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When to start deploying flaps.


Guest Wannabe-Pilot

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Guest Wannabe-Pilot
Posted

Hi all. I have been wondering when to start deploying flaps--and what fashion I should do it in.I'm using the PMDG 737-700. How far away from the airport should I start my flap deployment? If someone could help me out on this subject, that'd be great!Thanks.Tim

Posted

Hi Tim,Flap deployment is carried out in accordance with your airspeed. Look on the airspeed 'tape' on the left hand portion of your PFD. As you decelerate through about 240 knots you should see a green 'up' appear somewhere towards bottom of the speed tape (it varies based on weight but is normally located at about 220 knots or so). As you decelerate through the corresponding speed, lower the first stage of flaps. A green '1' will appear further down the speed tape, as you decelerate through THAT corresponding speed, lower the next notch of flaps. Then a green '2' will appear, continue deploying flaps in this manner until you're configured for landing. I normally lower the gear at the same time as I lower flap 15 but you can do so earlier if you need asssistance in slowing down.I'm assuming that you know how to slow your aircraft down to an appropriate approach speed. There are existing topics in the forum, but as a rule of thumb I slow to:-240 knots below 10,000 feet -220 knots within 7-10 miles of the start of my final approach-180 knots in time to intercept the approach-160 knots once established on final-Vref + 5 knots in time to descend through 1,500Others can chip in with their own techniques, mine is just based on what 'feels' right to me!

Mark Adeane - NZWN
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Posted

I don't fly the NG very much (Waiting for the NGX) but I do follow a similar procedure in the 744. The only difference is that I use the FS ATC and they have a bad habit of having me at FL110 when I start my final approach. What I do is drop the flaps to 5 once I hit 240 kts. This helps to keep my speed down during the remainder of my decent. Then I drop my flaps according to my speed and am usually at 10 when I intercept the localizer.BTW, does anyone know a good ATC addon for both FS9 and FSX? Particularly one that works at a very good majority of airports, has a good number of different voices, and above all else, lets me fly SID/STARS. (Not to mention will allow me to fly a final without having to decent 8000 ft in 2 miles.)Ryan Gamurothttp://www.precisionmanuals.com/images/forum/supporter.jpg

Guest Wannabe-Pilot
Posted

Thanks a lot for that info. I knew about how to deploy them, but I wasn't sure when to start dropping my speed. One more question. What exactly is the maneuvering speed? Because I see below the gear lever my flap deployment speed limits. Is it OK to deploy flap 5 above the maneuvering speed for it, yet below the limit?Tim

Posted

Maneuvering speed (Va) is the max safe speed for turbulence or maneuvers that generate g-forces (high angle banks, pitch ups etc). Below that speed the wing will stall before exceeding design allowance for g's; above that speed and the forces may cause problems.The max flap deployment speed determines the limit, not maneuvering speed; however, I wouldn't deploy flaps above Va in heavy turbulence.

Dan Downs KCRP

Guest Wannabe-Pilot
Posted

Ah, I see. Thanks!-Tim

Guest Jacob Lee
Posted

In the 737 I do flaps 1 on the downwind, flaps 5 on base, flaps 10 when I begin to intercept, gear down and flaps 20 when I intercept glide slope, and then landing flaps around 2000 AGL.

Posted

210 in the pattern on DW, 180 on base, 180 slowing to 160 after inbound intercept before the OM and landing flaps Vref + 5 with gear dropped right after the OM. The OM is typically 7nm out from the threshold.Flaps are by limit schedule. I use flaps as drag but also to lower the stall speed on roll (the action of roll raises the stall speed increasing with the angle of bank). Sometimes ATC requires tight turns at 30 degrees roll.Radar Contact asks for 210 max as it turns you on DW or long base or if straight in within 30 nm of destination.Scanning RW here at KMSP I often hear approach request limits of 180 further out or even 170 to allow traffic merging.Lookin up here at work I can observe base and part of inbound for KMSP 12L and 12R. It is often interesting to see a smaller regional hot rod it on a short base merge to inbound in front of a slower larger aircraft further out. By expediting speed on base and inbound to the OM, the smaller jet gained required seperation from the slower larger one trailing it.

Guest Wannabe-Pilot
Posted

OK, thanks for your help guys. It'll come in handy. :)-Tim

Guest fastbikkel
Posted

Good question, i had the same a long time ago.I'll try to give my view on this here :I will start descending from cruise at around 100 miles from the airfield.Drop down 1000fps, listening to the tower when he/she calls out the altitudes you have to descend to.I do not deply flaps over 10000 feet. So that is one thing for sure.My preference is to keep my speed at 245knots when i approach the field and flying under 10000feet.Now the actual deploying of flaps.Usually around 30 miles from the field will i start to drop flaps into 1st position. Still flying 245 knots.By now you will probably get a message from the tower which is something like this " turn heading 180, descend and maintain 2500 feet until established on the localizer, or "until runway in sight""Cleared blah blah.Now i drop the speed to 210/220 knots and drop flaps into position 2 or 3, depending on what how fast i wanna drop speed. By this i mean, if you have flap position 3, the next time you wanna drop speed, it goes down fast because you have more drag.I find that very helpful when you get to final, you need to drop the speed even more and when you have flaps 3, speed goes down in time.Now it is just a matter of bringing her down. On short final i drop the speed to 155/160 and drop flaps to full. During this all, i look at the flapgauges to see that i drop the flaps with the right speeds. In level D 767 for example, you cannot drop to full flaps if you are still flying 200 knots. You have to keep in mind the speeds that go with the flaps.

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