Hello to all;Why when I set my Boeing aircraft, 737,747,777 or the Lear45 to fly at 35000, I can't go faster than 300kts. The "Candi Bar", you know the one on the Air Speed Indicator. The highter I go to lower the "Candi Bar" moves forcing me to slow me speed down.Any help?Thank you all for your time.

As you go higher, the air gets thinner and your indicated airspeed drops. But your actual speed doesn't drop. At 35,000 feet, your indicated airspeed might be 260 kts, but your ground speed (actual speed) might be over 500 kts. That's why theres a switch on the MCP in the 737 to select a mach speed (speed as a fraction of the speed of sound). When you are crusing at altitude, set the autopilot to maintain a mach speed of, for example, .75.

Mr. Kent;Thank you for your help in this matter, Sir, on more question, at what altitude should I change to mach speed vs kts. What I mean is that when I'm taking off I'm using kts up to some altitude from that altitude on I can't no longer use the SI because its readings are not real, so please, can you help me here.Thank you for your time and have a nice day.

I usually switch to MCH when I pass FL250.. then I set the speed depending on which plane I'm flying in (for the B737 for example, I usually put 0.74, you should get a reference on the Aircraft manual for each plane)

Hello Mr. Fabrizio;Thank you for your reply to my question. I will follow your advice on the altitude matter. I will read the aircraft POD in order to know the correct aircraft airspeeds.Thank you;