How many fuel pumps does an aircraft have?
There isn’t a single universal number. Most aircraft rely on several pumps across the fuel system—engine-driven pumps, electric boost pumps, and sometimes center-tank transfer or jettison pumps. The exact count depends on the size and configuration of the aircraft.
What counts as a fuel pump on an aircraft?
Aircraft fuel systems use several pump types to ensure reliable delivery of fuel under all operating conditions. The main categories are:
- Engine-driven fuel pumps (EDPs): one pump dedicated to each engine, located in or near the engine, supplying fuel to the engine’s fuel control unit.
- Electric boost pumps (EBPs): electrical pumps located in the wings or inside fuel tanks that provide pressure to feed the engines and maintain supply if the engine-driven pump is not yet delivering sufficient pressure.
- Center-tank transfer pumps: pumps that move fuel from a center or intermediate tank to the wing tanks or engines, helping balance fuel load and ensure feed pressure.
- Fuel jettison pump: a dedicated pump used on aircraft that can dump fuel in flight for weight reduction, typically found only on larger or long-range aircraft.
It’s important to note that not all aircraft use every category. The exact combination and presence of these pumps vary by model and mission profile.
Typical pump counts by aircraft size
Below is a broad guide to how pump counts tend to scale with aircraft size and configuration. Real numbers can vary by exact model and options.
Small general aviation and light twin-engine aircraft
In smaller aircraft, you’ll typically encounter a compact set of pumps, with redundancy built into the engine-driven and primary electric pumps. A rough range might include:
- Engine-driven fuel pumps: usually 2 (one per engine).
- Electric boost pumps: commonly 1–2 total per wing or tank (some models have two per wing for redundancy).
- Center-tank transfer pumps: often none, or 1 if a center tank exists.
- Jettison pump: usually none, as fuel dumping is uncommon on small aircraft.
These configurations aim for reliable fuel delivery without adding excessive complexity.
Commercial single-aisle twinjets (e.g., Airbus A320 family, Boeing 737 family)
These aircraft employ more redundancy and a more distributed fuel-pump network. A typical setup includes:
- Engine-driven fuel pumps: 2 (one per engine).
- Electric boost pumps: about 4 total (two per wing/tank).
- Center-tank transfer pumps: 1–2 (depending on whether a center tank is used and its size).
- Fuel jettison pump: 0–1 (present on models designed for fuel dumping).
Overall, these aircraft commonly rely on a mix that ensures continuous engine feed and fuel balance across the wings.
Wide-body and multi-engine long-range jets
Large aircraft with multiple engines and sometimes sizeable center tanks tend to have larger pump counts to support redundancy and cross-utility across tanks. A typical configuration may include:
- Engine-driven fuel pumps: equal to the number of engines (e.g., 4 for a four-engine jet).
- Electric boost pumps: usually 4 or more total (often two per wing, plus additional pumps for center-tank feeds if present).
- Center-tank transfer pumps: 2–4 (to move fuel between tanks and toward the wings as needed).
- Fuel jettison pump: 1 (on aircraft equipped with fuel-dumping capability).
These systems are designed to maintain engine feed reliability, fuel balance, and, where applicable, outbound fuel dumping for long-range operations.
Why the number varies
The total count of pumps depends on several design factors: the number of engines, whether the aircraft has a center fuel tank, the required redundancy level, and whether fuel dumping is a necessity for the mission. Modern commercial jets prioritize multiple independent pathways to the engines to ensure safe operation even if one pump or power source fails.
Summary
There is no universal answer to how many fuel pumps an aircraft has. The system typically includes engine-driven pumps (one per engine), electric boost pumps (several per wing or tank), and sometimes center-tank transfer pumps and a jettison pump. The exact number scales with aircraft size, architecture, and mission requirements, with small planes having a few pumps and large airliners running into several dozen individual pump units across the fuel system. The goal across all configurations is reliable fuel delivery, redundancy, and fuel management throughout the flight.
