[ATR 42/72] Propeller brake operation without hydraulic pressure

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1

:wave: Thank you for using the Bug section, using templates provided will greatly help the team reproducing the issue and ease the process of fixing it.

Are you using Developer Mode or made changes in it?

no

Have you disabled/removed all your mods and addons?

yes (but not relevant)

Brief description of the issue:

Propeller brake can be operated without Blue hyd system being pressured

Provide Screenshot(s)/video(s) of the issue encountered:

Detailed steps to reproduce the issue encountered:

Start Cold&Dark. Power the battery. Prop brake shows “READY” despite no hydraulic pressure.

PC specs and/or peripheral set up if relevant:

Build Version # when you first started experiencing this issue:

latest (WU13)

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Do you have the same issue if you follow the OP’s steps to reproduce it?

Provide extra information to complete the original description of the issue:

If relevant, provide additional screenshots/video:

2

Which aircraft?
There it is…maybe mention it the text too.

3

I don’t believe they’ve simulated the electrical or hydraulic system. For example, start cold and dark, and you can move the flaps without electric or hydraulic power.

4

@Gilandred you’re right.
However, today I’ve noticed that after landing, if you switch off the hydraulics and the ACW generators, the propeller brake “READY” light goes off togheter with the hyd press. Therefore something is implemented at some level.

5

Do you have the same issue if you follow the OP’s steps to reproduce it?

Yes

Provide extra information to complete the original description of the issue:

The whole simulation of the Prop brake is flawed.

  • It’s operable without hydraulic pressure
  • The unlock local light does not come on during engagement (or I don’t see it)
  • The ready light should continually be on as long as engagement/disengagement conditions are met
  • If you try to engage it with the gust lock disabled, the ready light goes out. If you then disengage the prop brake again, you get a brief unlock indication, which should have either been on the whole time, or never turn on.

If relevant, provide additional screenshots/video:

1 Like
6

Did some testing to check your observations out…

The brake won’t come on without pressure but can be released. this is incorrect according to the FCOM. This can easily be observed by turning off the aux pump and trying to engage the brake. The ready light correctly turns off in this case and the prop continues spinning.

When engaged the unlock light does turn on for a second, then the prop brk indicator illuminates which seems correct as per the FCOM. I noticed the DC Aux pump should run on for a 15 seconds after the prop is braked but it turns off immediately which isn’t correct.

When the prop is braked and in Hotel mode you should have no hydraulic pressure but you can release the brake without any issue. This is wrong.

The FCOM notes you first need to press the small HYD AUX PUMP push button on the pedestal which turns the DC Aux pump on for a few seconds. The ready light should then come on which in turn allows you to release the brake.
The pump operation works more or less correctly but the ready light never comes on.
Instead it only comes on when you flip the prop brake switch.

The light sequence when unbraking appears to be wrong as well, currently the prop brake light turns off then unlock turns on and off momentarily.
According to the FCOM the prop brake light should turn on and off again momentarily followed by another momentary pulse of the unlock light before the sequence is completed.

So it more or less works correctly but it needs some adjustments to bring it in-line with the FCOM.

Also observed the odd unlock light pulsing on when you turn on the prop brake switch with the gust lock off, nothing correctly actually happens though to the prop. There shouldn’t be any lights as the brake shouldn’t be able to operate (no ready indication) with the gust lock disengaged.

7

You made me doubt my words so I did retest some stuff:
The prop brake works as you describe it, if Engine #2 is running.
If Engine #2 is off:

  • the Prop Brake is always ready
  • Will properly engage or disengage
  • No Unlock light for engagement or disengagement
  • Ready light will not remain on with the brake engaged and prop brake operation requirements met.

Which makes this whole case even more interesting

2 Likes
11

:wave: Thank you for using the Bug section, using templates provided will greatly help the team reproducing the issue and ease the process of fixing it.

2 tags are required: One for platform, and one for aircraft.

Are you using Developer Mode or made changes in it?

No

Have you disabled/removed all your mods and addons? If the issue still occurs with no mods and add-ons, please continue to report your issue. If not, please move this post to the Community Support section.

Yes, except ATR.

Which aircraft are you reporting an issue about? (Please also add the proper tag for it)

ATR-42

Brief description of the issue:

The prop brake can be activated/deactivated upon initial aircraft power-up with no hydraulic pressure present.

Provide Screenshot(s)/video(s) of the issue encountered:

Prop Brake - Create and share your videos with Clipchamp

Detailed steps to reproduce the issue encountered:

Load C&D, power on aircraft, open safety cover, turn on prop brake. Note PROP BRK indicator illuminates. Turn off prop brake. Note PROP BRK indicator extinguishes. Check hydraulic system status on F.O.'s display. Note no pressure in system. Repeat indefinitely.

PC specs and/or peripheral set up if relevant:

N/A

Build Version # when you first started experiencing this issue:

1.0.31

:loudspeaker: For anyone who wants to contribute on this issue, Click on the button below to use this template:

Do you have the same issue if you follow the OP’s steps to reproduce it?

Provide extra information to complete the original description of the issue:

If relevant, provide additional screenshots/video:

13

I am also experiencing this bug from a C+D state. I found that it would not come on when in hotel mode with ext power disconnected. I then reconnected external power and gave it a try, and it suddenly worked which seems to agree with some of the suggestions in this thread about it being in the AC/DC logic.

1 Like
14

I uploaded a vid where I walkthrough Jonathan Beckett’s vid doing everything he’s doing and showing how its not coming on for me. I am going to keep working on this because I’d love to find a way for it to reliably work. If anyone sees this and has some reason I’m bringing this on myself, I’m happy to hear what I could do differently. I really want to enjoy this plane using hotel mode. This vid is from C+D with no actions prior to loading in.

15

This video also shows that the prop brake can be engaged with no READY light and without hydraulic pressure. Sure, the Aux Pump switch doesn’t have a LoPr indicator illuminated, but switching to the hydraulic system status page on one of the touch displays will show the hydraulic circuit has no pressure. Additionally, pressing the button on the console to power on the aux circuit doesn’t do anything when utilized at this point in the C&D startup procedure – the aux circuit doesn’t react and the status page continues to show no pressure in the system.

The prop brake shouldn’t be able to be activated in this way.

From the ATR Flight Crew Training Manual:

“PROP BRK ON – Check the PROP BRK blue light is illuminated. If not, press the HYD AUX PUMP PB on the pedestal. When the READY green light illuminates, select PROP BRK ON. Check the UNLK red light is extinguished.”

16

Apologies as I realized this is a thread about the fact that you can engage the prop lock without hydraulics. I didn’t read carefully. For posterity, as this might help others who can’t get a reliable response from the HYD AUX button, I played with it all day and discovered that if I move the condition lever from FTR to AUTO, the READY light will come on if the HYD AUX has been previously pressed, and if it hasn’t been pressed, it will work at that point. If you get a green READY and you then go back to FTR, in my experience that READY light will fade. I can consistently get it to work if I am in AUTO on that prop condition. I’m not sure what the expected behavior is for an actual ATR or if this is related to some issue where AUTO is needed if there is not enough auxillery hydraulic power. In any case, it works reliably for me if I flip that up to AUTO.
Demo:

1 Like
17

Great work I will try this on my next flight. The issue has been driving me crazy as I like sticking to the checklist

18

Verified fixed in v1.0.9