Strange temperature/density altitude bug (?)

Look at screenshot! Read data bar! It’s 59 degrees C at over 20,000ft! If that doesn’t sound odd to you, that’s because you don’t realize that’s 140 degrees F! Even stranger? Find a true airspeed calculator. It would have to be almost 400C to yield a true airspeed of almost 600 at that altitude and ias. There’s a problem here.



What server?

Expert server maybe 30 min ago

IAS spike I can understand (Over 350 IAS or M.87)

But ground speeds got little to do with it…

You don’t think this ground speed is more than a little strange? Try flying an a380 to 600kts true airspeed and see what happens…

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IAS is what really matters.

Ground speed only really becomes a factor when landing…specially in microburst conditions.

I guess you’re right, aerodynamics would be a function of the ias. In any case, youre very knowledgeable and I appreciate that, but I’m wondering if you can confirm that you too find a ground speed of 600kts at that ias and altitude to be ridiculous. This is obviously an error- and anyway it’s 59C at 21000 ft. Maybe you’re not a meteorology buff?

Great point though, I appreciate. But I mean… can anybody confirm this is bizarre/incorrect?

Ground speed seems okay for that temperature at that altitude.

Kinda wonder what your temp would have been at sea level. I did a test on solo with ground temp at 70c and warmest I’m getting at FL210 is 28c. 282 IAS translated to 465 ground speed.

All this seems normal for the simulator. The tempature is going to be very low at FL200, and your speed is high, but that is most likely pilot error.

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282 kts indicated at fl210 is pilot error? Please explain. Yes, indeed the temperature is going to be very low at that altitude in reality. Why does it read 59c? Finally, maybe I should just simplify: 282 kts indicated should give ~360 kts true airspeed, NOT 600! Please explain the pilot error.

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This is a silly post, this is obviously not normal for the simulator. Please actually read.

Exactly what I thought, ground speed should be high given that temp. We’re aware that 59C is about 140 degrees F? Clearly a problem. Anyway, you don’t have to take my word for it but try a calculator- at that ias and altitude, even the absurd figure of 59C should give a true airspeed of about 430, not 600. I can’t explain this

This must be too long didn’t read, I’m going to simplify

So it’s taken me all day to get to a flight computer to respond here. At 59 deg celcius, 21,000ft pressure altitude, and a IAS of 280 knots I get a true airspeed of 440 knots. The unknown here is what the winds where doing but I doubt they were 160 knots as stated.
So I’d have to say this is a bug within the calculated true airspeed in app.
Tested this at KSFO on solo at first I set my air temp at the 59 deg celcius but realized it was compensating for my altitude. So I set it at 70 deg celcius to get it as high as possible. Leaving me with 28 deg celcius at 21,000 feet. Running that thru I came up with a true airspeed of 426 knots. GS was shown at 459 knots. So I couldn’t reproduce this exact scenario but it does appear the true airspeed and possibly the GS calculated is off by a substantial amount.
Since IF doesn’t offer a True airspeed selection I couldn’t compare those numbers. Theoretically they should be the same with no wind.

@david could you possibly explain why this is. Perhaps we are missing something or it’s a known issue.


Wow that’s great, thanks! The bug doesn’t bother me, I just had a hard time getting a response from anybody else thinking this just couldn’t be. Thanks very much for your help. Kind of a double issue in my view- the conversion to gs had to be off, and, separately or not, it should not be 59c up there, or anywhere really. Regarding wind, great point, I did check at the time and it was indeed zero, at least so it read. Best I can offer is my word on that, forgot to capture, but it’s true. In any case it would be an absurd wind… fun puzzler, thanks again :)

I have noticed that too!

I should also note that the problem did not persist, this happened for about 30 seconds maybe and then everything went back to normal and I landed safely. I want to say that my ias spiked impossibly fast immediately after but it might have honestly been due to me flipping out with the alarming groundspeed and the alarm bells going off for “overspeed” to great surprise. Kind of a blur but if I had to bet, I would say that indeed my ias spiked without any input to make it spike, maybe even to a level that would match the indicated ground speed. In my memory I went to like 400+ kts ias in about 5 seconds. I didn’t nose dive, so I don’t think that’s possible…

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The OAT isn’t really what got me the weather data is known to be glitchy at times. The true airspeed though is quiet odd.

sometimes the weather updates can be off a bit. Its a different reporting system from say this time last year and Its a known issue that happens now and then. It is not terribly critical unless its causing chronic problems. it’ll get better.