There really aren't many times where you need to use the SPEED button. You're basically telling the A/T to go in to ARM mode when you hit that button. Just hit V/S or LVL CHG and dial the speed you want and the the A/T do it's work.

There really aren't many times where you need to use the SPEED button. You're basically telling the A/T to go in to ARM mode when you hit that button. Just hit V/S or LVL CHG and dial the speed you want and the the A/T do it's work.

I never use LVL CHG, but now that you mention it, I think I noticed once that when I hit VS first, it activated the speed window. I normally press SPEED first, but I will check it next flight and try VS first. It might be a habit left over from my 757.

The speed is denoted according to the constraints computed by the FMS. This is also depicted on the NAV display, with a green little circle which tells you that at that point the stage of decelerating will initiate. Then the speed continues to reduce once you start increase flaps incremently, as by its 'law' and safety the aircraft will only decelerate to the minimium clean speed which is indicated on the speed tape as UP.

Thanks, Luke. I set up a short flight and kept my eyes glued to the FMA during descent and through the early approach phase. What I saw was the "Arm" annunciation, followed by "FMC Speed" annunciated right up until the GS was captured. It then immediately went to "MCP Speed". I think your statement and my observations are consistent.

Why not use the "speed Intervention" button? NOT the " speed" button. It's the very small button above LVL/CHG. You can stay in VNAV, and have the facility to adjust speed to whatever you desire. Thats what it's there for. No need to enter the FMC. No need to go out of VNAV. No need to make it complicated. I use the speed intervention button on most flights, it works perfectly.

Why not use the "speed Intervention" button? NOT the " speed" button. It's the very small button above LVL/CHG. You can stay in VNAV, and have the facility to adjust speed to whatever you desire. Thats what it's there for. No need to enter the FMC. No need to go out of VNAV. No need to make it complicated. I use the speed intervention button on most flights, it works perfectly.

I keep forgetting about that, the 757 doesnt have that option, going to give it a try, tks for the tip

For ATC restrictions tat can be cleared soon, I always used SPD INTV (ALT INTV for altitude), then, if you need to mantain the speed restriction/altitude for the rest of the flight, change it in the flight plan.If I'm Flying in VNAV I want to stay in VNAV mode as longer as I can. I prefer LVL CHG to the SPEED + V/S function

You can use speed intervention to adhere to NADP 2 when taking off with VNAV armed. Press the SPD INTV button at the reduction/acceleration height and set the MCP speed to Flaps Up manoeuvring speed (put the magenta bug on the UP symbol). Then press SPD INTV again when you reach 3000ft to let VNAV take control of the speed again.

Only time you would really use the "SPEED" button is to re-engage the autothrottle when in any of the modes on the bottom, like VS or FLCH. If in VNAV and the AT kicks off, then cycle the A/T Arm twitch to re-engage the AT.

This VNAV/LVL CHG/VS business is much to the taste of every pilot. Dont think you do something wrong just because somebody else does it differently.