I try to follow the (After) TakeOff procedure described in the PMDG Manual 05 (Normal Procedures)As far as I understand things I have to hold V2 + 15(20) until flap retraction altitude. How do I calculate flap retraction altitude?I usually take off with flaps = 5. That means that I do have to retract the flaps 3 times (1: 5->2, 2: 2->1, 3: 1->0). In the PMDG Manual No 5 (Normal Procedures) on page 10 there is a table showing "Takeoff Flap Retraction Speed Schedule". Under T/O FLAPS = 5 (left column) there is only shown 2 steps of retraction. Should there not be 3, or do we go from 5 directly to 1, and from 1 to 0??As you can see, I'm a little confused about the right time/way to retract the flaps. As I see the issue you can do it from an arbitrary or calculated FLAP RETRACTION ALTITUDE or you can do it at a certain speed - FLAP MANEUVERING SPEED. Can anybody help me in order to clarify things for me? I have been looking this forum after searching the relevant words, bu unfortunately I was just getting more confused. Maybe there is no clearcut rules here?CheersLars

LarsAs you probably can see in the post above you don't have a fixed flap retraction altitude. It's all about speed. For a flaps 5 take-off you go directly to flaps 1 once you've reached V2+15. Have in mind that is pretty much after your take off as you are pitching for a V2+20 speed. Flaps 2 are seldom(never?) used by the NG pilots I've talked to.Hope it helps,

Your HOLD v2 +20 until flaps retraction ALTITUDE which varies from airport/procedures. It is true you can select flaps 1 at V2 + 15 regardless of altitude but it's best to think of "retraction altitude" as FLAPS UP and Acceleration point. You don't calculate it because it is defined at each airfield departure procedure. Orange County California you do this at 5000 AFE! Best Wishes,[h4]Randy J. Smith[/h4]http://www.rawbw.com/~bdoolin/shinault/Animation1.gifCaution! Not a real pilot, but do play one on TV ;-)AMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | Maxtor 6Y080M0 SATA 80 GIG | 512 DDR 400 | Windows Xp Pro | Windows Xp Pro 64 |

Do I understand this right:1. retraction of flaps (5->1) is done when I reach V2+15. 2. retraction of flaps (1->0) is done in an altitude defined by the airport from which I take off?Lars

1] ONLY if you do a flaps 5 or greater TO. 2] Yes. Departure procedure defines. Like noise abatement procedures. Certainly different places have differet procedures and some might not have any then one would follow his SOPS....Best Wishes,[h4]Randy J. Smith[/h4]http://www.rawbw.com/~bdoolin/shinault/Animation1.gifCaution! Not a real pilot, but do play one on TV ;-)AMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | Maxtor 6Y080M0 SATA 80 GIG | 512 DDR 400 | Windows Xp Pro | Windows Xp Pro 64 |

Thanks for the answers.Lars

BTW Randy, what does SOPS mean.....?Cheers :-)Lars

Lars,It's Standard Operating Procedures.BTW, this leaves myself a bit baffled. I must say that I don't know the NG well enough to start with, but usually airport individual procedures don't dictate the acceleration altitude for an aircraft. For example on a 757 it's usually 1000 or 1500 ft AFE, and you don't commence any flap retraction until after that altitude (hold v2+15-25 until acceleration ht).If there's a noise abatement procedure, then it could certainly be different, but I think generalizing on this topic (at least on a 757) is allowed (this time). There is a fixed acceleration height, but it depends on the aircraft type / airline more than airport procedures.Tero

At Qantas we use 1000' for flap acceleration height, meaning when the aircraft reaches 1000 feet, pitch reduces to allow the aircraft to accelerate through the flap retraction schedule so it's company specific.800 feet is the engine out flap acceleration height, and flaps 5 for thrust reduction meaning when you reach flaps 5 the thrust mode changes from takeoff thrust to your selected climb thrust setting.Takeoff flap setting is either 10 or 20 units on the 747-400 and 25 but mostly 30 units on approach since OJH ran off the runway in Bangkok. Hopefully this info will help out for the upcoming PMDG 744.Jeff KitteltyQantas 747 Heavy MaintenanceAvalon AirportMelbourne

Flap retraction in general varies depending on the airplane and the airline's preferred way to fly it. It then can also be altered by an airport-specific schedule to comply with noise abatement or particular terrain concerns.From a checkride guide for the United 737-400 (this would be more or less valid for the NG):Fly at V2, accelerating to V2+20 by 500 feet AGLAt 500 feet AGL, retract flaps on schedule (schedule means put them up and stay within the flaps operating speed envelope), and accelerate to 220 or 230 knots. Hold this speed until 1000 AGL, at which point you can engage the autopilot and let VNAV accelerate you further or do it manually.Keep in mind that all this activity happens in about 40 seconds, since that's how long it takes you to climb the 1000 feet.I know of airlines that begin flap retraction at 400 AGL, and some that wait until 1000 AGL, so don't get too hung up on the "correct" way to do it - focus more on doing it the same way all the time.

Finnair std accel ht for the 757 is 1500ft AFE. Until that V2+15 is maintained. Std boeing accel ht for 757/767 is 1000ft AFE, don't know this for the NG though.Tero

Thanks everybody for your fine answers. This forum is really fantastic and to a lot of help to every (frustrated) flightsimmer!!Hope I can help others as times go by and I get a little more expirience. Cheers :-)Lars

GuysThere seems to be some confusion over what Accelleration altitude actually means so I'll try to clarify it for you. Accelleration alt is the alt at which you should commence accelleration from V2 (or in most cases between V" and V2+20). This means until accelleration alt you should leave the flap where it is!! Consider if you have a problem and have started retracting the flap at say 500ft or as soon as you hit V2+15 (which is often still on the runway when doing a full power take off) you are still very close to the ground and so have significantly less time to sort the poblem before impact! an example might be a flap asymmetry on retraction! Normal take off procedure on ALL the aircraft I have flown calls for Gear up at positive rate of climb then climb away to accelleration alt as published for the specific airfield. If not published accelleration in the UK is generally 1000ft above airfield level. Once at accelleration alt use either N1 or VAV mode to lower the pitch and increase the speed. Just for realism, standard ICAO noise abatement is generally used in major airports like AMS and CDG. This entails TOGA mode till passing 1500ft AAL then N1 mode to maintain V2+15 with take off flap until 3000ft aal. At 3000ft aal flap retraction may commence! Flap retraction technique varies on the classic and the NG but in the main once past the Green 'F' and accellerating it is safe to select the next stage of flap up. A good rule of thumb that I use is passing 170kt for flap 1 and passing 190kt for flap up. As discussed Flap 2 is rarely used in the same way flap 10 is rarely used! Hope that helpsKris

And to clarify the flaps retraction to 1 from 5 at V2+15 regardless of altitude I made mention of, the WestJet NG captian on the PMDG team is one who does this. He is of course in sync with the Boeing NG FCTM in this regard. Best Wishes,[h4]Randy J. Smith[/h4]http://www.rawbw.com/~bdoolin/shinault/Animation1.gifCaution! Not a real pilot, but do play one on TV ;-)AMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | Maxtor 6Y080M0 SATA 80 GIG | 512 DDR 400 | Windows Xp Pro | Windows Xp Pro 64 |

There are obviously (and naturally - I would say) diferent "opinions" concerning the "right" way in which to retract the flaps. And I guess it's because there is different ways - inside the margins of safety - to do this job. Maybe a result of habits. Like two doctors having different opinions about the treatment of the same patient. Thanks a lotLars