maybe this has been discussed b4 but i didnt find so sry if am repeating an old topic but...when to use flap 25 and when flap 30 postion on an approach? I read that flap 25 is the normal postion and 30 is used under certain condition but what are these conditions? btw u guys made a marvellous plane its a really pleasure to fly it cuz its so #### realistic!

Flaps are used on aircraft to primarily steepen the descent profile and also to enable the aircraft to fly slower (by increasing lift the stall speed decreases). Therefore I would use 30 flap for short runways and/or to avoid terrain features with a steeper descent.Hope that helps,Chris

Some ailines, such as Qantas, use flap 30 for all 747-400 landings to provide a slower approach speed and therefore a shorter runway stopping distance.

LH recommends Flaps 25 for normal operations due to noise reduction and fuel economy. Flaps 30 should be used for wet, slippery or short runways as has been pointed out before.Regards,

Hi,very nice info.Thanks! Flap 25 or 30 for landing.And for take off?Using the B 737NG I use normally flap 5 for take off.Using B 767 ER I use normally flap 5.Using B 747 QoS I use flap 10 or 20, but I'm not sure about that setting...

Gross weight lessa than 300 Tonnes I use flap 10 for take off300 Tonnes or more I use flap 20.On testing (with PS1 B747-400) I found that the extra drag from flap 20 at low weights did nothing to improve take off run, whereas at 300+ there was a noticeable improvement in take off run with lap 20.

thx for the replies much appreciatedso theres no rule for flap usage on landing its therefore up to the pilot right?

Even flight managers go around and around on this one.My airline recently (for not a good reason) flip-flopped on this and reversed their preferences.Takeoff is flap 10 or 20.10 produces less noise and perhaps a little less fuel consumption, flap 20 results in less tire wear (important) and reduces the chance of a tail strike. Some shorter fields may need flap 20 takeoff due to field length issues.Landing, flap 25 or 30.Again some fields at heavy weights may require flap 30, which is also easier on the tires and provides a better view of the runway due to a lower body pitch angle (important in low vis. Flap 25 is quieter and can be better handling in gusty and windy conditions, uses a little less fuel.Tom

The normal flap position for landing is 30. I know some airlines use flap 25 so extend the life of the flaps system.Some non-normal checklists call for the use of flaps 25 for landing, also if making an emergency return for an overweight landing flaps 25 should be used if the calculated flap 30 Vref is about 167kts.Cheers Jon