page_title: Learjet 25
section_title: Fuel
hierarchical_section_title: Learjet 25 / Design / Fuel
caption_attribution_description: English: C-GBFP Adlair Aviation Learjet 25B (LJ25) at Cambridge Bay Airport, Nunavut, Canada
context_page_description: The Learjet 25 is an American ten-seat, twin-engine, high-speed business jet aircraft manufactured by Learjet. It is a stretched version of the Learjet 24.
context_section_description: The Learjet 25 generally has five fuel tanks. Two wing tanks, a fuselage tank and two wing tip tanks. Each wing tank extends from the centre bulkhead outboard to the wing tip and provides separate fuel for each engine. A tank cross-flow valve is installed to prevent fuel transfer between wing tanks. Flapper-type check valves, located in the various wing ribs, allow free fuel flow inboard but restrict outboard flow. A jet pump and electrical boost pump are mounted in each wing tank near the centre bulkhead to supply fuel under pressure to the respective engine fuel system.
  The tip tanks provide additional fuel capacity to enable longer times aloft. A jet pump installed in each tip tank transfers fuel into the wing tanks. Fuel can also flow via the flapper check valves into the wing tanks, but the lower half of the fuel in the tip tanks must be transferred with the jet pump.
  Most Learjet 25 aircraft were fitted with a fuselage tank. The fuselage tank can be filled by the wing boost pumps through the transfer line and the fuel transfer valve. When the tank is full, a float switch de-energizes the wing boost pumps and closes the valve. During fuel transfer, the fuselage tank transfer pump pumps fuel into the both wing tanks.
caption: A Learjet 25D being refuelled
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