---
title: "CS 25J991 Fuel Pumps — CS-25 · Avioverse"
description: "(See AMC 25J991) For essential APUs: Main pumps. Each fuel pump required for proper essential APU operation, or required to meet the fuel system…"
url: "https://avioverse.aero/regulations/easa/cs-25/subpart-j/cs-25j991-fuel-pumps"
---

# CS 25J991 Fuel Pumps

Large Aeroplanes (CS-25) · CS-25 · EAR revision 26 Jan 2023

IR Implementing rule

## CS 25J991 Fuel Pumps

(See AMC 25J991)

For essential APUs:

(a) Main pumps. Each fuel pump required for proper essential APU operation, or required to meet the fuel system requirements of this subpart (other than those in sub-paragraph (b) of this paragraph), is a main pump. For each main pump, provision must be made to allow the bypass of each positive displacement fuel injection pump other than a fuel pump approved as part of the APU.

(b) Emergency pumps. There must be emergency pumps or another main pump to feed an essential APU immediately after failure of any main pump (other than a fuel pump approved as part of the APU).

\[Amdt 25/1]

\[Amdt 25/5]

IR — CS-25 · ED Decision 2008/006/R · CS-25 Easy Access Rules · EAR revision 26 Jan 2023

[All rules in SUBPART J – AUXILIARY POWER UNIT INSTALLATIONS](https://avioverse.aero/regulations/easa/cs-25/subpart-j)

Consolidated from the EASA Easy Access Rules (revision 26 Jan 2023, extracted 13 Oct 2026) for convenience. Not the official publication — verify against the Official Journal of the European Union and the EASA publications before operational use.