Steep descent After XXXX

[cavaricooper 2,615]

>Thanks Carl,>>I feel a string of questions coming on so apologies for that>but I don't recall finding much written which explains the>Speed Intervention button. How does it work. Do I enter a>speed into the MCP and then press the button and what actual>action does pressing the button do when in Level Change.>>Also if I select Level Change what speed / rate does it>descend at as when I have tried that I usually end up having>to using VS mode and then start getting problems with speed>and / or height again. I've tried various tutorials over the>years but don't recall reading much good tips for descent>planning. Also are you guys suggesting slowing to what sort>of speed at top of descent ?>>ThanksDave:Actioning the SPD INTV button from VNAV is as simple as depressing the IAS selector. As VNAV is active, the FMC commanded speed will appear. You can then accelerate or decelerate the aircraft by turning the knob. To cancel, another push.FL CH automatically opens the IAS window, selecting higher ALT engages in THR mode and CRZ (if active) changes to CLB unless an engine is inop in which case it changes to CON. Selecting lower ALT results in IDLE and HOLD. Once capture occurs, pitch changes to ALT and A/T engages SPD. This is a optimum performance mode so further taming with THRUST SEL might be in order.Selecting FL CH results in a computed optimum climb/descent rate that varies with available a/c performance- speed protection is offered, hence VS will vary. It is by far a preferred "tactical" MCP method for climb/descent because of that very reason. VS alone does NOT offer speed protection, however SPD VS will. Remember, all these interventions are just that- deviations from the FMC commanded profile, so when wanting to cross SABER at FL150 that VS dial, and the resultant green arc become very useful!As far as slowing before TOD, that is not a standard practice- just an option when begining a descent profile you decide will push the VS comfort limits. 20-30 knots makes all the difference when needed. Remember the STARS are usually comfortably within performance limits, and that can assist in initial descent planning. The fun usually starts around FL180 when ATC gets busy and leaves you high and fast.Jeff N's- "I think what it boils down to is individual technique and lots of experience in your particular airport or airspace to be more comfortable in the aircraft. The more you fly, the more you might be able to keep your aircraft in the VNav during through tough arrivals and even through ATC adjustments and vectors." is bang on capturing the idea that the more familiar you are with the aircraft (and its performance) and the route (and its unique difficulties) the easier it is to "write" the steps correctly. Its kind of like the fuel issue- Steve and I chat about the HUGE, nay ENORMOUS amount of experience, thought and planning involved (probably mostly sub-consciously) when a trans-Atlantic skipper mumbles someting about adding few more tons of fuel tonight....... experience beats book smarts- every time.Hope this helps a bit. One of our experts can chime in with further detail. The intracasies of the automatics in the 744 are food for much thought and discussion. I am constantly learning new techniques and subtle differences in application- she's a grand girl!Best-Carl F. Avari-Cooper BAW0225http://online.vatsimindicators.net/980091/523.png