Learjet 28

The first flight of the Learjet 28 took place on August 24, 1977. The Learjet 28/29 was based on the Learjet 25, and received a completely new wing fitted with winglets which resulted in improved performance and fuel economy. The Learjet 28/29 was the first production jet aircraft to utilize winglets (entering service in 1977). Both models were commercially unsuccessful, showing reduced range compared to the Learjet 31, as the addition of winglets required the deletion of the earlier model's wingtip tanks, and they sold mainly to customers with a requirement for good altitude performance. Both types were subsequently replaced by the Learjet 31. The first production aircraft was used by Neil Armstrong to set five aerospace records. ==Noise compliance==

In 2013, the FAA modified 14 CFR part 91 rules to prohibit the operation of jets weighing 75,000 pounds or less that are not stage 3 noise compliant after December 31, 2015. The Learjet 28 is listed explicitly in Federal Register 78 FR 39576. Any Learjet 28s that have not been modified by installing Stage 3 noise compliant engines or have not had "hushkits" installed for non-compliant engines will not be permitted to fly in the contiguous 48 states after December 31, 2015. 14 CFR §91.883 Special flight authorizations for jet airplanes weighing 75,000 pounds or less – lists special flight authorizations that may be granted for operation after December 31, 2015. ==Specifications (Learjet 28)==