Am I doing something wrong?

[Guest prepareforlanding]

I program the FMC with all details and take off for the destination.On this flight I will not use the VNAV only LNAV with ALT, SPEED,etc.Climb is fine but when I reach my FL the speed tape has red barson any speed above 290KIAS.Now is this right? I thought the B737-700 could do cruisingspeeds in excess of 290KIAS. Surely I must be doing something wrong.Any advice much appreciated.

[Guest wkzzo]

At FL310 290 indicated is Mach .80If your reaching FL350 - 272 KIAS is Mach .80, FL410 its drops to an IAS of around 234 KIAS , remember this is indicated air speed, your TAS will be around 460 Kts,groundspeed will be 460+ -winds.

[Guest PoM]

Well like WKZZO said that your speed in KIAS isn't in knots.....another facture like he said could have been wind......but maybe when you program your FMC....you cost index is low....push that baby up a little

[Guest Balrog]

The "K" in KIAS is for Knots. It`s normal what you are seeing, it has to do with thinner air at altitude.The air speed indicator (ASI) shows the speed of the aircraft in relation to the air mass outside. Thinner air means that less pressure is exerted on the membrane inside the pitot tube, so the indicated speed will be less than the true air speed (TAS). If you look at the top left of your EHSI you`ll see both ground speed and true airspeed shown.As you descend you`ll see the yellow line, the VNE (Velocity Never Exceed) move up, as your IAS is getting closer to your TAS since the air mass outside the aircraft is getting denser with decreasing altitude.Cheers,Kjell.

[Guest Balrog]

The "K" in KIAS is for Knots. It`s normal what you areseeing, it has to do with thinner air at altitude.The air speed indicator (ASI) shows the speed of the aircraftin relation to the air mass outside. Thinner air means thatless pressure is exerted on the membrane inside the pitottube, so the indicated speed will be less than the true airspeed (TAS). If you look at the top left of your EHSI you`llsee both ground speed and true airspeed shown.As you descend you`ll see the yellow line, the VNE (VelocityNever Exceed) move up, as your IAS is getting closer to yourTAS since the air mass outside the aircraft is getting denserwith decreasing altitude.Cheers,Kjell.Just a quick edit to myself, the VNE is not a yellow line, but the red bars. :-)