777-200 Mach .1029 bug?

[Cap737Jon 1]

So flying into Rome last night I had a crazy tail wind. Hit Mach 1.029 it read out on the display Mach .1029 Just happen to see that and wanted to let PMDG know that. This was on FSX.

 

Jon

[scandinavian13 5,192]

 

 

So flying into Rome last night I had a crazy tail wind. Hit Mach 1.029 it read out on the display Mach .1029 Just happen to see that and wanted to let PMDG know that.

 

Wait...what?

 

Tailwind isn't going put you over Mach 1, despite what that dumb article said back in January...

 

 

 

Can you be more specific about what you saw? Were you in a dive? Either way, I'm not sure it's of huge consequence because nobody has any business putting a 777 that close to or beyond Mach 1.

[Cap737Jon 1]

My video on Twitch @ 6:09:48 shows it. I was having weather issues. I normally wouldnt post my videos here but to show you what I saw....

 

 

 

http://www.twitch.tv/jonfocus03/c/6209832 (made a highlight)

 

Jon

TAS was 585 at Fl370 computed on http://www.hochwarth.com/misc/AviationCalculator.html it checks with a mach of 1.020(rounded up)

 

Jon

[PMDG777 231]

This one really made me laugh. What weather program are you using?

[kevinh 409]

If you had a high tailwind which suddenly reduced it could cause TAS to go high temporarily. A kind of high altitude windshear. FSX without any wind smoothing does do that kind of thing.

[PMDG777 231]

If you had a high tailwind which suddenly reduced it could cause TAS to go high temporarily. A kind of high altitude windshear. FSX without any wind smoothing does do that kind of thing.

Watch his video. His winds are all over the place.

[kevinh 409]

Watch his video. His winds are all over the place.

I just watched it (my iphone wouldn't let me watch Twitch for some reason). The wind suddenly shifting from a 100 knot crosswind from 014 to a headwind from 124 will do give you a dramatic windshear. The aircraft gains 100 knots TAS instantly. PMDG clearly has a Mach number display format issue there, but it's not one you would usually get to see, not even in testing. I doubt the real PFD would show 0.1029 like that.

 

Watching this makes me wonder how much internet server space is taken up with real time videos of flights. A lot of people seem to make them these days.

[TheHoser11 39]

Not a PMDG problem - - It's a user's weather program problem. Get a stable one like ASN.

 

R. Edwards

[kevinh 409]

Not a PMDG problem - - It's a user's weather program problem. Get a stable one like ASN.

 

R. Edwards

The weather no, but the Mach display issue is a PMDG problem (albeit a very minor one).

[scandinavian13 5,192]

Again, I agree that it's technically an issue, but if you're breaking Mach 1 in a 777, you have more important issues to contend with than the Mach display...like...you know...airframe failure.

[Jazz 1,046]

Interesting Jon but I have to ask why is your flight deck grey?

[Rossicev 0]

Just a curiosity, the triple 7 can resist (even for a little time) to a Mach 1? Or it will desintegrate with the sonic boom?

[captain2255 0]

Generally, airliners are not designed at all to fly in the transsonic regime. The Forces are rising dramatically around Mach 1. But the real maximum speed is defined by the structure. Take the maximum operating speed and multiply it by 1.25. Thats the dive speed which you never want to exceed if you like intact airplanes. I hope I remember everything correctly what I said. 

 

So I would say no, an airliner disintegrates when coming to mach1 or beyond.

[downscc 1,327]

One immediate issue would be 'jet tuck.'  When you get into the transonic/sonic region the center of lift moves aft resulting in a nose down force which increases the speed and forces the nose down further.  I don't think the B777 will enter this edge of the flight envelope without criminal negligence.

 

I recommend you dump that weather add-on, what ever it was.  Very unrealistic.  Not even cutting across a jet stream will cause that in reality.

[Cap737Jon 1]

Interesting Jon but I have to ask why is your flight deck grey?

I changed the backlighting to white and flood lighting silver. The green was ok but wanted to go custom with it.

 

As for the rest I'm not saying this is normal or a every flight thing it's just something I noticed and wanted to say something about. That's all.

 

Jon

One immediate issue would be 'jet tuck.'  When you get into the transonic/sonic region the center of lift moves aft resulting in a nose down force which increases the speed and forces the nose down further.  I don't think the B777 will enter this edge of the flight envelope without criminal negligence.

 

I recommend you dump that weather add-on, what ever it was.  Very unrealistic.  Not even cutting across a jet stream will cause that in reality.

 

It was my FSUIPC having a issue. That's why I was having such harsh wind changes.

 

Jon