Revolutionary Design Features
The Learjet 55 marked a significant evolution in business aviation when Gates Learjet announced the ambitious 50-series program at the 1977 Paris Air Show. The engineering team, building on Bill Lear's legacy, incorporated groundbreaking NASA-developed winglets—nicknamed "Longhorn"—that dramatically improved fuel efficiency and range performance. Construction of the prototype began in April 1978, leading to the successful first flight on April 19, 1979.
The aircraft represented a substantial leap forward from earlier Learjet models, offering the largest cabin in the company's lineup at the time. The passenger compartment measured 13.7 feet in length, 5.9 feet in width, and 5.7 feet in height, providing 407 cubic feet of space for up to 10 passengers plus a two-person crew. This represented a major advancement over the smaller Learjet 25 series that had established the company's reputation in the 1960s.
Production and Variants
Production commenced on March 18, 1981, with the first aircraft delivered on that same date from the Wichita, Kansas manufacturing facility. Over the production run, which lasted until approximately 1987, Gates Learjet built exactly 147 aircraft across all Learjet 55 variants. The base model accounted for 126 of these aircraft, with serial numbers ranging from 001 to 126.
The most significant variant was the Learjet 55B, introduced in 1986 with only eight examples built. This model featured an advanced glass cockpit display system and improved performance characteristics. The 55C variant, launched in 1987, incorporated distinctive delta fins for enhanced stability, though this modification resulted in reduced maximum speeds. Extended-range versions included the 55C/ER and the 55C/LR, the latter equipped with an additional 259-pound fuel tank for long-range missions.
Powerplant and Performance
The Learjet 55 was powered by two Garrett TFE731 turbofan engines mounted on the rear fuselage, marking a significant departure from the turbojet engines used in earlier Learjet models. These Garrett engines, manufactured by AiResearch (later Honeywell), provided increased power output while substantially reducing noise levels compared to their turbojet predecessors.
Performance specifications were impressive for the era, with a maximum speed of 541 mph and a cruise speed of 462 mph. The aircraft could reach a service ceiling of 49,000 feet, providing access to high-altitude airways and weather avoidance capabilities crucial for business operations. The extended-range variants offered significantly improved range performance, addressing the growing demand for transcontinental business travel.
Manufacturing Heritage
The aircraft emerged from the storied Learjet company founded by aviation pioneer Bill Lear. Although initial development began in Switzerland, operations shifted to Wichita, Kansas by February 1963, where the first Learjet 23 prototype flew in October 1963. By the late 1960s, Gates Rubber Company of Denver, Colorado had acquired a controlling stake, rebranding the operation as Gates Learjet.
By the time the Learjet 55 entered production, the company had already delivered more than 500 jets, establishing Learjet as synonymous with business aviation. The success of earlier models like the Learjet 23 and 25 series provided the financial foundation and market credibility necessary to develop the more ambitious 50-series program.
Market Impact and Service
The Learjet 55 served exclusively in the civilian market, operated primarily by corporations, charter companies, and high-net-worth individuals. Unlike smaller business jets designed for short-range missions, the 55 could accommodate larger passenger loads for medium-range flights, filling a crucial market gap between light jets and heavy cabin aircraft.
The aircraft's combination of speed, range, and passenger capacity made it particularly attractive to Fortune 500 companies requiring efficient transportation for executive teams. The spacious cabin could be configured for various missions, from high-density passenger transport to cargo-carrying operations.
Legacy and Transition
Production ended around 1987 as Bombardier Aerospace, which had acquired the Learjet line, focused development resources on the next-generation Learjet 60, which entered service in 1992. The 147 Learjet 55 aircraft built during the production run represented the culmination of the company's expertise in mid-size business jet design.
The Learjet 55 solidified the company's dominance in the business aviation sector, demonstrating that the Learjet brand could successfully expand beyond the light jet category that had made it famous. The NASA winglet technology pioneered on the 55 would become standard throughout the industry, influencing business jet design for decades to come. While current airworthiness numbers remain undocumented, the aircraft's robust construction and proven powerplant suggest many examples continue to serve in corporate and charter operations worldwide.