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Evidence from Resource 4 pieces of evidence from this resource.

Degani, A., & Heymann, M. (2000). Pilot-Autopilot interaction: A formal perspective. Eighth International Conference on Human-Computer Interaction in Aeronautics, Toulouse, France.

  1.  
  2. Evidence Type: Excerpt from Incident Study
    Evidence: Actually, not. The display is also inadequate for the task – and here is why: To resolve what the aircraft will do we need to know the altitude at which the autopilot transitions to capture (e.g., 7,000 feet). But in practice, it is almost impossible to obtain this value with the current display. First, the pilot has no preview of this value and the interface does not display it. Secondly, the transition to the "Capture" mode happens automatically. In order to obtain the altitude at which the autopilot transitions to "Capture", the pilot must "hunt" for the automatic transition, and at that very moment look down to the altitude tape on the interface and catch the aircraft altitude as it rolls by. Thirdly, this altitude value is not retained by the display; once the transition takes place, the value is gone and there is no way to retrieve it. For all practical purpose, it is impossible to reliably obtain this value. The current display is indeed inadequate for the task. (page 7)
    Issue: displays (visual and aural) may be poorly designed (Issue #92) See Issue details
    Strength: +1
    Aircraft: unspecified
    Equipment: automation: displays

  3.  
  4. Evidence Type: Excerpt from Incident Study
    Evidence: Actually, not. The display is also inadequate for the task – and here is why: To resolve what the aircraft will do we need to know the altitude at which the autopilot transitions to capture (e.g., 7,000 feet). But in practice, it is almost impossible to obtain this value with the current display. First, the pilot has no preview of this value and the interface does not display it. Secondly, the transition to the "Capture" mode happens automatically. In order to obtain the altitude at which the autopilot transitions to "Capture", the pilot must "hunt" for the automatic transition, and at that very moment look down to the altitude tape on the interface and catch the aircraft altitude as it rolls by. Thirdly, this altitude value is not retained by the display; once the transition takes place, the value is gone and there is no way to retrieve it. For all practical purpose, it is impossible to reliably obtain this value. The current display is indeed inadequate for the task. (page 7)
    Issue: information integration may be required (Issue #9) See Issue details
    Strength: +1
    Aircraft: unspecified
    Equipment: automation: displays

  5.  
  6. Evidence Type: Excerpt from Incident Study
    Evidence: The autopilot behavior is perplexing; it responds differently to the same pilot action. Setting the altitude to a value behind the current aircraft altitude results in two different responses: In the first case the aircraft will continue at the current climb-rate and "kill the capture". In the second case the aircraft will capture the newly set altitude. So how can the pilot anticipate what the aircraft will do in each case? It turns out that there is a hidden condition here, that revolves around the altitude at which the aircraft transitions to the "Capture" mode (7,000 feet in our example): If the newly set altitude is below (e.g., 6,000 feet) the "start capture altitude", then the aircraft will kill the capture. But if the newly set altitude is above (e.g., 8,000 feet) the "start capture altitude", the aircraft will capture the specified altitude. Do pilots know about this behavior and the condition? No. It’s not in the manual nor is it mentioned in ground school or Initial Operating Experience (IOE) -- it is practically unknown! Now we are not talking about some minor deficiency, but a critical maneuver that sometimes takes place very close to the ground. The pilots’ user-model is inadequate for the task of capturing an altitude after resetting the altitude to a value behind the aircraft. If we go back to our earlier discussion, we have a condition in which the user-model is inadequate for the task. This deficiency corresponds to region 3 in Figure 1. (page 6/7)
    Issue: behavior of automation may not be apparent (Issue #83) See Issue details
    Strength: +1
    Aircraft: unspecified
    Equipment: autoflight: autopilot

  7.  
  8. Evidence Type: Excerpt from Incident Study
    Evidence: The autopilot behavior is perplexing; it responds differently to the same pilot action. Setting the altitude to a value behind the current aircraft altitude results in two different responses: In the first case the aircraft will continue at the current climb-rate and "kill the capture". In the second case the aircraft will capture the newly set altitude. So how can the pilot anticipate what the aircraft will do in each case? It turns out that there is a hidden condition here, that revolves around the altitude at which the aircraft transitions to the "Capture" mode (7,000 feet in our example): If the newly set altitude is below (e.g., 6,000 feet) the "start capture altitude", then the aircraft will kill the capture. But if the newly set altitude is above (e.g., 8,000 feet) the "start capture altitude", the aircraft will capture the specified altitude. Do pilots know about this behavior and the condition? No. It’s not in the manual nor is it mentioned in ground school or Initial Operating Experience (IOE) -- it is practically unknown! Now we are not talking about some minor deficiency, but a critical maneuver that sometimes takes place very close to the ground. The pilots’ user-model is inadequate for the task of capturing an altitude after resetting the altitude to a value behind the aircraft. If we go back to our earlier discussion, we have a condition in which the user-model is inadequate for the task. This deficiency corresponds to region 3 in Figure 1. (page 6/7)
    Issue: automation behavior may be unexpected and unexplained (Issue #108) See Issue details
    Strength: +1
    Aircraft: unspecified
    Equipment: autoflight: autopilot
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