On FSX why do I get an overspeed warning at 340 kias when flying a jet?

Question

This is an intresting one, on Flight Simulator X when im flying a 737 for an example I can only fly up to 340 knots then i will get an overspeed warning but this perplexes me because i just came off a flight from the US to London and the flight info channel said we were flying at 560mph which i know is not exactly the same in knots but certainly isn't anywhere near 340!

So does this mean that the pilots get an overspeed warning aswell and just continue to fly at 500 knots??

Answer 1

Because you have not been schooled in how an airspeed indicator works, or the principles of air at different altitudes.



The airspeed indicator measures airspeed by the force of oncoming air against a small diaphragm in relation to static air of the same atmospheric pressure.



As an aircraft climbs to higher altitudes, the air is less dense, meaning the individual air molecules are farther apart. This means that even though you are traveling at the same speed, there are fewer molecules of air pushing against that diaphragm, so the needle on the airspeed indicator reads a slower speed.



When you adjust for temperature and altitude, you can convert indicated airspeed to true airspeed, and you will see the difference from 340 knots to 500 knots.



this is why flight simulator pilots are much different from trained pilots.

Answer 2

What you saw or heard on the real-world flight was your speed over the ground in miles per hour. What you are seeing in the cockpit of a 737 in Flight Simulator is your indicated or true airspeed (depending on which option you've selected in the sim) in knots.



For example, at 36,000 feet, your speed on the airspeed indicator might be 280 knots, but your speed over the ground (with no wind) would be 553 mph. The airspeed indicator shows indicated (not true) airspeed in a real aircraft, which diminishes in relation to true airspeed at higher altitudes.



The relationship is a bit complicated. Study up on flying and how airspeed works if you want to know how it all fits together. Suffice it to say that 340 knots indicated is way too fast for a 737 at cruise altitude (it's more than 580 mph).

Answer 3

The flight info was giving you ground speed, not airspeed. (560 mph = 487 K).



At 40,000 ft, the calibrated airspeed (essentially what the indicator shows) is just about ½ of the true airspeed, and is more an indicator of the dynamic pressure of the air than any actual speed.



Airspeed measurement is more of a art than a science, but you have to get the science right before applying the art.........