Engineering topics

Oseguera, Rosa M.

Publications and source records attributed to Oseguera, Rosa M..

4 records

NASA NTRS1993

Microburst avoidance crew procedures for forward-look sensor equipped aircraft

Microburst, airplane, and sensor characteristics relevant to the development of crew procedures are summarized. A set of system requirements and performance standards which are consistent with microburst and airplane performance characteristics have been developed. It is suggested that an evasive turn to avoid a microburst is not required for airplane survival, if the microburst detected in time to effectively perform the turn. The use of straight-ahead recovery procedures will reduce the impact of windshear equipment on the ATC system and prevent secondary hazards.

Hinton, David A.↗

NASA NTRS1992

NASA wind shear flight test in situ results

The main objectives in developing the NASA in situ windshear detection algorithm were to provide a measurement standard for validation of forward-look sensors under development, and to demonstrate the algorithm's ability to operate with a suitably low nuisance alert rate. It was necessary to know exactly how the algorithm was implemented and what parameters and filtering were used, in order to be able to fully test its effectiveness and correlate in situ results with forward-look sensor data.

Oseguera, Rosa M.↗

NASA NTRS1992

Airborne in situ computation of the wind shear hazard index

An algorithm for airborne in situ computation of the wind shear hazard index (F-factor) was developed and evaluated in simulation and verified in flight. The algorithm was implemented on NASA's B-737-100 airplane, and tested under severe maneuvering, nonhazardous wind conditions, and normal takeoffs and landings. The airplane was flown through actual microburst conditions in Orlando, FL, where the algorithm produced wind shear measurements which were confirmed by an independent, ground-based radar measurement. Flight test results indicated that the in situ F-factor algorithm correctly measured the effect of the wind environment on the airplane's performance, and produced no nuisance alerts.

Oseguera, Rosa M.↗

NASA NTRS1988

A simple, analytic 3-dimensional downburst model based on boundary layer stagnation flow

A simple downburst model is developed for use in batch and real-time piloted simulation studies of guidance strategies for terminal area transport aircraft operations in wind shear conditions. The model represents an axisymmetric stagnation point flow, based on velocity profiles from the Terminal Area Simulation System (TASS) model developed by Proctor and satisfies the mass continuity equation in cylindrical coordinates. Altitude dependence, including boundary layer effects near the ground, closely matches real-world measurements, as do the increase, peak, and decay of outflow and downflow with increasing distance from the downburst center. Equations for horizontal and vertical winds were derived, and found to be infinitely differentiable, with no singular points existent in the flow field. In addition, a simple relationship exists among the ratio of maximum horizontal to vertical velocities, the downdraft radius, depth of outflow, and altitude of maximum outflow. In use, a microburst can be modeled by specifying four characteristic parameters, velocity components in the x, y and z directions, and the corresponding nine partial derivatives are obtained easily from the velocity equations.

Oseguera, Rosa M.↗