AC 120-53B

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
November 5, 2013
Last reviewed
August 9, 2024
Cancels
AC120-53A
Cancelled by
AC120-53B CHG 1
Family
AC 120-53 · 5 versions
Revision
B
14 CFR parts
60, 61, 91, 121

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

U.S. Department of Transportation Federal Aviation Administration Advisory Circular Subject: Guidance for Conducting and Use of Flight Standardization Board Evaluations Date: 11/5/13 Initiated by: AFS-200 AC No: 120-53B Change:

1. PURPOSE. This advisory circular (AC) has two purposes:

a. Evaluating Manufactured or Modified Aircraft. It provides a means but not the only means of evaluating manufactured or modified aircraft by the use of standard systems, processes, and tests necessary to determine pilot training and qualification requirements.

b. Differences in Training and Qualification between Aircraft. It describes an acceptable means, but not the only means, of compliance with applicable Title 14 of the Code of Federal Regulations (14 CFR) that provide for differences in training and qualification between aircraft with the same type certificate. It further describes an acceptable means for providing related aircraft differences training and qualification under provision of 14 CFR part 121 between aircraft with different type certificates that have been “designated” by the Administrator as related. Both of these processes use the provision of the Flight Standardization Board (FSB) report as the basis for the approval of pilot training and qualification necessary for the operation of aircraft. This AC is intended to enhance safety by:

(1) Providing a standard method of assessing applicant programs.

(2) Directly relating pilot training and qualification requirements to fleet characteristics, operating concepts, and pilot assignments.

(3) Permitting better industry planning and management by outlining what FAA requirements apply, what training resources or devices are needed, and what alternatives are possible.

(4) Encouraging aircraft manufacturers to design with the goal of developing common characteristics between related aircraft

(5) Providing a recommended framework for application of suitable credits or constraints to better address new technology and future safety enhancements.

2. CANCELLATION. AC 120-53A, Guidance for Conducting and Use of Flight Standardization Board Evaluations, dated October 15, 2008, is canceled.

3. FOCUS. This AC addresses aircraft manufacturers or modifiers who design, test, and certificate aircraft. In addition, it reflects those changes in part 121 applied to operators whose

pilots operate related aircraft of the same manufacturer in a mixed fleet seeking training and qualification credit in those related aircraft.

4. DISCUSSION. When requested by industry, the Flight Standards Service (AFS) of the FAA, through the Aircraft Evaluation Groups (AEG) undertake analyses of new and related aircraft and their associated systems for the purpose of providing recommendations for pilot training and qualification. These recommendations are documented in FSB reports for each specific or related aircraft, and may be used by a certificate holder to develop its training and qualification programs.

5. SUMMARY OF REVISIONS. As part of its process of evaluating aircraft for the assignment of a type rating, the FSB, when asked, may make comparisons with other aircraft of the same type to evaluate their differences. This AC recognizes the concept of designating related aircraft, provided for in part 121, as an extension of a differences evaluation to include aircraft of different types.

/s/ for John S. Duncan Director, Flight Standards Service Par 3 Page 2

Appendix 1 APPENDIX 1. DEFINITIONS AND REFERENCES

TABLE OF CONTENTS

1. DEFINITIONS…………………………………………………………..1

2. REFERENCES (current editions)………………………………………4 Page 1 (and 2)

Appendix 1 APPENDIX 1. DEFINITIONS AND REFERENCES

1. DEFINITIONS.

NOTE: Definitions provided in Appendix 1 apply exclusively to this advisory circular (AC).

a. Aircraft Evaluation Group (AEG). Federal Aviation Administration (FAA) organization that sets training, checking, currency, type rating, Master Minimum Equipment List (MMEL), and maintenance standards for assigned certificated aircraft types. AEGs also address operational aspects of aircraft type certification and resolution of service difficulties.

b. Applicant. For the purposes of this AC, an applicant may be a manufacturer, modifier, or operator.

c. Base Aircraft. An aircraft identified by the applicant and used as a reference to compare differences with another aircraft.

d. Candidate Aircraft. The aircraft that will be subjected to the Flight Standardization Board (FSB) evaluation process outlined in this AC for comparison purposes.

e. Check. An assessment of crewmember proficiency during which limited training or practice is allowed. The assessment is of knowledge and skill in tasks to the standards identified by the FAA. If the check is given for the purpose of flightcrew member certification it will be considered a test and must be administered by the FAA or a designated examiner.

f. Common Takeoff and Landing Credit (CTLC). CTLC is a program/process that identifies recency of experience credit between related aircraft (same make) with different type certificates that can be demonstrated to have an equivalent level of safety (ELOS) during the following:

• Takeoff and initial climb, and

• Approach and landing, including the establishment of final landing configuration.

NOTE: The T6 test is used for aircraft that were not tested (T2) during the initial aircraft evaluation for type rating designation.

g. Configuration. Aircraft physical features, which are distinguishable by pilots, with respect to differences in systems, cockpit geometry, visual cutoff angles, controls, displays, aircraft geometry, and/or number of required pilots.

h. Currency. Currency is the experience necessary, within a specified period of time, for the safe operation of aircraft, equipment, and systems as determined by the FSB. Currency may include, but is not limited to, recency of experience.

i. Difference Levels. Difference levels are formally determined levels of training methods or devices, checking methods, or currency methods that satisfy difference requirements between Page 1

Appendix 1 related aircraft. A range of five difference levels in order of increasing requirements, identified as A through E, are specified for training, checking, and currency purposes.

j. Differences Training. Training required before any person may serve as a required crewmember on a particular aircraft type, when the Administrator finds differences training is necessary before a crewmember serves on a particular variation of that aircraft.

• Related Aircraft Differences Training. Training required before any person may serve as a required flightcrew member in part 121 operations on an aircraft with a different type certificate (TC) that has been designated as related by the Administrator.

k. Differences Checking. Checking between related aircraft with the same aircraft TC based on the certificate holder’s approved training and qualification program.

• Related Aircraft Differences Checking. When permitted, checking between designated related aircraft based on the certificate holder’s approved training and qualification program.

l. Flight Characteristics. Flight characteristics are handling characteristics or performance characteristics perceivable by a pilot. Flight characteristics relate to the natural aerodynamic response of an aircraft, particularly as affected by changes in configuration and/or flight path parameters (e.g., flight control use, flap extension/retraction, airspeed change, etc.).

m. Flight Simulation Training Device (FSTD). A full flight simulator (FFS) or a flight training device (FTD).

n. Flight Standardization Board (FSB). The FSB is responsible for specification of minimum training, checking, currency, and type rating requirements, if necessary, for U.S.

certificated civil aircraft. The board members are drawn from the FAA (AEG, headquarters (HQ), Flight Standards (AFS) field offices operations personnel).

o. Handling Characteristics. The manner in which the aircraft responds with respect to rate and magnitude of pilot initiated control inputs to the primary flight control surfaces

(e.g., ailerons, elevator, rudder, spoilers, cyclic, collective, etc.).

p. Line Oriented Flying (LOF). The LOF phase of the test is used at the discretion of the FSB during the T3 test to validate the proposed training and checking. The LOF fully assesses particular difference areas, examines implications of mixed fleet flying, assesses special circumstances such as minimum equipment list (MEL) effects, and evaluates the effects of pilot errors potentially associated with the differences.

q. Master Difference Requirements (MDR). MDRs are those requirements applicable to pilot training and qualifications that pertain to differences between related aircraft. MDRs are specified by the FSB in terms of the minimum difference levels. MDRs form the basis for an operator to develop their operator differences requirements (ODR).

Appendix 1

r. Mixed Fleet Flying. Mixed fleet flying is the operation of a base aircraft and one or more related aircraft for which credit may be taken for training and/or checking events. The FSB process defines minimum training, checking, and currency difference levels between related aircraft.

s. Operator Difference Requirements (ODR). If differences exist within an operator’s fleet that affect pilot knowledge, skills, or abilities pertinent to systems or procedures, ODR tables provide a uniform means for operators to comprehensively manage differences or related aircraft differences training programs and provide a basis for FAA approval of mixed fleet flying.

t. Qualification. The process by which a flightcrew member completes the certificate holder’s FAA-approved curriculum including any necessary checks or tests for the aircraft type and duty position.

u. Recency of Experience. With respect to flight experience as required by the applicable CFR, means a pilot’s completion of the required number of takeoffs and landings as sole manipulator of the controls within a specified period of time.

v. Related Aircraft. Any two or more aircraft of the same make with either the same or different type certificates that have been demonstrated and determined by the Administrator to have commonality.

• Designated Related Aircraft. Any two or more aircraft of the same make with different type certificates that have been designated as related by the Administrator based upon a request from the part 121 operator. This designation may allow credit between those aircraft to be applied for training, checking, recent experience, operating experience, operating cycles, and line operating flight time for consolidation of knowledge and skills.

w. Supervised Line Flying (SLF). Supervised experience associated with the introduction of equipment or procedures requiring post qualification skill enhancement during which a pilot occupies a specific pilot position and performs particular assigned duties for that pilot position under the supervision of a qualified company check airman.

x. Type. As used with respect to the certification of aircraft, means those aircraft which are similar in design. Examples include: Boeing 737/Boeing 737-300 and A320/A321. These examples are described as series of the same type.

y. Type Rating. A type rating is a “one time,” permanent endorsement on a pilot certificate indicating that the holder of the certificate has completed the appropriate training and testing as required by the applicable CFR. It is recorded by the FAA on the pilot’s certificate indicating the make and type. In some cases it will include the series of aircraft (for example Boeing 747-400), if applicable.

NOTE: Common Type Rating. Common type rating is a term used in FSB reports to describe a relationship between type ratings for aircraft with different TCs that have no greater than level D training differences. The type Page 3

Appendix 1 rating for a certificated aircraft can be determined to be related to another type rating of another certificated aircraft of the same make provided the aircraft meet the criteria of the T1 (equivalence) or the T2 (handling characteristics) and T3 (core pilot skills with no greater than level D differences).

NOTE: The pilot who is receiving a type rating on the basis of being related must be current and qualified in the base aircraft at the time of the check and is issued a type rating after receiving designated related aircraft differences training and checking on the candidate related aircraft as described in this AC under training and checking difference levels. This check is not a “full” proficiency check, but an abbreviated check on the differences (B, C, and D) from the base to the candidate aircraft. The designated related aircraft differences check, unless it includes the requirements for a recurrent check, cannot reset the “recurrent clock” (a pilot’s base month for checking purposes).

2. REFERENCES (current editions).

• Title 14 CFR Parts 60, 61, and 121,

• FAA Order 8900.1, Flight Standards Information Management System (FSIMS),

• AC 61-89, Pilot Certificates, Aircraft Type Ratings,

• AC 120-35, Line Operational Simulations: Line Oriented Flight Training, Special Purpose Operational Training, Line Operational Evaluation,

• AC 120-40, Airplane Simulator Qualification,

• AC 120-45, Airplane Flight Training Device Qualification,

• AC 120-51, Crew Resource Management Training, and

• FAA-S-8081-5, Airline Transport Pilot and Aircraft Type Rating Practical Test Standards for Airplane.

Appendix 2 APPENDIX 2. PILOT TRAINING, QUALIFICATION, AND RATING

REQUIREMENTS

TABLE OF CONTENTS Paragraph Page

1. PURPOSE1

2. FOCUS1

3. INTRODUCTION1

a. Comprehensive System for Pilot Training and Qualification ........1

b. Designation of Related Aircraft .....................................................1

c. Master Differences Requirements (MDR) Formulation by FAA ..2

d. Specification of Constraints or Credits ..........................................2

e. Recognition of Unique Operator Characteristics ...........................2

f. Basis for Requirements ...................................................................2

g. Relationship to Other FAA Policies ..............................................2

4. CONCEPTS2

a. An Integrated System for Pilot Training and Qualification. ..........2

b. MDRs .............................................................................................3

c. Difference Levels ...........................................................................5

d. Training Difference Levels ............................................................6

e. Checking Difference Levels ...........................................................8

f. Currency Difference Levels ............................................................9

g. Operating Experience (OE), Operating Cycles, and Consolidation of

Knowledge and Skills ........................................................................12

h. Supervised Line Flyign (SLF) .......................................................12

i. Recency of Experience……………………………………………12

j. ODR ................................................................................................13

5. FORMULATION OF FSB REPORTS, MDRs, AND DETERMINATION OF

TYPE RATINGS21

a. Formulation Process Overview ......................................................21

b. Proposals for MDRs, Example ODRs, and Special Requirements21

c. Difference Level Tests ...................................................................22

d. FSB Assessments and Proposal Formulation ................................24

e. Comments Solicited .......................................................................28

f. FSB Final Determinations and Findings ........................................28

g. FSB Report Preparation Distribution and FAA Application. ........29

h. FSB Report Revision .....................................................................30

6. OPERATOR’S APPLICATION OF FSB RECOMMENDATIONS,

PREPARATION, USE, AND REVISION OF ODRs31

a. General ...........................................................................................31

b. Application of MDRs and Preparation and Use of ODRs .............31

c. Selecting Base Aircraft ..................................................................32

Appendix 2

d. Identification of Differences and the Analysis of Effects of Those

Differences .........................................................................................32

e. Identification of Compliance Methods...........................................33

f. When Proposed ODR Compliance Methods Do Not Meet MDRs33

g. Application, Review, and Approval ...............................................33

h. Transition Period for ODR Implementation ..................................34

i. ODR Revision .................................................................................34

7. FAA REVIEW AND APPROVAL OF OPERATOR PROGRAMS36

a. General ...........................................................................................36

b. Operator Application of ODRs ......................................................36

c. Base and Other Aircraft Identification ...........................................37

d. Approval of ODRs .........................................................................38

e. FSB Revision of MDRs or Other FSB Recommendations ............38

f. Proving Tests ..................................................................................38

g. Line-Oriented Flight Training (LOFT) or SLF ..............................38

h. OE ..................................................................................................39

i. Limitations on the Total Number of Related Aircraft ....................39

j.Compliance Checklist for CHDOs ..................................................39

k.Aircraft That Do Not Have an FSB Report ....................................39

8. APPLICATION OF FSB REQUIREMENTS39

a. General ...........................................................................................39

b. Checks Regarding Complex Systems ............................................40

9. FSTD APPROVAL40

a. NSP Representation to the FSB .....................................................40

b. Coordination of NSP Criteria with the FSB ..................................40

10. REVIEW AND APPROVAL40

11. APPEAL OF FAA DECISIONS40

ILLUSTRATIONS

Figure 1. Master Difference Requirements (MDR) Table4

Figure 2. Difference Level Table12

Figure 3-1. Design Operator Difference Requirements Table Example15

Figure 3-2. Systems Operator Difference Requirements Table Example16

Figure 3-3. Maneuver Operator Difference Requirements Table Example20

Figure 4. Master Requirements Formulation25

Figure 5. Test Definitions26

Figure 6. “T” Tests 1 Thru 527

Figure 7. Standard Method and Flight Simulation Training Device29

Figure 8. Flight Standardization Board Process35

Appendix 2 APPENDIX 2. PILOT TRAINING, QUALIFICATION, AND RATING

REQUIREMENTS

1. PURPOSE. This appendix describes a comprehensive system for pilot training and 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.

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

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

3. INTRODUCTION.

a. Comprehensive System for Pilot Training and Qualification. This AC and its appendices provide a systematic means to address requirements for training, checking, and currency within applicable CFR. 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, and currency are clarified. This includes defining the role and criteria for determining type ratings for existing, new, or modified aircraft. The system is particularly suited to addressing transition, differences and related aircraft differences training 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. Designation of Related Aircraft. Certain aircraft with different type certificates may be demonstrated and determined to have commonality to the extent that credit between those aircraft may be applied for training, checking, recency of experience, operating experience, operating cycles, or line operating flight time for consolidation of knowledge and skills. In order for a certificate holder to use these training and qualification efficiencies in that certificate holder’s operation, the certificate holder must obtain a related aircraft designation from the Administrator. The process for related aircraft designation and deviation approval is as follows:

(1) The certificate holder identifies the related aircraft (including specific information regarding make and type) and makes a request through the POI to AFS-200 for the designation.

This designation should be based on FAA analysis published in the applicable FSB report.

(2) Request for deviation provided in §§ 121.434, 121.439 and 121.441 must be sent to the Air Transportation Division (AFS-200) through its associated CHDO and regional office.

AFS-200 will consider the deviation on the basis of guidance from the AEG and its FSB reports and will provide a memo of concurrence or non-concurrence to the CHDO through its associated regional office.

Appendix 2

c. Master Differences Requirements (MDR) Formulation by FAA. The FAA’s Flight Standardization Board (FSB) formulates MDRs to address differences between related aircraft.

These MDRs are presented in tabular format in the appropriate FSB Report. See subparagraph 4b.

d. Specification of Constraints or Credits. The system permits the specification of constraints or permissible credits. Constraints or credits may relate to knowledge, skills, abilities, FSTDs, 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.

e. Recognition of Unique Operator Characteristics. The system recognizes the unique characteristics of individual operators while achieving uniformity in application of FAA safety standards. FAA MDRs determine uniform bounds to tailor individual operator’s unique requirements to a particular fleet and situation. Principal operations inspectors (POI) approve each operator’s unique requirements within FAA MDRs. Operator unique requirements accommodate particular combinations of related aircraft flown, pilot assignment policies, training methods and devices, and other factors that relate to the application of the FAA MDRs.

Accordingly, the system preserves operator flexibility while standardizing the FAA’s role in review, approval, and monitoring of training, checking, currency, and mixed fleet flying programs as applicable.

f. Basis for Requirements. The determination of 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.

g. Relationship to Other FAA Policies. Although this AC, and the FSB recommendations 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 recommendations 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 Training and Qualification.

(1) System Elements. An integrated FAA/industry system and process established to determine appropriate requirements, apply the requirements, and meet those requirements on a continuing basis, for uniform pilot training and 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’ (usually an aircraft manufacturer) support for analysis, and testing. FSB reports for Page 2

Appendix 2 related aircraft describe FAA master requirements. MDRs express the minimum acceptable difference levels between related aircraft. An operator’s training and qualification program, checklist, operations manuals, 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. Operator Difference Requirements (ODR) 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.

b. MDRs.

(1) MDR Applicability. MDRs are those requirements applicable to training and qualification that pertain to differences between related aircraft. MDRs specify the minimum acceptable difference levels between related aircraft that may be approved for operators. One related aircraft is selected by the operator 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 number. Difference levels between the base aircraft and other related aircraft then specify the minimum difference requirements to be met for pilot training and 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, checking, and currency difference levels as shown on an MDR table.

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

(3) MDR Formulation, Description, and Revision. MDRs are formulated by the FAA FSB for related aircraft. MDRs are originally specified when an aircraft is first type certificated.

MDRs are formulated using standardized tests and evaluations in conjunction with the aircraft type certification or supplemental type certification process. MDRs are based on an applicant’s proposal, FAA evaluation of that proposal, in-service experience, and test results when tests are necessary. FSB determinations also consider operator recommendations, safety history, and other relevant information. MDRs are described in recommendations of an FSB report and may be revised if necessary. MDRs are revised when aircraft are developed or modified, tests or in-service experience 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 or related aircraft differences training program.

(5) The MDR Table. An example of typical MDRs for the Boeing 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 difference training, checking, and Page 3