FLAPS Config on SMS Boeing 737

[alexshaggy 0]

Hello guys!!i´m new at avsim forum,my question is about flap configuration...how can i know the right flap position when landing?another thing is,when is the right time to retract it after takeoff?tks!!!

[207p 0]

Full flaps on landing about 15 degrees on takeoff and retract 30-45 secs. after T/O

[alexshaggy 0]

tks man!but is full flaps always necessary when landing?cause i land with 15..25...if i set full flaps,what should be my speed ?cause landing speed depends on flaps right?

[207p 0]

Yes remember that will cause drag 15-25 actually is more lift. Yer speed should be in the manual it vary from aircraft to aircraft i think for the 73 it is 135-140ktas. remember pitch+power=performance.

[alexshaggy 0]

ok man!i will remember!!tks!

[kiwiflyer45 123]

ok man!i will remember!!tks!

Retracting flaps after take off is more about altitude and air speed than time. Typically you don't touch the flaps until you've passed through at least 300 feet in a jet like the 737. Airspeed should be sufficient that the aircraft won't lose any altitude (you will need to slightly raise the nose as the flaps come up) and you are well above stalling speed - remember that stalling speed is higher with no flaps. So roughly 300 feet and around 180 knots - though in real world you would factor in weight and weather conditions... Raise them in increments rather than all at once...For landing in a 737, I would say there is almost no normal situation where you would use less than full flaps. The only time you would consider landing with less than full flaps is with an engine out when you need to maintain a higher airspeed to maintain control and don't want to be in a "dirty configuration" (full flaps and gear down) if you have to go around on one engine. In the case of the 737, an engine out is almost a non-event other than take off so even with an engine out I'd probably still use full flaps.

[alexshaggy 0]

oh pennkiwi,tks for the explanation!just one more thing,flaps must be set on final approach and with AP off or on?heres what i´m doing: during final approach(AP on,with rnw in sight,landing gear down,~160,150 kts) i start to set flaps incrementaly,5....10....15...25...is it right?or should i set flaps to 45 at once?

[kiwiflyer45 123]

oh pennkiwi,tks for the explanation!just one more thing,flaps must be set on final approach and with AP off or on?heres what i´m doing: during final approach(AP on,with rnw in sight,landing gear down,~160,150 kts) i start to set flaps incrementaly,5....10....15...25...is it right?or should i set flaps to 45 at once?

No, keep doing what you're doing. Lowering flaps incrementally means you only have small changes of trim and allows you to start lowering flaps at a safe speed and then bring the speed down - each flap setting has a different maximum speed. (The more flap the more pressure the airstream exerts on the flap so too high a speed can cause severe damage)These are just rough figures but in a 737 you would probably start your approach at around 210 kts, 5 flaps, 190 - 10 flaps etc. You want to aim for a target speed of around 150 as you cross the rwy thresh-hold. Assuming you are going to do a manual landing, you would disengage the autopilot at around 1500' AGL so you have time to settle yourself down for the flare and landing.At some later time you will probably move on to a more advanced product like the iFly 737 or LevelD 767 and then you will need to be a bit more sophisticated about calculating speeds - but the flight management computer will give you the numbers. For now, stick with those approximate figures and have fun!CheersIan

[alexshaggy 0]

ok!!i will do that!!EDIT: man,i tried and it went great!!one of my most perfect landing!right speed,right flaps!i came increasing flap selection every -10KTS!thank you very much!!

Edited November 14, 2011 by alexshaggy

[kiwiflyer45 123]

ok!!i will do that!!EDIT: man,i tried and it went great!!one of my most perfect landing!right speed,right flaps!i came increasing flap selection every -10KTS!thank you very much!!

Excellent! You'll be a pro in no time!! Keep having fun!Ian