Freeware 777 speed drops automatically

Pitot Heat? Shift+H.

Chuck B

Pitot Heat? Shift+H.

Chuck B

+1

I don't know for sure as I don't have that plane, but it's likely that the FMC is not

full functioning. IE: some free jets use a freeware FMC which is not realistic at all when

used with a Boeing jet. Are there actually speed restrictions for those waypoints, or

does it just get a wild hair and change speed for no good reason?

Are these waypoints at high or low altitude? IE: high alt speeds should be mach speeds

and not IAS.

I am not that knowledgeable about this but I do use the High altitude option in the FSX Flight planner and the speed setting in the 777 is in IAS. Could that be the cause? If so, what route planning option allows me to fly in IAS?

The FSX flights won't effect the FMC in the plane. Totally separate.

The high vs low in the planner chooses between the low alt enroute, vs the high

alt enroute plans/waypoints/fixes. Or I think anyway.. The FMC runs whatever plan

you punch into it.

You don't normally need to worry about speeds in the FMC unless you have speed

restrictions for waypoints/fixes. And most all of those will be at lower altitudes under

FL180, where IAS is used. The change from IAS to mach speed or visa versa is

automatic, and both speeds should be shown in the FMC assuming the 777 FMC is

about the same as the 737.

Say I use a certain cost index and the FMC decides to climb out at 300 knots, and

the cruise mach speed will be .79. When 300 IAS merges with mach .79, the FMC

should switch, and also you should see the change on the PFD. And visa versa on the

descent. When you start the descent, it will be at mach .79, but as you merge with

IAS 300 knots, or whatever speed the FMC decided, it will switch to IAS on both the

FMC, and the PFD.

One almost never cruises with IAS. Even if at a fairly low altitude for cruise, the

FMC will usually switch from IAS to mach speed. IE: when I fly a short route where

the cruise alt is low, say FL220 as in the case of KHOU to KAUS, when I get to FL220,

the FMC and PFD will switch to mach speed, which will be pretty low.. Say mach .66,

or whatever.. Much lower than any flight long enough to let the plane climb to it's

normal fairly high altitude and mach speed for cruise. " IE: say mach . 79 at FL390 or

whatever. The FSX plan has nothing at all to do with any of this.

edit..btw, the automatic switching would be in VNAV. But if flying the vertical

path semi manually, you will have to switch from IAS to mach or visa versa manually.

But the FMC should still show both speeds whether VNAV or manual.

IE: say I'm at FL390, and I decide to descend using vertical speed. In that case,

when the mach speed of .79 merges with the 300 IAS, I will have to switch from

mach to IAS myself using the MCP.

Whenever I use the Honeywell FMC, this problem occurs. However, when I use the JB777 panel FMC, there is no speed drop. Works perfectly except I have to change altitude manually. The FMC does not trigger an altitude change when I reach waypoints on my way to cruise altitude.

I will try a few flights and see what works. Thanks for the help guys.