AC 120-35D

editorial update

Advisory circular · Flightcrew Member Line-Operational Simulations: Line-Oriented Flight Training, Special Purpose Operational Training, Line Operational Evaluation

Approved
May 1, 2020
Last reviewed
August 7, 2024
This change
Editorial update to AC 120-35D.
Cancels
AC120-35D
Family
AC 120-35 · 4 versions
Revision
D
14 CFR parts
60, 121, 135, 142

Guidance, not mandatory unless a rule or AD requires it. DRS record last changed November 21, 2025.

Show pages 15–26

Par 3-1 Page 23 CHAPTER 3. TYPES OF LINE-ORIENTED FLIGHT TRAINING

3-1. GENERAL. There are two types of Line-Oriented Flight Training (LOFT): recurrent LOFT and qualification LOFT. Guidelines for designing and conducting these types of LOFT are presented below.

3-2. RECURRENT LOFT. Recurrent LOFT is designed to ensure that each crewmember maintains proficiency in the type of aircraft and flightcrew member duty position involved.

Recurrent LOFT is intended for flightcrew members who are presently qualified in a particular make, model, and series (M/M/S) aircraft. (Refer to part 121, §§ 121.409, 121.427, 121.433, and 121.441.)

3-3. GUIDELINES FOR RECURRENT LOFT. Recurrent LOFT should meet the following guidelines:

a. Instruction or Interruption. Recurrent LOFT does not permit direct instruction and does not permit interruption of the scenario by the instructor, except for the nondisruptive acceleration of uneventful en route segments.

b. Crew Substitutes. Recurrent LOFT must utilize a complete flightcrew, who should be line qualified. The use of substitutes is discouraged, and substitution should be rare. When the composition of the scheduled line-qualified flightcrew cannot be maintained, the operator may use substitutions based on the guidelines in Table 3-1, Recurrent LOFT Substitution Table.

However, the operator will first attempt to substitute with another line-qualified flightcrew member. This table should be used only as a last resort, to prevent interruption of scheduled training.

c. Number of Segments. Recurrent LOFT must include at least two flight segments that are representative of the operations conducted by the operator. However, two gate-to-gate operating cycles are not necessary. The flightcrew completing recurrent LOFT must perform at least one taxi-out and one taxi-in. Additional segments need only consist of takeoff, climb, en route, descent, and landing.

d. Stall Prevention Training (Approach to Stall). Recurrent LOFT must include scenario-based or maneuver-based stall prevention training (approach to stall) before, during, or after the LOFT scenario for each pilot.

e. Scenario. Recurrent LOFT must provide an opportunity for each pilot to demonstrate workload management and pilot monitoring skills. Recurrent LOFT must also include at least the maneuvers and procedures (abnormal and emergency) that may be expected during line operations (refer to AC 121-42, Leadership and Command Training for Pilots in Command, for additional requirements for recurrent LOFT).

f. Training Media. The highest fidelity full flight simulator (FFS) available should be scheduled for recurrent LOFT.

Par 3-3 Page 24 TABLE 3-1. RECURRENT LOFT SUBSTITUTION TABLE Pilot in Command (PIC) Position Second in Command (SIC) Position Flight Engineer (FE) Position

1. PIC1 SIC1 FE1

2. SIC2 PIC1 FE Instructor3

3. Pilot Instructor3 Pilot Instructor3 1Includes those who are either line qualified or in training and are line and task familiar with the position in which they are substituting.

2An SIC may be substituted for this position if the pilot holds a type rating in the aircraft the flight simulation training device (FSTD) replicates.

3An instructor (aircraft or simulator) as provided for under part 121, § 121.412 or part 135, § 135.338, as applicable. The instructor should not have previous knowledge of the scenario;

however, when this is unavoidable, the instructor should not use that knowledge to influence or direct the scenario.

NOTE: The instructor conducting the Line-Operational Simulation (LOS) session will not act as a substitute crewmember.

3-4. QUALIFICATION LOFT. Qualification LOFT is designed for crewmembers whose training has been provided using advanced simulation. Qualification LOFT provides training that facilitates the transition from FSTD training to operational flying. Scenarios are designed to represent typical flight segments (refer to part 121 appendix H).

a. Crew Composition. Qualification LOFT requires a complete crew complement. It is preferable to schedule a crewmember who is qualifying with other crewmembers who are fully line qualified. As a minimum, LOFT crewmembers will be task familiar with their assigned flightcrew member duty position. The use of substitutes is highly discouraged and substitution should be implemented rarely. When the composition of the scheduled crew cannot be maintained, the operator may substitute crewmembers using Table 3-2, Qualification LOFT Substitution Table.

TABLE 3-2. QUALIFICATION LOFT SUBSTITUTION TABLE Pilot in Command (PIC) Position Second in Command (SIC) Position Flight Engineer (FE) Position

1. PIC1 SIC1 FE1

2. SIC1 PIC1 FE Instructor2

3. Pilot Instructor2 Pilot Instructor2 1Includes those who are either line qualified or in training and are task familiar with the position in which they are substituting.

2An instructor (aircraft or simulator) as provided for under part 121, § 121.412 or part 135, § 135.338, as applicable. The instructor should not have previous knowledge of the scenario;

however, when this is unavoidable, the instructor should not use that knowledge to influence or direct the scenario.

Par 3-4 Page 25 (and 26) NOTE: The instructor conducting the LOS session may not act as a substitute crewmember.

b. Scenario and Number of Segments. Qualification LOFT must consist of at least two flight segments representative of the operations conducted by the operator. One segment must contain strictly normal operating procedures from pushback at one airport until arrival at the gate at another airport. Another flight segment must contain appropriate abnormal and emergency operations. Qualification LOFT must provide an opportunity for each pilot to demonstrate workload management and pilot monitoring skills.

c. Training Media. Qualification LOFT will be conducted in a Level C or higher FFS (refer to part 121 appendix H).

Par 4-1 Page 27 (and 28) CHAPTER 4. SPECIAL PURPOSE OPERATIONAL TRAINING

4-1. GENERAL. Special Purpose Operational Training (SPOT) is designed for training crewmembers in a flight simulation training device (FSTD). SPOT is useful whenever coordinated crew performance is required. It may not be substituted for recurrent Line-Oriented Flight Training (LOFT) or qualification LOFT. SPOT may include training which:

• Focuses on Crew Resource Management (CRM) skills.

• Provides differences training on variant aircraft.

• Provides specific phase of flight training.

• Trains in special aircraft equipment (e.g., navigational equipment and flight management system (FMS)).

4-2. GUIDELINES FOR SPOT. The components of SPOT vary, depending on the purpose or objective of the training. Therefore, the following provides only general guidelines for SPOT.

a. Instruction and Interruption. SPOT permits direct instruction and allows for interruption of the scenario by the instructor.

b. Crew Composition. SPOT may include use of a complete or partial crew, depending upon the training objectives.

c. Crew Substitutes. The use of crew substitutes in SPOT depends upon the type of training being provided.

d. Number and Type of Segments. SPOT may contain any number of full or partial flight segments, depending upon the training objectives.

e. Training Media. SPOT may use a wide range of FSTDs, depending upon the training objectives.

4-3. SPECIFIC SCENARIOS FOR OPERATORS OF ALL-CARGO AIRCRAFT OR COMBINATION CARGO/PASSENGER (COMBI) AIRCRAFT. Operators of all-cargo or combi aircraft should conduct SPOT to provide pilots training on situations unique to all-cargo and combi operations, such as:

• Indications of improper loading during preflight, taxi, and initial takeoff roll.

• Indications of cargo shifting during taxi and initial takeoff roll, resulting in an aborted takeoff.

• Indications of cargo shifting, leading to excessive pitch changes during takeoff and initial climb.

• Unanticipated pitch mistrim during takeoff, resulting in an aborted takeoff.

Par 5-1 Page 29 (and 30) CHAPTER 5. LINE OPERATIONAL EVALUATION

5-1. GENERAL. The Line Operational Evaluation (LOE) is the primary means of proficiency evaluation in an Advanced Qualification Program (AQP). This evaluation addresses the individual’s ability to demonstrate technical and Crew Resource Management (CRM) skills appropriate to fulfilling job requirements in a full mission-scenario environment. The intent of an LOE is to evaluate and verify that an individual’s job knowledge, technical skills, and CRM skills are commensurate with AQP qualification standards. The LOE is conducted in a flight simulation training device (FSTD) qualified in accordance with part 60 and approved for its intended use in the AQP. LOE development methodology, substitution tables, success criteria, and remediation strategy will be included in the carrier’s approved AQP documentation.

5-2. ELEMENTS RESEMBLING LINE-ORIENTED FLIGHT TRAINING (LOFT). LOE contains elements similar to those in LOFT (e.g., line environment, complete crew, real-world scenarios, real time, and must run uninterrupted). A complete crew complement should be scheduled and maintained. Flightcrew member substitution is highly discouraged. If crew substitutions are necessary, the substitute crewmember will be either another line-qualified crewmember or a task-familiar crewmember in a training status comparable to the person being evaluated. Evaluators conducting the LOE may not serve as a substitute crewmember. The LOE substitution table/matrix will be part of the carrier’s approved AQP documentation.

5-3. EVALUATION. The LOE addresses the individual’s ability to demonstrate technical and CRM skills appropriate to fulfilling job requirements in an operational environment. The intent of an LOE is to evaluate and verify that an individual’s job knowledge, technical skills, and CRM skills are commensurate with AQP qualification standards. Part 121, § 121.907 requires that the LOE evaluate both CRM and technical skills in a scenario which is designed to test both.

While encouraged and widely practiced, it is not mandatory that CRM be graded on a pass/fail basis. The alternative is to assume that failed CRM performance will, in almost all cases, drive a technical failure. That technical failure will then be recorded with CRM annotated as a contributing factor. This still allows CRM shortfalls to be documented and remediated.

5-4. EVALUATOR. An evaluator must have satisfactorily completed the certificate holder’s AQP evaluator training. The Administrator must approve all LOE evaluators. It is essential that LOE evaluator training include specific exercises to achieve and verify standardization among such personnel in grading performance.

5-5. LOE MEDIA. Operators conducting LOE may be approved to use any level of FSTD, depending on the objective of the evaluation, the capability of the FSTD, and compliance with part 60.

Par 6-1 Page 31 CHAPTER 6. THE ROLE OF LINE-OPERATIONAL SIMULATION FACILITATORS

6-1. MINIMUM QUALIFICATIONS. Line-Operational Simulation (LOS) facilitators/instructors/evaluators should be trained in the philosophy, skills, and conduct of LOS and Crew Resource Management (CRM). They should be able to effectively observe and critique both individual and crew performance during the scenario. To do this, they should meet the minimum requirements discussed in the following paragraphs.

a. Line Familiar. Facilitators should be line familiar. This will ensure that facilitators accurately perceive and evaluate situations as they arise.

b. Qualified as Instructors/Evaluators. To conduct Line-Oriented Flight Training (LOFT) or Special Purpose Operational Training (SPOT), facilitators should be qualified as defined in part 121, §§ 121.412 and 121.414 and appendix H; or part 135, §§ 135.338 and 135.340, as applicable, and as required by the approved Advanced Qualification Program (AQP), if appropriate. To conduct Line Operational Evaluation (LOE), facilitators should be qualified as defined in §§ 121.411 and 121.413 and part 121 appendix H; or §§ 135.337 and 135.339, as applicable, and as required by the approved AQP.

c. Trained in CRM Skills. Facilitators will receive training in CRM skills in order to observe and critique these areas in LOS. Refer to the current edition of Advisory Circular (AC) 120-51, Crew Resource Management Training, for further information.

d. Trained in Methods for Briefing, Debriefing, and Critique. Facilitators should be trained to conduct the briefing and debriefing/critique phases of LOS, including how to provide effective feedback.

6-2. FACILITATOR RESPONSIBILITIES. The following is a description of the roles and responsibilities of facilitators:

a. Briefing and Preparation. Facilitators should be able to effectively convey the purpose of the LOS and how it is representative of line operations. Facilitators should also explain their role as observers during the training/evaluation, in that they are not considered present unless playing a non-flightcrew member role in the scenario (e.g., air traffic control (ATC), flight attendant (F/A), or dispatch). This does not apply to SPOT, which allows for an interactive role on the part of the facilitator.

b. Flight Segment. Facilitators should be able to observe and perform ancillary roles.

They should be trained in observing and assessing technical and CRM skills. Facilitators should also be trained in proper pacing, proper introduction of abnormal/emergency procedures, and methods of handling unforeseen crew actions.

c. Simulation. Of vital importance to the effectiveness of LOS is the creation of a strong illusion of reality in the simulated flights. This requirement dictates that many routine activities, such as flight paperwork, manuals, and communications should be carefully prepared. Previous experience with LOFT and LOE has shown that overlooking these activities can destroy this illusion.

Par 6-2 Page 32

d. Resources. The facilitator’s goal is to produce crew performance and behavior that is typical for an actual line flight in the same set of circumstances as those developed in the scenario. In keeping with this goal, it is essential that crews have access to all the resources they would have during an actual line flight. The briefing should include mention of the roleplaying aspect of LOS and its importance to overall LOS effectiveness.

e. Facilitator Role. The role of the facilitator in LOFT or LOE should be viewed as that of communicator, observer, and moderator in the debriefing process. He or she is not an instructor in the traditional sense during the flight simulation training device (FSTD) period. He or she is the facilitator or manager of the flight, using appropriate radio calls or responses to direct the flight along the desired path. The facilitator must be prepared to accept and manage alternate courses of action that the crew may wish to follow. The facilitator should remain as unobtrusive as possible within the physical limitations of the FSTD. He or she should resist the temptation to instruct, and must not intrude in any way into the situation.

f. Communication. All communications must be conducted in the manner normally found on a line flight; that is, via radio from outside the “aircraft;” via interphone or normal conversations between flight deck crewmembers; or, in the case of communication between the flight deck and cabin, via the usual aircraft equipment for this purpose. All external communications (e.g., ATC and ground crew) must be credible and realistic.

g. Recorded Feedback. The entire FSTD phase of the flight, including initial flight deck setup, should be recorded, if the equipment is available. The importance of the correct use of recording cannot be overstated: LOS with recording is one of the most powerful tools we have for reinforcing desirable behavior in CRM. During debriefing, the recording should be reviewed and discussed by the flightcrew with emphasis being placed upon crew performance, including their use of CRM behavioral markers and skills. When crewmembers have learned and can appreciate the importance of open and direct critique for purposes of operational review and analysis, a platform is in place for effective post-LOS discussion that reviews more than stick-and-rudder skills or systems knowledge. Following review of the recording, it may be erased.

h. Debriefing and Critique. Facilitators should provide both positive and negative feedback during critiques of individual and crew performance. Prior to the facilitator’s critiques, crewmembers should be encouraged to critique themselves. Facilitators will provide feedback to the crew to encourage the changes needed for improved performance. Facilitators should also provide specific recommendations to improve individual crewmembers’ performance.

Par 7-1 Page 33 CHAPTER 7. LINE-OPERATIONAL SIMULATION SCENARIO DESIGN

7-1. SCENARIO DESIGN METHODOLOGIES. This chapter provides a Line-Operational Simulation (LOS) scenario design methodology that has proven effective. There may be other, equally effective LOS development methods. The important aspect of LOS development is that a disciplined methodology is employed.

7-2. PHILOSOPHY OF LOS DESIGN AND CONDUCT.

a. Scenarios. LOS scenarios are best designed to be operationally relevant, believable, and good tests of the crew’s technical and Crew Resource Management (CRM) skills. LOS training is systematic and is intended to simulate actual problem situations on the line that require good crew skills for effective resolution and decision making.

b. Line Realism. Because LOS requires as much realism as possible, LOS design and evaluation guidelines should maximize line realism. Preflight activities and detailed review of flight paperwork, manuals, and conduct of communications should be included in the scenario.

This requirement does not preclude employing scenarios that use short segments beginning or ending in an en route environment, if the objectives of the LOS can be met. If the scenario is designed to begin in an en route environment, enough quiet time should be present for the crew to become acclimated to the flight routine. These en route segments are identified as Special Purpose Operational Training (SPOT). Line Operations Safety Audit (LOSA) data demonstrate that a flightcrew addresses 40 percent of the risks encountered during a flight prior to takeoff.

Therefore, SPOT should not be employed simply to shortcut this phase of flight, unless the objectives of the scenario warrant it. An operator should not change the name of a Line-Oriented Flight Training (LOFT) to a SPOT simply to avoid the requirement for FAA approval.

c. Open Communication. LOS scenarios should be designed to foster an environment where free and open communication is practiced. This encourages crewmembers to provide necessary information at the appropriate time (e.g., initiating checklists, advocating positions, and problem definition). Furthermore, the LOS design should encourage active participation in the decision-making process and questioning of actions and decisions by all crewmembers.

d. Level of Difficulty. One misconception is the belief that LOS training should continuously increase crew operational workload until the crew becomes overloaded. This is not the purpose or intent of LOS and can actually help to defeat its effectiveness. The difficulty of the LOS should not be designed to saturate a flightcrew or impose an unrealistic level of difficulty or complexity. On the other hand, the LOS must provide enough difficulty to adequately test the flightcrew’s skills and capabilities. LOS scenarios are most effective if they are straightforward. For example, choosing a departure airport that requires an effective preflight briefing might be one way to begin. A scenario that allows the crew to choose from different options is very useful. One scenario can have a wide variety of outcomes and choices, depending on the decision and course of action that a crew undertakes. Again, the scenario should be realistic, and the situation should be one where crewmembers live with whatever problems they have until the situation is either resolved or the aircraft (flight simulation training device (FSTD)) is back on the ground.

Par 7-2 Page 34

e. Briefing and Debriefing. The effective LOS experience begins with a briefing to discuss the LOS objectives and expectations. To be complete, the LOS must include a debriefing to examine the crew performance demonstrated during the LOS. The facilitator draws on personal experience and training in CRM and technical issues to elicit discussions of points of interest and operational relevance. Positive comments regarding crew performance should be emphasized in the debriefing, as well as comments regarding areas of crew performance that need improvement. Crewmembers must be given the opportunity to critique and analyze their own performance and review key points.

7-3. SCENARIO DESIGN PROCESS.

a. Developing the Scenario. The framework described here for developing LOS scenarios is based on the concept of an event set, a group of related tasks and conditions that are part of the scenario and are integrated into the LOS session with specific CRM and technical training objectives. Included in the framework is a new method for identifying specific CRM skills appropriate for the event sets and a tool for developing the CRM category profile of LOS scenarios. The result is an approach that makes LOS sessions more manageable and easier to assess by allowing the facilitator to concentrate on a few CRM categories within any given event set. It also limits the specific crew behavior observations to very specific behavioral markers and indicator behaviors that are either observed or not observed. Not only is the facilitator focusing on a single CRM category, such as “Communication,” but he or she is also looking for a particular, predetermined result driven by the details of the event, such as “Second in command (SIC) communicates Weight and Balance (W&B) for passenger count.”

b. Minimizing Subjectivity. One of the major goals of the use of the event set methodology is to remove as much subjectivity from the grading process as possible, particularly for CRM skills. By engineering the event in such a way that there is a clear indicator of the desired performance, the performance issue is focused down to, for example, whether the SIC either did or did not communicate W&B at the appropriate time and in the appropriate manner.

That is what is being graded, not some subjective notion of “communication.” The assessment is not based on the general adequacy of the SIC’s communication skills, but instead on the adequacy of a very specific behavior. This technique has allowed evaluators to be trained to grade CRM skills with the same consistency with which they grade technical skills.

c. The Event Set. The primary unit of both LOS design and CRM assessment is the event set. The event set is made up of one or more events, including an event trigger, distracters, and supporting events. The event trigger is the condition or conditions under which the event is fully activated. The distractors are conditions inserted within the event set timeframe that are designed to divert the crew’s attention from other events that are occurring or are about to occur. Event sets with extremely disruptive triggers do not necessarily require a distractor. Finally, supporting events are other events taking place within the event set designed to further CRM and technical training objectives, usually the normal events of that phase of activity.

d. Training Objectives. In LOS scenario design, the CRM and technical training objectives should be integrated into the event sets. This event set framework allows the design team to present the appropriate degree of realism in the LOS. Instead of focusing on a single technical issue, the event set integrates the entire complex line environment (e.g., terrain, air