapter in this chapter discusses what the applicant must or should show to establish compliance with applicable certification requirements and guidelines. Compliance is not the same as industry “best practices.” The guidance presented here is the compliance guideline to part 25. The part 25 design re quirements and the requirements for training, licensing, qualification, and operations procedures are necessary and complementary. Section
25.1302 and this AC were developed with the intent of linking these complementary requirements.
e. As described in Chapters 2 and 3, flightcrew error is a contributing factor in accidents.
Section 25.1302 provides a regulatory basis for designing ways to avoid and manage flightcrew error. This AC provides guidance for addressing those methods and designs.
f. Section 25.1302 mandates design characteristics known to reduce or avoid flightcrew error in light of flightcrew capabilities and limitations. Requirements in § 25.1302(a)-(d) are intended to reduce the design contribution to such errors by ensuring information and controls needed by the flightcrew to perform tasks associated with the intended function of installed equipment are provided, in a usable form, without unduly interfering with other required tasks.
(1) Section 25.1302(a) requires flight deck controls be installed to allow accomplishment of all tasks required to safely perform the equipment’s intended function and information must be provided to the flightcrew necessary to accomplish the defined tasks.
(2) Section 25.1302 (b) requires flight deck controls and information intended for the flightcrew use be provided in a clear and unambiguous form, at a resolution and precision 12
appropriate to the task. The flight deck contro ls and information must be accessible and usable by the flightcrew (e.g. including all lighting conditions and all phases of flight) in a manner consistent with the urgency, frequency, and duration of their tasks, and must enable flightcrew awareness, if awareness is required for safe operation, of the effects on the airplane or systems resulting from flightcrew actions.
(3) In addition, operationally relevant system behavior must be understandable, predictable, unambiguous, and supportive of flightcrew tasks. That is, § 25.1302(c) requires operationally-relevant behavior of the installed equipment be predictable and unambiguous, and designed to enable the flightcrew to intervene in a manner appropriate to the task. This chapter provides guidance on avoiding design-related flightcrew error.
(4) Finally, § 25.1302(d) requires that, to the extent practicable, installed equipment must incorporate means to enable the flightcrew to manage errors resulting from flightcrew interactions with the equipment that can be reasonably expected to occur in service. Since flightcrew errors will occur, even with a well-trained and proficient flightcrew operating welldesigned systems, system and equipment design must support management of those errors to avoid safety consequences. Subchapter 5-7 provides relevant guidance.
5-2. Applicability of Material to § 25.1302.
a. Part 25 contains some requirements for the design of flightdeck equipment that are system specific (§§ 25.777, 25.1321, 25.1329, 25.1543, etc.), some that are generally applicable (for example §§ 25.1301(a), 25.1309(c), 25.771(a)), and some that establish minimum flightcrew requirements (for example, § 25.1523 and part 25 Appendix D). Section 25.1302 augments generally applicable part 25 requirements by adding more explicit requirements for design attributes related to the avoidance and management of flightcrew error. Other ways to avoid and manage flightcrew error are regulated through operational requirements in 14 CFR governing licensing and qualification of flightcrew members and aircraft operations. Taken together, these complementary requirements provide an appropriate degree of safety and certification.
b. This complementary approach to avoiding and managing flightcrew error is important.
It recognizes that equipment design, training, qualifying through licensing, and establishing correct operations and procedures all contribute to safety by avoiding or minimizing risk. An appropriate integration is needed among them. In the past design characteristics known to contribute to flightcrew error were accepted, with the rationale that training or procedures would mitigate that risk. We now know such an approach is often inappropriate. Conversely, it would also be inappropriate to require equipment design always provide complete risk avoidance or mitigation, because such an approach may not be practicable in some cases, and may even create new risks.
c. The part 25 design requirements and the requirements for training, qualifying through licensing, and establishing correct operations and procedures are necessary and complementary.
Section 25.1302 and this AC were developed with the intent of linking these complementary requirements together.
(1) Section 25.1302 Introduction. The in troductory sentence of § 25.1302 states the provisions of this paragraph apply to each item of installed equipment, individually and in combination with other such equipment, intended for the flightcrew’s use in operating the airplane from their normally seated positions on the flightdeck. The equipment must be designed so that qualified flightcrew members trained in its use can safely perform all of the tasks associated with the equipment’s intended function. Tasks associated with the intended function or functions include all of the tasks required to operate the equipment, such as entering flight plan data into a flight management system (FMS), and tasks for which the equipment’s intended function provides support, such as “indicator bugs” for minimum and critical speeds to support airspeed management by the flightcrew.
(a) “Intended for the flight crewmember’s use in the operation of the airplane from their normally seated position” means that the intended function of the installed equipment includes its use by the flightcrew in operating the airplane. An example of such installed equipment would be a display providing information that enables the flightcrew to navigate. The phrase “flightcrew members” is intended to include any or all individuals comprising the minimum flightcrew as determined for compliance with § 25.1523. The phrase “from their normally seated position” means flightcrew members are seated at their normal duty stations for operating the airplane. Note th at § 25.777(c) is referenced in Table 3 of this document to emphasize the controls are operated by the flightcrew with seat belt and shoulder harness (if provided) fastened.
(b) The words “individually and in combination with other such equipment” from the introduction to § 25.1302 mean that showing compliance with the requirements of this rule for any particular equipment must consider its use in context with other installed equipment, including flight controls, and not simply in isolation. The requirement of this rule must be met when equipment is installed on the flightdeck with other equipment. The installed equipment must not prevent other equipment from complying with these requirements. As an example, applicants must not design a display so that the certain symbology it provides is either inconsistent with or conflicts with the same or similar symbology displayed on other installed equipment.
(c) Provisions of this paragraph presume a qualified flightcrew is trained to use the installed equipment as required by the operational requirements in 14 CFR. It also presumes the installed systems and equipment intended for flightcrew members are designed so that the flightcrew can safely perform all the tasks associated with the installed equipment’s intended functions. If the applicant seeks type design or supplemental type design approval before a training program is accepted, the applicant should document any novel, complex, or highly integrated design features and assumptions made during design that have the potential to affect training time or flight crew procedures. The requirement and associated material are written assuming that either these design features and assumptions, or knowledge of a training program (proposed or in the process of being developed) will be coordinated with the appropriate operational approval organization when judging the adequacy of the design.
(d) The applicant should initiate proposals for flightcrew qualification criteria (minimum training, checking, and currency) through the FAA Flight Standardization Board (FSB) process, specified in AC 120-53A, Guidance for Conducting and Use of Flight Standardization Board Evaluations, in coordination with their application for a type certificate or supplemental type certificate.
(e) The requirement that equipment be designed so the flightcrew can safely perform all tasks associated with the equipment’s intended function applies in both normal and non-normal conditions. Tasks intended for performance under non-normal conditions are generally those prescribed by non-normal procedures and emergency flightcrew procedures. The words “safely perform all tasks” are meant to describe one of the safety objectives of this rule.
The requirement is that equipment design enable the flightcrew to perform all tasks with sufficient accuracy and in a timely manner, without unduly interfering with other required tasks.
The phrase “all tasks associated with its intended function” is meant to characterize either tasks required for operating the equipment or tasks for which the equipment’s intended function provides support.
(2) Section 25.1302(a) requires the applicant to install appropriate controls and provide necessary information for any flightdeck equipment identified in the first paragraph of § 25.1302. Controls and information displays must be sufficient to allow the flightcrew to safely accomplish all of their tasks. To show compliance, the applicant should identify the tasks associated with each piece of installed equipment, and show the controls for the equipment, and the information provided for operation of the equipment, are adequate to enable the flightcrew members to perform the identified tasks, per Paragraph 5-3.c.
(3) Section 25.1302(b) contains requirements for flightdeck controls and information necessary and appropriate so the flightcrew can accomplish all of their tasks, as determined by compliance with § 25.1302(a). The intent of § 25.1302(b) is to ensure the design of control and information devices are usable by the flightcrew. This sub-paragraph seeks to reduce designrelated flightcrew errors by imposing design requirements on flightdeck information presentation and controls. Sub-paragraphs (1) through (3) of the regulation specify these design requirements. Design requirements for information and controls are necessary to:
(a) properly support the flightcrew in planning and decision making for their tasks;
(b) make available to the flightcrew appropriate, effective means to carry out planned actions and decision making; and
(c) provide the flightcrew with appropriate feedback information about the effects of their actions on the airplane.
(4) Section 25.1302(b)(1) requires controls and information be provided in a clear and unambiguous form, at a resolution and precision appropriate to the task. As applied to information, “clear and unambiguous” is defined as follows:
(a) The information can be perceived correctly (is legible).
(b) The information can be comprehended in the context of all the flightcrew tasks associated with the intended functions of the equipment, such that the flightcrew can perform all the associated tasks.
(c) For controls, the requirement for “clear and unambiguous form” presentation means the flightcrew must be able to correctly and reliably identify the control by using control distinctiveness such as control shape, color and/or location as stated in §§ 25.777, 25.779,
25.781, 25.1543, and 25.1555.
(d) Section 25.1302(b)(1) also requires that the information or control be provided, or that it operate at a level of detail and accuracy which is appropriate to accomplishing the task. If the resolution or precision of the control is insufficient, the flightcrew cannot perform their task adequately. Conversely, if information has excessive resolution, the task could be too difficult because of poor readability. Excessive resolution of control may imply that the task requires more precision than it needs.
(5) Section 25.1302(b)(2) requires controls and information be accessible and usable by the flightcrew in a manner consistent with the urgency, frequency, and duration of their tasks.
For example, controls used more frequently or urgently must be readily accessed, or require fewer steps or actions to perform the task. Less accessible controls may be acceptable if they are needed less frequently or urgently. Controls mu st also meet the requirements of § 25.777(a) and
(b) for convenient location and inadvertent operation.
(6) Section 25.1302(b)(3) requires that equipment present information advising the flightcrew of the effects of their actions on the airplane or systems, if safe operation depends on their awareness of those effects. This enables them to detect and correct their own errors. This sub-paragraph is included because new technology may enable new kinds of flightcrew interfaces that previous requirements did not address. Specific deficiencies of other existing requirements in addressing human factors are described below.
(a) Section 25.771(a) addresses this topic for controls, but does not include criteria for information presentation.
(b) Section 25.777(a) addresses control location to provide convenient operation, and to prevent confusion and inadvertent operation.
(c) Sections 25.777(b) and 25.779 address the direction of motion and actuation of controls, but do not encompass new types of controls such as cursor devices. These requirements also do not cover types of control interfaces that can be incorporated into displays by using menus, for example, thus affecting their accessibility.
(d) Section 25.1523 and part 25 Appendix D have a different context and purpose (determining minimum flightcrew), so they do not address these requirements in a sufficiently general way.
(7) Section 25.1302(c) requires installed equipment be designed so that its behavior that is operationally relevant to flightcrew tasks must be:
(a) predictable and unambiguous, and
(b) designed to enable the flightcrew to intervene in a manner appropriate to the task and intended function.
(c) Improved flightdeck technologies involving integrated and complex information and control systems have increased safety and performance. However, they have also sometimes illustrated the need to ensure proper interaction between the flightcrew and those systems. Service experience has found the behavior of some equipment, especially from automated systems, can be complex or dependent upon logical states or mode transitions that are not well understood or expected by the flightcrew. Such design characteristics can confuse the flightcrew and have been determined to contribute to incidents and accidents.
(d) The phrase “behavior that is operationally relevant” is the combined effect of system’s operational logic, placement and function of controls, and displayed information on the flightcrew’s perception and awareness of the system’s operation. It is this combination of factors that affects the flightcrew’s operation of the system. The phrase “behavior that is operationally relevant” distinguishes between the system behavior as perceived by the flightcrew and the functional logic of the systems flightcrews operate. The specific functional logic is normally transparent to the flightcrew. For example, in a software operated control system, the flightcrew needs to know how to use the system and its limitations, but does not need to know the actual computer code used to make the system work.
(8) Section 25.1302(c)(1) requires system behavior be such that a qualified flightcrew can know what the system is doing and why. It re quires operationally relevant system behavior be “predictable and unambiguous.” This means a flightcrew can retain enough information about what their action or a changing situation is so they will know what the system will do under foreseeable circumstances. This “predictable and unambiguous” behavior enables the flightcrew to operate the system safely.
(a) System behavior must be predictable and unambiguous as stated in § 25.1302(c)(1) because the actions of the flightcrew on the airplane depend on the current state of the controls or operational circumstances. Section 25.1302 (b)(3) also requires flightcrew awareness. Under some circumstances, the same actions may affect airplane performance and/or flying qualities differently. For example, autopilo t response to selection or arming of a different mode can depend on which mode is currently active. In such a case, the autopilot must be designed to avoid ambiguity about the result of possible flightcrew selections, § 25.1302 (b)(1).
(9) Section 25.1302(c)(2) requires the design enable the flightcrew to determine a need for, choose, and take appropriate action, or to change or alter an input to the system, in a manner appropriate to the task, and to monitor the system and airplane response to the action. For example, to respond appropriately to a new Air Traffic Control (ATC) altitude clearance, the 17
flightcrew needs information about the active flight guidance and flight management mode, what means are available to comply with the new ATC requirement given the current airplane and system states, how to select those means, and how to determine the expected response is being achieved.
(10) Section 25.1302(d) addresses the reality that even well trained, proficient flightcrews using well designed systems will make errors. It requires equipment be designed to enable the flightcrew to manage such errors to the extent practicable. For the purpose of this rule, errors “resulting from flightcrew interaction with the equipment” are those errors in some way attributable to, or related to, design of the controls, behavior of the equipment, or information presented. Examples of designs or information that could cause errors are indications and controls that are complex and inconsistent with each other or other systems on the flightdeck. Another example is the presentation of a procedure inconsistent with equipment design. Errors caused by such designs or by conf using information are within the scope of this requirement and AC.
(a) The intent is for the type design to enable the flightcrew members to manage errors by one or more of the following means, as implemented in the type design. For each of these means used by the designer, the design should incorporate error prevention and management to the extent practicable so that:
1 the design enables the flightcrew to detect and/or recover from errors resulting from their interaction with the equipment; or 2 the design makes the effects of such flightcrew errors on the airplane functions or capabilities evident to them and enables them to continue a safe flight and landing;
or 3 the design discourages flightcrew errors by switch guards, interlocks, confirmation actions, or other effective means; or 4 the effects of errors with potential safety consequences should be precluded by system logic or other aspects of system design that will detect and correct such errors. See paragraph 5-7, F lightcrew Error Management.
(b) The list above identifies different means for managing errors. The intent is for the installed equipment design to be such that it enables the flightcrew members to manage errors by one or more of those means. “To the extent practicable” refers to the implementation of error management capability within the one or more of those means, as provided within the equipment design.
(c) The requirement to manage errors applies to those errors that can be reasonably expected to occur in service from qualified and trained flightcrews. The term “reasonably expected in service” means errors that have occurred in service with similar or comparable equipment. It also means errors that can be predicted to occur based on general 18
experience and knowledge of human performance capabilities and limitations related to use of the types of controls, information, or system logic being assessed.
(d) Section 25.1302(d) includes the following statement: “This sub-paragraph does not apply to skill-related errors associated with manual control of the airplane.” That statement means to exclude errors resulting from flightcrew proficiency in the control of flight path and attitude with the primary roll, pitch, yaw, and thrust controls. These issues are considered to be adequately addressed by existing requirements. We do not intend the design be required to compensate for deficiencies in flightcrew training or experience. This rule assumes at least the minimum flightcrew requirements for the intended operation, as discussed at the beginning of subchapter 5-2.
(e) This rule is not meant to require the management of errors resulting from flightcrew decisions, acts, or omissions not made in good faith. While we recognize that the dictionary definition of “error” is “an act, assertion or belief that unintentionally deviates from what is correct, right, or true," some people, including human factors researchers, have constrained the meaning of the term to include “only unintentional acts that have incorrect results.” Following the recommendations of the Aviation Rulemaking Advisory Committee (ARAC) working group and the requirements of EASA CS 25.1302, the FAA intends that the proposed rule also include “intentional acts that have unintended consequences” in the consideration of flightcrew errors. An example of such an intentional, good faith error would be a situation in which a valid alert occurs, but the flightcrew does not perform the associated procedure because they believe it to be a nuisance alert rather than a valid alert as defined in § 25.1302(d). Refer to paragraph 5-7 in this AC for showing compliance to § 25.1302(d).
(f) The error discussed in (e) is the intentional act of disregarding a valid alert. In this example, the flightcrew’s misinterpretation of the alert as being a nuisance alert (i.e. it is invalid) may be caused by design deficiencies that lead to frequent nuisance alerts. This is one underlying design deficiency that § 25.1302 is intended to address. While this particular example relates to nuisance alerts, there may be other design characteristics that lead flight crewmembers to make other kinds of intentional errors.
(g) The rule does not include errors committed from decisions, actions, or omissions with malicious or purely contrary intent, (that is, actions intended to have incorrect or unsafe results); or errors arising from a flight crewmember’s obvious, intentional disregard for safety (that is, reckless conduct). Section 25.1302 doe s not consider errors resulting from acts or threats of violence (for example, actions taken under duress). It is unreasonable to expect that airplane designers would be able to anticipate and prevent these types of actions.
(h) The EASA regulation, CS-25.1302, allows applicants to assume that the flightcrew is “acting in good faith.” While our proposed § 25.1302(d) replaces this term with a more detailed enumeration of exceptions, our intent is the same, and the regulatory effect would be harmonized.
(i) The intent of requiring errors to be manageable only “to the extent practicable” is to address both economic and operational practicability. It is meant to avoid imposing 19
requirements without considering economic feasibility and commensurate safety benefits. It is also meant to address operational practicability, such as the need to avoid introducing error management features into the design that would inappropriately impede flightcrew actions or decisions in normal or non-normal conditions. As an example, we do not intend to require so many guards or interlocks on the means to shut down an engine that the flightcrew would be unable to do this reliably in a timely manner commensurate with the severity of the situation.
(j) Section 25.1302(d) was included because managing errors resulting from flightcrew interaction with equipment that can be reasonably expected in service is an important safety objective. Section 25.1302(d) limits the scope of applicability of this rule to errors for which there is a contribution from, or relationship to, design. However, § 25.1302(d) itself is expected to result in design changes that will contribute to safety. Two examples, among others, are the incorporation of "undo functions” or a cancel button in certain designs.
5-3. Intended Function and Associated Flightcrew Tasks.
a. Section 25.1301(a) requires each item of installed equipment must “be of a kind and design appropriate to its intended function.” Section 25.1302 establishes requirements to ensure the design supports flightcrew members’ ability to perform all tasks associated with a system’s intended function. For the applicant to show compliance with § 25.1302, the intended function of a system and the associated flightcrew tasks expected of the flightcrew must be described.
b. To comply with § 25.1302 the applicant’s statement of intended function must be sufficiently specific and detailed that the FAA can evaluate whether that system is appropriate for the intended function(s) and the associated flightcrew tasks. For example, a statement that a new display system is intended to “enhance situation awareness” must be further explained. A wide variety of different displays enhance situation awareness in different ways. Examples are terrain awareness displays, vertical profile displays, and even the primary flight displays. The applicant may also need to provide more detailed descriptions for designs with greater levels of novelty, complexity, or integration.
c. An applicant must describe intended functions and associated tasks for equipment. This type of information is of the level typically provided in a pilot handbook or an operations manual. It would describe indications, controls, and flightcrew procedures. Compliance to § 25.1302 must be shown for:
(1) each item of flightdeck equipment;
(2) flightcrew indications and controls for that equipment; and
(3) individual features or functions of that equipment.
d. As discussed in Chapter 4, novel features may require the applicant provide more detailed information to show compliance, while previously approved systems and features typically require less. Subcha pter 4-2 discusses when functions are sufficiently novel that 20