AC 120-53A

Historical

Advisory circular · Guidance for Conducting and Use of Flight Standardization Board Evaluations

A newer version is currentThis is a historical version. AC 120-53C is the version in force, approved September 11, 2025.
Approved
October 15, 2008
Last reviewed
August 9, 2024
Cancels
AC120-53
Cancelled by
AC120-53B
Family
AC 120-53 · 5 versions
Revision
A
14 CFR parts
121

Guidance, not mandatory unless a rule or AD requires it. DRS record last changed November 22, 2025.

Show pages 1–11

Appendix 2 APPENDIX 2. PILOT QUALIFICATION AND PILOT RATING REQUIREMENTS

TABLE OF CONTENTS

1. PURPOSE4

2. FOCUS…4

3. INTRODUCTION

a. A Comprehensive System for Pilot Qualification4

b. Master Differences Requirements (MDR) Set by FAA4

c. Specification of Constraints or Credits4

d. Recognition of Unique Operator Characteristics4

e. Basis for Requirements5

f. Relationship to other FAA Policies5

4. CONCEPTS

a. An Integrated System for Pilot Qualification5

b. MDRs5

c. Difference Levels8

d. Training Difference Levels9

e. Checking Difference Levels11

f. Currency Difference Levels12

g. Operating Experience (OE) for Aircraft15

h. Supervised Line Flying (SLF)15

i. Recency of Experience16

j. Operator Difference Requirements (ODR)16

5. FORMULATION OF FSB REPORTS, MDRs, AND DESIGNATION OF PILOT TYPE RATINGS.

a. Requirements Formulation Process Overview24

b. Proposals for MDRs, Example ODRs, and Special Requirements24

c. Difference Level Tests25

d. FSB Assessments and Proposal Formulationc27

e. Comments Solicited31

f. FSB Final Determinations and Findings31

g. FSB Report Preparation Distribution and FAA Application32

h. FSB Report Revision33

6. OPERATOR’S APPLICATION OF FSB PROVISIONS, PREPARATION, USE, AND REVISION OF ODRs.

a. General34

b. Application of MDRs and Pr eparation and Use of ODRs34

c. Selecting Base Aircraft36

d. Identification of Differences and the Anal ysis of Effects of Those Differences36

e. Identification of Compliance Methods36

f. When Proposed ODR Compliance Methods Do Not Meet MDRs36

Appendix 2

g. Maximum Number of Related Aircraft37

h. Application, Review and Approval37

i. Implementation Provisions Transition Period37

j. ODR Revision38

7. FAA REVIEW AND APPROVAL OF OPERATOR PROGRAMS

a. General40

b. Operator Application of ODRs40

c. Base and Other Airc raft Identification42

d. Approval of ODRs42

e. POI Uncertainty Regarding Program Compliance43

f. Proposals that do not Comply with FSB Provisions43

g. FSB Revision of MDRs or Other FSB Provisions43

h. Proving Tests44

i. Line-Oriented Flight Trai ning (LOFT), LOS, or SLF44

j. OE44

k. Limitations on the Total Numb er of Related Aircraft44

l. Compliance Checklist for CHDOs45

m. Implementation of FSB Provisions45

n. Aircraft That Do Not Have an FSB Report45

8. APPLICATION OF REQUIREMENTS TO AIRMEN CERTIFICATION.

a. General45

b. Checking Specifications45

c. Checks Regarding Complex Systems45

9. TRAINING DEVICE AND SIMULATOR APPROVAL.

a. Training Device and Simulator Characteristics46

b. Aircraft/Simulator/Device Compatibility46

c. Simulator and Device Approvals46

10. REVIEW AND APPROVAL47

11. APPEAL OF FAA DECISIONS47

ILLUSTRATIONS

Figure 1. Master Difference Requ irements (MDR) Table Example7

Figure 2. Difference Level Table15

Figure 3-1. Design Operator Differe nces Requirements Table Example18

Figure 3-2. Systems Operator Differe nces Requirements Table Example19

Figure 3-3. Maneuver Operator Difference Requirements Table Example23

Appendix 2

Figure 4. Master Requirements Formulation28

Figure 5. Test Definitions29

Figure 6. “T” Tests 1 Thru 530

Figure 7. Standard Method, Devices, And Simulators32

Figure 8. FSB Process39

Appendix 2 APPENDIX 2. PILOT QUALIFICATION AND PILOT RATING REQUIREMENTS

1. PURPOSE. This appendix describes a comprehensive system for pilot qualifications outlined in this advisory circular (AC). It includes definitions, criteria, processes, tests, methods, and procedures necessary for uniform application of the system.

2. FOCUS. The appendix applies to and is used by:

• Aircraft manufacturers or modifiers who design, test, and certificate under Title 14 of the Code of Federal Regulations (14 CFR).

• Operators who operate under 14 CFR.

• Operator, manufacturer, or other training centers having programs approved for use under 14 CFR.

• Federal Aviation Administration (FAA) offices and inspectors administering programs under 14 CFR.

3. INTRODUCTION.

a. A Comprehensive System for Pilot Qualification. This AC and its appendices provide a systematic means to address requirements for training, checking, and currency within applicable 14 CFR parts. Definitions, criteria, processes, procedures, tests, and methods are consistent with and clarify application of current rules in particular situations for specific aircraft.

This AC describes a comprehensive system for the FAA and industry to evaluate, and approve use of particular aircraft and operator programs. The respective roles of training, checking, currency and airmen certification are clarified. This includes defining the role and criteria for designation of pilot type ratings for existing, new, or modified aircraft. The system is particularly suited to addressing transition, differences programs, and mixed fleet flying. The system aids in assuring that pilots attain and maintain the knowledge, skills, and abilities needed to operate assigned aircraft safely.

b. Master Differences Requirements (MDR) Set by FAA. The FAA’s Flight Standardization Board (FSB) sets MDRs to address differences between related aircraft.

c. Specification of Constraints or Credits. The system permits the specification of constraints or permissible credits. Constraints or credits may relate to knowledge, skills, abilities, devices, simulators, maneuvers, checks, currency, or any other such factors necessary for safe operations. Constraints or credits may apply generally to aircraft, particular pilot positions, or other situations or conditions.

d. Recognition of Unique Operator Characteristics. The system recognizes the unique characteristics of individual operators while achieving uniformity in application of FAA safety standards. FSB MDRs provide a uniform basis for principal operations inspectors (POI) to use in tailoring individual operator’s ODRs. POIs may approve each operator’s ODRs within the context of FSB MDRs. ODRs accommodate particular combinations of related aircraft flown, pilot assignment policies, training methods and devices, and other factors that relate to the Page 4

Appendix 2 application of the FSB MDRs. Accordingly, the system preserves operator flexibility while standardizing the FAA’s role in review, approval, and monitoring of training, checking, and currency programs within 14 CFR.

e. Basis for Requirements. The determination of pilot type rating, minimum differences training, checking and currency requirements focus on basic operation of aircraft in the National Airspace System (NAS) under both instrument flight rules (IFR) and visual flight rules (VFR).

Included are all flight phases from preflight to shutdown under both normal and nonnormal conditions.

f. Relationship to other FAA Policies. Although this AC, and the FSB provisions in some instances, address particular types of operations or specific aircraft systems (e.g., use of flight guidance control systems for Category II/III instrument approaches, long-range navigation, etc.), other ACs address these issues more thoroughly. This AC and FSB provisions address such issues only to the extent necessary to assure that pilots are qualified to operate pertinent systems or equipment as part of initial or continuing qualification.

4. CONCEPTS.

a. An Integrated System for Pilot Qualification.

(1) System Elements. An integrated FAA/applicant system and process established to determine appropriate requirements, apply the requirements, and meet those requirements on a continuing basis, for uniform pilot qualification.

(2) System Overview. The system uniformly applies FAA master requirements in a way that tailors a particular aircraft, to any operator’s unique situation or fleet. The FAA approves unique operator and fleet requirements for each operator based on FAA master requirements.

The system develops FAA master requirements based on objective criteria and tests, with applicants’ support for analysis, and testing. FSB reports for related aircraft describe FAA master requirements. MDRs express FAA master requirements (the minimum acceptable difference levels between related aircraft). An operator’s training program, checklist, operations manuals, pilot certification, CTLC programs, and other such approvals are by-products of compliance with MDRs. Operators comply with MDRs using unique ODRs, tailored to that operator’s programs and approved by the FAA. ODRs, based on and in compliance with the MDRs, specify requirements uniquely applicable to a particular operator’s mixed fleet flying situation. An operator’s specific document describes ODRs by identifying a base aircraft, differences between related aircraft, and that operator’s compliance methods for each related aircraft. Paragraph 4j describes ODRs. Paragraph 6 describes ODR preparation and use. Paragraph 7 describes FAA approval of ODRs.

b. MDRs.

(1) MDR Applicability. MDRs are those requirements applicable to pilot qualification that pertain to differences between related aircraft. MDRs specify the minimum difference levels between related aircraft that may be approved. One related aircraft is selected by the applicant as a reference for comparison purposes and is considered a base aircraft. This is typically the first aircraft on which pilots are qualified, or is the aircraft of which an operator has the largest Page 5

Appendix 2 number. Difference levels between the base aircraft and other related aircraft then specify the minimum difference requirements to be met for pilot qualification. Major differences in a particular fleet are defined between groups of related aircraft rather than specifying differences between each possible configuration and combination of configurations between related aircraft.

MDRs are specified in terms of training, check, and currency difference levels described in paragraph 4d and are shown on an MDR table.

(2) MDR Content. MDRs specify the minimum training, checking, and currency acceptable to the FAA for pilot qualification regarding differences.

(3) MDR Formulation, Description, and Revision. MDRs are formulated by the FAA FSB for each related aircraft. MDRs are formulated using standardized tests and evaluations in conjunction with the type certification or supplemental type certification process. MDRs are based on an applicant’s (usually an aircraft manufacturer) proposal, FAA evaluation of that proposal, OE, and test results when tests are necessary. FSB determinations also consider operator recommendations, safety history, and other relevant information. MDRs are described in provisions of an FSB report and may be revised if necessary. MDRs are revised when aircraft are developed or modified, tests or OE shows a need for revision, a revision is requested by an applicant and evidence indicates the need for revision, or rules or FAA policies change. MDRs are revised by a process similar to that used for initial formulation of requirements.

(4) MDR Use. MDRs are applied to specific operators through formally described ODRs that are developed by and tailored to each operator. FAA field offices use the MDRs as the basis for approval of individual operator’s differences programs for approval of initial or transition programs where credit for previous training or experience with other related aircraft is sought.

(5) The MDR Table. An example of typical MDRs for the B-737-200, 300, 400, 500, 600, 700, 800, and 900 is shown in Figure 1. MDR table requirements are shown for each pair of aircraft by notations in each element of corresponding columns and rows of the table. Each element of the table identifies the minimum differences training, checking, and currency requirements applicable to mixed fleet flying. The MDR table identifies a pertinent base aircraft and particular aircraft for which requirements are sought. Note the minimum difference levels that correspond to the pertinent column and row, and special requirements in footnotes, if applicable.

(6) Use of MDR Difference Levels. Operators must satisfy difference requirements by using the methods acceptable for the specified level or higher levels. Lower level methods may be used in addition to the required levels but may not substitute for the required level or be used exclusively instead of the required level.

Appendix 2 FIGURE 1. MASTER DIFFERENCE REQUIREMENTS (MDR) TABLE

FROM AIRCRAFT

PILOT TYPE RATING: B-737 B-737 BASIC B-737-100, 200 (SP77) B-737-200 ADV B-737-300, 400, 500 (NON-EFIS) B-737-300, 400, 500 (EFIS) B-737-600, 700, 800, 900

B-737 BASIC A/A/A B/A/B

(2) NAV-B/B/C

(6) PMS-C/B/C C*/C*/D C*/C*/D D/D/D

(7) Differences within a Series. Differences may exist even within series shown on an MDR table, such as within the A-318/319/320/321 series. MDR elements may show requirements from one series to another identified in the footnotes. Such requirements however, apply only if pertinent differences exist between those aircraft.

(8) More than Two Related Aircraft. When pilot assignments apply to more than two related aircraft, such as the A-320, A-330, and A-340, each pertinent requirement of the MDR table applies. Applications of multiple requirements for flying two or more related aircraft and certain limits to flying large numbers of related aircraft are described in paragraph 7k.

(9) Special Requirements.

(a) MDR Footnotes. Footnotes can be used to credit, constrain, or set alternate levels when special situations apply. Use of footnotes permits accommodation of variations in installed equipment, options, pilot knowledge or experience on other aircraft, training methods or devices, or other factors that are not addressed by basic levels between aircraft. For example, a footnote B-737-100, 200 (SP77)

(2) NAV-B/B/C

(6) PMS-C/B/C

B-737-200 ADV B/A/B

(1) PDCS- C/B/C

(2) NAV-B/B/C

(4) AFCS- C/B/C

(6) PMS-C/B/C A/A/A

(1) PDCS- C/B/C

(2) NAV-B/B/C

(4) AFCS- C/B/C

(6) PMS-C/B/C C*/C*/D

(1) PDCS- B/B/C

(2) NAV-B/B/C

(5) LIMITED

FMS-C/B/C C*/C*/D

(1) PDCS- B/B/C

(2) NAV-B/B/C

D/D/D

(1) PDCS- B/B/C

(2) NAV-B/B/C

B-737-300, 400, 500

TO AIRCRAFT C*/C*/D

(5) LIMITED

FMS-C/B/C C*/C*/D

(5) LIMITED

FMS-C/B/C A/A/A

(7) CROSS

MODEL- (NON-EFIS) A/A/B C/B/B (8) C/B/B B-737-300, 400, 500 (EFIS)

(3) C*/C*/D

(5) LIMITED

FMS-C/B/C

(3) C*/C*/D

(5) LIMITED

FMS-C/B/C

(3) C/B/B A/A/A

(7) CROSS MODEL- A/A/B

(8) C/B/B

(9) PFD/ND- D/C/C

B-737-600, 700, 800, 900

D/D/D D/D/D (8) C/B/B

(9) PFD/ND- D/C/C

(8) C/B/B

(9) PFD/ND- D/C/C A/A/A

(9) PFD/ND- D/C/C

(11) EDFCS- C/C/C Page 7

Appendix 2 may allow credit or apply constraints to the use of a particular flight guidance control system (FGCS), flight management system (FMS), or electronic flight instrument system (EFIS), which is installed on aircraft. Footnotes are an appropriate means to address requirements that relate to specific systems (e.g., flight director and FMS) rather than a particular aircraft. In such instances, generic knowledge or experience with the particular system may be readily transferable between related aircraft. Footnotes may also be used to set different requirements for initial training or checking rather than for recurrent training or checking. When necessary, footnotes are fully described in the body of the FSB report.

(b) Other Limitations. Other limitations may occasionally be identified within a difference level (e.g. C*/C*/C). The asterisk following the difference level in such instances identifies a special requirement or limitation pertaining to a particular training method or device.

Such notes typically relate to acceptable training device characteristics when the simulator evaluation and approval process or standard criteria of this AC are not available to address a particular situation appropriately.

(10) MDRs for Aircraft with the Same or Common Pilot Type Ratings. A single FSB report and MDR table may apply to aircraft that are assigned the same pilot type rating (same aircraft TC). For example, a single MDR table may cover the A-318/319/320/321 that have a same pilot type rating. A single FSB report and MDR table may also apply to aircraft that are assigned a common pilot type rating. For example, a single MDR table may cover both the B-767 and B-757 that have a common pilot type rating. When level E training is required for an aircraft with a same aircraft TC and an additional pilot type rating is assigned, such as the B-747 and B-747-400, a single MDR table for all series of a type-certificated aircraft still applies.

(11) Minimum acceptable difference levels are recommended by the FSB based on standard tests described in Appendix 3.

c. Difference Levels.

(1) General Description. Difference levels are formally designated levels of training methods or devices, checking methods, or means of maintaining currency that satisfy minimum difference requirements or pilot type rating requirements. Difference levels specify FAA requirements proportionate to and corresponding with increasing differences between related aircraft. A range of five difference levels in order of increasing requirements, identified as A through E, are each specified for training, checking, and currency. MDRs are specified in terms of difference levels. Difference levels are used to credit knowledge, skills, and abilities applicable to an aircraft for which a pilot is already qualified and current, during initial, transition or upgrade training for other related aircraft. Operators, who conduct mixed fleet flying where credit is sought, should apply difference levels and address all mixed fleet flying requirements to ensure compliance with FAA requirements necessary to assure safe operations.

(2) Basis for Levels. Difference levels apply when a difference with potential to affect flight safety exists between related aircraft. Differences may also affect knowledge, skills, or abilities required of a pilot. If no differences exist or if differences exist but do not affect knowledge, skills, abilities or flight safety, then difference levels are not assigned nor are they applicable to pilot qualification. When difference levels A through E apply, each difference level Page 8

Appendix 2 is based on a scale of differences in design features, systems, or maneuvers. In assessing the effects of differences, both flight characteristics and procedures are considered, since flight characteristics address handling qualities and performance, while procedures include normal and abnormal/nonnormal/emergency items.

(3) Relationship Between Training, Checking, and Currency Levels. While particular aircraft are often assigned the same level (e.g., C/C/C) for training, checking, and currency, such assignment is not necessary. Levels may be assigned independently. For example, an aircraft may be assigned level C for training, level D for checking, and level C for currency

(e.g., C/D/C).

(4) Designation of a Pilot Type Rating. Candidate aircraft having the same TC are assigned the same pilot type rating if training differences are not greater than level D. Candidate aircraft of the same make having different TCs that have training differences no greater than level D may be assigned a common pilot type rating. A candidate aircraft with systems such as heads-up display (HUD), Enhanced Vision Systems (EVS), or Synthetic Visions Systems (SVS) may require Level E training without requiring a new pilot type rating. The FSB, with the concurrence of the Air Transportation Division, AFS-200, will make this determination. When different pilot type ratings are assigned because of one or more candidates requiring level E training, pilot type ratings may be assigned to related aircraft consistent with a logical grouping of the most similarly related aircraft.

d. Training Difference Levels.

(1) Level A Training. Level A difference training is that differences training between related aircraft that can adequately be addressed through self-instruction. Level A training represents a knowledge requirement that, once appropriate information is provided, understanding and compliance can be assumed. Level A compliance is achieved by such methods as issuance of operating manual page revisions, dissemination of operating bulletins, or differences handouts to describe minor differences in aircraft. Level A training is limited to the following situations:

(a) A change that introduces a different version of a system/component for which the pilot has already shown the ability to understand and use (e.g., an updated version of an engine).

(b) A change that results in minor or no procedural changes and does not adversely effect safety if the information is not reviewed or forgotten (e.g., a different vibration damping engine mount is installed, expect more vibration in descent; logo lights are installed, use is optional).

(c) Information that highlights a difference, which is evident to the pilot, inherently obvious, and easily accommodated (e.g., different location of a communication radio panel, a different exhaust gas temperature limit that is placarded, or changes to nonnormal “read and do” procedures).

(2) Level B Training. Level B difference training is applicable to aircraft with system or procedure differences that can adequately be addressed through aided instruction. At level B, Page 9

Appendix 2 aided instruction is appropriate to ensure pilot understanding, emphasize issues, provide a standardized method of presenting material, or aid retention of material following training.

Level B aided instruction can utilize slide/tape presentations, computer based tutorial instruction, stand-up lectures or video tapes. Situations not covered under the provisions of level A training may require level B (or higher levels) if certain tests described in later paragraphs fail.

(3) Level C Training. Level C differences training can only be accomplished through use of devices that are capable of systems training. Level C differences training is applicable to related aircraft having part task differences that affect skills or abilities and knowledge. Training objectives focus on mastering individual systems, procedures, or tasks, as opposed to performing highly integrated flight operations and maneuvers in “real time.” Level C may require selfinstruction or aided instruction, but cannot be adequately addressed by a knowledge requirement alone. Training devices are required to supplement instruction, ensure attainment or retention of pilot skills and abilities, and accomplish the more complex tasks, usually related to operation of particular aircraft systems. While level C systems knowledge or skills relate to specific rather than fully integrated tasks, performance of steps to accomplish normal, nonnormal, alternate, recall procedures, or maneuvers related to particular systems (e.g., flight guidance control systems/flight management systems) may be necessary. Typically, the minimum acceptable training media for level C training would be interactive computer-based training, cockpit systems simulators, cockpit procedure trainers or part task trainers (e.g., flight management system (FMS) or traffic collision avoidance system (TCAS)).

(4) Level D Training. Level D training can only be accomplished with devices capable of performing flight maneuvers and addressing full task differences of knowledge, skills, and/or abilities. Devices capable of flight maneuvers address full task performance in a dynamic real time environment. The devices enable integration of knowledge, skills, and abilities in a simulated flight environment, involving combinations of operationally oriented tasks and realistic task loading for each relevant phase of flight. Level D training, knowledge, and skills to complete necessary normal, nonnormal, alternate, or recall procedures are fully addressed for each related aircraft. Level D differences training requires mastery of interrelated skills that cannot be adequately addressed by separate acquisition of a series of knowledge areas or skills that are interrelated. The differences are not so significant that a full transition training course is required. If demonstrating interrelationships between the systems is important, use of a series of separate devices for systems training will not suffice. Training for level D differences requires a training device that has accurate, high fidelity integration of systems and controls, and realistic instrument indications. Level D training may also require maneuvers, visual cues, motion cues, dynamics, control loading or specific environmental conditions. Weather phenomenon such as low visibility, CAT III, or windshear may or may not be incorporated. Where simplified or generic characteristics of an aircraft type are used in devices to satisfy difference level D training, significant negative training must not occur as a result of the simplification. Typically, the minimum acceptable training media for level D training would be Flight Training Device level 6.

(5) Level E Training. Level E training is applicable to candidate aircraft having such significant full task differences that require a “high fidelity” environment to attain or maintain knowledge, skills, or abilities. Training at level E can only be satisfied by the use of a simulator qualified at level C or D consistent with FAA criteria. Level E training, if done in an aircraft, Page 10

Appendix 2 should be modified for safety reasons where maneuvers can result in a high degree of risk (i.e., an engine set at idle thrust to simulate an engine failure). As with other levels, when level E training is assigned, suitable credit or constraints may be applied for knowledge, skills, and/or abilities related to other pertinent related aircraft. Credits or constraints are specified for the subjects, procedures, or maneuvers shown in FSB reports and are applied through the ODR table.

NOTE: Training differences levels recommended by the FSB represent minimum requirements. Operators may use a device associated with a higher difference level to satisfy a training differences requirement. For example, if level C differences are assessed due to installation of a different FMS, operators may train pilots using the FMS installed in a full flight simulator (FFS) as a system trainer if a dedicated part task FMS training device is not available.

e. Checking Difference Levels.

(1) Initial and Recurrent Checking. Difference checking addresses any pertinent pilot testing or certification that includes pilot type rating checks, proficiency checks, Advanced Qualification Program (AQP) evaluations, and any other checks specified by FSB reports. Initial and recurrent checking levels are the same unless otherwise specified by the FSB in the MDR. In certain instances, it may be possible to satisfactorily accomplish recurrent checking objectives in devices that do not meet initial checking requirements. In such instances, the FSB may recommend certain devices that do not meet initial check requirements for use to administer recurring checks. The POI/Training Center Program Manager, in coordination with the FSB, may require checking in the initial level device when doubt exists regarding pilot competency or program adequacy.

(2) Level A Checking. Level A checking indicates that no check related to differences is required at the time of differences training. A pilot is responsible for knowledge of each related aircraft flown. Differences items should be included as an integral part of subsequent recurring proficiency checks.

(3) Level B Checking. Level B checking indicates that a “task” or “systems” check is required following transition and recurring differences training. Level B checking typically applies to particular tasks or systems such as FMS, TCAS, or other individual systems or related groups of systems.

(4) Level C Checking. Level C checking requires a partial proficiency check using a device suitable for meeting level C (or higher) differences training requirements following transition and recurrent differences training. The partial check is conducted relative to particular maneuvers or systems designated by the FSB. Example of a level C check: Evaluation of a sequence of maneuvers demonstrating a pilot’s ability to use a FGCS or FMS. An acceptable scenario would include each relevant phase of flight that uses the FGCS or FMS.

(5) Level D Checking. Level D checking requires a partial proficiency check for one or more related aircraft following both transition and recurrent training. The partial proficiency check covers the particular maneuvers, systems, or devices designated by the FSB. Level D Page 11