Flap extend/retract schedules

[cpurick]

Can someone explain real-world flap extend and retract schedules in a B727? I was surprised to see that the DF manual's performance charts anticipate keeping the airplane clean till 2000 feet in the descent. From my personal experience I'd have guessed that the flaps start coming out quite a bit higher than that.

Also, any help with the climb profile is appreciated. I realize they keep the a/c below 250Kts until 10K -- then what? In the real world, is climb based on airspeed, pitch angle, rate of climb, or what?

[pschlute]

Can someone explain real-world flap extend and retract schedules in a B727? I was surprised to see that the DF manual's performance charts anticipate keeping the airplane clean till 2000 feet in the descent. From my personal experience I'd have guessed that the flaps start coming out quite a bit higher than that.

Also, any help with the climb profile is appreciated. I realize they keep the a/c below 250Kts until 10K -- then what? In the real world, is climb based on airspeed, pitch angle, rate of climb, or what?

Hi

If you look in the manual you will see maneuver speeds for a given a/c weight. As you accelerate through a flap limited maneuver speed you retract the flap to the next setting. Reverse is true for descent. Clean config is most efficient, so dont add flaps until you need to. At most landing weights I dont need to add flap until i go below 190-195 KIAS.

Climb profile. When you reach acceleration height (approx 1500 ft above airport elevation) set climb thrust. Lower the nose to accelerate to 250 KIAS and retract flaps when passing maneuver speed for each setting. At 250 KIAS you will need to pitch up to avoid overspeed. Above 10,000 feet lower nose again (3-5 degrees should do it), until you reach 310/320 KIAS, then use pitch to maintain speed.

As you climb you can add more climb power (see manual). At about 26,000 feet you will hit your Mach cruising target speed (between 0.78-0.82). At this point use pitch to maintain Mach (not KIAS) until you reach cruise flight level.

Peter

[Pilotwannabe]

Just had to say, flew into Gen. Mitchell airport a month ago on Jet Blue I think, and had my GPS going so I could monitor flaps vs speed. Was on a 737 and he was doing > 250 knots at FULL FLAPS on approach! :eek:

He did seem to be in a bit of a hurry! :D

TRB

[Captain Smithy]

Must have had quite a tailwind then! :)

There's a table in the manual giving best climb speeds for both -100 and -200 models at various weights. Varies between 280 and 330 Kts., depending on weight - obviously a higher weight entails a higher climb speed.

pschlute - I do the same with regards to flap extension on approach.

Smithy

[cpurick]

That's great. Pschlute, what am I doing with airspeed between rotation and 1500' AFL?

[R1830]

On takeoff, obviously rotate at Vr, climb away at V2-V2+10 to 1000' min before starting to clean up. At 1500 feet you can call for (or in this case) set climb thrust.

At V2+10 you can retract flaps to 5(if you are using a flaps 15 takeoff). Limit bank to 15 degrees until you get your speed up to min flaps 5 speed. Continue to climb at about 1000 Feet Per minute and accelerate.

When you get within 10kts of your flaps 2 speed you can go to flaps 2 as long as you are accelerating. Again when you get within 10 kts of your clean speed you can go flaps up. The idea being by the time you get to the flap settings you will be above the min speed required as you accelerate.

Below 10'000 target 250kts, at 10'000 pitch down to target about 1000 FPM again and as mentioned accelerate to about 300kts, that should put you in the balpark of least cost climb sched, depending on weight. Adjust pitch to maintain this speed until you transition to Mach. We use a transition of .78.

When you reach your target speed of .78 use pitch to maintain that speed until you reach cruising altitude. Accelerate to your cruising speed and then reduce thrust to maintain your cruise Mach .79-.84, or with fuel as it is these days even .78.

For approach this is what I use, it works quite well. Two miles back of the Initial Approach fix (IAF, so about 12 miles from the airport) you should be level at about 2000-3000' AGL and slowing back towards 200kts (obviously based on having available terrain clearance.

Select flaps 2, then flaps 5 basically right after. As the glideslope comes alive( or assumed glideslope using 300' of altitude AGL for every 1nm back of the threshold) select flaps 15. About 1 dot below the glideslope select gear down. As you are intercepting the glideslope go to flaps 25, then 30. In most cases that will be your landing flap setting. Decend on the glideslope.

This will let you slow back gradually, and make minimal power changes so you have an organized, stabilized approach. You should be carrying 1.4-1.2 EPR to maintain your speed right to the flare, depending on your weight.

[ramford]

Is it similar to car retraction? Hyundai Motors (http://www.cardealexpert.com/news-information/buyer-beware/hyundai-and-kia/) and Kia, two partnered Korean auto makers, have admitted to over-estimating the mileage claims of some 2011-2013 models to the EPA. The automakers have agreed to make restitution to affected owners.

[mrzippy]

4 year old thread here!