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Evidence from Resource 10 pieces of evidence from this resource.

Damos, D.L., John, R.S., & Lyall, E.A. (1999). Changes in pilot activities with increasing automation. In R.S. Jensen, B. Cox, J.D. Callister, & R. Lavis (Eds.), Proceedings of the 10th International Symposium on Aviation Psychology, 810-815. Columbus, OH: The Ohio State University.

  1.  
  2. Evidence Type: Excerpt from Observational Study
    Evidence: "It was apparent from the performances of many of the pilots and from the posttest interviews that the GA pilot population would benefit greatly from training, particularly if it contained both procedures for responding to identifiable malfunctions and a thorough explanation of the workings of the AP system and its interaction with and use of the elevator trim (conceptual model development). Such an effort should lead to a reduction in the frequency of misdiagnoses. Training could also help pilots differentiate between malfunctions that may be safe to fly through (i.e., failure of AP to hold heading) and those that should receive an immediate disconnect." (page 172)
    Issue: training may be inadequate (Issue #133) See Issue details
    Strength: +1
    Aircraft: unspecified
    Equipment: autoflight: autopilot

  3.  
  4. Evidence Type: Excerpt from Observational Study
    Evidence: "Runaway pitch trim. This failure was different from the others in that only by pulling the pitch trim circuit breaker would the problem be corrected. The interim solution was the AP disconnect/trim interrupt switch. Only three pilots chose the optimal response, depressing and holding the disconnect, then pulling the circuit breaker. Four others depressed and held the disconnect at various times during the recovery. The vast majority of initial responses were yoke AP disconnect (15), followed in frequency by panel-mounted AP-engage switch (5), mode manipulation (2). manual override (2), and pitch trim circuit breaker (1). Data from 4 participants were removed from consideration due to circumstances that contaminated these data. Of the 25 remaining, 21 of the pilots were classified as immediate responders, 2 were classified as manual overriders, and 2 as mode changers. It should also be noted that two pilots never heard the warning tone, possibly due to high-frequency hearing loss, responding only to aircraft performance changes." (page 163)
    Issue: failure assessment may be difficult (Issue #25) See Issue details
    Strength: +1
    Aircraft: unspecified
    Equipment: autoflight: autopilot

  5.  
  6. Evidence Type: Excerpt from Observational Study
    Evidence: "Soft pitch (pitch sensor). The soft pitch failure was rated as most difficult to diagnose (by 12 of 26 pilots [46%]) and was rated third easiest to correct, missing a tie fot second by one tally. Performances were again categorized as either immediate disconnect (12 out [of 29 or 41%]) or manual override (17 [out of 29 or 58%]), ... Three pilots never diagnosed the failures [3 out of 29 or 10%,] manually flying the airplane without disconnecting the AP; their scores and one other outlier were removed, leaving 13. Immediate disconnects averaged 17.7 sec (range = 6.5-3 1 .5), and the 13 remaining manual overrides averaged 46.19 (range = 15.2-76.2)." (page 162)
    Issue: failure assessment may be difficult (Issue #25) See Issue details
    Strength: +1
    Aircraft: unspecified
    Equipment: autoflight: autopilot

  7.  
  8. Evidence Type: Excerpt from Observational Study
    Evidence: "Soft roll (roll sensor). The soft roll failure was rated as third in difficulty to diagnose but was rated easiest to correct (by 13 of 26 pilots [50%]). Following removal of one outlier (194 sec) pilot performance was again categorized as immediate disconnect (16 out of 28 or 57%) or manual override (12 out of 28 or 42%). Those categorized as immediate disconnect responses averaged 1 1 .72 sec (range = 4.52-I 6.69), whereas those categorized as manual overrides averaged 37.45 sec after one outlier was removed (range = 13.16-85.14; outlier shown in Figure 2)." (page 161)
    Issue: failure assessment may be difficult (Issue #25) See Issue details
    Strength: +1
    Aircraft: unspecified
    Equipment: autoflight: autopilot

  9.  
  10. Evidence Type: Excerpt from Observational Study
    Evidence: "The commanded-roll failure emulated an AP-commanded roll that exceeded the target bank angle. Analyses for both roll malfunctions and the soft-pitch malfunction are based on time from initial failure to disconnect of the AP by any means (yoke-mounted disconnect, panel disengage, circuit breaker). Times ranged from 1.8 sec to 107.1 sec (means, medians, and ranges are summarized in Table 1). However, 69% of the pilots disconnected within 13 sec of the initial failure and half within 8 sec. These “immediate” disconnects by 18 of the 29 pilots [62%] were defined by sequences in which no other significant actions occurred between failure onset and AP disconnect…Using an RT of 8.7 sec or less as a cutoff value, 93.7% [18 out of 29 pilots or 62 % ] of the sample of immediate responders were included. Eleven pilots [11 out of 29 or 37%] initially chose to manually override the AP prior to their disconnecting the AP, whether by using the control-wheel steering option or by ovirpowering the aileron servo. One extreme outlier was removed, however, reducing the number to 10 [10 out of 29 or 34%] for the examined distribution." (page 160)
    Issue: failure assessment may be difficult (Issue #25) See Issue details
    Strength: +1
    Aircraft: unspecified
    Equipment: autoflight: autopilot

  11.  
  12. Evidence Type: Excerpt from Observational Study
    Evidence: "Runaway pitch trim. This failure was different from the others in that only by pulling the pitch trim circuit breaker would the problem be corrected. The interim solution was the AP disconnect/trim interrupt switch. Only three pilots chose the optimal response, depressing and holding the disconnect, then pulling the circuit breaker. Four others depressed and held the disconnect at various times during the recovery. The vast majority of initial responses were yoke AP disconnect (15), followed in frequency by panel-mounted AP-engage switch (5), mode manipulation (2). manual override (2), and pitch trim circuit breaker (1). Data from 4 participants were removed from consideration due to circumstances that contaminated these data. Of the 25 remaining, 21 of the pilots were classified as immediate responders, 2 were classified as manual overriders, and 2 as mode changers. It should also be noted that two pilots never heard the warning tone, possibly due to high-frequency hearing loss, responding only to aircraft performance changes." (page 163)
    Issue: failure assessment may be difficult (Issue #25) See Issue details
    Strength: -1
    Aircraft: unspecified
    Equipment: autoflight: autopilot

  13.  
  14. Evidence Type: Excerpt from Observational Study
    Evidence: "Soft pitch (pitch sensor). The soft pitch failure was rated as most difficult to diagnose (by 12 of 26 pilots [46%]) and was rated third easiest to correct, missing a tie fot second by one tally. Performances were again categorized as either immediate disconnect (12 out [of 29 or 41%]) or manual override (17 [out of 29 or 58%]), ... Three pilots never diagnosed the failures [3 out of 29 or 10%,] manually flying the airplane without disconnecting the AP; their scores and one other outlier were removed, leaving 13. Immediate disconnects averaged 17.7 sec (range = 6.5-3 1 .5), and the 13 remaining manual overrides averaged 46.19 (range = 15.2-76.2)." (page 163)
    Issue: failure assessment may be difficult (Issue #25) See Issue details
    Strength: -1
    Aircraft: unspecified
    Equipment: autoflight: autopilot

  15.  
  16. Evidence Type: Excerpt from Observational Study
    Evidence: "Soft roll (roll sensor). The soft roll failure was rated as third in difficulty to diagnose but was rated easiest to correct (by 13 of 26 pilots [50%]). Following removal of one outlier (194 sec) pilot performance was again categorized as immediate disconnect (16 out of 28 or 57%) or manual override (12 out of 28 or 42%). Those categorized as immediate disconnect responses averaged 1 1 .72 sec (range = 4.52-I 6.69), whereas those categorized as manual overrides averaged 37.45 sec after one outlier was removed (range = 13.16-85.14; outlier shown in Figure 2)." (page 161)
    Issue: failure assessment may be difficult (Issue #25) See Issue details
    Strength: -1
    Aircraft: unspecified
    Equipment: autoflight: autopilot

  17.  
  18. Evidence Type: Excerpt from Observational Study
    Evidence: "The commanded-roll failure emulated an AP-commanded roll that exceeded the target bank angle. Analyses for both roll malfunctions and the soft-pitch malfunction are based on time from initial failure to disconnect of the AP by any means (yoke-mounted disconnect, panel disengage, circuit breaker). Times ranged from 1.8 sec to 107.1 sec (means, medians, and ranges are summarized in Table 1). However, 69% of the pilots disconnected within 13 sec of the initial failure and half within 8 sec. These “immediate” disconnects by 18 of the 29 pilots [62%] were defined by sequences in which no other significant actions occurred between failure onset and AP disconnect." (page 160)
    Issue: failure assessment may be difficult (Issue #25) See Issue details
    Strength: -1
    Aircraft: unspecified
    Equipment: autoflight: autopilot

  19.  
  20. Evidence Type: Excerpt from Observational Study
    Evidence: "...initial examination of the questionnaire and interview data indicated that all pilots understood they could manually overpower the AP servos [100%], and 22 were aware of the potential interaction between a runaway pitch trim motor and AP pitch-attitude (elevator servo) inputs [22 out of 29 or 75%]. Four pilots had not considered the potential interaction previously but grasped the concept immediately during the interview [4 out of 29 or 13%]." (page 165)
    Issue: understanding of automation may be inadequate (Issue #105) See Issue details
    Strength: -5
    Aircraft: unspecified
    Equipment: autoflight: autopilot
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