Seville, Spain 24-25 June 2008 REACT: The FMS Perspective Keith Wichman – GE Aviation Systems.

Seville, Spain • 24-25 June 2008

REACT: The FMS Perspective

Keith Wichman – GE Aviation Systems

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REACT Workshop Seville, Spain 24th-25th June 2008

Background

• The Flight Management System computes the full 4D trajectory from runway to runway

• This trajectory represents the optimal way to fly the entered route while honouring all constraints

• The FMS then provides closed-loop guidance to this trajectory

• The trajectory is continuously updated to account for changing conditions or to reflect deviations from the planned route

However….

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Background

• The FMS and Ground-based Trajectory Predictors / DSTs have been developed independently

• Different inputs, models, and requirements lead to different trajectories for the same aircraft

• Often leads to non-optimal, tactical commands to ensure separation and safety

≠

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Background

• Thus, there is an urgent need to synchronize the trajectory as well as how the aircraft intends to fly that trajectory.

• Using the Reference Business Trajectory as the initial reference, this collaborative trajectory management allows for an “optimization” of the system as a whole while minimizing the deviation from that RBT.

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Previous Experiments

• Boeing 737 FMS provides ARINC 702A-1 Trajectory-Intent Bus

• Output via 429 bus and/or ACARS

• Examined as part of NUP2+ project

• Dedicated flight trials in 2006 and 2007

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– ARINC 702A-1 Trajectory Bus

– Aircraft current-state information 2Hz

– Aircraft 4D trajectory predictions (Intent)

– Each minute or when FP changes

– Full trajectory to runway

– Includes vertical wpts and turns

– Dedicated ARINC 429 Bus and/or via ACARS

Intent Bus in B737 U10.6 & U10.7 FMS

ARINC42

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Traje

ctory

Bus

AOC ATC

Current A/C State and Trajectory Predictions

ACARS

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• NUP2+ Examined

– dynamics and stability of trajectory data

– Frequency of downlink

– Bandwidth issues

• Now need to look at content and synchronization issues

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Motivation: The FMS Perspective

• The flight intent is the only directly controllable input, but it is the aircraft intent that really differentiates the output trajectory

Flight Intent

(Flight script)

Export Process

Predicted TrajectoryPredicted Trajectory

Trajectory

Computation

Process

Trajectory

Computation

Process

Aircraft Intent

Initial ConditionsInitial Conditions

Update Process

(Trajectory Script)

Aircraft Intent Generation

Process(Preparation Process)

Flight Plan

- Company Route

- SID/STAR

- Airways

- Crz FL

- Waypoints

- Constraints

AC Modelling

- ECON Speeds

- Thrust Limits

- FPA / Vert Speed

- Turn (Dir/Hdg)

- Flyover or Flyby

“Rules”

- Bank Angle

- Max Alt

- Perf Defaults

- Geo vs Idle

- Min/Max Vert Spd

Path Construction

- Lateral Geometry

- Equations of Motion

- Accuracy

- Limiting

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• Problem:

– The Aircraft Intent generation process is hidden

– Only Flight Intent can be “tweaked” to change the trajectory

– The output trajectory is useful for conflict detection, but…

– …conflict resolution via a new trajectory is not so simple

• Possible Solution:

– Knowledge of the Aircraft Intent

– Use of an “Inverse Trajectory Engine” to translate Aircraft Intent to a new Trajectory

– Use of an “Inverse Intent Engine” to translate Aircraft Intent to new Flight Intent for input to the FMS

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AirGround

TE’FlightIntent

AircraftTrajectory

TEFlightIntent

AircraftIntent

AircraftTrajectory

FP

N,

Con

str

ain

ts

IE

IE’-1


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Summary

• Need to break down the wall between the air & ground trajectories

Seville, Spain 24-25 June 2008 REACT: The FMS Perspective Keith Wichman – GE Aviation Systems.

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Transcript of Seville, Spain 24-25 June 2008 REACT: The FMS Perspective Keith Wichman – GE Aviation Systems.