Originally Posted by
III Corps
If you think you need the boards to slow down, you needed them earlier. If you think you need the gear to slow down, drop the gear NOW. If you know you need the gear to slow down, get ready for a go-around.
The 737, 757 and 767 as well as the A320 series do not slow down as well as the DC-9/MD-80 or the 727. In the -80 and the 727, you can throw away a lot of energy fairly easily.
So, on the Boeings, drop the gear, pull the nose UP and get lots of flaps out. Less than 15deg and you are not getting lots of drag. Greater than 15deg and the drag rise is noticeable.
In the 757, the spoilers are used all the time in the terminal area at large airports. At 250 knots, the airplane will descend around 1500 FPM clean and at 210 knots its around 1200 FPM clean. The boards will add around an extra 500 to 800 FPM. Its the only way to come down. Usually, I will leave the flaps up until a speed reduction below 210 knots is required. It conserves gas and is a good estimate for all but the heaviest of weights. Flaps 5, 180 knots and spoilers extended will yield around a 1800 FPM descent. With spoilers extended, roll control is much more pronounced so when hand flying its something you will notice.