Tutorial 6: Case Study

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Tutorial 6Case Study

• Return from Salyut
• Rental Car
• SY DE 142 June 28, 2004
• Introduction to Human Systems Engineering
• Waterloo, Ontario, Canada

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Outline

• Case 1 Return from Salyut
• Question and Discussion on Case 1
• Case 2 Rental Car
• Questions and Discussion on Case 2

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Case Study 1Return from Salyut

• Time June 3, 1971
• Place Suyoz 11 spacecraft
• Synopsis Firing of the explosive bolts
  -connecting the command module with the orbital
  module - opened the pressure evaluation valve.
• Result All three cosmonauts were dead.

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Return from SalyutQuestions

• 1. Break down the valve closing situation in
  terms of Human Action Cycle.
• 2. Why were the cosmonauts unable to close the
  valve?
• 3. Why didn't the cosmonauts in the Salyut
  capsule have suits?

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Return from Salyut HAC

• Goal Restore oxygen to the capsule. (or Stop
  oxygen leak)
• Intention Close the valve.
• Sequence of Actions Turn the valve.
• Execution of Actions Physically turning the
  valve
• World Valve turns and each turn closes it
  further.
• Perceive state of the world Visual change in
  valve control, feel of valve turning
• Interpret Valve has turned and is closing
• Evaluate Has valve turned enough to stop oxygen
  leak? No. Goal not achieved.

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Return from Salyut Solutions

• 2. Why were the cosmonauts unable to close the
  valve?
• It required more turns than were physically
  possible to execute under conditions of lost
  oxygen. The designers of the valve had not taken
  into consideration its conditions of use.

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• 3. Why didn't the cosmonauts in the Salyut
  capsule have suits?
• The capsule was being used for three
  cosmonauts instead of the two it was designed
  for. This is an example of a system being used
  outside of its design parameters.

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Rental Car Overview

• Time Middle of World War II
• Place US Army Air Base, Small Pacific Island
• Synopsis Redesign of P-47 Thunderbolt fighter
  plane was about to cost a pilots life in the
  middle of an attack from the Japanese airfighters
  

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Rental CarQuestions

• Use Action Cycle analysis to describe the
  situation that occurred in this case.
• Identify the Gulf of Execution in this case. What
  does this suggest for design?

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Rental CarSolutions

• Goal survive the Japanese attack and protect the
  planes
• Intention flying a P-47 Thunderbolt
• Sequence of actions run to the ready-room, find
  a free plane, identify controls, use controls to
  fly the plane
• Actions physical actions of running, finding,
  identifying, eluding (could not find controls to
  fly the plane)

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Rental Carcont.. Solutions

• World the plane was raced up, down, across, and
  around the airstrip on the island, bombs dropping
• Perception state of the world physically seeing
  and sensing the plane moving relative to the
  bombs dropping
• Interpreting the perception Plane did not fly,
  but the bombs did not hit the plane
• Evaluation of interpretation the goal was
  achieved even though the plane did not take off.

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Rental Car Gulf of Execution

• Occurs between intention and action
• Example intending to fly the plane (intention)
  and not finding the controls that will allow you
  to do that (action)
• Suggests poor control/display design, lack of
  consistency with prior designs, not intuitive, no
  consideration that use will be under
  circumstances where there may not be time to
  train the pilots on the new design.