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Virtual738
21st Apr 2010, 00:20
The scenario is this !
Toga..........80kts.........v1.............Rotate !
Positive rate gear up.
Flaps 1
The plane is now at 836 ft and v2+20.

At what stage would you dial in your flaps up speed ????

1. Would you just engage the autipilot ?
2. press N1 and dial in maybe 210 kts ?
3. wait till I am at 1500ft (thrust reduction altitude) ?

Do not want to engage Lnav or Vnav fo now.

All ideas welcome !

neville_nobody
21st Apr 2010, 01:27
You accelerate at the acceleration altitude whatever that is for the airport. I think the newer versions of the FMC will do it for you so you have a LNAV/VNAV takeoff

ImbracableCrunk
21st Apr 2010, 01:28
NADP2

@1000'AGL set Vclean +10 to +20
Trend indicator moving to UP, call Flaps UP.
N1 (Previous company it was Speed, N1, then flaps.)

NAPD1

3000'AGL VNAV
Trend indicator moving to UP, call Flaps UP.

B-HKD
21st Apr 2010, 01:31
I presume you are talking about some simulation, but regardless of that you should begin accel. at your acceleration height/alt and not before that.

Tends to be 800' AGL for most U.S. operators and 3000' AGL on a ICAO NADP.

iflytb20
21st Apr 2010, 05:32
As per our SOP, Both the Thrust Reduction Altitude AND the Acceleration Altitude are at 1000 ft AGL. Once the Flap retraction is complete, we select VNAV.

de facto
21st Apr 2010, 08:59
At what stage would you dial in your flaps up speed ????
>>1st :Follow your SOP.
If you dont have any SOPs(unemployed) or don't understand them:
>>Normally the Acceleration in JAA land is 800FT as it is the end of the second mandatory safe climb gradient.(Boeing recommends 1000ft but for training only as it is easier to remember and works in 99% of cases)
>>The acceleration altitude can not be below the FRA (Flaps retraction altitude) from the Runway performance analysis.Most ICAO airports have minimum FRA below 1000FT(around 400AGL).However if FRA is >1000ft you have to use the highest of the two.

1. Would you just engage the autipilot ?
>>Most Airlines prefer you get the Flaps up before you engage the A/P.(min NG is 400AGL, Minimum CL is 1000 AGL).
Some airlines require you to engage the A/P at which the Noise reduction is to be started(NDP A :1500ft,NDP2/NDPB:1000ft,NDP1:>800FT).Obviously (N1 indication)reduced thrust (if you are heavy) will occur when you engage the A/P rather than selecting manually or waiting for the FMC preselected automatic reduction occurs.

2. press N1 and dial in maybe 210 kts ?
210 kts is ok for CL aircrafts below 57 T if i remember correctly,,,,check your take off mass before selecting 210...could be 220kts.
Press N1 if you havent engaged the A/P by then and if you havent selected the automatic thrust reduction in the FMS.
3. wait till I am at 1500ft (thrust reduction altitude) ?
1500ft works in most cases,watch for airports with NDP B for example.(1500ft would be too late to initiate thrust reduction/in some cases when you are light it would be a thrust INCREASE!).

Hope that helps,

regards.:)

Denti
21st Apr 2010, 09:24
Pre-Takeoff program the Take Off page 2 with the correct values depending on NADP in use (1500 thrust reduction in any case, acceleration according to NADP [1500 or 3000], EO acceleration at 1500, 1500 being a SOP value).

After takeoff and gear up select VNAV at 1500ft and clean up according schedule, the autopilot can be used from 400ft AGL on. As soon as boeing is able to deliver the VNAV T/O able software select VNAV before takeoff, same as LNAV allready.

de facto
21st Apr 2010, 09:36
Denti,

Pre-Takeoff program the Take Off page 2 with the correct values depending on NADP in use (1500 thrust reduction in any case

>>>this is not correct.The 1500 ft thrust reduction would not work in case of an ICAO B procedure.
We all know that A and B procedures are old ICAO and were replaced by NDP 1 and 2.However some airport still use them,from memory warsaw airport used the B procedure on one of its runway,in that case 1500ft would be too late for an acceleration.(you need to acc AT 1000ft).

After takeoff and gear up select VNAV at 1500ft and clean up according schedule

>> i believe the poster wasnt interested in VNAV.
Selecting VNAV does not provide flaps overspeed protection, be careful!!!!

Denti
21st Apr 2010, 16:16
Yup, seems EPWA is the odd one, however it is not on our route network and not a used alternate, we only fly to one destination in poland. Our SOPs and limits are based on NADP 1 or 2, not the old procedures.

However, VNAV does protect your flap speeds if you fly the commanded VNAV speeds. It commands speeds based on current flap setting and protects even the retraction phase from 1 to up with a 20kts margin (speed will go no higher than 230kts until everything is cleaned up). Indeed the VNAV during takeoff procedure is a boeing suggested one in preparation for the next FMC-Version. In fact VNAV takeoff was already available for the short time 10.8 was around and will be the standard boeing procedure with the next FMC version which is apparently due sometime this summer.

Not using LNAV and VNAV is simply not the way boeing wants the plane to be operated. Of course it is possible, but it is not standard anymore.

de facto
22nd Apr 2010, 12:41
denti,

You made me doubt for a second so i opened my FCTM(dated 31/oct 2006).Page 3.26.
It states:<After flaps and slats retraction is complete,select VNAV or set the the desired climb speed in the MCP speed window.Before selecting VNAV,flaps should be retracted because VNAV DOES NOT PROVIDE OVERSPEED PROTECTION FOR THE LEADING EDGE DEVICES>

The vnav would make the aircraft accelerate to 230 kts (5 kts below the overspeed for leading edge devices),remember loss of system B, you are limited to 230 kts as the LED wont retract.(its on speed placard in front of you).
If you are in vnav and enter an increased headwind along with a slow A/T response you will get a slats overspeed....and in todays QAR big brother watch id rather not do it...

Also most NDP require to accelerate to enroute climb after 3000 feet(250 if limited below 10000) and keeping max flaps up speed before that.,so i dont see the point to accelerate with vnav on take off,especially if the aircraft is not fitted with speed intervention.

Anyways bit deep for a VIRTUAL738:E

regards

Denti
22nd Apr 2010, 16:59
Wonder, what is the max flap operation speed for your variant of NG? Ours is 250kias for flaps 1 and 5, which includes slats to mid and kruger flaps extended, a configuration that stays valid for all approved take off flap settings (1 through 25). Therefore we do not have a leading devices max speed below 250kts on our plackard or in our FCOM (except alternate flap extension), however the non-normal checklist tells us to remain 230kts or less if more than one leding edge device is not retracted and all trailing flaps are up, with only one leading edge device it's 300kts, those speed limits are there to prevent increased stress on the flaps due to longer than normal operation at those speeds and it is sufficient to decrease from 250 to 230 during the non-normal checklist, which VNAV wouldn't do anyway as it stays at max 230kts as long as any high lift device is extended.

The point of VNAV take-off is that it is boeings preferred method of operation because it offers (their words, not mine) increased speed protection both for structural and SID limits since FMC-Version 10.8, however since that was pulled back due to several bugs we cannot actually do real VNAV take-offs yet, and therefore the 1500' VNAV operation is boeing's preparation for the coming FMC-Version.

Sue Ridgepipe
23rd Apr 2010, 06:51
Most Airlines prefer you get the Flaps up before you engage the A/P.
I have never heard this one before. What is the reason for this?

There are some airports we operate to that I try and get the AP in as soon as possible after takeoff due to the high workload associated with low altitude level offs and ATC instructions and frequency changes, so it just overloads the PM if AP is not engaged at at 400'.

Of course this does not always apply and I quite often hand fly a bit longer, but we do not have any specific company policy except the Boeing limitation of 400'.

Virtual738
25th Apr 2010, 21:21
@1000'AGL set Vclean +10 to +20
Trend indicator moving to UP, call Flaps UP.
N1 (Previous company it was Speed, N1, then flaps.)

Could I turn on the autopilot instead of the N1 mentioned above ???
The autopilot would engage in N1 anyway and level change to my Alt and also hold the commanded speed dialed in previously.

I am involved in professional flight simulation.
I am not a stranger to 737 fcoms and cbt.