1-1 CHAPTER 1. BACKGROUND INFORMATION
1.1 General. Standard operating procedures (SOP) are universally recognized as fundamental to safe aviation operations, yet accidents and incidents continue to occur as a direct result from, or related to, a failure by the flightcrew to follow SOPs, particularly during critical phases of flight.
This advisory circular (AC) provides guidance for the design, development, implementation, evaluation, and updating of SOPs. It emphasizes that SOPs should be clear, comprehensive, and readily available within the manuals used by flight deck crewmembers. Although this AC is directed towards Title 14 of the Code of Federal Regulations (14 CFR) part 121 and part 135 air carriers, the FAA encourages all air carriers, aircraft operators, pilot schools, and training centers to utilize this guidance. The basis for this guidance is contained in the related regulations and FAA guidance sections of this AC. This AC is not mandatory and does not constitute a regulation. This AC describes an acceptable means, but not the only means, to design, develop, update, and use SOPs.
Effective crew coordination and crew performance depend on the crew’s having a shared mental model of each task. That mental model, in turn, is founded on SOPs. SOPs should serve to provide a consistent, standardized model of each task that must be performed by each crewmember during each phase of flight and during any reasonably anticipated abnormal, non-normal, or emergency situation. SOPs must be kept current and may be individually developed by the operator or by incorporating those procedures found in their aircraft operating manuals into their daily operations. Once established, the SOPs must be applied with consistency and uniformity throughout the operation.
Implementation of any procedure as an SOP is most effective when:
1. The procedure is appropriate to the situation.
2. The procedure is practical to use.
3. Crewmembers understand the reasons for the procedure.
4. Pilot flying (PF) and pilot monitoring (PM) duties are clearly delineated.
5. Effective training is conducted.
6. Adherence to the standard is emphasized by flightcrews, and reinforced by instructors, check pilots, and managers alike.
7. Crewmembers are aware of the potential risks/hazards if SOPs are not followed.
1.2 Cancellation. This AC cancels AC 120-71A, Standard Operating Procedures for Flight Deck Crewmembers, dated February 27, 2003.
1.3 Summary of Changes. Many changes have been made to improve clarity, accuracy, completeness, and consistency. Significant changes include adding regulatory
1-2 requirements contained in part 121 for PM and removing many of the examples previously found in the appendices. The stabilized approach criteria has been removed from this AC and can be found in AC 91-79A, Mitigating the Risks of a Runway Overrun Upon Landing (include Chg 1).
1.4 Terms and Definitions. For the purpose of this AC, the following definitions and terms are provided:
1. Checklist. A checklist is a tool to reduce the potential for flightcrew error in configuring the aircraft safely for various phases of flight, and for any malfunctions that may have occurred.
2. Crew Resource Management (CRM). The effective use of all available resources to achieve safe and efficient flight, to include human resources, hardware, and information.
3. Electronic Checklist. A checklist that is displayed to the flightcrew by means of an electronic device.
4. Flightpath. The aircraft trajectory and energy state, in flight.
5. Flightpath Management. Flight deck planning, execution, and assurance of the guidance and control of the flightpath.
6. High Workload Environment. Any environment in which multiple demands on the flightcrew necessitate the prioritizing of work functions. For example, IFR operations below 10,000 feet during arrival or departure from a terminal area (including taxiing) are considered to be high workload environments.
7. Pilot Flying (PF). The pilot who is controlling the path of the aircraft at any given time, in flight or on the ground.
8. Pilot Monitoring (PM). The PM monitors the aircraft state and system status, calls out any perceived or potential deviations from the intended flightpath, and intervenes if necessary.
9. Procedure. A logical progression of actions, decisions, or both in a sequence which is prescribed to achieve a specified objective.
10. Standard Operating Procedure (SOP). Written and tested procedures that are applied uniformly and consistently within an operation and involve all aspects of flight operations, normal, abnormal, non-normal, and emergency.
1.5 Related 14 CFR Sections.
• Part 91, §§ 91.1033 and 91.1079.
• Part 121, §§ 121.133, 121.135, 121.141, 121.315, 121.401, 121.403, 121.424,
121.542, and 121.544.
• Part 125, § 125.287.
• Part 135, §§ 135.83, 135.100, 135.293, and 135.327.
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1.6 Related Guidance and Information. Related FAA guidance and other reading material may be found in Appendix A.
2-1 CHAPTER 2. DETERMINING WHEN PROCEDURES NEED TO BE DESIGNED
OR MODIFIED
2.1 Requirements for Procedures. Operators are required to provide flightcrews with operating procedures per the applicable regulations as identified in the related regulations section. Although an Original Equipment Manufacturer (OEM) will typically supply its customers with suggested procedures and checklists for its equipment, operators may choose to develop, or modify, the procedures and checklists provided by the OEM. Some procedures may require a “No Technical Objection” from the OEM to modify them.
Also, some procedure modifications may require acceptance or approval from an operator’s principal operations inspector (POI). Operators should work with the OEM and FAA to determine if involvement in a SOP modification is necessary.
2.2 Modifying OEM Procedures. Procedures and checklists published by the OEM are designed to reflect that manufacturer’s flight deck design and operating procedures. They promote optimum use of aircraft features as envisioned by the designers, but may be generic in their applicability. Potential factors which may drive changes to OEM procedures and checklists include new or modified equipment, changes to the operational environment, company mandated procedures, standardization among related fleets, observed operational problems, incidents, accidents, or airline mergers.
3-1 CHAPTER 3. CREATING A PROCEDURE DEVELOPMENT PROCESS
3.1 Characteristics of Good Procedures. A well-designed procedure aids flightcrews by specifying a sequence of actions that, if followed, helps ensure that the primary task will be carried out in a manner that meets the basic guidelines of being clear, correct, reliable, and robust.
In general, as a minimum, good procedures cover the following elements:
• What the procedure is designed to accomplish.
• When and under what conditions the procedure should be executed.
• Who is responsible for executing each step in the procedure.
• How, in sufficient detail, the procedure is to be performed.
• How to confirm the procedure has been accomplished properly.
3.2 Collaborating for Effective SOPs. Collaboration can improve the effectiveness of SOPs. Partners in the collaboration could include representatives of the aircraft manufacturer, pilots having previous experience with the aircraft or with the type of operations planned by the operator, training organizations, and representatives from the FAA. Procedure developers should pay close attention to the approved Airplane Flight Manual (AFM) or Rotorcraft Flight Manual (RFM), to AFM/RFM revisions and operations bulletins issued by the manufacturer, and to the applicable FAA Flight Standardization Board (FSB) report. It is especially important for a new operator to establish a periodic review process that includes line flightcrews. Together, managers and flightcrews are able to review the effectiveness of SOPs and to reach valid conclusions for revisions. A trial period might be implemented, followed by feedback and revision, in which SOPs are improved. The review process will be meaningful and effective when managers promote prompt implementation of revisions to SOPs when necessary.
3.3 Resources to Develop SOPs. The procedure development process should start with a careful analysis of the factors driving the need to develop or modify a procedure and the implications of these factors.
Procedure developers should research all available sources of information that pertain to the process or procedure being developed or revised. This may include reviewing data from an Aviation Safety Action Program (ASAP) or a flight operations quality assurance (FOQA) program. Procedure developers should also understand the entire system of procedures and how they fit within the framework of existing policies, guidance, and the operator’s overall operational philosophy. Any new process or procedure should be consistent with that framework.
Employee groups who will be affected by the procedures in question may also add value in the development process. Procedures which interface with other employee groups should be coordinated accordingly.
4-1 CHAPTER 4. WRITING PROCEDURES
4.1 General Guidelines. Procedures should be communicated and trained effectively after they are developed.
4.1.1 Information to Include. Include only the information needed to validate it is the correct procedure to use and information to properly execute the procedure. While it is important to document and communicate the rationale behind the procedure design, this information should be provided in a separate training manual or other document.
4.1.2 Avoid Visual Clutter. Include supplemental detail only when necessary. When the addition of supplemental information is necessary, separate the supplemental information from the presentation of the actual steps to be accomplished.
4.1.3 Use Plain Language. Use simple English; the use of uncomplicated wording will increase comprehension while reducing ambiguity.
4.1.4 Use Short Sentences. Break long sentences into short sentences with a simple sentence structure.
4.1.5 Use Active Verbs. Sentences with active verbs (e.g., “Do X”) are easier to read and less likely to be misunderstood than sentences using passive verb forms (e.g., “X should be done”).
4.1.6 Write Steps as Imperatives. Imperative commands are direct; they tell someone what to do, and are often used when giving instructions. Avoid negatives when possible.
Negative statements are difficult to read and if it is missed, the meaning of the sentence will be misunderstood. When negatives are required, clearly specify what is being negated.
4.2 Organization.
4.2.1 General Organization. Procedures should be organized as simply as possible by order of tasking. Normal procedures are typically organized in sequence by phase of flight. When applicable, abnormal, non-normal, and emergency procedures should be organized by the triggering condition (e.g., smoke in the flight deck) rather than the potentially related system (e.g., electrical system).
4.2.2 Navigation and Place Keeping. Steps should follow a simple numbering system to assist pilots in maintaining their place in the procedure. Excessively detailed hierarchies should be avoided. Use headers when necessary to distinguish major sections of multifaceted procedures. Headers should provide useful cues to the purpose of the section of the procedure they address.
4.2.3 Lists. One step in a procedure may require that the pilot perform several actions or check several different indications. These components should be presented on separate lines in an indented numbered or bulleted list rather than in the body of the text.
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4.2.4 References. References to other procedures or appendices should be avoided unless necessary for completion of the procedure.
4.2.5 Memory Items. Memory items should be avoided whenever possible. If the procedure must include memory items, they should be clearly identified, emphasized in training, less than three items, and should not contain conditional decision steps.
4.2.6 Indices. An index should be provided for every procedure manual. In designing the index, ensure that the format accurately reflects the operator’s philosophies and training. If a procedure is identified in more than one way (e.g., if there are multiple indications), include all likely parameters in the index.
4.3 Vocabulary.
4.3.1 Use Words Consistently. Word use should be simple and consistent throughout the SOPs.
If possible, avoid creating new terms. Use words in their common English sense unless they have a widely accepted aviation-specific meaning. Match flight deck nomenclature.
4.3.2 Avoid Using Words with Multiple Common Meanings. Avoid using words with multiple meanings (e.g., use “correct” rather than “right”). Avoid using the same words as both nouns and verbs (e.g., display, position); if a word is to be used that could be a noun or a verb, choose one usage and apply it consistently (e.g., move the switch into the ON position vs. position the switch to ON).
4.3.3 Use Abbreviations Carefully. Only use abbreviations that are defined and commonly used in the industry (e.g., Vertical Navigation (VNAV), reference landing speed (VREF), air traffic control (ATC)), and avoid creating new abbreviations whenever possible.
Abbreviations should also only be used that are defined in the operating environment.
4.4 Numbers.
4.4.1 Use Arabic Numbers. Arabic numbers (e.g., 0, 1, 2) are easier to read than numbers that are spelled out (e.g., one, two). However, use spelled-out numbers for references when two or more different values must be presented in close proximity to other numbers
(e.g., use “one 10 kg weight,” rather than “1 10 kg weight”).
4.4.2 Include Units of Measurement. Do not specify numbers in greater precision than is necessary, or than can be read from instruments.
4.5 Format. In determining how to format procedures, the purpose, mode, and conditions under which the displayed procedures will be used must be considered. The presentation of procedures that are meant to be used on the ground at leisure in printed form may use a different format from procedures that will be read from a tablet computer in flight during turbulence or at night under time pressure. The presentation should be evaluated under conditions approximating those under which the procedure display might be needed.
4.5.1 Type Size. Use a type size that is large enough to be readable under all conditions likely to be encountered. In general, a 14- to 20-point laser printed sans serif font is adequate
4-3 for flight deck conditions. However, this should be tested under all potential operational conditions.
4.5.2 Line Spacing. Place sufficient space between lines of text. Using 25 to 33 percent of the font size between lines (e.g., 3 to 5 points space between lines using 14 point font) will make the text easier to read than if there was less space between the lines.
4.5.3 Font. Unusual or ornate fonts should be avoided.
4.5.4 Case. Use standard capitalization rules. Text in all capital letters is harder to read than text in lowercase. Use all capitals very sparingly and only for meaningful emphasis, or to represent labels that are commonly encountered in capitals (e.g., VNAV).
4.5.5 Grouping. Use visual techniques (e.g., white space created by extra lines, indentation) to delineate grouping of steps, lists, and the components of logic statements.
4.5.6 Justification. Paragraphs of text should be left aligned. Do not use right and left justified to produce aligned right and left edges, because it adds spaces between letters and/or words that make the paragraph harder to read.
4.5.7 Line Length. Traditionally, checklists have been formatted to resemble an index or table of contents with corresponding components (e.g., Challenge…Response) left and right justified and joined with dots or lines. This format is acceptable; however, excessively large gaps between the components should be avoided. The wider the gap, the greater the chance the pilot will inadvertently skip to the next line due to perceptual misalignment.
4.6 Place Keeping.
4.6.1 Title. Clearly identify the procedure by title (e.g., “Before Start”) and the objective of the procedure when it is not obvious from the title.
4.6.2 New Lines. Begin each step in a procedure, each element in a logic statement, and each item in a multiple item list on a separate line.
4.6.3 Bullets and Numbering. Use numbers, bullets, and lines, as appropriate, to indicate the beginning of each step. Using numbered lines can reduce navigation and place-keeping errors in the event that an interruption occurs. Numbered steps also facilitate navigation between procedures when it is necessary to “GO TO” a step within a procedure.
4.6.4 Continuation. Clearly specify if a procedure continues onto another page
(e.g., “Continues on Next Page”).
4.6.5 End. Clearly mark the end of a procedure with a standard symbol or wording
(e.g., “Checklist Complete”).
4.7 Emphasis. Emphasize cautions and warnings (e.g., CAUTION, WARNING), conditional words (e.g., IF, THEN), and important notes (e.g., NOTE). Timed events or steps that must be monitored for a period of time should be emphasized. Irreversible items should
4-4 be emphasized before the action is specified or taken. Techniques for calling attention to certain words or phrases should be used sparingly but consistently. Overuse of emphasis reduces its effectiveness and makes the procedure hard to read. Techniques for emphasis include:
4.7.1 Typographical. Typographical emphasis techniques include bolding, italicizing, underlining, and capitalization.
4.7.2 Graphical. Graphical emphasis techniques include framing, shading, coloring, and the use of standard symbols.
4.7.3 Spatial. Spatial techniques for conveying emphasis include using white space to group text and reserving places on the page or screen for selected types of messages.
4.7.4 Verbal. Verbal emphasis may be conveyed by using reserved words (e.g., Important, Note, Caution, and Warning).
4.8 Conditional Steps. In many procedures, some steps should be executed only when specified conditions occur. These conditional statements are a frequent source of confusion, particularly for novices, or with rarely used procedures. This problem can be alleviated by keeping the statements well structured, clearly phrased, and as short as possible.
Conditional statements should present all of the conditions clearly so that the correct choice is easy to identify. The steps that are associated with each condition should be grouped clearly. The end of this block of steps should be clearly identified and the action or procedure to be performed after completion of the block should be clearly specified. If there are embedded choices, then these subsidiary conditions also should be clearly delineated and the associated steps grouped in an unambiguous fashion.
Conditions should always precede actions. Actions that are irreversible should be identified in the condition preceding the action. Conditional statements may begin with one of the following words:
1. IF – use to indicate a condition that may or may not happen.
2. WHEN – use to indicate a condition that must be met before an action is taken and that condition is very likely to occur (e.g., “WHEN pressure reaches 120 psi THEN put gear down.”).
3. THEN – use to identify actions that should be taken when the specified condition occurs.
4. AND – use to combine two conditions that must be met before the action is taken.
5. OR – use to indicate that one or more of several conditions must be met before the action is taken.
4-5 If alternative formats are used, ensure they are used consistently and the intention is clear.
For example:
IF light x is lit THEN open valve y IF light x is NOT lit THEN open valve z Which also may be expressed as:
CHOOSE one:
Light x is illuminated ● Open valve y Light x is extinguished ● Open valve z
4.8.1 Complex Conditional Statements. Avoid using combinations of AND and OR whenever possible. In general, use separate steps instead.
4.8.2 Waiting, Continuous Actions, Repeated Actions. In some cases, an action must be continued or repeated until some condition occurs. In these cases, specify (1) what actions are to be repeated, (2) the conditions under which those actions should be stopped, and (3) whether the remaining steps in the procedure can be continued in the meantime. For example: “Hold button depressed UNTIL pressure reaches 120 psi, THEN GO TO step 5 in this procedure.”
4.9 Cross-References. Cross-references to other procedures should be avoided whenever possible. In most cases, a “Go-in, Stay-in” strategy should be used whereby all necessary steps for completing a procedure are included in that procedure. In some cases, this may prove impractical.
4.9.1 Explicit Reference. When used, cross-references should be explicit and use consistent wording.
4.9.2 Version Control. When references to other procedures are required, a system should be in place to monitor version control. Changes made to either the referring or referred procedures could affect the execution of the included steps.
4.10 Warnings and Cautions. Warnings and cautions in procedures should be used sparingly.
Overuse of warnings will decrease their effectiveness. Often “warning” is used to convey a more urgent or critical matter than “caution.” AC 25.1322-1, Flightcrew Alerting, contains definitions for these terms.
4.10.1 Components of Warnings and Cautions. Each warning or caution should identify a single hazard, the consequences of the hazard, and any critical time constraints. Actions should not appear in warnings or cautions.
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4.10.2 Placement. Warnings and cautions should be placed on the same page, and prior to, the steps to which they apply. Procedural steps should be graphically separated from warnings and cautions.
5-1 CHAPTER 5. DEVELOPING CHECKLISTS
5.1 General. Checklists are a special type of procedure. They are often the form into which extended procedures are distilled, and often the most common and most frequent form through which people interact with formal procedures. On the flight deck, checklists are an important tool in making sure that operational tasks are performed in a standardized fashion.
Checklists are of no value if the flightcrew is not committed to their use. Without discipline and dedication to using the checklist at the appropriate times, errors will inevitably occur.
Although it may be published in a manual, a checklist is designed for independent use so that the user will seldom need to reference that manual, especially after having been previously trained on the content therein. Checklists are used to ensure that a particular series of specified actions are accomplished in the correct sequence and to verify that the correct aircraft configuration has been established in specified phases of flight.
Checklists have been a significant part of the foundation of pilot standardization and flight deck safety for years. Such procedures, when applied in a disciplined and standardized fashion, are intended to support human performance regardless of circumstance. The checklist is an aid to the memory and helps to ensure that critical items necessary for the safe operation of aircraft are not overlooked or forgotten.
Checklists must be easy to access, easy to read, and easy to use. Checklists should provide enough information to enable the flightcrew to verify it is the correct checklist before they begin using it. Instructions should be concise, but sufficient information must be provided so that actions are performed correctly and essential issues are considered.
The checklist must accommodate the demands of high-workload phases of flight and the performance limitations experienced by humans when under stress. It should respond to the specifics of the situation but also assist crews in their management of the overall task.
5.1.1 Consistency. Operators should standardize checklist items and the sequence of those items to the maximum extent practicable, given possible make, model, and series (M/M/S) and variant differences across the fleet.
5.1.2 Type of List and Manner of Execution. For most normal procedures on the flight deck, a “flow” is conducted as a sequence of actions done from memory to configure the aircraft and its systems. The flow is followed by a checklist containing a subset of items from the flow that may be the most critical items within that flow and items that confirm the flow was done correctly.
5.1.3 Timing. Given the criticality of the checklist procedure, the crew’s ability to pay full attention to its execution is crucial. The timing of the checklist must be such that it would minimize the distractions and concurrent tasks. Timing of checklists should be designed not to interfere with other tasks and be resistant to interruption. For example, a “Taxi Checklist” that is to be accomplished during taxi might appear as an efficient use of crew