Transcript Tutorial 6: Case Study “Return from Salyut” “Rental Car”

Tutorial 6:
Case Study
“Return from Salyut”
“Rental Car”
SY DE 142 – June 28, 2004
Introduction to Human Systems Engineering
Waterloo, Ontario, Canada
Outline
 Case 1: “Return from Salyut”
 Question and Discussion on Case 1
 Case 2: “Rental Car”
 Questions and Discussion on Case 2
Case Study #1
Return 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.
Return from Salyut
Questions
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?
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.
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.
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.
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 pilot’s life in the middle
of an attack from the Japanese airfighters
Rental Car
Questions
 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?
Rental Car
Solutions
 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)
Rental Car
cont….. 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.
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.