When deploying speedbrakes with default FSX planes you can see the speed drops very fast, the plane goes nose-up and looses stability like it's stalling. You have to use them like 3 or 4 seconds to already get your desired speed. It's not realist at all.

CS 767 is realist on that point. Like in real aircraft, speedbrakes take a little time to slow down the plane, specially if you go heavy.

What is your approximate approach speed, just before flare out..?

wb2002 wrote on Jan 28^th, 2012 at 6:28am:


There is an airline and/or FAA thing which sets a minimum altitude for speedbrake mid-air deploy. You shouldn't use them below a few thousand feet from the ground, and that's pushing it. Your speed may drop close to stall, specially if you have already selected a flap setting.

Look, there is a maneuver for rapid descending spin-push-spin-pull, if you have a bit trouble going down at time and holding your desired speed. It's designed to descend quickly and smoothly without 360ºs or agressive dives.
Terrain may be higher than 9,000 ft and your autopilot with autothrottle must be properly engaged to this procedure.
-Spin: spin the MCP altitude to your setting alt.
-Push: push FL CH.
-Spin: spin the airspeed up to above Mmo(Mach maximum operating)/Vmo(Maximum operating speed). Initially spin it above and then adjust it to less once the descent is established. Do not overspeed.
-Pull: pull the speedbrake lever.

From the FL300+ club, predict your dive and keep and eye on the speed so you may have full control when you begin approaching your destination.

Rigo.

wb2002,

The speed brakes on the 767/757 are less effective than the 727. The speed you are flying at the time of deployment also had some bearing.
Above 250 knots the spoilers tend to "blow down" or be less effective since the angle of the deployment is less than at lower speed. The area of the speed brake is also smaller than the 727 which also has some blow down.

Try this:

At cruise altitude (FL300) and at high speed ( M.80 ) with the autopilot on, give this a try.

First just close the throttles and see the speed bleed from say M.80 to M.75. Time it.

Next, do the same, but after you close the throttles, deploy the speed brakes and time it as well.

Now in lower altitude fly the plane at 250 knots, 10,000 on the autopilot. Do the same test as above. First just close the throttles then use the brakes and see the difference.

BTW, you can use the speed brakes with any flap setting something that is verboten in the 727. You can also use the speed brakes on approach if needed, but keep an eye on the speed!

The 757/767 is a very clean plane and hard to slow down. The 757 being a bit harder than the 767. It takes some planning to make crossing altitudes in both planes. You can either use the default / key to deploy or in VC, you can grab the handle and use just small amounts or anything in between. I would always try to sneak on the brakes so as not to disturb the passengers since there will be some vibration with deployment.

Let me know what you discover in this test.

I find they work pretty much as they do in the RW.

Lou