The Learjet 31 is an American built twin-engined, high speed business jet.

This version featured increased cruising speed, a digital avionics system with EFIS supplied by AlliedSignal (today Honeywell) and an instrument panel layout change.

The addition of Delta-Fins at the bottom of the empennage simplified the certification process of the aircraft by eliminating the need for a “stick pusher” stall avoidance device.

The model 31A boasted numerous modifications, however the most notable changes were on the flight deck.

Key modifications and updates to the model 31A cockpit and avionics include a Bendix King (now Honeywell after the merger with Allied Signal) Electronic Flight Information System 50, with Universal 1M, 1B and 1C flight management system; a dual KFC 3100 two-axis autopilot and flight director with yaw damper; and dual Bendix King (Radios sold to Chelton Avionics when Allied Signal combined with Honeywell) VCS-40A com units, VN-411B Series III navigation receivers.

Overall the numerous enhancements have led to more than 200 Learjet 31s in service with private operators and governments worldwide.