Engineering topics

Trujillo, Anna C.

Publications and source records attributed to Trujillo, Anna C..

42 records · Page 3

NASA NTRS1997

Pilot Performance With Predictive System Status Information

Research has shown a strong pilot preference for predictive information of aircraft system status in the flight deck. However, the benefits of predictive information have not been quantitatively demonstrated. The study described here attempted to identify and quantify these benefits if they existed. In this simulator experiment, three types of predictive information (none, whether a parameter was changing abnormally, and the time for a parameter to reach an alert range) and four initial times to an alert (1 minute, 5 minutes, 15 minutes, and ETA+ 45 minutes) were found to affect when subjects accomplished certain actions, such as accessing pertinent checklists, declaring emergencies, diverting, and calling the flight attendant and dispatch.

Trujillo, Anna C.↗

NASA NTRS1996

Uncertainties that flight crews and dispatchers must consider when calculating the fuel needed for a flight

In 1993, fuel accounted for approximately 15 percent of an airline's expenses. Fuel consumption increases as fuel reserves increase because of the added weight to the aircraft. Calculating fuel reserves is a function of Federal Aviation Regulations, airline company policy, and factors that impact or are impacted by fuel usage enroute. This research studied how pilots and dispatchers determined the fuel needed for a flight and identified areas where improvements in methods may yield measurable fuel savings by (1) listing the uncertainties that contribute to adding contingency fuel, (2) obtaining the pilots' and dispatchers' perspective on how often each uncertainty occurred, and (3) obtaining pilots' and dispatchers' perspective on the fuel used for each occurrence. This study found that for the majority of the time, pilots felt that dispatchers included enough fuel. As for the uncertainties that flight crews and dispatchers account for, air traffic control accounts for 28% and weather uncertainties account for 58 percent. If improvements can be made in these two areas, a great potential exists to decrease the reserve required, and therefore, fuel usage without jeopardizing safety.

Trujillo, Anna C.↗

NASA NTRS1996

Airline Transport Pilot Preferences for Predictive Information

This experiment assessed certain issues about the usefulness of predictive information: (1) the relative time criticality of failures, (2) the subjective utility of predictive information for different parameters or sensors, and (3) the preferred form and prediction time for displaying predictive information. To address these issues, three separate tasks were administered to 22 airline pilots. As shown by the data, these pilots preferred predictive information on parameters they considered vital to the safety of the flight. These parameters were related to the checklists performed first for alert messages. These pilots also preferred to know whether a parameter was changing abnormally and the time to a certain value being reached. Furthermore, they considered this information most useful during the cruise, the climb, and the descent phases of flight. Lastly, these pilots preferred the information to predict as far ahead as possible.

Trujillo, Anna C.↗

NASA NTRS1996

Flight Crew Task Management in Non-Normal Situations

Task management (TM) is always performed on the flight deck, although not always explicitly, consistently, or rigorously. Nowhere is TM as important as it is in dealing with non-normal situations. The objective of this study was to analyze pilot TM behavior for non-normal situations. Specifically, the study observed pilots performance in a full workload environment in order to discern their TM strategies. This study identified four different TM prioritization and allocation strategies: Aviate-Navigate-Communicate-Manage Systems; Perceived Severity; Procedure Based; and Event/Interrupt Driven. Subjects used these strategies to manage their personal workload and to schedule monitoring and assessment of the situation. The Perceived Severity strategy for personal workload management combined with the Aviate-Navigate-Communicate-Manage Systems strategy for monitoring and assessing appeared to be the most effective (fewest errors and fastest response times) in responding to the novel system failure used in this study.

Schutte, Paul C.↗

NASA NTRS1994

Effects of historical and predictive information on ability of transport pilot to predict an alert

In the aviation community, the early detection of the development of a possible subsystem problem during a flight is potentially useful for increasing the safety of the flight. Commercial airlines are currently using twin-engine aircraft for extended transport operations over water, and the early detection of a possible problem might increase the flight crew's options for safely landing the aircraft. One method for decreasing the severity of a developing problem is to predict the behavior of the problem so that appropriate corrective actions can be taken. To investigate the pilots' ability to predict long-term events, a computer workstation experiment was conducted in which 18 airline pilots predicted the alert time (the time to an alert) using 3 different dial displays and 3 different parameter behavior complexity levels. The three dial displays were as follows: standard (resembling current aircraft round dial presentations); history (indicating the current value plus the value of the parameter 5 sec in the past); and predictive (indicating the current value plus the value of the parameter 5 sec into the future). The time profiles describing the behavior of the parameter consisted of constant rate-of-change profiles, decelerating profiles, and accelerating-then-decelerating profiles. Although the pilots indicated that they preferred the near term predictive dial, the objective data did not support its use. The objective data did show that the time profiles had the most significant effect on performance in estimating the time to an alert.

Trujillo, Anna C.↗

NASA NTRS1993

The effects of history and predictive information on the ability of the transport aircraft pilot to predict an alert

The early detection of a developing aircraft-subsystem fault has the potential to lessen its ultimate severity. The lack of capability for such early detection is becoming critical in the aviation community. In the commercial sector, for example, twin-engine aircraft are being used for extended transport operations over water. One method to decrease the severity of a developing problem is to predict its behavior and to take appropriate corrective action. In order to investigate pilots' ability to predict events, an experiment was conducted where eighteen airline pilots predicted the time to an alert using three different displays of dials and three different time profile complexities. The three displays of dials were as follows: standard, resembling current aircraft dial presentations; history, indicating the value five seconds in the past; and predictive, indicating the value five seconds into the future. The time profiles describing the behavior of the parameter consisted of constant velocity profiles, decelerating profiles, and accelerating then decelerating profiles. Although pilots indicated that they preferred the predictive dial, the objective data did not support its use. The objective data did show that the time profiles had the most significant effect on performance in estimating the time to an alert.

Trujillo, Anna C.↗