Does this get used a lot in Sim as well as in RW? Up to now I have not used at all.ThanksPeter Meinel

Do you fly online with ATC? If not, these two are not used very much. But when you approach and land at a crowded airport that's staffed by ATC they are essential.

RW, they are used a fair amount. They can help keep your head out of the FMC.SPD INTV is used by some when encountering moderate turbulence - they'll set the turbulence penetration speed of .76/280. (Not strictly required, but that's what's done.) Also in descents, if you get above profile, you can spin in a faster airspeed until you get back to your profile and then cancel the SPD INTV and go back to the planned speed.ALT INTV is used quite a bit, if the plane is so equipped (many airlines have one or both INTV disabled). It has several uses and it is fairly handy.

Does this get used a lot in Sim as well as in RW? Up to now I have not used at all.ThanksPeter Meinel

I guess Speed Interveen is used quite often, (without having to change speed for a ceratain wp in CDU).That´s what I´ve seen in a couple of RW videos though. I have the 737-800 Norwegian DVD, and there they do it.I´m always using Speed Intv in the sim, when decending in Vnav or Lv Ch, since I´m using (ATC) Radar Contact./ Leffe

What exactly does ALT Intervention do. I always press it when I reach my MCP alt to get the plane to fly higher, that is all its used for right?

What exactly does ALT Intervention do. I always press it when I reach my MCP alt to get the plane to fly higher, that is all its used for right?

If you're at MCP alt then either need to climb or descend, dial in the new alt required, then press atl intervention. You need to do this, otherwise the plane will just sit at current alt.The other main use is if you're climbing or descending and there is an altitude restriction, if you dial in an alt higher (in a climb) or lower (in descent) then press alt intervention, it'll delete the restriction.

The first thing to remember about Speed and Altitude intervention is that they are only used in VNAV mode.Speed Intervention is simply for changing the FMC's target airspeed in any phase of flight.Alt Intervention can be used for deleting altitude restrictions above you in a climb or below you in a descent.It is also used to take the plane out of VNAV ALT. (it's nice that the NGX has VNAV ALT otherwise VNAV would disengage and go into ALT HOLD)It can be used to initiate a Speed Descent, an Early Descent and also set a new cruise altitude during climb or cruise.Fred.

Thanks a lot for the answers. As I fly mainly online, the altitudes given by ATC rarely match my VNAV profile therefore I use FTLChange or V/S and in these modesI can change my speed anyways. But I will try more with the Intervention.Peter Meinel