# SIMULATOR FIDELITY CONSIDERATIONS FOR TRAINING AND EVALUATION OF

# TODAY\'S AIRLINE PILOTS

Thomas Longridge,^1^ Judith Bürki-Cohen,^2^ Tiauw H. Go,^3^Andrew J.
Kendra^2^

^1^Federal Aviation Administration, Advanced Qualification Program
AFS-230

Washington, DC

^2^DOT/Volpe National Transportation Systems Center DTS-79

^3^Massachusetts Institute of Technology

Cambridge, Massachusetts

## ABSTRACT

Regulatory changes in response to today's airline pilot training and
evaluation needs push the twin issues of effectiveness and affordability
of flight simulators for use by U.S. airlines to the forefront. The
Federal Aviation Administration (FAA) is sponsoring two research
programs with high pay-off potential in this area, namely, platform
motion and realistic radio communications. This paper describes the
rationale and the initial results of this work.

## today's airline environment

Managers of airline pilot training programs today are increasingly being
faced with some unprecedented challenges. Of these, changing
demographics in the available new-hire population is clearly the most
prominent. Many of the nation\'s largest airlines have found it
necessary to dramatically decrease their entry-level requirements in
terms of flight hours and prior experience. This in turn has placed even
greater pressure on smaller airlines, where entry levels have been
lowered to bare minimums, while turnover among pilots leaving for
positions with major airlines is at an all time high. All of this is
occurring in a backdrop of increased congestion within the National
Aerospace System (NAS), associated short-term strategies (such as Land
and Hold Short) to manage capacity, the acquisition of newer aircraft
with increasingly automated cockpit systems, the merging of airlines
which may differ in their operating procedures and their corporate
cultures, and near term plans for new ways of operating within the NAS,
such as free flight, and Air Traffic Control (ATC) data link.

## Change IN Training and Evaluation Needs

These developments clearly have implications for the design and content
of pilot training. Pilot training curricula which were based on certain
entry level assumptions that no longer are valid must be revised to
incorporate training in areas either not previously required for airline
new-hires, or not previously addressed in depth. In some cases this will
require a substantial increase in the footprints allocated to training
and assessment of basic knowledge and hands-on flying skills. In all
cases it will require that flight operations training include specific
emphasis on building proficiency in the integration of cognitive and
motor flying skills. While these needs are particularly pertinent to
initial qualification curricula, they may also necessitate certain
changes in recurrent training curricula, in order to assure that
requisite proficiency is maintained, especially for rarely practiced
skills, or those with very low prior experience histories.

Similarly, it becomes increasingly important for each airline to assure
that pilot training for both new-hire and existing pilot populations
appropriately reflects its dynamically changing environment, whether
that be in terms of aircraft systems, flight procedures, or corporate
culture.

With regard to the regulatory environment pertinent to these
developments, there is both good and bad news. On the positive side, the
Federal Aviation Administration (FAA) has established a voluntary
regulatory program for airlines that is well suited to meet the training
challenges of today and tomorrow. The Advanced Qualification Program
(AQP), which was established as Special Federal Aviation Regulation
(SFAR) 58 (FAA, 1990), is specifically designed to assure that pilot
training programs remain responsive to changing needs, and that the
graduates of such programs not only possess the requisite knowledge and
hands-on skills, but that in particular, they can demonstrate
proficiency in the integration of cognitive and motor skills in
operationally realistic scenarios that test both.

On the negative side, the traditional pilot training regulations,
Subparts N & O of Part 121 of the Code of Federal Regulations, which
constitute the only alternative to AQP, are sorely out of date relative
to today\'s needs. The FAA is presently in the process of rewriting
Subparts N & O. A Notice of Proposed Rulemaking (NPRM) detailing
proposed changes to traditional pilot training, testing, and checking
requirements is anticipated at a future date.

AQP requires airlines to employ a systematic instructional design
process in determining the content of pilot training, testing, and
checking, as well as in the allocation for those purposes of training
equipment to curricula. It specifically requires the use of entry level
analysis to assure that training content is appropriately matched to an
airline\'s pilot population, and it mandates the implementation of a
continuing quality control process for monitoring the effectiveness of
curricula. While it allows flexibility in equipment selection, AQP is
not ordinarily intended for use in curricula that employ the aircraft
for training. Rather, AQPs typically employ a suite of training
equipment, which includes flight training devices and full flight
simulators.

The revised Subpart N & O rules are expected to incorporate a similar
philosophy, in contrast to the existing rules, which permit training,
testing, and checking to be conducted entirely in the aircraft. It can
reasonably be expected, therefore, that within a few more years, all
airline pilot training in the U.S. will require the use of full flight
simulators for certain training, testing, and checking tasks, while
allowing for the use of flight training devices for many but not all
such tasks. It can also be expected that pilot training addressing both
cognitive and motor skills in simulated scenarios that require both sets
of skills will be a requirement for all curricula, both in AQP and
otherwise.

A related regulatory development is the pending issuance of a NPRM on
simulator qualification. Whereas presently U.S simulator qualification
procedures and standards are detailed only in a FAA Advisory Circular
(AC120-40B, FAA, 1991, as amended), the proposed new rule is intended to
establish a regulatory basis for those procedures and standards. If
issued as a final rule, airlines and training centers that do not
maintain their flight simulators in accordance with the procedures and
standards on which basis the FAA originally qualified the equipment
could be subject to FAA enforcement action.

## IMPLICATIONS FOR SIMULATORS

The net result of these developments is that ultimately all pilot
training in the U.S. will be conducted in FAA qualified training
equipment (full flight simulators, and, where permitted, flight training
devices) rather than in aircraft. Airlines will be required by
regulation to maintain the fidelity of such equipment in accordance with
FAA qualification criteria. Furthermore, it can be expected that
regardless of whether an airline is conducting pilot training under an
AQP or under revised traditional rules, all curricula will require
training in operationally realistic scenarios.

While these developments will be largely transparent to major airlines
under AQP, they will be especially challenging to smaller airlines that
do not presently employ simulators, or that have limited access to such
equipment. Depending on the particular aircraft make, the availability
of flight simulators may be problematic, and for some operators, cost
could be prohibitive.

It should be clear from the various considerations discussed above that
two related issues of particular importance for meeting the challenges
of the future will be training effectiveness of flight simulators and
their affordability. While the effectiveness of flight simulators for
initial and recurrent training of airline pilots is well recognized,
there are two areas that warrant further examination in light of the
preceding discussion. These are platform motion and the simulation of
realistic radio communications.

While all FAA qualified full flight simulators are required to have
platform motion, there remain a number of questions yet to be
empirically addressed through appropriate research. Specifically, the
question to be answered is whether the training conducted in a
fixed-base simulator with a wide Field Of View (FOV) visual system
produces a result equivalent to that which would be obtained in a like
system having platform motion cueing. An additional question from a
regulatory perspective is whether proficiency checks conducted in a
visually equipped fixed-base simulator provide an equivalent opportunity
to verify the line-operational readiness of air-carrier pilots.

If the answers to these questions can reliably and validly be obtained,
the FAA may be better able to determine what level of equipment should
be required for initial or recurrent training programs in the future,
and whether changes to future qualification criteria for such equipment
are warranted. These decisions could significantly affect the cost and
availability of flight training equipment in light of future regulatory
plans, particularly for small operators.

One of the widely recognized deficiencies in the current state of the
art in full flight simulation is realistic radio communications. The
simulation of such communications is typically accomplished by the pilot
instructor/evaluator (I/E), who is also tasked with operating the
simulator while observing trainee performance. This mode of simulation
is a highly simplified representation of radio communications, and does
not even begin to approach the challenges to hearing, acknowledging, and
appropriately responding to radio communications within a real world
environment. It follows that scenario based training, testing, and
checking that is based on such an unrepresentative means of simulation
is not likely to be fully effective in developing the cognitive and
workload management skills associated with radio communications. While
this is obviously a deficiency of long standing, it may assume greater
significance in light of the changing demographics of the pilot new-hire
population. It follows that research is needed to measure the impact of
realistic radio communications on training effectiveness, and to make an
assessment of whether there may be an affordable means of better
simulating this function in light of developing technology.

## Simulator Motion Fidelity Requirements

Subject Matter Expert (SME) Opinion

The focus on simulator motion originated from a series of joint
FAA-industry symposia on the most costly aspects of airplane simulation
organized by the Department of Transportation's Volpe Center (Longridge,
Ray, Boothe, Bürki-Cohen, 1996). This was part of a FAA-sponsored review
of simulator requirements as outlined in AC120-40B (FAA, 1991). The SMEs
from industry, academia, and FAA participating in the discussions on
simulator motion generally perceived that the absence of platform motion
cueing in fixed-base devices is likely to have a detrimental effect on
pilot control performance, particularly in maneuvers entailing sudden
motion-onset cueing with limited visual references. It was also noted,
however, that there was no scientific evidence that training in a
fixed-base device would lead to degraded control performance in the
actual aircraft (Transcript, 1996). This issue is especially pertinent
in a device equipped with a wide FOV visual system, which can generate
an illusion of motion (vection).

### Literature Review

An extensive literature review confirmed that platform motion in the
simulator might improve the acceptability of the simulator, at least
when the pilots were aware of the motion manipulation (Reid and Nahon,
1988; but see Bussolari, Young, and Lee, 1987). Motion also improved
pilot performance and control behavior in the simulator, especially for
disturbance tasks and tracking tasks of aircraft with low dynamic
stability (Hosman and van der Vaart, 1981; Hall, 1978; Hall, 1989). Some
of the benefits of platform motion have also been shown to transfer to a
higher fidelity simulator (Levison, 1981). However, the literature
review also showed that the benefits of platform motion have not been
proven in the case of transfer of training to the airplane (see, e.g.,
Waag, 1981).

Volpe has therefore been tasked to obtain objective data on simulator
motion requirements. Questions to be answered include, but are not
limited to, the following: Are there any flight tasks for which a
measurable difference in simulator training effectiveness can be found
with and without platform motion? What is the relationship in motion
cueing effectiveness for a wide FOV visual display versus platform
motion? Are existing platform motion qualification criteria optimal? Is
there a relationship between pilot experience level and the
effectiveness of platform motion for training?

### Current Findings

A first experiment intended to answer some of these questions used a FAA
qualified Level C simulator with a six degree-of-freedom (DOF)
synergistic motion system and a wide angle high-quality visual system,
simulating a 30 passenger turboprop airplane with twin wing-mounted
engines (Bürki-Cohen, Boothe, Soja, DiSario, Go, and Longridge, 2000;
Go, Bürki-Cohen, and Soja, 2000). Deficiencies identified in a review of
prior research designs were avoided by measuring both pilot stimulation
and response, testing both maneuvers and pilots that are diagnostic of a
need for motion, preventing pilot and instructor bias, and ensuring
sufficient statistical power to capture operationally relevant effects.
Experienced airline pilots were evaluated and trained in the simulator,
half of them with and the other half without motion. Then the transfer
of skills acquired by both groups during this training was tested in the
simulator with the motion system turned on as a stand-in for the
airplane (quasi-transfer). The test maneuvers selected were engine
failures on take-off with either rejected take-off (RTO) or continued
take-off (V~1/R~ cut), which satisfied the criteria described in the
literature as diagnostic for the detection of a motion requirement.
These criteria included 1) closed loop, to allow for motion to be part
of the control feedback loop to the pilot; 2) disturbance maneuver, to
highlight an early alerting function of motion (Gundry, 1976; Hall,
1989); 3) high gain, to magnify any motion effects and to reduce the
stability of the pilot/airplane control loop (Hall, 1989); 4) high
workload with crosswind and low visibility, to increase the need for
redundant cues such as provided by motion, out-the-window view,
instruments and sound; and 5) short duration, to prevent pilots from
adjusting to a lack of cues. Both subjective (I/E grades,
questionnaires) and objective data recorded from the simulator were
collected from the experiment.

The results of the study indicate that the motion provided by the test
simulator did not, in an operationally significant way for the tasks
tested, affect either evaluation, training progress, or transfer of
training, acquired in the simulator with or without motion, to the
simulator with motion. It also didn't consistently affect the Pilots'
Flying (PF), Pilots' Not Flying (PNF), and I/Es' subjective perception
of the PFs' performance, workload, and training, or of their own comfort
in the simulator. Neither did it affect the acceptability of the
simulator to the PF and the PNF.

Note, however, that because the current simulator qualification
procedures do not provide a means to objectively assess the quality of
the produced motion (Lahiri, 2000), the motion provided by the test
simulator may not be typical of other FAA qualified Level C simulators.
Specifically, the observed lack of lateral acceleration produced by the
simulator shortly following the engine failure compared to the lateral
acceleration from the aircraft mathematical model suggests that the
simulator used in the study may not have provided sufficient motion
stimulation to the pilot. Clearly, additional steps must be taken to
determine the extent to which it may or may not be appropriate to draw
generalization based on these results.

### Further Studies

To validate and generalize the previous results, two follow-up studies
are underway. One examines the typicality of the test simulator used in
the previous experiment, by gathering data from other Level C and D
simulators and then comparing these data to the test simulator. This
effort will provide information on whether the earlier results may apply
to other FAA qualified simulators, at least for the maneuvers and pilot
population tested.

The second study will be similar to the previous one, while eliminating
any possible causes of not having found an effect of motion. For
example, the motion system of the test simulator will be tuned to
provide the best possible performance within its operational envelope.
Also, test subjects will fly different maneuvers considered to be
diagnostic for detecting an effect of motion. Finally, the type of
airplane simulated and the pilot population will be different from the
previous experiment. Results of this study will help determine whether
the benefits of tighter motion standards, as currently considered, would
justify the potential reduction in simulator availability due to an
inevitable increase in acquisition, maintenance, as well as enforcement
efforts.

## Realistic Radio Communications Simulation Fidelity Requirements

Given the engineering efforts expended on the simulation of the
airplane, the lack of sophistication in representing the operational
environment, of which radio communications represent the largest aspect,
may be due both to a historical emphasis on motor flying skills as well
as the technical difficulties of simulating radio communications
realistically without additional personnel. As has been explained
earlier, however, today's training and evaluation needs increasingly
require the inclusion of the cognitive aspects of the flying task.
Volpe, in collaboration with NASA Ames, has therefore examined 1)
airlines' current methods of simulating radio communications, 2) the
effect of these practices on training and evaluation according to
subject matter experts, literature, and reports on initial operating
experience (IOE), and 3) industry efforts to improve the current
situation. A summary of this work follows (see Bürki-Cohen, Kendra,
Kanki, and Lee, 2000, for details). Future efforts may experimentally
examine the impact of providing realistic radio communications.

### Current practices

The findings summarized below are based on information collected from 29
I/Es from 14 AQP airlines, including seven major, one cargo, four
regional, and two foreign airlines. I/Es were queried about their
simulation of different events, including ATC (tower,
approach/departure, en route) and company communications (dispatch,
ramp, maintenance, flight attendants) to own aircraft, ATC
communications to and from other aircraft or ground vehicles (the
so-called party line), as well as visual representation of other
traffic.

A first finding was that the method of simulating radio communications
is indeed almost exclusively I/E role-play, where the I/E issues
instructions and responds from his station directly behind the crew.
This was found both for company and ATC radio communications.

With regard to communications to own airplane, all I/Es reported
simulating ATC clearances in the terminal environment, and all but two
provide communications en route. Fewer I/Es make time to role-play
company communications, between 63 (ramp/gate) and 94 percent
(dispatch).

I/Es were also queried about representation of other traffic. Only 59
percent indicated that their simulators provide some out-the-window view
of traffic, mainly on the airport surface. Ten reported simulation of
traffic via the Traffic Alert and Collision Avoidance System (TCAS).
With regard to the party line, only 38 percent of all I/Es reported
simulating any communications to and/or from other aircraft or vehicles,
mainly on the airport surface.

### Instructor/Evaluator Opinions

I/Es were asked to indicate their allocation of time and effort between
running the simulation, simulating radio communications, instructing and
observing. I/Es spend about 50 percent their time and effort observing,
twenty percent each role-playing radio communications and operating the
simulator, and less than ten percent instructing.

Not surprisingly, I/Es rated their workload consistently higher for
training and checking in the simulator than in the actual aircraft with
real communications and no simulator to run. On the other hand, they
feel that the communications workload of the pilots is significantly
reduced. One I/E mentioned that even the manual workload of pilots is
reduced, because "\[p\]ilots are not normally given a chart frequency,
nor do they need to redial a new frequency to communicate."

I/Es stressed the importance of radio communications simulation for
teaching such skills as (new) ATC procedures, Crew Resource Management
(CRM) and situation awareness effectively. The overall importance of
radio communications is perceived highest in the terminal environment.
I/Es concern with simulating radio communications may have best been
summarized by the I/E who stated: "Without communication simulation,
when the pilot trainee finally arrives in the 'real world,' he must add
another component...This new (additional) component can really
complicate line flying."

### Literature review

Many of the I/E opinions found in the previous section are confirmed in
the literature (for more detail, see Bürki-Cohen et al., 2000). Both AQP
and CRM recognize that coordination with ATC, company, and flight
attendants is an integral part of line operations and that frequency
monitoring is important for maintaining traffic and weather situation
awareness (FAA, 2000; FAA, 1998).

Incident and accident investigations highlight the importance of radio
communications. The Flight Safety Foundation Approach and Landing
Accident (ALA) Reduction Task Force recommends that operators
"\[i\]nclude training scenarios that allow crews to experience overload,
task saturation, loss of situational awareness, out-of-control and
too-far-behind-the aircraft-situations, and communications in stressful
circumstances." Joint training should be held between pilots and air
traffic controllers including scenarios that "promote mutual
understanding of issues on both the flight deck and in the ATC
environment, and foster improved communications during emergency
situations" (Khatwa and Helmreich, 1999).

There is much theoretical and experimental evidence that whole-task
training in a fully loaded environment is superior to part-task training
in an incomplete environment that may induce a false sense of
operational simplicity akin to tunnel vision (see, e.g., Fabiani,
Buckley, Gratton, Coles, Donchin, and Logie, 1989). Learning is an
active process, and practice can lead to either activation or inhibition
of cognitive pathways (Bransford and Franks, 1976). If pilots are
consistently exposed to an impoverished environment during training,
they may end up unprepared for the "quick pace of an airline environment
and \[its\] associated distractions,"[^1] where their inexperience may
prove fatal.

### Effect on initial operating experience (IOE)

A search of the ASRS database from January 1993 to October 1999,
resulting in 93 reports related to flight events during IOE, confirmed
some of the concerns expressed by I/Es and the literature (see
Bürki-Cohen and Kendra, manuscript, for details). Most of the errors
reported involved altitude deviations or course deviations. Other
multiple errors were landing or take-off without clearance, approach to
or landing on the wrong runway or airport, runway incursions, and loss
of communications.

Radio communications played a major role in 72 percent of the reports.
Demanding, inadequate, or even erroneous ATC instructions spearheaded
the factors leading to events deemed worthy of a report. Amended
clearances requiring reprogramming of the automation or erroneous
"expect" instructions were often cited. This was followed by inadequate
CRM or task management related to radio communications, ATC
interruptions including traffic calls and frequency congestion, stuck
microphones blocking an entire frequency, or pilots stepping on an
ongoing conversation. Next were radio-tuning problems and unfamiliar
phraseology and accent, the latter usually in non-English speaking
territory.

### Industry initiatives

Given all the evidence presented in the previous section, it is not
surprising that both airlines and simulator industry are striving to
improve radio communications realism. Only efforts known to have been
used in airline training will be discussed (see Bürki-Cohen et al, 2000,
and Bürki-Cohen and Kendra, manuscript, for details).

Among the most operationally realistic efforts is United Airlines'
Interactive Real Time Audio System (IRAS). It is based on field
recordings of actual ATC communications, including both communications
to own and to and from other aircraft with controller voices dubbed with
the individual instructors' voices. The system, however, is no longer
operational due to high scenario-development, integration and
instructor-training costs.

The Canadian simulator manufacturer CAE has developed the Ground Air
Traffic Environment System (GATES) after a request from a foreign
airline to provide a visual representation of traffic in the airport
terminal environment. It soon became obvious that correlated and
meaningful radio communications would have to be an essential component
of such traffic representation. The I/E still provides all ATC
communications to own airplane, however. Several domestic airlines and
training facilities as well as foreign airlines and military are
currently equipping their simulators with GATES.

Lufthansa and the German ATC organization Deutsche Flugsicherung (DFS)
are collaborating on Joint Operational Incidents Training (JOINT). Up to
eight Lufthansa simulators can be linked to two DFS ATC control sector
simulators, resulting in highly effective recurrent training of both
pilots and controllers. Each ATC simulator consists of a controller work
station with a radar display showing the simulated airplanes flown by
the flight simulator crews as well as other airplanes sharing the same
airspace operated by a pseudo pilot sitting at a connected computer
station.

## conclusionS

The twin issues of training effectiveness and affordability of flight
simulators for use by U.S. airlines will become increasingly critical in
light of anticipated regulatory changes, dramatically reduced pilot
new-hire experience levels and growing operational complexity. In that
regard, two research areas with high pay-off potential are platform
motion and realistic radio communications. Initial FAA sponsored
research on the training effectiveness of a fixed-base simulator with a
wide field-of-view visual system compared to a like system having
platform motion failed to find an operationally significant effect of
motion using FAA qualified equipment. Acquisition of objective data to
determine the extent to which the platform motion characteristics of the
equipment employed are typical of other FAA qualified simulators is
presently ongoing. A second training effectiveness study is planned
using a test simulator tuned to provide the best possible platform
motion performance and maneuvers selected to be especially diagnostic.
However, considering the controversial nature of this issue, the safety
implications, and the fact that no changes in regulatory requirements
can be expected without absolute confidence in the reliability and
validity of the results, it is likely that considerable additional
research in this area will still be needed. Initial research on the
simulation of radio communications for U.S. airline pilot training
strongly suggests that in order to be fully effective in developing the
cognitive and workload management skills associated with radio
communications, significant improvements are needed in the resources
available to the pilot instructor for that purpose. The present practice
of relying on IOE to compensate for the deficiencies in simulator
resources for training radio communications skills may become
increasingly inadequate in view of the changing demographics of the
pilot new-hire population, as well as the anticipated future regulatory
requirement for all airlines to conduct training in operationally
realistic flight simulator scenarios. Although there have been a number
of promising developments in this arena, considerable additional
research is needed to reduce the cost and labor requirements associated
with simulating radio communications in an operationally realistic
fashion.

## ACKNOWLEDGMENTS

This work has been supported by FAA Office of the Chief Scientific and
Technical Advisor for Human Factors, AAR-100, where we thank the Program
Manager, Dr. Eleana Edens, for her guidance and insights. We also thank
the airline and industry representatives that have contributed to this
work, and Ms Young Jin Jo.

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[^1]: From an ASRS report

[^2]: Available in electronic format from Dr. Thomas Longridge, Advanced
    Qualification Program Manager, AFS-230, tel. (703)-661-0275.