Hey guys, recently i did a flight on a 777 and the ft plan called for me to climb and maintain FL 390 as i got past about FL 320 i began to see a slow but constant decrease in my Air Speed. I was holding full throtles and by the time i got to FL 390 i was down to 180 KIAS, but 300 - 400 Ground Speed. There was apoint i was loosing speed yet my ground speed was constant.Why ? and way to avoid that ?Latertj

Too much fuel or payload. Remember, the higher you go, the more your speed will reduce.

Hello tj,as you are displaying indicated air speed the thinner air will give you a lower indication.IAS/TAS = sqrt(relative air density)see my ISA tables at:http://perso.wanadoo.fr/hsors/FS_Soft/fsdocs.htmlIan

TJ, as Ian and the others indicated your IAS will decrease with altitude. Just to expand a bit as you leave 10,000 ft and start to increase speed to climb speed (around 300 to 310 in the 777) once you get up around 20,000 you want to switch over to mach and let it rise to around .80 or .82. Do this by changing pitch to increase mach speed.You'll see your IAS decrease but you mach will remain constant.