My PFD air speed display resets....

[Nick1150]

Hi,

It happened twice, and I know that most probably it is something in my setup or something that has to do with my flight plans settings, but I do not know how to fix this, so here it goes...

Both times it happened after or before (I am onot sure) the last STAR of the flight plan, when the ATC gave me a specific HDG and left LNAV/VNAV to HDG mode. After that my PFD airspeed display resets to zero (30 knots to be more specific) and the A/T doesnot operate and does not listen any speed I input.

After the usual approach procedures, when the aircraft is on final the airspeed display comes back again to the real speed.

Note: During all this, all other information including the altitude tape work perfectly.

Any idea ?

[yoss]

Just guess

Are you engaging pitot heating?
You should do that
Otherwice pitot tubes freezing and wierd speed anhd altitude values displayed
Whe you are low again on approach- -temperature raising , the pitot not blocked by ice anymore and all cames to normal
This phenomina is simulated

[Nick1150]

If this is true, I am amazed !!!

In fact I do not engage pilot heating, but really could this be true ?

Just asking...

[yoss]

Thats what happends in real life ,Nick

I have somewhere Discovery channel video abot B767 crached in the see , at night , becouse the ground crew forgot to remove the maskentapes from pitot tubes
The perfectly operational aircraft with expierienced crew crached only becouse they lost their altitude and speed indications by night over the see

Real storry with many lives lost

[Nick1150]

Thanks yoss,

I will try it and let you know ;)

[leilson]

If this is true, I am amazed !!!

In fact I do not engage pilot heating, but really could this be true ?

Just asking...

You should always engage probe heat on ( pitots heat), just after starting both engines . The sequence before initiating taxi is eng gen on , probe heat on , eng start switches cont , apu off , recall, flaps 5 .

[Nick1150]

Thanks for the response,

Actually I do not have an overhead yet, but I have an 11 switch panel located on my pedestal box instead connected with a Leo Bodnard card for that reason. All switches are assigned mainly for the lighting panel and autostart, shutdown of both engines plus generators a and b....

http://i638.photobucket.com/albums/uu109/Nick1150/My%20Cockpit/IMG_0425.jpg

Unfortunately the switches are all occupied, I will have to exchange a switch with pilot heat on/off, until I add more switches in this panel.

Thanks,

[saabpilot]

I have the very same symptoms in the B737 PM PFD - Speed suddenly goes to zero (30) and after 30 sec it is back to normal again.
This happens on 1-2 hr flights randomly - mostly only once per flight.
All anti-icing and probe heat is on, so that is not the problem.

Full Magenta suit incl. pmSystems - build 480.

Bjorn

[Thomas Richter]

I have the very same symptoms in the B737 PM PFD - Speed suddenly goes to zero (30) and after 30 sec it is back to normal again.
This happens on 1-2 hr flights randomly - mostly only once per flight.
All anti-icing and probe heat is on, so that is not the problem.

Full Magenta suit incl. pmSystems - build 480.

Bjorn

Hi

It is the only reason when the Speed tape fails.
Just check it is in FS really set to ON, may be pmSystems doesn't switch it correct in FS to ON.

[leilson]

I have the very same symptoms in the B737 PM PFD - Speed suddenly goes to zero (30) and after 30 sec it is back to normal again.
This happens on 1-2 hr flights randomly - mostly only once per flight.
All anti-icing and probe heat is on, so that is not the problem.

Full Magenta suit incl. pmSystems - build 480.

Bjorn
Try one thing: set OAT to 25 a 30 degrees Centigrades before takeoff . I´m saying this because this was happening in an friend of mine A320 simulator and work out.

[saabpilot]

Hi

It is the only reason when the Speed tape fails.
Just check it is in FS really set to ON, may be pmSystems doesn't switch it correct in FS to ON.

Thanks Thomas - this is what I thought too yesterday, so I will load a default a/c and ensure the pitot heat and master switch is set to ON - then load the a/c I use (POSKY) and see if this fixes the problem. :)

Best,
Bjorn

www.boeing737sim.se (http://www.boeing737sim.se)

[Thomas Richter]

Thanks Thomas - this is what I thought too yesterday, so I will load a default a/c and ensure the pitot heat and master switch is set to ON - then load the a/c I use (POSKY) and see if this fixes the problem. :)

Best,
Bjorn

www.boeing737sim.se (http://www.boeing737sim.se)

Hi

Best is when you run already pmSystems to see if pmSystems logic reflects correct to the default AC and its Pitot heat switch in FS panel.

[JonathanRichardson]

Hi

You can also limit the icing to zero in FSUIPC (no ice 0 / 1 / 2 / 3 options) - this is another work around if you don't have pmSystems or other means to control PITOT. Check the options in FSUIPC.

Regards
Jonathan Richardson
Project Magenta

[Nick1150]

Hi

You can also limit the icing to zero in FSUIPC (no ice 0 / 1 / 2 / 3 options) - this is another work around if you don't have pmSystems or other means to control PITOT. Check the options in FSUIPC.

Regards
Jonathan Richardson
Project Magenta

Great hint Jonathan !!!

Thanks :)

[Nick1150]

Hi to all,

It happened again today :roll:

I have selected icing to zero in FSUIPC (clouds tab) already. I thought that was the solution, but from the today's incident I see it was not....

Something else I noticed is that when the air speed tape resets, PMsounds stops working too !!!! I closed PMsounds just to check if that is the problem, but nothing happened.

Below 5000 ft usualy the speed tape comes back again. I suppose because of the rise of temperature, right ?

Any hint ?

[Thomas Richter]

Hi

It is still the same problem and nothing else than that, Pitotheat is OFF.
The reason that pmSounds suddenly doesn't give you wind sounds is that pmSounds reads as well the speed from FS and in the case that FS doesn't give any speed info (frozen Pitot) it will not give any wind sounds depending on speed, is at the moment zero(0).
Just momitor the Pitiot with FSUIPC logging in Adventure display,
0x029C , 1 Byte , Pitot Heat switch (0=off, 1=on)

So you can make sure it is really ON.

[Nick1150]

Just momitor the Pitiot with FSUIPC logging in Adventure display,
0x029C , 1 Byte , Pitot Heat switch (0=off, 1=on)

So you can make sure it is really ON.

Hi Thomas,

Thanks for the reply,

I would appreciate if you could give me more info on the above.

FSUIPC / Logging tab / there is a tick box AdvDisplay indeed. What should I do after that ?

Thanks but I am not so good in programming and I am now starting to learn FSUIPC.

Regards

[Thomas Richter]

Hi

Pic "Log1" shows how to do in FSUIPC
Pic "Log2" shows what you will see in FS screen
The switch by side is the Pitiot switch from default B737. In the pic Log2 you see the value "1" that means the Pitot heat is ON, value "0" would show Pitot heat is OFF.
Simple than that to make sure it is in FS on, and not only a guess because of a switch or what ever.

[Nick1150]

Thanks Thomas for the hint,

I will try it this afternoon, and let you know ;)

Thanks again,

[Nick1150]

Hi

Pic "Log1" shows how to do in FSUIPC
Pic "Log2" shows what you will see in FS screen
The switch by side is the Pitiot switch from default B737. In the pic Log2 you see the value "1" that means the Pitot heat is ON, value "0" would show Pitot heat is OFF.
Simple than that to make sure it is in FS on, and not only a guess because of a switch or what ever.
Hi again,

Just tried and it is zero ( 0 )

SHIFT + H is the shortcut for PITOT HEAT ON/OFF in FS9 ;)

That was a great help Thomas,

I really appreciate it

:)

[saabpilot]

Hi all,

Meanwhile I have moved to SE Asia and cannot access my sim before April, but will surely try all suggestions then.
Many thanks for all tips.

Bjorn

[Nick1150]

Hi all,

Meanwhile I have moved to SE Asia and cannot access my sim before April, but will surely try all suggestions then.
Many thanks for all tips.

BjornJust an update...

Since Thoma's advise everything is going fine ;)