Launch and recovery of shipboard helicopters is a safety critical task which requires an accurate assessment of ship motions. Typically, during the aircraft hover and landing phases, a Landing Signals Officer (LSO) monitors whip motions from a position close to the flight deck and communicates the state of deck quiescence to the pilot.

The goal of my Master's thesis was to improve the safety and efficiency of helicopter-ship operations by developing a Flight Deck Motion Display (FDMD) System which would have the primary functionality of:

  1. Operator real-time motion data display
  2. Indication of motion limits for each flight deck operation
  3. Allow an operator to quickly determine whether ship motions are within acceptable limits.

Secondary functionality included:

  1. Recording and playback of all ship motions.
  2. Computation of flight deck motion statistics to support mission planning.

This project was a collaboration between Carleton University and General Dynamics Canada. Construction of a prototype was performed based on design specification from Defence Research and Development Canada (DRDC), and Maritime Helicopter Project (MHP).

The above image shows the hardware architecture for the FDMD which was designed to provide both backup and redundant functionality. The primary use-case under which the system operates is that the data from the 'Primary Sensor' is transferred to the 'LSO FDMD Client' which displays information on the current ship state. The data is then transferred over a network connection to the 'FDMD Server' which records the data for future analysis. The 'Backup Sensor' connected to the FDMD Server has two purposes. The first is to confirm that the primary sensor is operating correctly. The second purpose is in the case of failure of the primary sensor, in which case the data from the backup sensor can be transferred to the LSO FDMD client.

The primary screen of the FDMD was the operations screen. It provided instantaneous values and a two minute history of roll, pitch, and vertical accelerations. It also included a quiescent period indicator. The purpose of this indicator was to allow an operator, in a quick glance, to determine whether ship deck motions were within limits, whicn motions are beyond their limits if applicable, and whether ship motions were tending to move closer or farther away from quiescence. It also did this without prediction future ship motions in any way, as any false positives would not be acceptable in a military environment.

 

On both the client and server FDMD computers it was possible to store and play back any of the data recordings. Data recordings were marked with their time stamps as shown in the image on the right and could be plotted and browsed as shown in the image on the left. It was also possible to replay a recording on the operations screen so that the exact values that were visible on the instantaneous indicators at a specific time could be verified. Event markers are also visible on this screen and functionality for using them to navigate the data recording was provided.

While the connection status of each of the sensors was provided on every screen, if more information was required the above startup/communications screen could be used. All of the hardware components were designed to automatically connect to each other.

 

In order to refine the user interface of the FDMD so that it would be of maximum utility and accepted by actual operators, an evaluation of the FDMD system was arranged. Six current military Sea King pilots with LSO experience from 12 Wing, Shearwater took part in the evaluation. The test subjects were exposed to a ship motion simulation of limited immersion and were instructed to use the FDMD To mark when they believed ship motions were within safe limits for a helicpter landing based on a predefined definition of quiescence. An image taken during the evaluation is shown below.

The design and layout of the user interface of the FDMD was refined based on their performance and feedback.

Two conference papers were published based on this work:

Canadian Society for Mechanical Engineering Forum (CSME) 2008 - Design and Implementation of a Flight Deck Motion Monitoring System

14th International Ship Control Systems Symposium (SCSS 2009) - Refinement of a Flight Deck Motion Monitoring System Through User Interface Evaluation Trials