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1American Institute of Aeronautics and Astronautics

A Piloted Evaluation of a Ship Deck Landing TrainingSimulation

CMDR Chris Smallhorn*

Royal Australian Navy, HMAS ALBATROSS, Nowra NSW 2540, Australia

Mr. Colin Wilkinson† and Mr. Gery VanderVliet‡

Anteon Corporation, California, MD 20619

During the period 16-27 May 2004 a piloted evaluation was conducted of the LiftShipboard Integration Program (LSHIP) simulation as integrated into a US Army UH-60ABlack Hawk flight simulator at Fort Campbell, KY. The LSHIP system comprised the UH-60 Lift Simulator Modernization Program (LSMP) flight simulator with elements of theJoint Shipboard Helicopter Integration Process Dynamic Interface Modeling and SimulationSystem integrated, including a computational fluid dynamics wind-over-the-deck shipairwake model.

The intent of the trial was to perform a qualitative and quantitative assessment ofshipboard launch and recovery evolutions, with the ultimate aim of identifying the level ofcertification of the product for the maintenance of ship landing pilot currency and/or initialpilot training and qualification. Upon initial assessment of the device a significant transportdelay was apparent along with blurred visuals and minimal motion cues. The combinedeffects of these issues were adverse physiological effects and a strong tendency for pilotinduced oscillations during the shipboard evolutions. Following a two day integration effort,focusing on reducing the transport delay as the primary issue, it was determined that theevaluation as planned was not appropriate. A modified method of test was developedwhereby a focused integration and tuning effort would be pursued in order to conductqualitative comparative proof-of-concept evaluations between the baseline LSMP and theLSMP with LSHIP integrated.

The program offered numerous unique challenges emphasising the importance of thecorrect test team skill set structure, and the value of the combined pursuance of lateralproblem solving techniques within the confines of cost and schedule limitations. This paperwill highlight the lessons learned throughout the trial concentrating on the productpreparation, integration challenges and the test team’s technical solutions, the importance ofa well structured test team, and the project management techniques and philosophiesemployed to achieve a successful project outcome despite significant technical and schedulechallenges.

I. IntroductionS an element of the Joint Shipboard Helicopter Integration Process (JSHIP) significant research, test andevaluation was conducted into the Dynamic Interface Modeling and Simulation System (DIMSS)1,2. DIMSS

developed a process using modeling and simulation to help establish shipboard launch and recovery Wind-Over-the-Deck (WOD) flight envelopes and provided a high level of fidelity simulation for training aircrews for launch from

*Experimental Test Pilot† Principal Engineer, Information Systems and Engineering Group.‡ Group Vice President, Information Systems and Engineering Group

A

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This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States.


and recovery to air capable ships. DIMSS delivered a series of legacy products in the form of enhanced system andsubsystem simulation elements designed where possible with open architecture philosophy to enable easierintegration into operational simulators, including:

a. A time accurate ship airwake model based on computational fluid dynamics (CFD) and validatedwith airwake data collected at sea and in model scale testing3-5;

b. UH-60A aerodynamic, cockpit, flight controls and landing gear models;c. Ship and ocean visual models, a ship dynamics model and a Landing Signal Enlisted (LSE) visual

model;d. Body force cueing system; and,e. Aural cueing system.

DIMSS was evaluated in the Vertical Motion Simulator (VMS) at NASA Ames, using multiple fidelity levels inthe aural, visual and body force cueing subsystems to help determine required fidelity for the shipboard task.Verification and validation of DIMSS fidelity was performed through the collection of truth data from instrumentedaircraft conducting deck operations at sea aboard an amphibious helicopter carrier. A key outcome of the DIMSSeffort was that the enhanced fidelity levels offered by the various systems and subsystems, as integrated intooperational flight training simulators, would enable the training of aircrew in the deck landing and take-off task to anextent limited by the base simulator fidelity levels.

The UH-60 Lift Simulator Modernization Program (LSMP) identified the DIMSS simulation capabilities asbeing valued-added to the training of its pilots for shipboard operations and subsequently tasked a Front-EndAnalysis to be conducted at the 101st Airborne Division UH-60 device located at Fort Campbell, KY. This effortwas titled the Lift Shipboard Integration Program (LSHIP). To enhance LSMP capabilities for the shipboard landingtask, DIMSS models were required to be integrated with LSMP to include:

a. A CFD ship airwake model for the LHA, comprising multiple datasets for individual relative windazimuths;

b. A UH-60A blade element aerodynamic model; and,c. A UH-60A landing gear model.

A high resolution ship and ocean visual model and Landing Signalman Enlisted (LSE) model were inherent toLSMP

Currently, the US Army has been approved by Chief of Naval Operations to “self-certify” its simulation trainingdevices for shipboard operations to allow for deck landing qualification (DLQ) currency extensions after initial at-sea shipboard qualifications. The self-certification process, however, now requires approval from Commander NavalAir Forces and Commander Naval Air Pacific. In order to comply with the approval process, the US Army executeda test and evaluation effort of the enhanced simulation capability for shipboard operations. The test and evaluationeffort is the subject of this paper.

II. LSHIP System DescriptionTwo test configurations, designated configurations I and II, were assessed:

I. The baseline UH-60 LSMP configuration utilizing a rotor disk aerodynamic math model and a PC-based image generator with associated ship, ocean and LSE models.

II. The UH-60 LSMP configuration utilizing the LSHIP enhancements which included a CFD LHAship airwake model, UH-60 blade element air vehicle model and landing gear model, and enhancedship dynamics. The LSHIP enhancements were hosted on a computer separate to the LSMP host, sothat they could be switched in and out as required, without interfering with the baseline LSMPconfiguration.

The motion base system of the current UH-60 LSMP was used for both configurations. Table 1 lists thesubsystems associated with each configuration.


Table 1. Subsystems for Configurations I and II

Subsystem ConfigurationVisual display and database I and II: Collimated displays with PC-based, high-fidelity ship model, LSE model and 3D

ocean model.Aural I and II: Sound model with 6 non-directional speakers.Body force I and II: 6 degree of freedom ram with vertical-axis seat shaker.Airwake I: Steady state wind component with random forcing function.

II: Time-varying, computational fluid dynamics model.Aerodynamic I: Rotor disk model.

II: Blade element model.Landing gear I: Existing LSMP landing gear model.

II: Enhanced landing gear model.Cockpit I and II: Existing LSMP cockpit and field-of-view configuration.

III. Method of TestThe aims of the 10-day test and evaluation effort were to:

a. Verify that the DIMSS models and subsystems had been added to the UH-60 LSMP simulationdevice;

b. Measure the capability of the enhanced simulation for replicating the pilot workload associated withthe shipboard landing task;

c. Assess the utility of the system for conducting DLQ training and currency extension;d. Assess the system fidelity to help establish the minimum fidelity standards for any shipboard

simulation scenario; and,e. Provide a written assessment of the simulation capability to support the certification process.

The method of test required a qualitative evaluation of the integrated LSHIP system by Experimental Test Pilotsto determine the suitability of the system for the conduct of the training mission. This was to involve an evaluationof both configurations detailed in section II to enable a comparative assessment of the improvements afforded by theintegrated LSHIP system. In the event of a successful outcome from this evaluation UH-60A Black Hawk pilotinstructors from the 101st Airborne Division and 160th Special Operations Aviation Regiment were to conduct aseries of evaluations controlled and structured by the LSHIP test director. On completion, a final recommendationwas to be formulated for the suitability of the system to support the certification process, specifically detailing thelevel of operational pilot training and currency that could be achieved.

The initial evaluation of the integrated LSHIP system, however, identified numerous issues, the most significantof which was a transport delay that rendered the system unsuitable for the evaluation. This resulted in a re-scopingof the project aims and expectations within the confines of cost, resources and schedule. It was determined that thetest team would direct attention to system rectification with the aim of establishing a level of fidelity that wouldallow a ‘proof-of-concept’ evaluation to be conducted. In the event that a fidelity level could be achieved that, in theopinion of the test team, was sufficient to enable a limited evaluation by operational pilots, the system would beevaluated against the original aims. The final outcome was to be a recommendation on the LSHIP concept andintegration for application and further development, if appropriate.

The original test plan required experimental test pilots to assess the simulation at both subsystem and systemlevel, prior to an evaluation by operational instructor pilots. However, system rectification involved repeatedassessments of the simulation in multiple configurations by the test pilots and it was not considered that they wouldbe able to make an impartial assessment of the overall simulation after tuning the system. Therefore, the evaluationof the training potential of the simulation was confined to the instructor pilots. This paper focuses on the assessmentand tuning of the subsystems.

The subsystems were evaluated individually during day conditions with unlimited visibility for both the LSMPand LSHIP systems using the Fidelity Rating Scale (FRS)2 developed under the JSHIP program and presented atFig. 1.


Is realismgood orbetter?

Is realismfair orbetter?

Reality. 0

Model/subsystem is as reality; although model/subsystem is knownto be a simulation, there are no noticeable imperfections.

Model/subsystem is very close to reality; imperfections are barelyrecognizable.

1

2

Model/subsystem is very close to reality but has infrequent, slightlyrecognizable imperfections. 3

Model/subsystem is close to reality but has frequent, slightlyrecognizable imperfections.

Model/subsystem is close to reality; imperfections are clearlyrecognizable but are infrequent.

4

5

Model/subsystem has frequent, clearly recognizable imperfectionswith respect to the specific system but is a good generic model. 6

Model/subsystem has infrequent, major imperfections with respectto the specific system but is close to a generic model.

Model/subsystem has frequent, major imperfections with respect tothe specific system and is a poor representation of a generic model.

7

8

Model/subsystem has an excessive number of major imperfectionsand is of no value. 9

No model. 10Does model

exist?

Model/subsystemfidelity is low

Model/subsystemfidelity is medium

Model/subsystemfidelity is high

Yes

Yes

Yes

No

No

No

Is realsubsystem/model used?

No

Pilot/engineer decision

Yes

Figure 1. Fidelity Rating Scale

IV. LSHIP Integration Issues

A. GeneralInitial experience with the LSHIP system highlighted numerous integration issues that rendered the system

unsuitable for the evaluation method of test as originally planned. The integration issues experienced aresummarized below. Where the issues were corrected the method of rectification is also summarized. Thetuning/integration achieved levels of simulation and integration suitable for a proof-of-concept evaluation.

B. Excessive Transport DelayOn initial evaluation of LSHIP the transport delay was qualitatively estimated to be in the order of 200 msec.

This resulted in strong adverse physiological effects on the pilots and a tendency for Pilot Induced Oscillations(PIO) to easily develop, in particular when attempting a deck landing or hovering in the airwake of the ship. Uponreviewing the integrated system the test team believed the system should only be suffering a theoretical 90 msecdelay, however qualitatively the delay was significantly longer and rendered the integrated LSHIP simulationunsuitable for the intended evaluation.


It was anticipated that if the transport delay could be reduced to a physiologically manageable level theevaluation could proceed. The cause of the excessive delay was identified but, despite extensive efforts, could not berectified within the confines of the scheduled evaluation period. At this point the test team determined that theimplementation of lead compensation filters should be explored to provide the pilot with the perception of a reducedtime delay through stronger initial aircraft responses to pilot input.

Lead compensation filters were developed for the pitch, roll, yaw and vertical axis controls in order to mask thetime delay by advancing the phase angle of aircraft response to a pilot input. The filters comprised four mainelements, two of which were tuned in order to achieve the desired responses, requiring four days and some 30iterations to achieve satisfactory results. The elements of the filters were as follows:

a. Rate limiter. Input rates to which the compensator would react were limited to 4 inches per secondof control input.

b. The compensator limited the input force at the swashplate, i.e. the force ultimately applied to thehub, to ±3000 lbs.

c. A gain factor was tuned to the desired value on each compensator that was defined as a percentageof the compensator force limit, e.g. the pitch axis compensator gain was ultimately set to 0.75,representing 75% of 3000lbs.

d. A first order filter was applied to the filter to washout the enhanced response. The first order filtertime constant was tuned to the desired value on each compensation filter.

The successful implementation of the lead compensation filters was the key tuning and integration element thatenabled the continuation of the LSHIP evaluation. Such a tuning effort requires a balance to be struck between thegains, rates and washout time constant for the filter. The final result required the consideration of both quantitativedata, and Test Pilot qualitative opinion. This element of the LSHIP integration corrective activity highlighted theintrinsic importance of a well balanced skill set in the test team. Here the combined expertise of the softwareengineer, aerodynamicist and Test Pilots enabled an efficient iterative fly-test-fly philosophy to be employed toreach a satisfactory result, which ultimately enabled the continuation of the program.

C. Incorrect Moments of InertiaWhile troubleshooting the lower motion response of the LSHIP system as compared to LSMP (section IV F) it

was found that the values for the Moment of Inertia (MoI) around all axes differed between LSHIP and LSMP. Itwas determined that the MoI values for LSMP were correct and the LSHIP values were possibly in error by as muchas 50% in some axes and were higher than the LSMP values in all cases. Suspecting that the higher MoI values werecausing reduced motion cues, the MoI values for LSHIP were changed to reflect the LSMP values. Furtherinvestigation revealed that the LSMP values were for a clean UH-60, while the LSHIP model was set for a UH-60with external fuel tanks fitted, but no fuel in the external tanks. The change to MoI values occurred after 10iterations of the lead compensator filter tuning; therefore the change had an effect on the tuning effort. The reducedMoIs resulted in additional tuning effort to the roll axis in particular.

The MoI changes ultimately had little effect on the motion system cues and also resulted in a coupling betweenthe landing gear and rotor system models causing uncomfortable and excessive lateral motion cues upon landing onthe ship. Due to the adverse results of the MoI changes, the mass properties were returned to the original LSHIPvalues. These MoI values were ultimately the configuration used for test.

D. Landing Gear Model ResponseThe landing gear response was too soft when qualitatively compared to the real aircraft, particularly in the deck

landing task. The simulation appeared to bounce slightly and had a spongy feel as the aircraft settled on the oleos.Upon landing, the aircraft tended to slide laterally on the ship without any appreciable ship roll or command fromthe pilot. The tire model included a static coefficient of friction term that aimed to prevent slide. To address theaircraft dynamics once a slide occurred, longitudinal and lateral springs and a dynamic coefficient of friction termwere used. The oleo model consisted of a generally linear model of force vs. oleo compression combined with adamping term.


The tendency for the aircraft to slide on deck was addressed by increasing the static and dynamic coefficients offriction (between tire and deck), and modifying the spring stiffness associated with the tire model. The spongy feelon landing was corrected by increasing the stiffness and damping ratio for the main landing gear oleos.

E. On Deck Motion CuesUpon touching down on the flight deck excessive motion cues were experienced, particularly in the lateral axis.

Cues were of sufficient severity to result in maximum travel of the device motion jacks, and on occasion forced themotion system into an automatic reset. The cues provided powerful and uncomfortable physiological effects on thetest crew.

The cause for the magnitude of these effects remains unknown. The excessive motion cues were ultimatelyaddressed by scaling down the motion commands calculated by the flight model to an acceptable level achieving theminimum acceptable standard to enable the proof-of-concept trial to continue.

F. Motion SystemThe in-flight motion cues for the LSHIP system were notably less than those for the LSMP. Tuning the base

motion system software was not considered an option within the schedule and resources available for the trial. It wasexpected that the correction to the MoIs (section IV C) would improve the motion cues, particularly in the roll axis,but this did not prove to be the case. To investigate the reduced cueing, a series of quantitative control input-to-motion command tests were conducted on both the LSMP and the LSHIP. The following tests were conducted:

a. 1-inch aft longitudinal cyclic step input;b. 1-inch right lateral cyclic step input;c. 1-inch left yaw pedal step input;d. 1-inch up collective step input; and,e. Frequency sweeps in longitudinal, lateral, yaw and collective axis.

Data for the step inputs were analyzed to compare the forcing function values resulting from each input betweenLSMP and LSHIP. The aim was to assess whether the LSHIP outputs were less than LSMP thus explaining thelower motion cues. Plots for the roll step inputs are shown in figure 2. The LSHIP integration utilized a bladeelement rotor model which provided second order responses to the control inputs while the LSMP utilized a rotordisc model which provided a first order response. The motion system had been tuned for the disc model and wouldhave required a focused tuning effort to facilitate a second order response system. It was determined throughdiscussions with test team personnel that the motion system driver software would be unable to provide adequatecues without modification, even though the amplitude of the motion command was greater for LSHIP than LSMP,as can be seen in Fig. 2. Tuning of the motion system was considered beyond the scope of the evaluation within thetime and resources available. The reduced cues offered by the motion system were accepted as a limitation of theintegrated system for the purpose of the proof-of-concept evaluation.

G. Ship Airwake SimulationThe integration of the blade element model with the CFD ship airwake simulation resulted in the airwake

turbulence magnitude being excessive compared to that experienced onboard the real ship. This necessitated thetuning of the magnitude of the airwake model output. All evaluations and tuning were qualitative. The magnitude ofthe airwake force output was tuned to a percentage of the original model output. Following numerous evaluationswith the magnitude as low as 50% of the original, a final factor of 70% of the original magnitude was implemented.

It should be noted that a qualitative evaluation of the feel of the airwake is dependent on the fidelity of multiplesubsystems including body force cueing, visual cueing, aerodynamic modeling, airwake/aerodynamic integrationand transport delay, as well as the airwake model itself. Tuning of the airwake was probably compensating fordeficiencies elsewhere in the system and does not necessarily imply a lack of fidelity in the airwake model.

H. Visual SystemThe visual system presented an image that did not provide sufficiently fine cueing fidelity for a high gain task

such as the deck landing evolution. The fidelity of the visual resolution was a limitation of the LSHIP integrateddevice.


Figure 2. Response of LSHIP and LSMP to Step Input in Roll

The LSMP was fitted with a chin window visual simulation. Initial assessment highlighted that the chin windowvisuals were not aligned with the main screen visuals indicating that the same design eye point had not been utilizedfor the chin window and main screens. This could not be corrected for the evaluation. When integrated with theLSHIP system the presentation through the chin window was blurred when less than 10 ft above the ship’s deck,although the window provided good resolution from greater altitudes.

V. Evaluation Result

A. GeneralFollowing the integration effort, each subsystem was qualitatively evaluated and assigned an FRS value (Fig. 1).

The FRS values assigned for each subsystem are shown in Table 2. The subsections below provide furtherqualitative evaluation comments to complement the quantitative and qualitative assessments shown in the table.

B. Visual Display and DatabaseThe visual display and database were evaluated during approach and landing to the ship at various spots. The

image was generally blurry preventing the landing spot deck markings from being utilized until very late finalapproach. The 45º line-up line, marked on the landing spot, was therefore unusable during the majority of theapproach preventing the required 45º relative arrival flight path being flown with reference to the intended cues. Theapproach path was estimated based on overall ship aspect only. Once over the deck, the image did not presentsufficient fine detail to provide the necessary cues to appreciate small drift, resulting in larger drifts developingbefore becoming apparent to the pilot. This necessitated larger control inputs to control the drift and an overallincrease in workload. The chin window was blurred below 10 ft and not aligned with the remainder of the visualdisplay. The low fidelity display in the chin window was distracting to the task and was therefore consciouslyremoved from the pilot’s visual scan during the landing evolution. The combined effects of the LSHIP visual system


resulted in moderate eye strain and headaches following periods in the simulator in excess of 30-45 minutes. Thevisual system was contributory to the overall adverse physiological effects experienced by evaluating crews in theLSHIP system. The blurred image in the visual display will unrealistically increase pilot workload during theshipboard landing mission, cause the onset of fatigue due to eye strain, and increase the likelihood of experiencingsimulator sickness.

Table 2. Subsystem Evaluation Qualitative Results

FRS ValueSubsystemLSHIP LSMP

Remarks

Cockpit Layout 0 0 NilField of View 6 6 NilFlight ControlPositions

0 0 Nil

Layout ofInstruments

0 0 Nil

Instrument / CockpitAppearance forDaylight Conditions

5 5 Higher rating due to need for use of instrument lighting in dayconditions.

Flight Control Feel 3 3 ½” slop in cyclic with a small feel of a counterweight feedback belowcockpit deck. Note: Test pilot not current on US Army Blackhawk.

InstrumentDynamics

ASI: 3Alt / VSI: 1

other: 0

ASI: 3Alt / VSI: 1

other: 0

Air speed indicator (ASI) shows smooth response for 0-40 knots – notrealistic. Altimeter (Alt) and Vertical Speed Indicator (VSI) perfectlysmooth at all times – not realistic.

Motion 7.5 6 Cues minimal in all axes for LSHIP. Cues were slightly improved inLSMP but were still less than desired.

Ship Overall Image 5 5 Good aspect, but blurred image.Ship Superstructure 3 3 Good detail.Ship Hull 3 3 Good detail, but lacked reality of rust streaks from drains etc.Flight DeckMarkings

2 2 Assessment based on layout.

Flight DeckMarking Useability

8 8 Extremely poor resolution resulted in the cues being unusable untilwithin an estimated 50-80 feet of the deck.

LSE 4 4 Good representation. However aircraft distance from desired landingpoint before LSE will direct back to spot is too far. Additionally LSE isvery slow to respond.

Ocean Appearance 6 6 Good generic model. White appearance not realistic.Flight Model 6 3 LSHIP – good generic model, but transport delays caused pilot to suffer

from PIO. Once apparent transport delay was corrected with leadcompensators the flight model had a quickened initial response notaccurately representing real model. Should be re-evaluated uponrectification of transport delay

Landing Gear 8 6 Too soft both LSHIP and LSMP. After landing bounces and slides inLSHIP must be corrected.

Airwake 5 10 LSHIP airwake was not complemented by a tuned flight model ormotion system. Motion system was not tuned to provide the short andsharp cues characteristic of deck turbulence. Cues were minimal andinteraction with flight model fairly severe. Combined with poor visualcues, the outcome was a greater than realistic workload. Should be re-evaluated with a fully integrated platform.

C. Motion SystemThe motion cues, as integrated with the LSHIP system, were evaluated in forward flight, low airspeed flight and

during hover within the ship airwake environment. The motion cues were minimal in all axes. Very little tonegligible cues were evident in the heave or yaw axes. The initial pitch acceleration cue was adequate, but thelongitudinal long-term acceleration and deceleration cues (g-align) were negligible. Roll acceleration cues wereminimal with lateral (or sway) g-align cues being moderate for angles of bank greater than 20º, and minimal forsmaller bank angles. Acceleration and deceleration cues during low airspeed flight were evaluated during lateralsidesteps and longitudinal maneuvers to an aim point while over the ship deck. Acceleration and deceleration cues


were minimal. The minimal motion cues resulted in a generally uncomfortable ‘feel’ during the high gain task of thedeck landing and, as such, reduced training value. Additionally, the minimal motion cues, when combined with theblurred visual cues, can increase the tendency for adverse physiological effects.

D. Ship AirwakeThe ship airwake, as simulated by the CFD model integrated in the tuned LSHIP system, was evaluated during

multiple take-offs and landings to the ship. Winds were evaluated from relative azimuths of 330º to 090º and relativewind velocities of 5 through 35 knots. The tuned airwake model markedly increased workload in those relative windconditions and landing spot combinations prone to turbulence. The magnitude of the turbulence effect on the aircraftas integrated with the blade element flight model was, on occasion, excessive resulting in workload above thatrequired for the real task. However the training value of experiencing the increased workload in airwake turbulencewas apparent.

The evaluation of the airwake model is given with cognizance of the evaluation of the motion system atsection IV F and is based on the evaluators’ experience with the airwake model during the JSHIP DIMSS program.Motion cues were minimal within the turbulent environment, and it is anticipated that improvement of the motionsystem would improve the training value of the airwake model. Such an integration was evaluated during the JSHIPDIMSS program resulting in an extremely realistic airwake/aircraft interface.

E. Flight ModelAn evaluation of the LSHIP blade element flight model could not be reasonably achieved due to the tuning effort

necessary to mask transport delays. These modifications quickened responses in all axes beyond the flight model’svalidated performance. Actual UH-60 flight data was not available for direct comparison, and a structuredassessment against the actual aircraft was not conducted, nor was it considered within the scope of the trial.Qualitatively, however, the flight model sufficiently represented the handling and performance qualities of a UH-60for the purpose of the evaluation.

F. Landing GearThe landing gear model, after tuning, was evaluated during multiple deck landing evolutions. Upon landing the

initial motion feedback was less than the real aircraft, but sufficient to alert the crew to a landing. Following thelanding the aircraft tended to slide on deck and the motion system provided abrupt vertical bumping feedback atrandom intervals. The after landing effect was unrealistic of the real aircraft.

G. Cockpit Field of ViewThe cockpit field of view was evaluated from the right seat during the shipboard landing and takeoff tasks to the

ship in daylight conditions with unlimited visibility. The device field of view was limited in comparison to the realaircraft with large gaps in the field of view in the forward right quarter, lower right and forward lower regions. Thereduced field of view significantly increased the workload necessary to accurately position the aircraft to the desiredlanding positions as the pilot is consistently short of the necessary cues to appreciate small drift, resulting in largerdrifts developing and larger and more regular control activity to compensate. The reduced field of view will result inunrealistically increased workload during the shipboard landing and takeoff tasks and will reduce training benefit tocrews.

VI. Conclusion - Lessons Learned

A. Product PreparationAs is the case in many programs, the burden of aggressive schedules often set without due cognizance of the

complexity of the task, was a significant factor in the readiness of the product prior to the evaluation. Reflection onthe weeks and months leading to the evaluation highlighted a tale of insufficient integration time, insufficient testand evaluation, and therefore insufficient characterization of the product. Again the age old lesson was learned thatpreparation is the key to a successful evaluation event.

B. Test Team StructureThe LSHIP test team consisted of a US Army project manager, industry project manager, flight model and

aerodynamicist engineer, integration engineer, simulation engineer with significant test and evaluation experience,


two experimental test pilots, and simulator support staff. Of the engineering staff, all were directly involved in theproduct integration and some had significant experience reaching back to the JSHIP concept, design and testing. Thetest team was structured to enable an evaluation of the product such that a recommendation could be made on thecertification of the product for training and qualification of pilots in the shipboard environment. The structure, onecould argue, was excessive for such a task. However, following an unexpected failure of the product integration,such a test team structure consisted of the necessary skill sets to re-group and re-task such that the product couldenter another preparation and integration phase prior to final evaluation. The use of experimental test pilots, viceoperational pilots (the US Army’s normal process for simulator acceptance activity), ensured a developmentalenvironment with mutual appreciation of engineering concerns. The test team structure, and its ability tosuccessfully shift focus from evaluation, to developmental and integration engineering, then re-scope and executethe evaluation, was the backbone of the success of the trial.

It is recommended that all current and future simulator flight trials and development activity employexperimental test pilots as a core element of the engineering and evaluation team.

C. Cost Schedule and Results – Management PhilosophyThe initial integrated product was assessed as unsuitable for the intended evaluation within the first test serial.

Following significant effort to investigate the integration issues the test team was faced with the decision to cancelthe program. This ultimately would have been the path of least resistance. However such a path did not duly weighthe resource implication of bringing together the team’s skill sets either initially, or again following productcorrection. Indeed it was clear that no better rectification team could be brought together. Similarly, the concept ofintegrating the JSHIP DIMSS enhancements remained an open question that must be answered if the concept was togain further advancement towards a final application. The test team and project management reconfirmed a beliefthat the concept would ultimately deliver the expected operational enhancements and savings in the training ofaircrew in the ship deck environment. It was therefore considered imperative, and worthy of the cost risk, to pursuethe modified scope of test.

The final result is that the proof-of-concept evaluation resulted in a positive operational assessment. The intent isto further evaluate improved integrations of the LSHIP concept aboard numerous in-service helicopter simulators.Management flexibility, and the ability to employ lateral thought at a time when the project may well have faced afailure, was key to the successful outcome of this trial.

D. LSHIP PotentialThe evaluation of the system was ultimately conducted with a view to a proof-of-concept assessment. The fully

integrated capabilities of the LSHIP concept were demonstrated during the JSHIP DIMSS effort, although theintegration was within the NASA AMES Vertical Motion Simulator rather than an operational flight training device.The DIMSS integration represented the quality that can be achieved with a fully integrated product, albeit withsignificantly enhanced motion cues. The LSHIP trial has demonstrated that DIMSS products can be integratedwithin existing simulation devices provided dedicated and sufficient tuning and integration effort is scheduled.

Any operational simulator program whose mission involves shipboard operations can benefit from DIMSSintegration similar to that of LSHIP, with the potential to significantly reduce the training burden to maintaincurrency and DLQ for shipboard operations. The simulated environment will enable extremely efficient training in awide variety of recovery conditions that will not be available in a single training sortie at sea. Emergency recoveriesthat cannot be risk mitigated sufficiently to warrant training in the real environment may be practiced in thesimulated environment in both day and night conditions. Exposure to the broad range of conditions that may beexperienced by ship borne helicopter crews, prior to initial qualification sorties at sea, will greatly reduce the risk ofthe training event, and is likely to reduce the number of recoveries and takeoffs required to achieve initialqualification. The ongoing exposure to shipboard operations in the simulated environment will reduce the risk ofshort notice embarkations and reduce the burden on the ship for training periods upon embarkation. Overall, aDIMSS-enhanced simulation offers the potential for significantly increased safety in shipboard operations throughregular simulated deck exposure for UH-60 crews, reduced cost in training and maintaining currency, and increasedtraining productivity when considered against the time necessary to plan and execute at sea training periods.


References1Wilkinson, C. H., VanderVliet, G. M., & Roscoe, M. F., “Modeling and Simulation of the Ship-Helicopter Environment,”

AIAA Modeling and Simulation Technologies Conference, 2000-4583, AIAA, Denver, Colorado, August 2000.2VanderVliet, G. M., Wilkinson, C. H., & Roscoe, M. F., “Verification, Validation and Accreditation of a Flight Simulator:

The JSHIP Experience,” AIAA Modeling and Simulation Technologies Conference, 2001-4061, AIAA, Montreal, Canada, August2001.

3Polsky, S. A., & Bruner, C. W. S., “Time-Accurate Computational Simulations of an LHA Ship Airwake,” AIAA AppliedAerodynamics Conference, 2000-4126, AIAA, Denver, Colorado, August 2000.

4Polsky, S. A., “Computational Study of Unsteady Ship Wake,” AIAA Aerospace Sciences Meeting, 2002-1022, AIAA, Reno,Nevada, January 2002.

5Polsky, S. A., “CFD Prediction of Airwake Flowfields for Ships Experiencing Beam Winds,” AIAA Applied AerodynamicConference, 2003-3657, AIAA, Orlando, Florida, June 2003.

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