Retaining airspeed hold engagement in low speed maneuver

US4371937A · kind A · utility

Assignee

• UNITED TECHNOLOGIES CORPORATION · US

Inventors

• Don L. Adams · Bartlesville, US
• William C. Fischer · Monroe, US
• Stuart C. Wright · Woodbridge, US
• David J. Verzella · Guilford, US

Key dates

• Filing date: Mar 30, 1981
• Grant date: Feb 1, 1983
• Expiry date: Mar 30, 2001

Classification

• Technology area (CPC G): Physics
• CPC primary: G05D1/0858
• WIPO field: Control
• WIPO sector: Instruments

Abstract

In an aircraft automatic flight control system (FIG. 1) having an airspeed controller (84), the engagement of the airspeed control function (244, FIG. 4 ) is initiated (123, FIG. 2 ) only in response to airspeed being greater than a 45 knot threshold (88). But once the speed threshold is attained, should the pilot override the airspeed control by applying force (35, 109) to the pitch attitude controller, airspeed engagement is retained (122) until a small airspeed error (126) indicates that the system has substantially regained the reference airspeed.