A350 MSFS 2024 - Loss of braking pressure during Dual Engine Failure

Hello iniBuilds Team,

I would like to report a bug regarding the hydraulic and braking logic on the Airbus A350 in Microsoft Flight Simulator 2024 during a dual engine failure scenario.

Issue description:

After experiencing a dual engine failure, I correctly started the APU. On the ECAM, the hydraulic pressure drops to the minimum allowed, but brake pressure is still indicated as available. However, when trying to brake after touchdown, the brake pressure fails to reach its maximum level. The aircraft accumulates almost no braking force and slows down very little, making it impossible to stop safely.

Temporary workaround found:

If I manually turn ON the Ground Electric Pumps (Emergency Ground Hydraulics) from the overhead panel, the system forces the hydraulic pressure back to high levels, and the aircraft is finally able to brake normally.

Real-world behavior:

With the APU running and available, the aircraft's electrical network should fully power the normal electric hydraulic pumps, restoring proper high pressure to the Green/Yellow systems and allowing full braking capability without needing to touch the ground maintenance switches.

It looks like the system logic is not correctly restoring full hydraulic pressure to the brakes when running on APU power alone during this emergency.

Could you please investigate this for the next updates? Thank you for your amazing work on this aircraft!

Edited Tuesday at 04:48 PM2 days by Jacopo Costantino

In normal flight, the A350 hydraulics are powered by engine-driven pumps, not electric pumps. Starting the APU does not restore these.

In-flight with APU/RAT only, the APU will only power the side 1 buses (1A and 1B). 2A/2B are unpowered and EMER 1 / EMER 2 are powered by the RAT.

The electric pumps are 400Hz only and are inhibited if any engine is running. It's not clear from the FCOM what engine signal that is - generator online, above idle, switch in on position?

The Green electric pump is on 1B so could be powered by the APU - you need to start it manually with the maintenance switch, or press ACCU REINFLATE.

The Yellow electric pump is on 2A so cannot be run in APU/RAT-only flight.

What should happen is the braking accumulators (on both yellow and green systems) would give you enough fluid/pressure for about 6 full brake applications, enough to stop the aircraft and apply the parking brake but not taxi to the gate.

(you would also likely get some degree of residual hydraulic pressure from windmilling engines, as long as no high-flow items like gear or flaps were selected)

Edited 1 hour ago1 hr by Someone Somewhere