PTU SOUND

[RemySarkis 16]

in the checklist, Preliminary Cockpit preparation, we have to check the Break Pressure, and in order to do so, i am turning on the hydraulic pumps so as to be able to check them and recharge. during this phase I hear the PTU sound, but dont hear it anymore during the engine start. is this normal ? should i turn off the hydraulic pumps after checking and charging the break pressure? thank you

[Israel Ponte 20]

The PTU will be active when there's flow of hidraulic pressure through the pumps. When you hear the PTU sound, it means that one of the pumps is feeding its own system and another hydraulic system to make it simple.

Since you turned the hydraulics on, all the systems were pressurized.

When you start the engines, the systems are already pressurized, so you won't hear the PTU again.

Normally the brake check is done after the engine start.

[RemySarkis 16]

The PTU will be active when there's flow of hidraulic pressure through the pumps. When you hear the PTU sound, it means that one of the pumps is feeding its own system and another hydraulic system to make it simple.

Since you turned the hydraulics on, all the systems were pressurized.

When you start the engines, the systems are already pressurized, so you won't hear the PTU again.

Normally the brake check is done after the engine start.

True, but in the Provided Checklist, [Normal Procedures Vol2] Preliminary cockpit preparation , it is there and not able to skip it unless turn the hydraulics on. any work around to check them. [ and i am using the automated check list, but no co-pilot i am doing all the job]. in real life we hear the PTU Sound during engine start and not before. thank you