1000000 LBS RTO

[ASCTU744]

Goodday,

https://www.youtube.com/watch?v=_g6UswiRCF0
I recreated this test in PSX and found some things I wanted to share.

LBS Gross weight problem
https://youtu.be/03deUjH_Zu0
When setting max ZFW and fuel qty on the ground in any .situ using a LBS configured airplane, the calculated gross weight value on the PERF INIT page seems to get confused (042.3 or 001.5 etc.). The value on the upper eicas displays the correct gross weight.

Gear temp
https://youtu.be/10FmELTBkw4
After braking the airplane the temp sensors need some time to display the current brake temp (that can be seen on the analysis page). When the brake temp is finally up-to-date the plugs in the tires deflate and the EICAS messages FIRE WHEEL WELL along with TIRE PRESSURE pop-up. Shouldn't the plugs and fire loops be activated independant of the brake temp sensors?

EICAS questions
Lots of manuals say different things when it comes to the tire pressure eicas message. Some say that there only is a carreted advisory and others say both a non-carreted caution and a carreted advisory. The advisory appears when:
-THR in T/O range
OR
-Flight
OR
-30 sec after landing
Which option does PSX currently use?

Maybe it has something to do with carbon vs steel brakes.....

Thank you all in advance,

-Nadir

[Hardy Heinlin]

Why do you set a gross weight higher than 999.9 LBS? Neither the FMC indications nor the aircraft itself are designed for a GW higher than 999.9 LBS. If you increase the ZFW to the max you need to decrease the fuel weight accordingly and vice versa. The sim software won't reduce it automatically. If it were to do this, you might lose half of your fuel on board while playing with the ZFW setting.

[ASCTU744]

I wanted to test out a max weight RTO.

Is this a calculation or CDU display error (due to excessive weight)? The ADV/DUAL value doesn't go over 999.9 which may be because of the WBS logic. But the upper eicas and CDU "big font" gross wt values both use the FMC calculations to get to the gross wt. But the CDU says "043.2" and the upper eicas "999.9".

[Hardy Heinlin]

It's a CDU display overflow.

There is no real-world data for a 1 million LBS RTO, and such fictitious scenarios are not modelled in PSX. PSX is intended for use within the scope of real-world operations. PSX is not a tool for designing other aircraft types. For that purpose, X-Plane, for example, may be the better choice.

[ASCTU744]

  Fair point

But my other findings aren't weight related right?

*Please implement a warning that says: weight limit exceeded, I have been doing this a while now as a quick way of simulating MTOW (now I learned that I went beyond MTOW).

[Hardy Heinlin]

In PSX the tires may deflate at random when the temp is anywhere between 720 and 880. When above 880 they will deflate immediately. This random generator sits in the gear model and isn't linked with any EICAS messages. When you see something happen at nearly the same time, it may be pure coincidence. Especially when the indications update slowly.

Please implement a warning that says: weight limit exceeded

Don't you see that a GW of 999 LBS is an exceedance?

[Hardy Heinlin]

Lots of manuals say different things when it comes to the tire pressure eicas message. Some say that there only is a carreted advisory and others say both a non-carreted caution and a carreted advisory. The advisory appears when:
-THR in T/O range

Yes. If thrust near idle and on ground, then caution message, else advisory.

[ASCTU744]

The thing with the tires is that immediately after an RTO the tires are already at 900 C (which can be seen on the analysis page). The fuse plugs should melt at that temperature. It now seems like they wait until the synoptic value goes to 9 and then deflate.

[Hardy Heinlin]

No, the analysis page doesn't show tire temp. It shows brake core temp. In the real world there are no sensors there. Just the sim model can know this value. The core heat needs to distribute to the other wheel components where the plugs are located. There are no plugs in the brake core.

Note the item name "brake temp". It's not "tire temp".

You can also see this effect in the real world. It takes a while until the tires deflate after an RTO.


P.S.: You may want to rename your thread subject. It's not a bug.

[ASCTU744]

No, the analysis page doesn't show tire temp. It shows brake core temp. In the real world there are no sensors there. Just the sim model can know this value. The core heat needs to distribute to the other wheel components where the plugs are located. There are no plugs in the brake core.

Note the item name "brake temp". It's not "tire temp".

You can also see this effect in the real world. It takes a while until the tires deflate after an RTO.


P.S.: You may want to rename your thread subject. It's not a bug.

I'm sorry, yeah this makes sense...

I don't really now how I should change the title..

[Hardy Heinlin]

You don't really need to change the subject; it's up to you :-) But, just for you info, users of this forum can edit their posts at any time; there's no time limit. Just click "More..." at the lower right of the respective post, then "Modify". Then you can edit the text and the subject.


Regards,

|-|ardy

[ASCTU744]

Changed !