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 
11/5/13 AC 120-53B

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
11/5/13 AC 120-53B

Appendix 1

APPENDIX 1. DEFINITIONS AND REFERENCES

TABLE OF CONTENTS

1. DEFINITIONS....................................................................1

2. REFERENCES (current editions).............................................4

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11/5/13 AC 120-53B

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 

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11/5/13 AC 120-53B

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).

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11/5/13 AC 120-53B

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 

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11/5/13 AC 120-53B

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.

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11/5/13 AC 120-53B

Appendix 2

APPENDIX 2. PILOT TRAINING, QUALIFICATION, AND RATING 

REQUIREMENTS

TABLE OF CONTENTS

Paragraph Page

1. PURPOSE...................................................................................................................1

2. FOCUS .......................................................................................................................1

3. INTRODUCTION ......................................................................................................1

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. CONCEPTS................................................................................................................2

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 RATINGS. .....................................................................................................21

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

b. Proposals for MDRs, Example ODRs, and Special Requirements ...................21

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 ODRs..............................................31

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

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

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

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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 MDRs ...................33

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

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

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

7. FAA REVIEW AND APPROVAL OF OPERATOR PROGRAMS.......................36

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 REQUIREMENTS..........................................................39

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

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

9. FSTD APPROVAL ..................................................................................................40

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

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

10. REVIEW AND APPROVAL ..................................................................................40

11. APPEAL OF FAA DECISIONS .............................................................................40

ILLUSTRATIONS

Figure 1. Master Difference Requirements (MDR) Table................................................4

Figure 2. Difference Level Table....................................................................................12

Figure 3-1. Design Operator Difference Requirements Table Example ........................15

Figure 3-2. Systems Operator Difference Requirements Table Example ......................16

Figure 3-3. Maneuver Operator Difference Requirements Table Example....................20

Figure 4. Master Requirements Formulation..................................................................25

Figure 5. Test Definitions...............................................................................................26

Figure 6. “T” Tests 1 Thru 5...........................................................................................27

Figure 7. Standard Method and Flight Simulation Training Device ..............................29

Figure 8. Flight Standardization Board Process .............................................................35

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11/5/13 AC 120-53B

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.

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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 

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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 

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Appendix 2

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 Higher or Lower Difference Levels. Operators will satisfy difference 

requirements by using the methods acceptable for the specified level or a higher level. 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.

FIGURE 1. MASTER DIFFERENCE REQUIREMENTS (MDR) TABLE

TYPE RATING: 

BOEING 737

FROM AIRCRAFT

Boeing 737 

BASIC 

Boeing 737-

100, -200 

(SP77)

Boeing 737-

200 ADV

Boeing 

737-300, -400, 

-500

(NON-EFIS)

Boeing 

737-300, -400, 

-500

(EFIS)

Boeing 

737-600, -700, 

-800, -900

TO AIRCRAFT

Boeing 737 

BASIC 

Boeing 737-100, 

-200 (SP77)

A/A/A

(2) NAV-B/B/C

(6) PMS-C/B/C

B/A/B

(2) NAV-B/B/C

(6) PMS-C/B/C

C*/C*/D C*/C*/D D/D/D

Boeing 737-200 

ADV

B/A/B

(1) PDCSC/B/C

(2) NAV-B/B/C

(4) AFCSC/B/C

(6) PMS-C/B/C

A/A/A

(1) PDCSC/B/C

(2) NAV-B/B/C

(4) AFCSC/B/C

(6) PMS-C/B/C

C*/C*/D

(1) PDCSB/B/C

(2) NAV-B/B/C

(5) LIMITED 

FMS-C/B/C

C*/C*/D

(1) PDCSB/B/C

(2) NAV-B/B/C

D/D/D

(1) PDCSB/B/C

(2) NAV-B/B/C

Boeing 737-300, 

-400, -500

(NON-EFIS)

C*/C*/D

(5) LIMITED 

FMS-C/B/C

C*/C*/D

(5) LIMITED 

FMS-C/B/C

A/A/A

(7) CROSS 

SERIESA/A/B

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

Boeing 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 

SERIESA/A/B

(8) C/B/B

(9) PFD/NDD/C/C

Boeing 737-600, 

-700, -800, -900

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

(9) PFD/NDD/C/C

(8) C/B/B

(9) PFD/NDD/C/C

A/A/A

(9) PFD/NDD/C/C

(11) EDFCSC/C/C

(7) Differences Within a Series. Differences may exist even within series shown on an 

MDR table. 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 One Related Aircraft. When an operator assigns a pilot to more than 

one related aircraft of the same type certificate (e.g., Boeing 737-100/-200/-300/-400/-500/next 

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Appendix 2

generation), or more than one aircraft with different type certificates (e.g. Boeing 757 and 

Boeing 767) designated as related, each pertinent requirement of the MDR table applies.

(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 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 FSTDs when the FSTD 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 Different Type Certificate . A single FSB 

report and MDR table may apply to aircraft that are assigned the same type certificate (TC) with 

the same type rating (e.g., Boeing 737-100/-200/-300/-400/-500 and next generation). .A single 

FSB report and MDR table may also apply to different type certificated aircraft (e.g., Boeing 757 

and Boeing 767). When it is determined that level E training is required for an aircraft with a 

same aircraft TC and a different type rating is determined, a single MDR table for all series of 

that type-certificated aircraft still applies (e.g., Boeing 747 and Boeing 747-400). Minimum 

acceptable difference levels are assigned based on standard tests described in Appendix 3.

c. Difference Levels.

(1) General Description. 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 

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Appendix 2

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 training and qualification. When difference levels A through E apply, each 

difference level 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) Evaluation for Determination of Aircraft Type Ratings. 

(a) Aircraft with the same TC being evaluated for type rating determination are 

assigned the same type rating if training differences are no greater than level D.

(b) Aircraft of the same make having different TCs that have training differences no 

greater than level D will be assigned different type ratings that may be considered in common 

with each other. 

(c) Aircraft of the same make that have level E training difference requirements will 

be assigned a different type rating. 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 type rating.

d. Training Difference Levels.

(1) Level A Training. Level A training is that 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 

affect 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 

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different exhaust gas temperature limit that is placarded, or changes to nonnormal “read and do” 

procedures).

(2) Level B Training. Level B training is applicable to related aircraft with system or 

procedure differences that can adequately be addressed through aided instruction. At level B, 

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 level A training may require 

level B (or higher levels) if certain tests described in later paragraphs fail.

(3) Level C Training. Level C training is applicable to related aircraft having part task 

differences that affect knowledge, skills and/or abilities. Level C training can only be 

accomplished through use of devices that are capable of systems training. The 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 self-instruction 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. Typically, the minimum acceptable training method for level C 

training would be interactive computer-based training, cockpit procedure trainers, or part task 

trainers (e.g., FMS or traffic collision avoidance system (TCAS)).

(4) Level D Training. Level D training is applicable to related aircraft having full task 

differences of knowledge, skills, and/or abilities. Level D training can only be accomplished with 

devices capable of performing flight maneuvers 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 requires mastery of interrelated skills that cannot be adequately 

addressed by separate acquisition of those skills. However, the differences are not so significant 

that a full transition training course is required. 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 method for level D training would be flight training 

device (FTD) level 6.

(5) Level E Training. Level E training is applicable to aircraft having such significant 

full task differences that a “high fidelity” environment is required to attain or maintain 

knowledge, skills, or abilities. Training at level E can only be satisfied by the use of a full flight 

simulator (FFS) qualified at level C or D consistent with FAA criteria. Level E training, if done 

in an aircraft, 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, 

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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 difference levels specified by the FSB represent minimum 

requirements. Operators may use a device associated with a higher 

difference level to satisfy a training difference 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 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. Differences and related aircraft differences 

checking addresses any pertinent pilot qualification requirements and any other checks specified 

by FSB reports. Initial and recurrent checking levels are the same unless otherwise specified by 

the FSB. 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 is required at the time 

of training. A pilot is responsible for knowledge of each related aircraft flown. Difference 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 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) difference training requirements following 

training. The partial check is conducted relative to particular maneuvers or systems determined 

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 training. The partial proficiency check covers the particular 

maneuvers, systems, or devices determined by the FSB. Level D checks are performed using 

scenarios representing a “real time” flight environment and devices permitted for level D 

difference training. A full proficiency check is typically conducted on the base aircraft, and a 

partial proficiency check on the related aircraft, covering all pertinent differences.

(6) Level E Checking. Unless specified, level E checking requires that a full proficiency 

check be conducted in a level C or D FFS. As with other levels, when level E checking is 

assigned, suitable credit or constraints may be applied for knowledge, skills, and/or abilities 

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Appendix 2

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: Assignment of level E checking requirements alone does not result 

in determining a separate type rating. Only the assignment of level E training 

requirements may result in a separate type rating determination.

f. Currency Difference Levels. The term “currency” as used in this AC addresses 

experience necessary for safe operation of aircraft as determined by the FSB. Currency issues not 

specified by the FSB are covered by regulation.

(1) Level A Currency. Level A currency is considered common to each related aircraft. 

Thus, assessment or tracking of currency for separate related aircraft is not necessary or 

applicable. Maintenance of currency in any one related aircraft or a combination of related 

aircraft will suffice for any other related aircraft.

(2) Level B Currency. Level B currency is “knowledge related” currency, typically 

achieved through self-review by individual pilots for a particular aircraft. Self-review is usually 

accomplished by review of material provided by the operator to pilot. Such currency may be 

undertaken at an individual pilot’s initiative; however, the operator will identify the material and 

the frequency or other situations in which the material should be reviewed. Self-review may be 

based on manual information, bulletins, aircraft placards, memos, class handouts, videotapes, or 

other memory aids that describe the differences, procedures, maneuvers, or limits for the 

pertinent aircraft that pilots are flying. Examples of acceptable compliance with level B currency 

are:

(a) The issuance of a bulletin that directs pilots to review specific operating manual 

information before flying a related aircraft. Level B currency may be regained by review of 

pertinent information to include bulletins, if that related aircraft has not been flown within a 

specified period (e.g., fly that related aircraft or have completed a review of the differences in 

limitations and procedures within a specified number of days).

(b) Pilot endorsement on a dispatch release that they have reviewed pertinent 

information for a particular related aircraft to be flown on that trip. Level B currency cannot, 

however, be achieved solely by review of class notes taken by and at the initiative of an 

individual pilot unless the adequacy of those notes is verified by the operator.

(3) Level C Currency. Level C currency is applicable to one or more systems or 

procedures, and relates to both skill and knowledge requirements. An example would be 

establishment of FMS currency, flight guidance control system currency, or other particular 

currency that is necessary for safe operation of a related aircraft. Establishment of level C for a 

related aircraft with an FMS would typically require a pilot to fly that related aircraft within the 

specified period of time or re-establish currency. Currency constraints for level C are established 

by the FSB. When level C currency applies, pertinent level B currency will also be addressed. 

Examples of methods acceptable for addressing level C currency are:

(a) Pilot scheduling practices resulting in a pilot being scheduled to fly a related 

aircraft with the pertinent system/procedure within the specified period of time;

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(b) Tracking of an individual pilot’s flying of related aircraft to ensure that the 

particular system/procedure has been flown within the specified period of time;

(c) Use of a higher level method (level D or E currency); or

(d) Other methods as determined or found acceptable by the FSB.

(4) Re-Establishing Level C Currency. When currency is lost, currency may be reestablished by completing required items using a device equal to or higher than that specified for 

level C difference training and checking. Other means to re-establish currency include flights 

with an appropriately qualified check airman, completion of proficiency training, or a 

proficiency check. In some instances, a formal refamiliarization period in the actual aircraft with 

the applicable system operating while on the ground may be acceptable if permitted by the FSB. 

Such refamiliarization periods are completed using an operator-established procedure under the 

supervision of a pilot designated by the operator.

(5) Level D Currency. Level D currency is related to designated maneuvers, and 

addresses knowledge and skills required for performing aircraft control tasks in real time, with 

integrated use of associated systems and procedures. Level D currency may also address certain 

differences in flight characteristics including performance of any required maneuvers and related 

normal/abnormal/emergency procedures for a particular related aircraft. A typical application of 

level D currency is to specify selected maneuvers, such as takeoff, departure, arrival, approach, 

or landing, which are to be performed using a particular FGCS and instrument display system. 

Either a pilot must fly a related aircraft equipped with the FGCS and particular display system 

sufficiently often to retain familiarity and competence within the specified currency period, or 

currency must be re-established. Currency constraints for level D are established by the FSB. 

When level D currency applies, pertinent level B and level C currency must also be addressed. 

Examples of methods acceptable for addressing level D currency are:

(a) Tracking of flights by a particular pilot in a particular related aircraft to assure 

experience within the specified currency period.

(b) Tracking the completion of specific maneuvers based on logbook entries, Aircraft 

Communication Addressing and Reporting System (ACARS) data, or other reliable records to 

assure experience within the specified currency period.

(c) Scheduling of aircraft or pilots to permit currency requirements to be met with 

verification that each pilot has actually accomplished the assigned or an equivalent schedule.

(d) Completion of pilot qualification in which designated maneuvers are performed in 

a FSTD acceptable for level D currency.

(e) Use of a higher level method (level E currency).

(f) Other methods as determined or found acceptable by the FSB.

(6) Re-Establishing Level D Currency. When currency is lost, currency may be reestablished by completing pertinent maneuvers using a device equal to or higher than that 

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Appendix 2

specified for level D difference training and checking. Other means to re-establish currency 

include flight with an appropriately qualified check airman during training or in line operations, 

completion of proficiency training, or a proficiency check.

(7) Level E Currency. Level E currency may specify system, procedure, or maneuver 

currency item(s) necessary for safe operations, as identified by the FSB, to be accomplished in a 

Level C/D FFS for that related aircraft. FSB recommendations related to takeoff and landing are 

applied in a way that addresses needed system or maneuver experience. For example, if FGCS, 

FMS, EFIS, navigation, or other system or maneuver experience is the basis for a currency 

requirement, approval of an operator’s program at level E includes the use of those systems in 

conjunction with satisfying takeoff and landing requirements. In this instance, making three FFS) 

takeoffs and landings in VFR closed traffic without using the FGCS, EFIS, or FMS may not be 

sufficient to meet level E currency requirements.

NOTE: Assignment of level E currency requirements alone does not result 

in determining a separate type rating. Only the assignment of level E training 

requirements may result in a separate type rating determination.

(8) Re-Establishing Level E Currency. When currency is lost, currency may be reestablished by completing pertinent maneuvers using a device specified for level E difference 

training and checking. Other means to re-establish currency include flight with an appropriately 

qualified check airman during training or in line operations, completion of proficiency training, a 

proficiency check, or AQP evaluation.

(9) Competency Regarding Abnormal/Nonnormal/Emergency Procedures.

Competency for nonnormal maneuvers or procedures is generally addressed by checking 

requirements; however, particular abnormal/nonnormal/emergency maneuvers or procedures 

may not be mandatory for checking or training. In this situation, it may be necessary to 

periodically practice or demonstrate those maneuvers or procedures even though it is not 

necessary to complete them during each check. In such instances, the FSB may specify a 

currency requirement for training or checking applicable to abnormal/nonnormal/emergency 

maneuvers or procedures that are to be performed. This is to assure that extended periods of time 

do not elapse in a series of repeated training and checking events in which significant maneuvers 

or procedures may never be accomplished. When an abnormal/nonnormal/emergency maneuver 

or procedure is not mandatory and is not accomplished during each proficiency training or 

proficiency check, but is still important to occasionally practice or demonstrate, the FSB may 

establish a currency requirement. When determined by the FSB, these currency requirements 

identify each abnormal/nonnormal/ emergency maneuver or procedure, the currency 

level applicable, and an applicable time period or any other necessary/appropriate constraints.

(10) Difference Level Summary. Difference levels are summarized in Figure 2 below for 

training, checking, and currency. Complete descriptions of difference levels for training,

checking, and currency are given above.

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Appendix 2

FIGURE 2. DIFFERENCE LEVEL TABLE

DIFFERENCE 

LEVEL

TRAINING CHECKING CURRENCY

A Self instruction Not applicable

(or integrated with next 

proficiency check)

Not applicable

B Aided instruction Task or system check Self review

C Systems devices Partial proficiency check 

using device

Designated system

D Maneuver devices Partial proficiency check

using level 6 or higher 

FSTD

Designated maneuver(s)

E Level C or D FFS

or aircraft #

Proficiency check using 

level C or D FFS or aircraft

Designated maneuver(s) 

# = New type rating is normally assigned

* = FFS or aircraft may be used to accomplish specific maneuvers

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

Skills. Credits towards 14 CFR part 121 requirements for operating experience, operating cycles, 

and line operating flight time for consolidation of knowledge and skills may be permitted if 

performed in “designated” related aircraft.

h. Supervised Line Flying (SLF). 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 check airman qualified for the operator. One or more of the reasons 

described below may apply:

(1) Introduction of new systems (e.g., Automatic Dependent Surveillance Broadcast 

(ADS-B), runway area advisory system (RAAS), etc.).

(2) Introduction of new operations (e.g., oceanic operations, Extended Operations 

(ETOPS)).

(3) Experience for a particular pilot position (e.g., PIC, SIC).

(4) Special characteristics (e.g., effects of unique airports, mountainous areas, unusual 

weather, special air traffic control procedures, or nonstandard runway surfaces) on this aircraft.

i. Recency of Experience. Credit towards the recency of experience requirements of 

14 CFR part 121 may be permitted for takeoffs and landings performed in designated related 

aircraft.

j. ODR.

(1) ODR Purpose. If differences exist within an operator’s fleet, which affect pilot 

knowledge, skills, or abilities pertinent to systems or procedures, ODR tables provide a uniform 

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Appendix 2

means for operators to comprehensively manage differences and related aircraft differences 

training programs and provide a basis for FAA approval of mixed fleet flying.

(2) ODR Content. ODRs identify a base aircraft, describe differences between aircraft, 

and show an operator’s methods of compliance with FAA requirements. The FAA approves an 

operator’s initial ODR and each subsequent revision for the following:

(a) Base Aircraft. ODRs identify an aircraft or group of aircraft within an operator’s 

fleet as a base aircraft. The base aircraft serves as a reference for comparison with other related 

aircraft to describe their differences.

(b) Significance of Differences. Differences are described in summary form and are 

categorized by differences in design features, systems, and maneuvers. Differences are evaluated 

relative to their effect on either flight characteristics, pilot skills, and/or procedures.

(c) Compliance Methods. ODRs show how each operator’s program addresses 

differences, through description of training, checking, or currency methods for each fleet. ODRs 

describe the specific or unique constraints or credits applicable, and any precautions necessary to 

address differences between aircraft. ODRs must comply with and be just as or more restrictive 

than FAA MDRs and other FSB recommendations if they are part of the operator approved 

training program. Constraints or credits may be applied to all aircraft in a fleet or only to certain 

aircraft. Constraints or credits may address FSTDs, checking and currency methods, knowledge, 

skills, procedures, maneuvers, or any other factors that apply to or are necessary for safe 

operations. Training, checking, and currency compliance methods are proposed and revised by 

each operator consistent with ODR examples from a variety of sources that are acceptable to the 

FAA. ODR examples are found in FSB reports.

(3) Standard ODR Format. ODRs are depicted in tables in summarized form. If 

necessary, any explanation of details about differences, constraints, and credits, precautions or 

compliance methods are included in attachments or appendices to ODR tables or are cross 

referenced to other operator documents. Figure 3 shows the general format for ODR tables, 

including examples of design, systems, and maneuver differences. The far-left column lists 

design, system, or maneuver differences that are pertinent. The “Remarks” column summarizes 

specific areas or items of difference. The “Flight Characteristics” and “Procedural Change” 

columns identify what (if any) difference effects are noted. The “Compliance Methods” section 

of the table notes the particular operator’s approved means of compliance with FAA MDR

recommendations. The following abbreviations apply:

• ACFT - Aircraft.

• AFDS - Auto Flight Display System.

• AVT - Audio Visual Tapes.

• CBT - Computer-Based Training.

• EFIS - Electronic Flight Instrument System.

• EICAS - Engine Indicating and Crew Alerting System.

• FSTD - Flight Simulation Training Device.

• FLT CHAR - Flight Characteristics.

• FMC - Flight Management Computer.

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Appendix 2

• FMS - Flight Management System.

• PROC CHNG - Procedural Changes.

• SU - Stand Up Instruction (traditional classroom instruction).

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Appendix 2

FIGURE 3-1. DESIGN OPERATOR DIFFERENCE REQUIREMENTS TABLE 

EXAMPLE

DESIGN OPERATOR DIFFERENCE REQUIREMENTS TABLE

COMPLIANCE METHOD

CHKG/CURR

CURR

B

FLT 

CHK

TRAINING

LVL

E

LVL

D

LVL

C

LVL

B

AVT/

SU/

CBT

AVT/

SU/

CBT

AVT/

SU/

CBT

LVL

A

DIFFERENCE AIRCRAFT: 737-300BASE AIRCRAFT: 737-200 ADVANCEDAPPROVED BY (POI): 

PROC 

CHNG

NONONO

FLT 

CHAR

MINOR

NONO

REMARKS

- BODY EXTENSION 104”- WING TIP EXTENSION 14”

- DORSAL FIN- w/STC ST01219SE, BLENDED WINGLET

- ADDITION OF FMC/AFDS/AT/IRS ETC.- GROWTH RELATED CHANGES

DESIGN FEATURE

AIRPLANECONFIGURA-TIONPANEL LAYOUTWEIGHTS

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Appendix 2

FIGURE 3-2. SYSTEMS OPERATOR DIFFERENCE REQUIREMENTS TABLE 

EXAMPLE

SYSTEMS OPERATOR DIFFERENCE REQUIREMENTS TABLE

COMPLIANCE METHOD

CHKG/CURR

CURR

D

90

DAYS

+

3 FLT

SEG.

FLT 

CHK

C*+OE

TRAINING

LVL

E

LVL

D

LVL

C

CBT/

FMS/

AT

LVL

B

AVT/

SU

AVT

AVT/

SU

AVT/

SU

AVT/

SU

LVL

A

DIFFERENCE AIRCRAFT: 737-300BASE AIRCRAFT: 737-200 ADVANCEDAPPROVED BY (POI): 

PROC 

CHNG

YESYES

NO

YESYES

FLT 

CHAR

NONONONONO

REMARKS

- RECIRC FAN REPLACES GASPER FAN- 3 POSITION PACK SWITCH- FWD OUTFLOW VALVE LIGHT DELETED- EQUIPMENT COOLING FAN LIGHT- ADDITIONAL FAN INSTALLED (EFIS ONLY)- DISTRIBUTION: MINOR CHANGES

- SP-300 AFDS REPLACES SP-77/SP-177

- AUTOTHROTTLE ADDED*

- AUTOLAND CAPABILITY ADDED*(*ONLY WHEN COMPARED TO SP-77 AIRPLANES)- LNAV/VNAV- TO/GA MODE

- MINOR CHANGES IN POWER 

DISTRIBUTION- CANNISTER OPTION ONLY*- NEW CREW MASKS*

(*OPTION ON SOME -200 AIRPLANES)- DUAL-LOOP DETECTION SYSTEM

- MINOR EXTING. EQUIP. CONFIG CHANGE- TWO SQUIBS PER BOTTLE

SYSTEM

21 AIR COND. & PRESSURIZATION22 AUTO-FLIGHT24 ELECTRICAL25 EMERGENCY EQUIPMENT26 FIRE PROTECTION

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Appendix 2

FIGURE 3-2. SYSTEMS OPERATOR DIFFERENCE REQUIREMENTS TABLE 

EXAMPLE (Continued)

SYSTEMS OPERATOR DIFFERENCE REQUIREMENTS TABLE

COMPLIANCE METHOD

CHKG/CURR

CURR FLT CHK

TRAINING

LVL

E

LVL

D

LVL

C

LVL

B

AVT/

SU

(CBT/

AVT/

SU)

AVT/

SU

LVL

A

DIFFERENCE AIRCRAFT: 737-300BASE AIRCRAFT: 737-200 ADVANCEDAPPROVED BY (POI): 

PROC 

CHNG

YES

(YES

MINOR)

YES

FLT 

CHAR

MINOR

NO

REMARKS

- ADD’L SPOILERS ADDED- ELECTRIC AIL TRIM

- DUAL CHANNEL MACH TRIM;TEST BUTTON DELETED- SPEED TRIM ADDED- STAB TRIM BRAKE DELETED

- TWO SPEED STAB TRIM- DIFFERENT STAB TRIM RANGE- ELECTRIC STAB TRIM OVERRIDE- ELECTRIC RUDDER TRIM

- AUTOSLAT SYS. ADDED- TE FLAP PLACARD SPEEDS

- CERTIFIED T/O FLAP SETTINGS- RUDDER SYSTEM ENHANCEMENT

- (OPTION: BLENDED WINGLET W/

SPEED BRAKE LOAD ALLEVIATION)

- CONTINUOUS FUEL HEAT SWITCHES DELETED- FILTER BYPASS LIGHT REPLACES ICING LIGHT- FUEL CAPACITY INCREASED- GND XFER OF FUEL

- AUX TANK (OPTIONAL)

SYSTEM

27 FLIGHT CONTROLS28 FUEL

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FIGURE 3-2. SYSTEMS OPERATOR DIFFERENCE REQUIREMENTS TABLE 

EXAMPLE (Continued)

SYSTEMS OPERATOR DIFFERENCE REQUIREMENTS TABLE

COMPLIANCE METHOD

CHKG/CURR

CURR FLT CHK

TRAINING

LVL

E

LVL

D

LVL

C

LVL

B

AVT/

SU

AVT/

SU

AVT/

SU

AVT/

SU

LVL

A

DIFFERENCE AIRCRAFT: 737-300BASE AIRCRAFT: 737-200 ADVANCEDAPPROVED BY (POI): 

PROC 

CHNG

YESYESYES

NO

FLT 

CHAR

NONONONO

REMARKS

- LANDING GEAR XFER UNIT

- SYS A & B SOURCES AND COMPONENTS CHANGED; A & B INDEPENDENT- GROUND INTERCONNECT DELETED- AUTOSLAT PTU- THRUST REVERSER - ONE ON EACH 

SYSTEM- B QUANTITY GUAGE ADDED

- STBY RUDDER ON LIGHT

- ENG INLET ANTI-ICE DELETED- WING ANTI-ICE OPERATION ON GROUND PERMITTED*(*OPTION ON SOME -200 AIRPLANES)- EFIS (AS INSTALLED)- ADI/HIS (AS INSTALLED)

- NAV SWITCH (AS INSTALLED)

- NORM/ALT REPLACES A & B SYS BRAKES- PAIRED WHEEL ANTI-SKID PROTECTION ON ALT BRAKES- TIRE SCREEN DELETED*- NO TOUCHDOWN OR LOCKED WHEEL PROTECTION ON ALT BRAKES- SINGLE ANTI-SKID SWITCH

(*OPTION ON SOME -200 AIRPLANES)

SYSTEM

29 HYDRAULIC30 ICE & RAIN PROTECTION31 FLIGHT INSTRUMENTS32 LANDING GEAR

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FIGURE 3-2. SYSTEMS OPERATOR DIFFERENCE REQUIREMENTS TABLE 

EXAMPLE (Continued)

SYSTEMS OPERATOR DIFFERENCE REQUIREMENTS TABLE

COMPLIANCE METHOD

CHKG/CURR

CURR

D

90

DAYS

+

3 FLT

SEG.

B

FLT 

CHK

C*

+

OE

C*

TRAINING

LVL

E

LVL

D

LVL

C

CBT/

FMS/

AT

FMS/

AT

LVL

B

AVT/

SU

AVT

AVT/

SU

AVT/

SU

AVT/

SU

AVT/

SU

AVT/

SU

LVL

A

DIFFERENCE AIRCRAFT: 737-300BASE AIRCRAFT: 737-200 ADVANCEDAPPROVED BY (POI): 

PROC 

CHNG

YESYES

NO

YESYES

NONO

FLT 

CHAR

NONONONONO

MINOR

NO

REMARKS

- ADDITIONAL SYS ANNUNCIATOR LIGHTS ADDED- GPWS MODE 6 WINDSHEAR OPTION*(* OPTION ON SOME -200 AIRPLANES)

- FMCS ADDED- IRS ADDED- ANCDU- DISTRIBUTION MINOR CHANGE- CFM-56 ENGINES

- NEW INDICATORS- CASCADING VANES TYPE REVERSER WITH AUTO RESTOW- PMC ADDED- IGN SELECT SWITCH

- AUTOMATIC RECOVERY AVAILABLE IF IN DUAL CHANNEL- FLIGHT DIRECTOR GUIDANCE AVAILABLE (OPTIONAL)- CHANGED

- GROWTH RELATED CHANGES

SYSTEM

33 WARNING34 NAVIGATION36 PNEUMATICS73, 74, 77, 80POWER PLANTWINDSHEAREQUIPMENTPERFORMANCELIMITATIONS

Page 19
11/5/13 AC 120-53B

Appendix 2

FIGURE 3-3. MANEUVER OPERATOR DIFFERENCE REQUIREMENTS TABLE 

EXAMPLE

MANEUVER OPERATOR DIFFERENCE REQUIREMENTS TABLE

COMPLIANCE METHOD

CHKG/CURR

CURRD90DAYS+

FLT CHKC*+OEC*

TRAINING

LVLE

LVLD

LVLCFMS/ATFME/AT

LVLBAVT/SUAVT/SU

LVLA

BASE AIRCRAFT: 737-200 ADVANCEDAPPROVED BY (POI): 

PROC CHNGSEEAPPSEEAPP

FLT CHARNONO

REMARKS- OPTIONAL USE OF AFDS, AND A/T(ALSO AN OPTION FOR -200 AFCS AIRPLANES)- OPTIONAL USE OF FMCS- OPTIONAL USE OF AFDS, AND A/T (ALSO AN OP;TION FOR -200 AFCS AIRPLANES)- OPTIONAL USE OF FMCS

MANEUVERNORMAL TAKEOFF, CLIMB, CRUISE, DESCENT, INSTRUMENT APPROACHES, LANDINGNON-NORMAL MANEUVERS

Page 20
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Appendix 2

(4) ODR Approval, Distribution, and Availability. ODRs are approved for each fleet 

by an operator’s FAA POI in accordance with FSB report recommendations. ODRs must be 

prepared, reviewed, approved, and then used to govern training before start of operations. The 

operator retains approved ODRs with a duplicate copy as part of FAA certificate-holding district 

office (CHDO) records.

(5) ODR Revision. ODR tables are revised by operators and re-approved by the FAA 

when fleet characteristics change or when compliance methods change. Fleet characteristic 

changes include redesignation of base aircraft, modification of aircraft, addition of aircraft, 

change of aircraft, or phaseout of aircraft. Changes in compliance methods refer to introduction 

of new or different training methods, contracting for use of different FSTDs, revision of 

checking or currency methods, or other such changes. Revisions to ODRs are also prepared, 

reviewed, and approved before operating.

NOTE: Paragraph 6 describes the development, approval, and application 

of ODR tables to individual operator’s programs. Paragraph 7 describes 

FAA review and approval of programs by POIs.

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

RATINGS.

a. Formulation Process Overview. The process for FAA formulation and revision of MDR 

requirements is shown in Figure 4. The process determines which information is required for an 

aircraft; it includes a proposal for requirements, tests, and evaluations of the proposed 

requirements; it then finalizes, applies, and implements the FSB recommendations. Applicants 

propose MDRs, examples of ODRs, and any other FSB recommendations that are necessary. 

Proposals for requirements are based on design objectives, analysis, evaluation of in-service 

experience, other programs that have been proved acceptable to the FAA, or other methods. 

Setting of requirements is based on an objective set of tests and standards, analysis of results, and 

FAA judgments considering in-service experience. The applicant and the FAA prepare and 

conduct standardized tests. The applicant provides test support, and the FSB conducts the 

evaluation. The FSB, in conjunction with the applicant, evaluates the results, and the FAA 

formulates proposed minimum requirements. The FSB sets final recommendations by specifying 

MDRs and other FSB recommendations. An FSB report that describes findings can be found on 

the FSIMS under Publications. The formulation and application process of FSB 

recommendations starts at the time a new aircraft is proposed to the FAA and continues 

throughout the fleet life of that aircraft. For aircraft already in service the process may be 

initiated when significant modifications are proposed, a new piece of equipment (e.g., a HUD) 

requiring operational evaluation is introduced and requested by operators, or when mixed fleet 

flying takes place. The FAA addresses periodic revisions of requirements when necessary, and 

revisions are initiated by the FAA and applicants as needed.

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

(1) When Proposals are Necessary. The FAA usually determines when proposals are 

necessary and advises the applicant what information is needed, in conjunction with aircraft type 

certification or supplemental certification programs. Necessary information may include MDRs 

Page 21
11/5/13 AC 120-53B

Appendix 2

for related aircraft or other elements of the FSB reports. The applicant considers existing MDRs 

and existing or proposed ODRs.

(2) Proposal Formulation. An operator, manufacturer, or an organization that modifies 

aircraft proposes a new design or modification. The applicant will then do the following:

(a) Formulate necessary information for training, checking, and currency for the 

aircraft in proposals for MDRs and example ODRs.

(b) Prepare example ODR tables for candidate aircraft to support development of a 

proposed MDR. These examples represent proposals for programs for those specific aircraft and 

configurations that the FAA could approve.

(c) Identify related aircraft for the proposed MDR table.

(d) Formulate any necessary tests to assess difference levels and associated training, 

checking, and currency requirements for incorporation in the MDR table.

(e) Identify interpretations of possible test results. The FAA and the applicant will 

then reach an agreement on specific tests, devices, and schedules to be used for the test program.

(f) The applicant submits proposals for the following items to the FAA, as necessary:

• MDRs,

• Example ODRs,

• Tests and criteria to be used, and

• Other supporting information associated with training, checking, or currency 

programs.

c. Difference Level Tests. A sequence of five standard tests, described in Appendix 3, is 

used to set MDRs, minimum acceptable training programs, other FSB recommendations, and 

define type rating requirements. One or more of these tests are applied depending on the 

difference level sought, and the success of any previous tests used in identifying MDRs. Only 

those tests needed are used to establish minimum requirements. The outcome of these tests, and 

any resulting difference levels that apply, establish minimum requirements for training, 

checking, currency, and type ratings. The FAA will establish an additional type rating if it is 

determined during this testing that the assignment of a level E difference training is required.

NOTE: One additional test, the T6 test, can be used to establish CTLC 

between related aircraft, when not previously demonstrated in a T2 test.

(1) Steps in the Testing Process. The typical steps of the testing process are as follows:

(a) The applicant develops representative training programs, differences and/or 

related aircraft differences programs, and necessary supporting information, as needed.

(b) The applicant identifies proposed MDRs and example ODRs.

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11/5/13 AC 120-53B

Appendix 2

(c) The applicant proposes and the FAA determines which tests and criteria apply.

(d) The applicant proposes and the FAA determines which aircraft, simulation 

devices, or analyses are needed to support testing.

(e) The applicant makes a proposal to the FAA, and agreement is reached on test 

procedures, schedules, and specific interpretation of possible results.

(f) Tests are conducted and results evaluated.

(g) The FSB draft minimum requirements are formulated.

NOTE: If the candidate aircraft is anticipated to have no greater than 

level A or B differences with the base aircraft, the FSB may elect to directly 

apply a T1 test for equivalency.

(2) Test Purpose and Application. A summary of the purpose and application of each of 

the six difference tests is shown in Figure 5.

(3) Test Relationships and Applications. This process is followed whenever a new 

aircraft is proposed, when significant changes are proposed, or when revisions to existing 

requirements are needed as a result of requests for change or in-service experience. The test 

process relationships, the sequence of conducting tests when more than one test is needed, and 

application of test outcomes are shown in Figure 6. The start of the process is shown at the top of 

Figure 6.

(a) When a new aircraft is certified and is not compared with an existing aircraft, the 

aircraft is evaluated using the T5 test to determine the effectiveness of the manufacturer training 

and evaluation plan. A type rating is determined as a result of the evaluation.

(b) When two aircraft with the same type certificate are compared, a T1 or T2/T3 test 

is used to determine the level of differences between the two aircraft. The result can be the 

assignment of a same type rating if no greater than Level D training differences exist or the 

assignment of a different type rating if Level E training differences exist.

(c) When two aircraft with different type certificates are compared, a T2/T3 test is 

used to determine the level of differences between the two aircraft. An example of this is a 

determination of B, C, D, or E training differences between the two aircraft.

(4) Test Failures and Retesting. Generally, failures do not have paths back to lower 

levels. T3 test failure at level C can lead to subsequent passage at C or D after modification of 

the system, operational procedures, or training and retesting. Similarly, failure at level D can 

subsequently lead to either D or E after modification of the system, operational procedures, or 

training and retesting, but not C. Failure at level E can only lead to retesting with increased 

programs, improved programs, or improved devices since there is no higher level. T5 test failure 

paths do not lead back to level C or level D. However, subsequent new programs do not preclude 

making a proposal at a lower difference level if technology changes, aircraft redesign takes 

place, training methods significantly change, or device characteristics and effectiveness change.

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Appendix 2

(5) Type Rating Tests. Aircraft seeking a same type rating or type rating in common 

will follow the path in Figure 6 from the top right “START” of Figure 6 through T1 or T2 and 

T3 tests resulting in the assignment of level A, B, C, or D differences.

(6) “Currency” Tests. T4 currency tests are not shown in Figure 6 because they are 

necessary only when the applicant seeks relief from system, procedural, and maneuver currency 

requirements set by the FSB.

(7) Detailed Test Specifications. A detailed specification for the evaluation process and 

tests to establish difference levels is described in Appendix 3.

d. FSB Assessments and Proposal Formulation. The FSB assesses the applicant’s 

proposals, test results, analysis, and any other relevant factors to formulate a draft FSB report, 

which includes MDRs and other pertinent training, checking, and currency requirements. The 

FSB either validates the applicant’s proposed MDRs, training programs, and other information, 

or generates alternate requirements, which may include more stringent requirements, additional 

training, additional testing, etc.

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Appendix 2

FIGURE 4. MASTER REQUIREMENTS FORMULATION

MASTER REQUIREMENTS FORMULATION

(AN FAA/APPLICANT PROCESS)

DESIGN

OBJECTIVES

PROPOSED

MDRS

EVALUATION

& TESTING COMMENTS

FSB REPORT 

MDRS AND 

SAMPLE 

ODRS

FSB REPORT 

APPROVAL 

AND FAA 

FIELD OFFICE 

USE

FSB

REVISION REQUESTS

OPERATORS

MANUFACTURERS

FAA PRINCIPAL OPERATION 

INSPECTORS

OTHER AVIATION ORGANIZATIONS

TYPICAL

MDRS & ODRS

APPLICANT

SUPPORT

FAA

FLIGHT 

STANDARDIZATION 

BOARD

(FSB)

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Appendix 2

FIGURE 5. TEST DEFINITIONS

TEST PURPOSE APPLICATION

T1 Establishes functional equivalence Sets levels A/B 

T2 Handling qualities comparison Pass permits T3, and A/B/C/D; failure sets 

level E and requires T5 

T3 Evaluate differences and sets 

training/checking requirements

Pass sets levels A/B/C/D; failure sets 

level E and requires T5

T4 Revises currency requirements Used to adjust FSB recommendations—if 

needed

T5 Sets training/checking for new or “E” 

ACFT Sets level E

T6 Evaluation for CTLC Sets recency of experience requirements

Note: Expanded descriptions are contained in Appendix 3.

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11/5/13 AC 120-53B

Appendix 2

FIGURE 6. “T” TESTS 1 THRU 5

“T” TESTS

1 THRU 5

Candidate

Level E? T1 Req’d?

T3 Req’d?

T1 T2

T3

T5 LEVEL E

No Commonality

or

T5 LEVEL E

With B/C/D

Commonality

SAME OR COMMON PILOT TYPE RATING

START

Level A

Differences

Level B

Differences

Level C

Differences

Level D

Differences

Level E Differences

New T/R

NO

YES Waive T1

NO

Pass

Fail

YES

Fail

Pass

YES

NO

Pass

Fail

LEVEL

A or B

A B C D E

Page 27
11/5/13 AC 120-53B

Appendix 2

e. Comments Solicited. The FSB proposal is circulated with interested parties representing 

the manufacturer, operators, and other pertinent FAA organizations such as engineering, flight 

test, pilots’ associations, and other aviation representatives for comment, relevant information, 

and recommendations.

f. FSB Final Determinations and Findings.

(1) FSB Determinations. Any comments submitted to the FAA are reconciled, and final 

FSB determinations are made. Specification of MDRs, example ODRs, acceptable training 

programs, and other FSB recommendations are completed. Any necessary pilot checking or 

currency recommendations are identified. Determination of any necessary type rating(s) is made.

(2) Basis for FSB Judgments. FSB judgments are based on review of the applicant’s 

supporting documentation, proposed ODR tables, test results, and any other pertinent 

information, such as FAA policies, in-service experience, and results of other similar FSB 

evaluations. Specifically, FSB report recommendations are based on the following:

(a) Appropriate Data, Evaluation, or Tests. Testing may include aircraft 

demonstration, simulation tests, device testing, or analysis.

(b) Direct Experience. The industry may have substantial experience with successful 

operational programs, which can be useful in the assignment of minimum difference 

level requirements. This experience may include particular training devices, 

training/checking/currency requirements, and mixed fleet flying.

(c) Indirect Experience. Applicable experience with foreign operators, military 

programs, or other programs that can establish the suitability of training, checking, or currency 

standards may be permitted as a means for FSBs to set MDR or ODR levels.

(d) Applicant and Industry. FSB recommendations are set following solicitation 

and review of comments.

(3) FSTD Characteristics. Minimum characteristics for FSTDs for training, checking, or 

currency are noted using 14 CFR part 60 FSTD definitions. When standard criteria for FSTDs

are not appropriate for an aircraft, the FSB identifies suitable criteria to be applied and 

coordinates with the FAA National Simulator Program (NSP). Standard FSTDs applicable to 

each difference level are shown in Figure 7.

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11/5/13 AC 120-53B

Appendix 2

FIGURE 7. STANDARD METHOD AND FLIGHT SIMULATION TRAINING DEVICE

Difference 

Level

Difference Level 

Definition Methods FSTD

A Self instruction

Bulletins

Manual revisions

Handout material

-------------------------

B Aided instruction

Slides/video tapes

Standup instruction

CBT

-------------------------

C System devices ------------------------- FTD or FFS

D Maneuver devices ------------------------- Level 6 or higher FSTD

E Level C or D FFS or 

aircraft ------------------------- Level C or D FFS or aircraft

g. FSB Report Preparation Distribution and FAA Application.

(1) Report Preparation and Approval. After MDRs are finalized, the FSB report is 

prepared and approved. Sufficient background or explanatory material is provided in the report 

to permit FAA personnel to apply FSB recommendations. The following are elements of an FSB 

report:

(a) Purpose and applicability,

(b) Type rating requirements,

(c) MDRs,

(d) Acceptable ODR tables,

(e) FSB specifications for training,

(f) FSB specifications for checking,

(g) FSB specifications for recency of experience,

(h) Aircraft regulatory compliance checklist,

(i) FSB specification for FSTDs,

(j) Applications,

(k) Alternate Means of Compliance,

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11/5/13 AC 120-53B

Appendix 2

(l) Regulatory Coordination and Approval, and

(m) Board Record.

(2) FSB Report Distribution. The FSB report is posted on the FSIMS under 

Publications for implementation in approval of particular operators’ programs. The FAA 

technical requirements described in FSB reports are primarily intended for the operators use to 

develop programs that will be approved by the FAA.

(3) FSB Report Implementation. FSB recommendations and guidance are provided to 

FAA field offices through FSB reports for each aircraft. These reports are recommendations to

FAA offices to identify acceptable criteria for modifying flightcrew member training and 

qualification programs under the applicable CFR. FSB recommendations set acceptable 

standards by which FAA inspectors approve, review, correct, or limit individual operator’s 

programs. The FSB report is the basis for approval of modifications of training, checking, and 

currency programs approved by the FAA.

h. FSB Report Revision.

(1) General FSB Revision Process. A general revision process is established to update 

determinations and findings contained in FSB reports. Revisions may be needed annually for 

active fleets with numerous change requests. Revisions may be needed infrequently for aircraft 

not undergoing significant change. 

(2) Revisions for New Aircraft. When an applicant proposes to develop or add a series 

of a type-certificated aircraft, MDRs and other FSB recommendations are revised to address that 

series. If an applicant initiates this action, the procedures noted in paragraph 5 regarding initial 

determination of minimum training, checking, currency, and type rating requirements are 

followed. If an operator proposes to add an aircraft that is not covered within an existing FSB 

report (e.g., a foreign manufactured aircraft) POIs should consult with the pertinent AEG. An

FSB will determine the best method of addressing the development of the necessary FSB report. 

This is particularly important for older aircraft fleets in which differences may be significant, but 

manufacturer support is no longer available and aircraft imported into the United States that have 

been used only by foreign operators.

(3) Revision for Aircraft Modified by Operators. When an aircraft is to be modified by 

an operator, the POI determines if the change affects MDRs, example ODRs, or other FSB report 

recommendations. The criteria for this assessment includes whether or not the difference affects 

pilot knowledge, skills, or abilities pertinent to flight safety. If a change meets the criteria, the 

operator should supply the POI with a difference description, an analysis of the effects of the 

difference and a proposed training program for the difference. The POI evaluates the proposal 

and if it is acceptable, seeks concurrence from AFS-200. AFS-200 will advise the applicable 

AEG/FSB. The AEG/FSB may concur with the POI’s analysis or propose other action. If FSB 

action is proposed and accepted by AFS-200, the AEG will initiate that action through the FSB 

chairman. The FSB may require that additional information or analysis be provided or that the 

entire test process or parts thereof be applied. The AEG may authorize the POI to approve 

Page 30
11/5/13 AC 120-53B

Appendix 2

assignment of the difference level. Changes to the MDRs will be made through the normal FSB 

revision process.

6. OPERATOR’S APPLICATION OF FSB RECOMMENDATIONS, PREPARATION, 

USE, AND REVISION OF ODRs.

a. General.

(1) Process Overview. FSB reports contain MDRs and other recommendations that are 

applied by FAA offices in approving operators’ flightcrew member training and qualification 

programs when operating mixed fleets. MDRs are applied through a particular method that 

identifies specific ODRs and compliance methods. This is necessary so that regardless of which 

aircraft is flown, uniform training, checking, and currency standards are met within the 

constraints of the applicable CFR. Paragraph 6 describes operator application of MDRs and other 

FSB recommendations for training, checking, and currency. This is done through operator 

preparation and FAA approval of ODRs for each operator. This AC and FSB reports 

comprehensively address differences and related aircraft differences training, checking, and 

currency for each aircraft when aircraft are used in mixed fleet flying. ODRs are used to identify 

credits or constraints between related aircraft. The overall process for operator application of 

MDRs and development, approval, use, and revision of ODRs is shown in Figure 8.

(2) Availability and Use of FSB Information. FSB recommendations are made 

available to operators through FAA CHDOs, applicants, industry trade associations, posted on 

the FSIMS under Publications, or other sources. When preparing training programs for specific 

fleets, individual operators apply the requirements of the applicable FSB report.

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

(1) Need for ODRs. When operating a mixed fleet, operators prepare the necessary ODR 

table proposals to describe their particular fleet and show compliance methods. This is done to 

assess effects of differences, plan compliance methods, and obtain POI approval for that 

operator’s specific program. ODR tables must be prepared and approved by the FAA for each 

fleet in which FSB recommendations are established.

(2) Operator Responsibilities. The operator’s responsibilities include:

(a) Specification of a base aircraft.

(b) Identification of differences between the aircraft within a mixed fleet.

(c) Preparation of proposed ODR tables.

(d) Assessment and description of the effects of the differences on training, checking, 

and currency.

(e) Proposal of training, checking, and currency methods consistent with MDRs, FSB 

recommendations, and authorized deviations.

Page 31
11/5/13 AC 120-53B

Appendix 2

(f) Presentation of proposed ODR tables with necessary supporting information to 

the FAA POI for approval.

(g) Revision of ODR tables when aircraft are introduced, modified, phased out, 

devices change, or MDRs change.

(3) Use of Standard ODR Format. A common format for ODR tables is used to 

facilitate preparation, review, use, comparison with MDRs, and ensure consistency of application 

and approval by POIs. The common format is used in all cases where ODR tables are required 

except when only a few minor differences exist and level A applies. In this event, letters between 

an operator and FAA containing the necessary information and approval may suffice if 

acceptable to the POI.

(4) Minimum Threshold for ODR Preparation. Within the mixed fleet, a minimum 

threshold for preparation of ODR tables occurs when there are differences that potentially affect 

knowledge, skills, or abilities necessary for flight safety. Differences not related to this criterion 

need not be addressed in ODR tables.

(5) ODR Description and Examples. ODRs are described in paragraph 4. Examples of 

acceptable ODR tables for a particular type-certificated aircraft are shown in each FSB report.

(a) Systems Shown on the ODR Table of Figure 3. An example of several pages 

from an ODR table is shown in Figure 3. Figure 3 shows the application of ODRs to address 

systems differences and compliance methods. In Figure 3 differences are grouped in the order 

associated with a typical operations manual. Air Transport Association of America (ATA) code

numbers are shown for cross-reference. The “Remarks” column depicts differences and the 

“Flight Characteristics” and “Procedural Change” columns address effects of differences.

(b) Maneuvers Shown on the ODR Table of Figure 3. The “Remarks” column 

depicts differences. The “Flight Characteristics” and “Procedural Change” columns address 

effects of differences. The reference “SEE APP” refers you to an appendix to the table, which the 

operator prepares to more fully list and explain the particular procedural changes that pertain to 

the maneuver in the “Procedural Change” column.

c. Selecting Base Aircraft. An operator chooses a base aircraft from one of the aircraft 

operated. Base aircraft are defined in Appendix 1. Additional information regarding base aircraft 

selection is in paragraph 7.

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

Differences must be described between base aircraft and other related aircraft. Differences may 

also be described from any related aircraft to each other related aircraft. As long as a complete 

and clear relationship can be drawn from the base aircraft to each other related aircraft and all 

MDR requirements are met from the base aircraft, to each other related aircraft, there is no need 

to describe each possible combination of aircraft. This permits a comprehensive identification of 

differences that exist in the fleet, determines the effects of those differences, and shows 

compliance methods. Differences are generally organized to follow an operations manual or 

flight manual to facilitate use and review, and should be categorized by design, systems, and 

maneuvers. Effects of differences are stated in terms of effects on flight characteristics and 

Page 32
11/5/13 AC 120-53B

Appendix 2

procedures. Procedures include normal, nonnormal, alternate, emergency, and recall procedures, 

as applicable. Since complete descriptions may be to lengthy for direct incorporation in ODR 

tables, appendices, or references to other operator’s documents may be used to describe 

differences or effects. Some differences or effects may be repeated in the analysis. For example, 

an FMS difference may be noted in both a navigation system section and maneuver section 

associated with preflight setup. The objective is to assure each difference that pertains to pilot 

training, checking, or currency is identified and addressed.

e. Identification of Compliance Methods. Once differences and difference effects are 

described, methods of comprehensively addressing each difference (compliance methods) are 

shown. With the difference descriptions, redundancy may occur. The same training or checking 

compliance item shown for one item may also be associated with and credited for other items. 

The objective for description of compliance methods is to show that each difference is addressed 

in some appropriate way, to show that the method and level chosen is consistent with the FSB 

MDRs, and example ODRs at a level at least equal to that required by the MDRs.

f. When Proposed ODR Compliance Methods Do Not Meet MDRs. If proposed ODR 

compliance methods do not satisfy MDRs or other FSB report constraints, the following 

alternatives exist:

(1) Differences may be reduced or eliminated by modification of aircraft, systems, or 

procedures.

(2) Other training methods or devices that fully comply with MDRs and other FSB

recommendations may be acquired, leased, or otherwise applied.

(3) Pilot assignments may be separated for a fleet so that mixed flying of related aircraft 

does not occur.

(4) MDR change proposals may be requested through FAA POIs to the FSB. If FSB 

authorized changes to the MDRs are made, the operator may then apply the revised criteria.

g. Application, Review and Approval. Paragraph 7 describes the FAA review and 

approval process. The process is summarized here to facilitate ODR table preparation. An 

operator submits the proposed ODR tables and necessary supporting information to the POI to 

apply for differences and/or related aircraft differences program approval. The supporting 

information may include any appendices to the ODR tables necessary for evaluation of the

proposal, a transition plan if needed, and a proposed schedule for implementation. POIs may also 

require review of such pertinent and additional information as copies of bulletins, manuals, or 

other training materials, before they approve proposed ODRs. If devices are proposed that are 

not approved by the POI, or evaluated by the NSP, a review and approval of those training 

devices may be necessary before ODR approval. Sufficient lead-time must be provided to the 

FAA for review. Lead-time depends on such factors as the complexity of program, proposed 

difference levels, number of related aircraft, other operator precedents already set, and FAA 

experience with the proposed aircraft, training devices, and methods. Many noncontroversial 

level A changes can be reviewed and approved in a few days. Complex programs with many 

related aircraft can require months for review and approval. It is the operator’s responsibility to 

Page 33
11/5/13 AC 120-53B

Appendix 2

consult with the POI to ensure that sufficient lead-time is provided to review initial submissions 

or changes. At least 60 days notice is acceptable for most programs. After the operator submits 

the program proposal, POIs compare the proposed ODR with the FSB report recommendations 

including the MDRs. POIs consult pertinent FAA policy directives (orders, notices, Safety Alerts 

for Operators (SAFO), etc.) for interpretations or guidance in accomplishing the review. If ODRs 

are consistent with authorized deviations and FAA policies and within the constraints of the 

MDRs and example ODRs, the POI will approve the operator’s ODR tables and its proposed 

differences and/or related aircraft differences program. When approved by the FAA, ODRs 

establish the basis for training, checking, and currency programs for a given fleet for that 

operator.

h. Transition Period for ODR Implementation. In certain instances, a transitional period, 

agreed upon by the POI with FSB concurrence, may be necessary to permit operators to continue 

operations under previously approved programs until they are able to comply with POI-approved 

FSB recommendations. This is necessary when these recommendations are initially set or revised 

and they require lead-time for program preparation, device acquisition, or to revise previously 

approved programs.

i. ODR Revision. ODR revisions are initiated when changes occur in an operator’s fleet 

relating to differences, difference effects, or compliance methods. ODR revisions are appropriate 

when such changes affect pilot knowledge, skills, or abilities relevant to flight safety. Examples 

of program changes or factors that may require ODR revision include:

(1) Addition or deletion of aircraft in a fleet;

(2) Modification of base aircraft or related aircraft in a fleet;

(3) Change of base aircraft;

(4) Discontinuation of use, addition of new or modification of training devices referenced 

by ODRs;

(5) Revision of training methods with a resulting change in compliance levels;

(6) Changes in effects of differences such as revised procedures, performance, or flight 

characteristics;

(7) FAA revision of MDRs or other FSB recommendations;

(8) Adverse in-service experience or training and checking experience that dictates 

inadequacy of ODRs, MDRs, or other FSB recommendations;

(9) FAA surveillance results, enforcement actions, or failure of an operator to comply 

with provisions of their approved ODRs; and

(10) Other factors as determined by the POI.

NOTE: Revisions to ODRs are approved using the same procedures as for 

initial ODRs approval.

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Appendix 2

FIGURE 8. FLIGHT STANDARDIZATION BOARD PROCESS

7. FAA REVIEW AND APPROVAL OF OPERATOR PROGRAMS.

a. General. FAA has the responsibility for review, approval, and continuing surveillance of 

individual operator programs consistent with this AC and FSB recommendations. Within a 

CHDO or FSDO, POIs have the responsibility for program review and approval.

FSB PROCESS

ORDER 8900.1

OTHER REQUIREMENTS

MDR TABLE

POI REVIEW

&

AFS-200

NONCURRENCE

FSB

REPORT

FAA

APPROVED

ODR

TABLE(S)

OPERATIONS

PROPOSED ODR 

TABLE(S) 

(FROM OPERATOR)

FSB CHDO

MDR ODR REVISIONS

REVISION

REQUESTS (IF 

NEEDED)

APPROVAL OF TRAINING 

PROGRAM(S) CHECK 

AIRMEN OPSPECS ETC.

MDR-Master Difference Requirements

ODR-Operator Difference Requirements

POI-Principal Operations Inspector

FSB-FAA Flight Standardization Board

OPSPECS-Operations Specifications

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Appendix 2

b. Operator Application of ODRs.

(1) Operators Using Related Aircraft in Mixed fleet Flying. If FSB recommendations 

are published, operators operating aircraft in mixed fleet flying in accordance with the applicable 

CFR may apply recommendations of this AC and the FSB report.

(2) Threshold Requiring ODR Preparation. Even though an operator has different 

configurations of aircraft used in mixed fleet flying, there is some threshold below which ODR 

tables and POI approval is not required. The threshold requiring AC and ODR application occurs 

when differences in related aircraft affect pilot knowledge, skills, and/or abilities pertinent to 

flight safety. If systems, controls, indications, procedures, or maneuvers are different and these 

differences have an effect that significantly relates to what the pilots needs to know or do for safe 

mixed fleet flight operation, then an operator should prepare ODR tables and must seek FAA 

approval. Conversely, ODR tables would not need to be prepared in situations that do not affect 

flight safety. In such instances ODR tables are not needed even though pilots routinely operate 

several related aircraft. A minimum threshold is set to preclude unnecessary administrative 

assessment of mixed fleet flying, which has no safety implications. If changes to the fleet do not 

affect pilot knowledge, skills, or abilities affecting flight safety, then such changes need not be 

considered in addressing FSB recommendations or this AC.

(3) FAA Review of ODR Proposals. After preparation the carrier submits proposed

ODR tables and supporting information to the CHDO and POI for review and approval. POIs 

evaluate the following:

(a) The operator has made an appropriate identification of a base aircraft.

(b) Operators have comprehensively identified differences in the particular fleet. This 

includes appropriate ODR table comparisons between the base aircraft and each related aircraft.

(c) The operator’s assessment of the effects of differences on flight characteristics 

and procedures for the base aircraft and each related aircraft are suitable and valid.

(d) The compliance methods listed are consistent with the requirements of the MDR 

tables, footnotes, other pertinent FSB report recommendations, the applicable CFR, authorized 

deviations, and associated advisory materials.

(e) ODR provisions adequately address any “subtle differences” between related 

aircraft that have a possibility of inducing potentially serious pilot errors.

(f) Training materials, methods, devices, and FSTDs proposed are acceptable, 

approved by the NSP if necessary, or if FSB recommendations are applied, the ODR tables meet 

FSB constraints.

(g) Aviation safety inspectors (ASI) and Aircrew Program Designee (APD) are 

prepared to apply FSB report checking standards.

(h) Implementation plans are adequate and consistent with FSB recommendations 

and other FAA policy.

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Appendix 2

(i) Other factors determined necessary by the POI are considered and any 

requirements met.

(4) Example ODR Tables and MDRs. The POI uses the example ODR tables and the 

MDRs provided in the FSB report as a basis for evaluating the suitability of a particular 

operator’s proposed ODR table. The MDR always remains the primary basis for comparison. 

The AEG should be consulted in the absence of conclusive guidance in making such judgments. 

Guidance for evaluation of specific system or maneuver items may be found by comparison of 

the proposal with the example ODR table shown in the FSB report and other approved ODR 

tables. The operator may use devices, techniques, or methods of an equal or higher difference 

level. Critical methods should be at least at the level specified by the FSB on the MDRs and 

shown in the example ODR table. Actual ODR tables proposed by the operator may show a 

variety of compliance methods to satisfy a particular item, ranging from level A through the 

level required by the MDRs. For example, if the MDR requirement is a minimum of level C, the 

operator may propose to use a combination of level A bulletins, level B slide tape presentations, 

and level C training devices to satisfy pertinent items. However, at least level C should be shown 

for critical items. The operator may choose to satisfy level C with level D or level E methods.

(5) ODR Review Example. The following is an example of the process for review of a 

specific item on a proposed ODR table. For each proposed ODR item both the FSB example 

ODR table and MDRs are consulted and compared with the operator’s proposal. If the MDRs 

specify that level C devices are needed for training, checking, and currency between the base 

aircraft and a related aircraft and the example ODR table shows applicable level C systems 

differences or maneuvers, then the POI should ensure that the proposed ODR table submitted 

also shows at least level C for those pertinent systems or maneuvers.

c. Base and Other Aircraft Identification.

(1) Selecting the Base Aircraft. Base aircraft are defined in Appendix 1. In general, base 

aircraft are used as reference for comparison of differences that affect, or could affect, pilot 

knowledge, skills, or abilities pertinent to flight safety. A base aircraft should typically be the 

aircraft that the operator trains to first, the aircraft that the operator has the largest number of, the 

aircraft most pilots fly frequently, or the aircraft that represents a configuration that the operator 

eventually will have as a standard. Another aircraft may be selected as a base aircraft when the 

previous base aircraft is being phased out, converted to a new configuration, or other such 

factors. A base aircraft may be reassigned at the discretion of the operator with FAA 

concurrence. A base aircraft is identified by make, type, and series or other distinguishing 

classifications. Classification should distinguish pertinent differences in configuration, handling 

characteristics, performance, procedures, limitations, controls, instruments, indicators, systems, 

installed equipment, options, or modifications.

(2) Identifying Related Aircraft. A related aircraft is an aircraft or a group of aircraft 

with the same characteristics that have pertinent differences from a base aircraft. Pertinent 

differences are those that require different or additional pilot knowledge, skills, and/or abilities 

that affect flight safety. Differences considered pertinent are those relating to configuration, 

handling characteristics, performance, procedures, limitations, controls, instruments, indicators, 

systems, installed equipment, options, or modifications. Related aircraft can exist between 

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Appendix 2

different types, series or within a type/series. When identified in FSB reports, any aircraft 

included in a MDR table is considered a related aircraft. Like base aircraft, operators identify 

related aircraft by one of the following:

• Type/series.

• FAA registration “N number.”

• Operator tail number.

• Any other classification that can uniquely distinguish pertinent differences 

between each related aircraft group and a base aircraft.

(3) Accounting for Each Related Aircraft. The important factor in base and related 

aircraft identification and ODR table preparation is that regardless of the combination used, there 

should be direct and complete traceability of both differences and compliance methods. There 

must be a clear description showing the adequacy of compliance methods to assure proper 

training, checking, and currency to safely operate each aircraft assigned.

d. Approval of ODRs. Following review and determination that an operator’s program 

addresses the FSB recommendations, the POI approves that particular program by signing 

ODRs. ODR tables are approved for each applicable related aircraft. Signature of ODRs or 

revisions, together with other relevant documents such as training programs and OpSpecs, 

constitute approval by the POI of that operator’s differences and/or related aircraft differences 

training, checking, and currency program requirements. ODR tables are used for most programs. 

In instances where aircraft have only a few minor differences at level A, approval may take the 

form of a letter including necessary information in lieu of using tables.

e. FSB Revision of MDRs or Other FSB Recommendations. When requested, the FSB 

reviews an operator’s proposals and if necessary modifies MDRs and other FSB 

recommendations. Major changes in the MDR table may require review by the full FSB. The 

FSB may consider minor changes or interpretations on an ad hoc basis between FSB meetings 

for that aircraft. For some requests changes can be made based on existing or the supplied 

information. Complex cases may require testing to be conducted by the applicant before the 

MDR table is changed. Should the MDRs be updated to accommodate a change request, the 

proposed ODR can be approved within the new MDRs.

f. Proving Tests. When a related aircraft is introduced by an applicant, the requirements for 

proving tests may be effected. FAA Order 8900.1 describes policies for FAA approval of 

proving tests.

g. Line-Oriented Flight Training (LOFT) or SLF. When operators have LOFT or SLF 

programs and additional related aircraft are approved, the POI should review those LOFT or SLF 

programs to assure applicability to each related aircraft. SLF in the aircraft, or in some instances 

FFS (as determined by the FSB), may be necessary in accordance with recommendations of the 

FSB report and with the approval of the POI.

h. OE. As described in this AC and FSB reports, OE is consistent with definitions and 

requirements of the applicable CFR.

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Appendix 2

i. Limitations on the Total Number of Related Aircraft. When mixed fleet flying 

involves pilots operating more than a base aircraft and a single additional related aircraft, 

additional constraints limiting the total number of aircraft may apply. When more than two 

related aircraft are flown, POIs should specifically ensure that subtle or compounded differences 

between the various related aircraft do not result in confusion of procedures, maneuvers, or 

limitations. ODRs proposed for the overall combination of aircraft to be flown should be 

examined to ensure the following:

(1) That multiple differences do not result in confusion of requirements or an excessive 

level of complexity for pilots to adjust to or retain important differences information;

(2) That subtle variations in difference information are not mistakenly applied and lead to 

unsafe conditions; and

(3) That the amount of difference information is not excessive, not applied to the wrong 

aircraft, or not forgotten.

j. Compliance Checklist for CHDOs. FSB reports provide a regulatory compliance 

checklist. The checklist identifies those 14 CFR, ACs, or other FAA requirements that are in 

compliance. Title 14 CFR items not shown on the checklist or items shown but not reviewed by 

the AEG/FSB for compliance should be reviewed by the CHDO before POI approval of OpSpecs 

permitting those aircraft to be used. Items found not compliant by the AEG/FSB should be 

reconciled and compliance established before operation. The compliance checklist is an aid to 

CHDOs used to show the status of those 14 CFR items evaluated by the AEG/FSB, but does not 

comprehensively address all possible items that an operator may need to demonstrate 

compliance. OpSpecs, exemptions, deviations, or other factors, which the AEG/FSB may not be 

aware of, may also apply and may modify compliance status or methods shown in the checklist.

k. Aircraft That Do Not Have an FSB Report. When an FSB report is not prepared for a 

given type-certificated aircraft, or when MDRs or other recommendations are not shown, 

programs are approved in accordance with the applicable CFR, Order 8900.1, and other pertinent 

inspector guidance material.

8. APPLICATION OF FSB REQUIREMENTS.

a. General. FAA pilot certification inspectors and Designated Pilot Examiners (DPE) 

should be familiar with FSB recommendations regarding the proper administration of any 

necessary checks or evaluations for aircraft covered by the FSB report.

b. Checks Regarding Complex Systems.

(1) Partial proficiency checking is required for differences associated with systems that 

are determined to be at or greater than level C.

(2) Complex systems checks include hands-on operation and ensure demonstrated 

procedural proficiency in each applicable mode or function. Specific items and flight phases to 

be checked are specified (e.g., initialization, takeoff, departure, cruise, arrival, approach, and 

pertinent nonnormals).

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Appendix 2

NOTE: The FSB may recommend additional training beyond that which is 

otherwise required by 14 CFR to qualify in each type certificated aircraft.

9. FSTD APPROVAL.

a. NSP Representation to the FSB. An NSP member may serve as an advisor to the FSB 

or as a member of the FSB, to address designation of and approval processes for FSTDs.

b. Coordination of NSP Criteria with the FSB. National simulator program development 

of criteria for FSTDs and approval test guides for new aircraft are coordinated with the FSB. 

This ensures compatibility of FSB/NSP requirements and effective use of resources for 

development of approval test guides and determination of FSB recommendations.

NOTE: FSTDs are approved for operator use in accordance with part 60.

10. REVIEW AND APPROVAL. FSB reports are approved as designated by AFS-1. In the 

event that revision of an FSB report is necessary, the FSB is provided with necessary policy 

guidance to implement applicable changes.

11. APPEAL OF FAA DECISIONS. When there is disagreement with recommendations of an 

FSB report, that disagreement may be expressed to the FSB chairman for the pertinent type 

certificated aircraft. If an issue cannot be resolved, the issue may then be addressed to AFS-200. 

Additional information, data, or analysis may be provided to support differing views regarding 

the FSB recommendations in question.

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Appendix 3

APPENDIX 3. RATING AND LEVEL TESTS—PLANNING AND APPLICATION

TABLE OF CONTENTS

Paragraph Page

1. PREPARATION..............................................................................................................1

2. TYPE RATING DETERMINATION THROUGH ANALYSIS-LEVEL A OR B 

TRAINING ONLY ..........................................................................................................2

3. FUNCTIONAL EQUIVALENCE-LEVEL A OR B TEST 1 (T1).................................3

a. Test Purpose ....................................................................................... ......................3

b. Test Subjects...................................................................................... ......................3

c. Test Process........................................................................................ ......................3

d. Safety Pilot......................................................................................... ......................3

e. Successful Test................................................................................... ......................3

f. Failure of Test..................................................................................... ......................4

4. HANDLING QUALITIES COMPARISON BETWEEN 

AIRCRAFT-TEST 2 (T2)................................................................................................4

a. Test Purpose ....................................................................................... ......................4

b. Test Subjects...................................................................................... ......................4

c. Test Process........................................................................................ ......................4

d. Safety Pilot......................................................................................... ......................5

e. Successful Test................................................................................... ...................... 5

f. Failure of Test..................................................................................... ...................... 5

5. SYSTEM DIFFERENCES TEST AND VALIDATION OF TRAINING AND 

CHECKING-TEST 3 (T3)...............................................................................................5

a. Test Purpose ....................................................................................... ...................... 5

b. Test Subjects...................................................................................... ......................5

c. Test Process........................................................................................ ......................6

d. Successful Test................................................................................... ...................... 6

e. Failure of Test .................................................................................... ......................6

6 CURRENCY VALIDATION-TEST 4 (T4).................................................................... 7

a. Test Purpose ....................................................................................... ......................7

b. Test Subjects...................................................................................... ......................7

c. Test Process........................................................................................ ......................7

d. Successful Test................................................................................... ......................7

e. Failure of Test .................................................................................... ......................7

7. INITIAL OR TRANSITION TRAINING/CHECKING PROGRAM 

VALIDATION-TEST 5 (T5)...........................................................................................8

a. Test Purpose ....................................................................................... ...................... 8

b. Test Subjects...................................................................................... ...................... 8

c. Test Process........................................................................................ ......................8

d. Successful Test................................................................................... ...................... 8

e. Failure of Test .................................................................................... ......................8

8. COMMON TAKEOFF AND LANDING CREDIT (CTLC)-TEST 6 (T6).................... 8

a. Test Purpose ....................................................................................... ......................8

b. Test Subjects...................................................................................... ......................8

c. Test Process........................................................................................ ......................9

d. Successful Test................................................................................... ......................9

e. Failure of Test .................................................................................... ......................9

Page 1 (and 2)
11/5/13 AC 120-53B

Appendix 3

APPENDIX 3. RATING AND LEVEL TESTS—PLANNING AND APPLICATION

1. PREPARATION.

a. The type rating, difference level definition, and test process are initiated when an 

applicant presents an aircraft for type certification. If the applicant presents a candidate aircraft 

to the Flight Standardization Board (FSB) as a new aircraft type certification with no anticipated 

application for type rating credit for similarities with aircraft previously type certificated, then 

the FSB analyzes the training program requirements using test T5. The results of T5 will 

determine a separate type rating and the minimum required training, checking, and currency 

standards as applicable to that type certificated aircraft. If the applicant presents an aircraft 

seeking pilot training, checking, or currency credit, based on similarities with an aircraft 

previously type-certificated, a series of possible tests (T1/T2/T3) are developed and used to 

determine its level of difference with the base aircraft of comparison. The results of these tests 

will determine the minimum required training, checking, and currency standards as applicable to 

the candidate aircraft. T6 comparisons may permit Common Takeoff and Landing Credit 

(CTLC) between different type-certificated aircraft. In Appendix 2 the details of these situations 

provide further amplification.

b. To begin the evaluation process for related aircraft, the applicant identifies the base 

aircraft and the candidate aircraft. The aircraft are then assigned to logical aircraft groups to be 

described in Master Difference Requirements (MDR) tables and the FSB report.

c. The applicant identifies major differences pertinent to the aircraft and makes comparisons 

with the proposed candidate aircraft. A differences document (i.e., an appropriate sample 

Operator Difference Requirement (ODR) table) summarizes the identified differences. Since 

combinations of related aircraft may be numerous and only typical differences are needed at this 

stage for test definition, the applicant may select representative ODRs for preparation.

d. Based on the above analysis (including preliminary flight test results or flight simulation 

estimates, if available), the applicant proposes difference levels to be specified in each cell of the 

MDR table for the various aircraft combinations.

e. The applicant proposes applicable elements of the test process (T1 through T5 and T6 for 

CTLC) and a plan for validation of the intended difference levels. Specific aircraft, times, 

devices, etc. are identified to conduct the required tests for the candidate aircraft. Included in the 

proposal are any necessary interpretations of expected results using established standards. Any 

special, unique, or additional definitions of successful outcomes are also identified.

f. The scope of T1 through T6 is keyed to basic visual flight rules (VFR) and instrument 

flight rules (IFR) operations in the National Airspace System (NAS).

g. An FAA/applicant agreement is reached on the grouping of aircraft, proposed tests, test 

plans, schedules, subjects, and interpretation of possible outcomes.

h. Test subject qualifications are addressed at the time of test specification when a test 

agreement is reached with the applicant. Test subjects for all tests except T6 are drawn from the 

FAA. Subject selection considers the factors such as the following:

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11/5/13 AC 120-53B

Appendix 3

(1) Background skills of test subject (previously qualified aircraft);

(2) General flight experience and currency;

(3) Test requirements such as location, short notice access, and skills needed for subjects;

(4) Technical areas, qualifications, or experience that subjects should not have to avoid 

test prejudice;

(5) Eventual FAA geographic or operator related distribution requirements for ASI, 

aircrew program managers (APM), and (POI) personnel; and

(6) Other special experience as needed for a particular program.

i. During preparation for testing and evaluation of results, appropriate Aircraft Certification 

Flight Test Branch coordination is accomplished so that flight characteristic issues and, in 

particular, special flight characteristics can be suitably identified and addressed.

NOTE: Tests T1 and T2 must be conducted in the candidate aircraft for the 

determination of training, checking, and currency requirements. A FFS may 

be used for FSB selected T-tests that involve partial task evaluation of 

systems or components, which do not directly relate to aircraft handling 

qualities or core pilot skills. These types of tests would normally require only 

a training device with no visual or motion capabilities. The FSB chairman 

may elect to use a FFS before its qualification by the National Simulator 

Program (NSP).

2. TYPE RATING DETERMINATION THROUGH ANALYSIS-LEVEL A OR B 

TRAINING ONLY.

a. Typically, with the introduction of a new aircraft, or when training credit is sought in a 

comparison of a base and candidate aircraft, the T1 through T5 testing process determines type 

rating. Not all changes or modifications to an aircraft or on occasion, the certification of a related 

aircraft may require flight-testing to assess their impact upon type rating. Type rating 

determination through analysis may be considered if the changes do not influence aircraft 

handling, introduce no significant change to systems operation or pilot procedures, and can be 

addressed at level A or B training.

b. The analysis process can be used if the aircraft handling has not changed significantly. In 

most cases, it should be obvious that the change will not affect aircraft handling but if additional 

data is needed to make the determination, the information can be obtained from the assigned 

FAA Aircraft Certification Service (AIR) or through the applicant’s flight test data. Following is 

a list of typical changes evaluated through the analysis process:

(1) Maximum operating weights (revised aircraft type certificate data sheet (TCDS)).

(2) An engine type or thrust change that does not require significant design changes to 

aircraft flight controls.

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Appendix 3

(3) Maximum passenger capacity (revised aircraft TCDS).

(4) Avionic upgrades (Supplemental Type Certificate (STC) or manufacturer production 

line upgrade).

(5) Proven electronic flight bag installation, (STC or manufacturer production line 

upgrade).

(6) Passenger to cargo conversions or freighter variation of passenger aircraft.

c. When the analysis process is completed, it is recorded as a revision to the training 

courseware and to the existing FSB report for the base and/or candidate aircraft.

3. FUNCTIONAL EQUIVALENCE-LEVEL A OR B TEST 1 (T1).

a. Test Purpose. The T1 test is conducted to determine if training level A or B is 

appropriate between the base and candidate aircraft.

NOTE: If the applicant communicates that the training, checking and 

currency requirements for the candidate aircraft may exceed level B, the T1 

test can be waived and the evaluation process then moves directly to the T2 

test. By waiving the T1, the applicant acknowledges that differences exist 

between the base and candidate aircraft, and may demand that training, 

checking, and/or currency requirements up to but not exceeding level D are 

applied.

b. Test Subjects. Test subjects are designated FAA FSB members, trained, experienced, 

and current on the base aircraft with no training for the candidate aircraft. The applicant may 

provide proficiency training in the base aircraft to the designated FSB members before testing 

begins.

c. Test Process. The applicant initiates the test process when they propose that the 

minimum training, checking, and currency requirements for the base and candidate aircraft are 

no greater than level B differences. T1 is typically conducted using one group of test subjects. 

Subjects will initially be given a “no jeopardy” flight check for their base aircraft to calibrate 

performance before taking the pertinent flight check in the candidate aircraft being evaluated. 

The flight check undertaken in the candidate aircraft will address the differences between the 

base aircraft and candidate aircraft. The test may be administered or observed by more than one 

FSB member to ensure consistency and uniformity of test procedures and common 

understanding of subject performance and outcomes.

d. Safety Pilot. A “safety pilot,” serving as PIC in the aircraft and functioning as pilot 

monitoring in either seat, will intervene to prevent damage to the aircraft or to limit maneuvers 

that endanger safety of flight.

e. Successful Test. FSB members decide the outcome of the T1 test consistent with 

previously agreed upon criteria. The FSB determines the areas of training required and specifies 

necessary devices or training limitations. If the T1 test is passed, the pertinent aircraft pairs are 

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Appendix 3

assigned to level A or level B training differences. Successful completion of T1 results in the 

designation of a type rating that is either the “same” as, or is “in common” with the base aircraft.

f. Failure of Test. If the T1 test is failed and retesting is not considered, level A or B 

cannot be assigned. This generally requires completion of T2 and T3. If requesting training 

credit, the applicant may ask for and receive credit for those items passed in T1. T1 retesting 

may be considered at the discretion of the FSB.

4. HANDLING QUALITIES COMPARISON BETWEEN AIRCRAFT-TEST 2 (T2).

a. Test Purpose. The T2 test compares handling qualities between the base and candidate 

aircraft. At the discretion of the FSB chairman the T2 test may be completed through analysis, 

without requiring an aircraft flight. Determining if the analysis process can be used requires 

verification that the aircraft handling has not changed significantly as described in the “test 

process”. In most cases, it should be obvious that the change will not affect aircraft handling but 

if the determination requires additional data, the information is obtained from the assigned FAA 

Aircraft Certification Office or through the applicant’s flight test data. With FAA agreement, 

elements of T2 may be incorporated within the T3 test to verify that an advanced FFS or aircraft 

training is not needed to address handling qualities.

NOTE: If T2 is conducted on an aircraft that is expected to require a 

separate type rating with CTLC, credit will be validated by using the T6 

process.

b. Test Subjects. Test subjects are designated FAA FSB members, who are trained, 

experienced, and current on the base aircraft with no training for the candidate aircraft. Training 

to proficiency may be provided in the base aircraft to the designated FSB members by the 

applicant before the start of testing.

c. Test Process. The applicant initiates the test process when they analyze available flight 

or simulation test data, and aircraft design or system differences, and determine that handling 

similarities exist between the base and candidate aircraft. From this determination the applicant 

makes their T2 proposal. Before the test, representatives of the FSB review the T2 test profile to 

ensure that critical handling quality aspects of the candidate aircraft are examined. The flight 

evaluation consists of relevant parts of a proficiency check as determined by the FSB chairman. 

T2 consists of a comparison between selected pilot qualification flight check maneuvers (normal 

and nonnormal) administered first in the base aircraft (using either the actual aircraft or a level C 

or D FFS) then in the candidate aircraft. Although T2 testing should always be accomplished in 

the candidate aircraft, some portions that significantly affect aircraft safety, such as flight control 

failures, may be conducted in a FFS suitable for the test. Subject pilots are evaluated on 

performance of required maneuvers consistent with standards set by the CFR and an assessment 

of the degree of difficulty in performing maneuvers in the candidate aircraft compared to the 

base aircraft. The test may be administered or observed by more than one FSB member to ensure 

consistency and uniformity of test procedures and common understanding of subject 

performance and outcomes.

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Appendix 3

d. Safety Pilot. The safety pilot serving as PIC in the aircraft and functioning as pilot 

monitoring in either seat, will intervene to prevent damage to the aircraft or to limit maneuvers 

which endanger safety of flight. The safety pilot can only assist the subject pilot in areas 

unrelated to the handling qualities determination. For example, the safety pilot can remove 

impediments to progression of the test but cannot fly, coach, or train the subject on any aspect of 

the test related to handling, vision cues, or motion cues. The safety pilot may not actuate primary 

flight controls during the evaluation, or instruct, lead, or coach test subjects in any manner. The 

safety pilot may:

(1) Perform all routine pilot monitoring duties.

(2) Set up or adjust systems including those normally operated by the pilot flying in 

accordance with pretest agreements.

(3) Address or resolve procedural impediments.

(4) Manage and satisfy checklists.

(5) Make normal call outs.

e. Successful Test. The FSB members decide T2 test outcome consistent with previously 

agreed upon criteria. Acceptable pilot performance in completion of designated maneuvers, 

without training, establishes that the candidate and base aircraft are sufficiently alike in handling 

characteristics to permit assignment of level B, C, or D. The test process can then advance to the 

T3 test.

f. Failure of Test. Failure of T2 means that major handling differences exist during critical 

phases of flight or that numerous less critical differences were identified that warrant training in 

a FFS or aircraft. Accordingly, level E differences will be assigned and the FAA will issue a 

separate type rating. With a T2 failure, the next step in the testing process is T5 to validate 

level E requirements and the proposed training course. Failure of the T2 does not necessarily 

mean that the base and candidate aircraft do not share a high degree of system and/or handling 

commonality. The applicant may elect to use the data collected during the T2 process to justify 

approval of a shortened type rating course for pilots that are trained on the base aircraft and are 

transitioning to the candidate.

5. SYSTEM DIFFERENCES TEST AND VALIDATION OF TRAINING AND 

CHECKING-TEST 3 (T3).

a. Test Purpose. The T3 test is used to evaluate the proposed differences and/or related 

aircraft differences training, checking, and training devices at levels B, C, or D.

b. Test Subjects. Test subjects are designated FAA FSB members, trained, experienced, 

and current on the base aircraft and have completed the applicant’s proposed differences or 

related aircraft differences training in the candidate aircraft. Training to proficiency in the base 

aircraft may be provided to the designated FSB members by the applicant before the start of 

testing.

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Appendix 3

c. Test Process. T3 is a system difference test and a validation of training and checking. It 

is used when the equivalent handling test (T2) is successfully completed or when T2 is being 

incorporated as part of T3. T3 is administered in two phases following differences or related 

aircraft differences training of a pilot in the candidate aircraft.

(1) First Phase. The successful completion of a pilot qualification flight check to assess 

pilot knowledge, skills, and abilities pertinent to operation of the aircraft being tested. If a full 

check is proposed, the tests are similar to those used for T1 as described in paragraph 2 above. If 

a partial check is used, the process is similar, but the FSB determines the test items based on the 

applicant’s proposals. The first phase will include either a proficiency check as defined by the 

applicable CFR, partial proficiency check, or individual aircraft system operation check 

administered to pilots in the FFS or candidate aircraft. The check is administered assuming 

currency in the base aircraft and completion of the proposed training in the candidate aircraft.

(2) Second Phase. Line oriented flying (LOF) following completion of the flight check. 

The LOF phase of the test is used to validate the training and checking being proposed, fully 

assess particular difference areas, examine implications of mixed fleet flying, assess special 

circumstances such as minimum equipment list (MEL) effects, and identify the effects of pilot 

errors potentially related to the differences. The test is done in a real line flight environment that 

includes typical weather, routes, airports, air traffic control (ATC), and other factors that are 

characteristic of those in which that aircraft will be operated. LOF tests may be conducted in test 

aircraft, FFS, or with a combination of these in conjunction with function and reliability aircraft 

type certification tests. The LOF portion of the test may be used to evaluate complex issues or 

issues that cannot be fully detailed in a brief flight check since a check only samples pilot 

knowledge and skills in a limited and highly structured environment. LOF is an integral part of 

T3 and must be successfully completed before “initial” assignment of difference levels. In 

developing and selecting scenarios for evaluation consider the following:

• Likelihood of occurrence,

• Possible consequences, or

• The timeliness of pilot discovery and correction.

d. Successful Test. The FSB members decide the outcome of the T3 consistent with 

previously agreed upon criteria and completion of LOF with appropriate pilot performance. 

Passing T3 leads to setting respective difference levels and validates differences and/or related 

aircraft differences training and checking at level B, C, or D between related aircraft.

e. Failure of Test. Failure of T3 occurs with either failure of the check, agreed criteria, or 

unsatisfactory performance during the LOF portion of the test. In certain failure cases, T3 can 

lead to assignment of level E and a separate type rating. When a T3 failure is due to deficiencies 

in the proposed training program, at the discretion of the FSB, T3 may be repeated using 

different test subjects (pilots) following revision of the training program addressing the 

deficiencies. The following are examples that may lead to the assignment of level E differences:

(1) T3 experience or difficulties that show the need for assignment of training levels 

approaching typical initial/transition levels.

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(2) T3 pilot performance that indicates that devices or methods associated with level D 

are not adequate to achieve training or checking objectives.

(3) Repeated failures of attempts to pass T3 test at level D training differences. In the 

case of retesting, new subjects may be required at the discretion of the FSB Chairman.

NOTE: Repeated failure of test at level D differences by one or more 

subject’s (pilot) inadequate performance, that is not an individual subject’s 

failure due to sub-par or atypical personal performance as determined by the 

FSB, may lead to assignment of level E differences.

6. CURRENCY VALIDATION-TEST 4 (T4).

a. Test Purpose. The T4 test is a currency test that can be used when an applicant seeks 

relief from existing FSB currency recommendations. In the context of this AC, currency 

addresses system procedural and maneuvering differences between related aircraft. T4 does not 

include takeoff and landing recency of experience.

b. Test Subjects. Designated FAA FSB members.

c. Test Process. If an applicant desires a change in the currency recommendations, a T4 test 

may be conducted. This test may be done before or after the aircraft enters into service. In the 

event the test cannot be done before entry into service, the FSB established limits apply. Criteria 

that may be used by the FSB to set level B, C, D differences for currency for initial FSB 

determinations include the following examples:

(1) Complex flight critical systems affecting control or navigation.

(2) Critical nonnormal maneuvers differing between related aircraft (e.g., V1 engine 

failure, emergency descent, etc.), requiring one acceptable demonstration/training or checking 

event (typically 6 months but demonstration period may also vary by pilot position).

(3) Secondary systems (e.g., Oxygen or auxiliary power unit (APU)).

d. Successful Test. The FSB members decide the outcome of T4 consistent with previously 

agreed upon criteria. A successful test validates that the proposed less restrictive currency 

recommendations are accepted as a means of compliance with applicable rules, 

recommendations of this AC, and/or currency recommendations and provide an equivalent 

level of safety.

e. Failure of Test. Failure indicates that the proposed less restrictive currency 

recommendations do not provide an equivalent level of safety. At the discretion of the FSB, 

retesting may be appropriate.

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7. INITIAL OR TRANSITION TRAINING/CHECKING PROGRAM 

VALIDATION-TEST 5 (T5).

a. Test Purpose. T5 test validates the applicant’s training course(s) at level E (new type 

rating). It is appropriate when:

• A full initial or transition training/checking program requires validation;

• An applicant seeks training credits between two aircraft with different type ratings (a 

typical goal under shortened training programs); or

• T2 or T3 are failed.

b. Test Subjects. Designated FAA FSB members.

c. Test Process. There are two methods to accomplish the T5 test process:

(1) Full Initial or Transition Training/Checking Program Validation. This method is 

used when an applicant has developed an aircraft and seeks a new type rating without any credit 

for commonality with any related aircraft. The applicant develops a training program to qualify 

and check pilots in the candidate aircraft at level E differences. Subjects are trained, given flight 

proficiency checks and complete LOF in a process similar to that described in paragraph 5.

(2) Shortened Transition Training/Checking Program Validation. This method is 

used when an applicant has developed an aircraft and seeks a new type rating and credit for 

commonality with related aircraft. The applicant conducts a handling qualities evaluation based 

on the applicant’s proposed ODR tables (similar to T2), followed by training and checking 

program validation (similar to T3). Subjects are trained, given flight proficiency checks and 

complete LOF in a process similar to that described in paragraph 5.

NOTE: When an aircraft is assigned level E differences because of a failure 

of T3 test at level D differences, credit for successfully passing individual 

elements of the T3 test may be used as justification for not duplicating those 

elements in the T5 test.

d. Successful Test. The FSB members decide the T5 outcome consistent with previously 

agreed upon criteria. A successful outcome of T5 validates the proposed training and checking 

programs.

e. Failure of Test. Failing T5 Indicates the proposed training or checking programs require 

modification. A retest by mutual agreement between the FSB and applicant would normally be 

required.

8. COMMON TAKEOFF AND LANDING CREDIT (CTLC)-TEST 6 (T6).

a. Test Purpose. The applicant uses T6 when they seek credit between related aircraft 

toward the takeoff and landing recency of experience requirements of the applicable CFR.

b. Test Subjects. The test should consist of a sufficient number of pilots not trained or 

qualified in the candidate aircraft. These subjects will be drawn from the manufacturer, industry 

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and the FAA that the FSB determines will represent a statistically relevant cross-section of 

operational pilots. The participants’ experience levels, type ratings and airplane currency should 

reflect the proficiency difference levels needed to validate testing assumptions.

c. Test Process. Test subjects are first provided refresher training in the base aircraft to 

establish a baseline of proficiency. This training may be accomplished in an approved C or D 

FFS. The subject is then tested in the candidate aircraft, without any training in it, accomplishing 

a minimum of three takeoffs and landings without use of the autopilot. It may not be practical to 

conduct some tests in an aircraft. A FFS may be used to conduct these tests. Test subjects should 

be evaluated on their ability to fly the aircraft manually through takeoff, initial climb, and 

approach and landing (including the establishment of final landing configuration). The applicant 

should consider the effects on the takeoff and landing maneuvers for the following factors when 

designing the T6 test:

(1) Aircraft weights.

(2) Aircraft center of gravity.

(3) Takeoff and landing crosswinds.

d. Successful Test. The FSB members decide the outcome of T6 consistent with the FAA 

practical test standards (PTS) by demonstrating that an equivalent level of safety can be 

maintained when full or partial credit for takeoffs and landings is given between the related 

aircraft.

e. Failure of Test. The test subjects’ performance relative to the FAA PTS demonstrates an 

equivalent level of safety cannot be maintained when either full or partial credit for takeoffs and 

landings is given between the related aircraft.

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