The Learjet 31 series of airplanes is essentially a Learjet 35 with a new wing that is 4 feet longer with almost 4-foot-high winglets, instead of wingtip fuel tanks and large “delta fins” attached to the tail cone. These changes made the plane a much more docile one to fly, greatly improved field lengths and added 6 knots to its normal cruise speed. With seats full, range decreased to 1,225 nautical miles plus NBAA IFR fuel reserves. In 1988, the Learjet 31 won its Supplemental Type Certificate (STC). The 31A got its STC in 191.
The 31A has a 1,450-pound higher ramp weight for more payload with full fuel. The Learjet 31A/ER has an optional extended range kit installed, which adds 275 nautical miles to the range.
