Learjet 31

Learjet 31
	Learjet 31A
Role	Business jet
Manufacturer	Learjet
First flight	May 11, 1987
Introduction	October 1990
Status	Active
Primary users	Private; Military; NASA
Produced	1987-2003

The Learjet 31 is an American built twin-engined, high speed business jet. Manufactured by Learjet, a subsidiary of Bombardier Aerospace, as the successor to the Learjet 29, it has a capacity of eight passengers and two crew.

History

Close view of the winglet at the wingtip of the "Longhorn" wing

The first flight of the LJ31 took place on 11 May 1987. The Learjet 31A variant was introduced in October 1990. This version featured increased cruising speed, a digital avionics system with EFIS supplied by AlliedSignal (today Honeywell) and an instrument panel layout change. The nose gear wheel is steered by a Steer by Wire system. The windshield could be heated electrically.

The Learjet 31ER with increased range was produced.

The first 31A serial number 31A-035 entered service 15 August 1991. The last 31A delivered, serial number 31A-242 was delivered 1 October 2003.

Variants

Learjet 31

The Learjet Model 31 is, arguably, the ultimate realization of the original Learjet series dating back to the Model 23 of 1963. Essentially combining the fuselage and engines of the model 35/36 with the “Longhorn” wing of the 28, 29 and 55 models, results in performance which is equaled by few aircraft. Normal cruise altitudes range from 41,000 to 47,000 feet (12,500-14,900 m) and the aircraft’s maximum cruise altitude of 51,000 feet (15,500 m) is a distinction shared by only a handful of civil aircraft. Improvements over earlier models, such as “Delta-Fins” and a “Ski-Locker” increased the utility and improved the performance of the model 31. 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. Increased directional stability, as a result of the Delta-Fins, was also a welcome benefit.

Learjet 31A

A Learjet 31A jet belonging to the Balochistan government

The Learjet 31A was announced in 1990 as a replacement after building 38 Learjet 31’s. The model 31A boasted numerous modifications, however the most notable changes would take place 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.

In the year 2000 the Learjet 31A was again revised. Takeoff and landing weights were increased.^[1] The original design N₂ digital electronic engine control (DEEC) was replaced with an N₁ DEEC,^[1]^[2] and the thrust reversers became standard equipment. The original R12 freon air conditioning system was replaced with an R134A system divided into two zones - cockpit and cabin.^[2]