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Guest kelvind80

How do I ensure the 747 reaches the required ALT in the...

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Guest kelvind80

I'm flying the WOBUN2F departure off of runway 27R at London Heathrow (LHR, EGLL). I have a pretty full pax (362,500 KGs), so I'm pretty heavy. I'm flying to San Francisco (KSFO).Looking at the WOBUN2F plate: http://www.nats-uk.ead-it.com/aip/current/...EGLL_6-4_en.pdf and it says that at D8 LON, we have to be above 3000ft. I'm trying to achieve this but I'm having trouble as VNAV doesn't want to fly at a high enough V/S. I have the Flaps set to 20/1,580ft (so they start reducing at this high) and the Climb Out also at 1,580ft (so the autopilot lowers the nose and CLB 1 is displayed on the Upper EICAS.The trouble with this is where it's so heavy, and wants to accelerate to flap reduction and climb speed, it only climbs at approximately 600FPM, which isn't enough to get to D8. I'm usually able to cross this at around 2,400ft which obviously isn't high enough at all.By the way, this is default weather, so no winds helping or subtracting.Also, is there some charts to help me determine Engine Out Acceleration, Flap Reduction Height and Climb Out Height etc.Thanks a lot...Edit: My paxload is 30,789 KGs; My Cargo is ~30,500 KGs, and fuel is 124,000 KGs

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If your using a combination of assumed temps and derates then use TOPCAT for your calculations combined with Active sky real weather. If your using full climb thrust you should not have any issues with the constrainsts, but remember flap 20 will give you a shorter take off run at the expense of lower climb preformance. Anyway why are you using CLB1 if your not getting the required power?Rob


Rob Prest

 

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Why do you delay flap retraction? Per the chart, climb straight to 583 (500 AGL), turn on course and allow flap retraction and acceleration from there. Once clean, use FL CHG instead of VNAV to 4000 and you'll have no problem getting above the two AT OR ABOVE constraints. Once above 4000 change to VNAV for the hard constraint at 6000.One of the reasons for their "get 'em high" design here is for noise abatement, so you've got to get cleaned up and get rid of that drag. They are only asking for a 4% gradient, which is 242 ft/nm. If you do the math, a GS=180kts is 3 nm/min so you need 726 ft/min V/S at that speed to stay on or above the minimum climb gradient. You get to work on your piloting technique. I can get an honest 800 fpm or better (depending on temperature) at MTOW.Hope this helps.


Dan Downs KCRP

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Kelvin?(Please do sign your entries so that we know who we are talking to).I took off from EGLL bound for KSFO yesterday afternoon with a GTOW 362,441 kgs. No problems at all with wind 240/10, OAT 20, and QNH 1021.This was with flaps 20 and no de-rate.All calculated for me by the wonderful TOPCAT.Cheers, Richard


Cheers, Richard

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With a heavy loaded 744 CLB 1 will give you a V/S of around 600FPM while accelerating to the minimum clean speed. The only way you will get CLB 1 is if you select it in the FMC. With a fully loaded 744 you should be using full takeoff and full climb power.Arm VNAV before you takeoff and when the nose pitches down after 1000FT AGL start retracting the flaps. You should be clean by the time you cross 3000FT MSA.EDIT: Sometimes a 747 is exempt from altitude and speed restrictions due to weight. If youre flying on VATSIM or even Radar Contact you can ask ATC to clear any restrictions simply because the 747 can't safely fly them.I'm not saying ignore the restrictions, but do your best to comply. Safety of the aircraft is always the number 1 concern.


Kevin Hester,

 

Indianapolis, Indiana

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Regarding early flap retraction:I believe Qantas LHR SOP is to begin flap retraction at 4,000ft - above the 4000A restrictions. They reduce to CLB thrust at 1,000ft.I believe BA have a similar SOP - select flap 10 at 1,000ft, as well as CLB thrust, until retracting completely at 4,000ft.I don't think you've got time when heavy to begin retracting at 1,000ft.


Rudy Fidao

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BA Noise Abatement Procedure:1. Carry out standard takeoff procedure up until 1000ft AAL.2. At 1000ft AAL reduce power to full CLB power.3. Speed intervene at flaps 10 minimum manoeuvring speed.4. Accelerate to flaps 10 minimum manoeuvring speed, retracting flaps to 10 on schedule.5. Climb at flaps 10 minimum manoeuvring speed to the terminating altitude (listed in the ARPT notes).6. Terminate speed intervention and accelerate on schedule to en-route climb speed.7. Once clean reduce CLB power to CLB1.(edit - this presumes that this is a VNAV departure, LHR - terminating ALT for noise abatement is 4000ft.)So on the TAKEOFF REF Page of the FMC the entries on the left hand side would look like this:FLAPS20/1000FTE/O ACCEL HT1080FTTHR REDUCTION1000FT CLBI always use this procedure out of LHR & never have issues meeting the altitude constraints...even at MAXTOW take offs. If you're an online flyer ask to cancel the speed restriction below FL100 once she is clean and accelerate to the ECON CLB SPD a soon as you can...the LHR ATC guys are always very helpful & professional and will normally grant this.The procedure described above ensures the aircraft gets away from the noise sensitive areas on the ground as soon as practically possible...and meets those 'close in' altitude constraints.BA also do their takeoffs above 300t TOW with the Packs OFF...enabling the engines to run at a cooler core temperature...one pack is selected ON once CLB power is set...once the cabin rate and pack have stabilised the remaining two are switched ON. This preserves the life of the engines and gives an additional performance factor...I guess this is prudent in today's climate of spiraling operational costs - even to the largest of airlines.As Dan has said...get that plane working for you!!! The takeoff and intial climb manoeuvre in the 744 is a very precise procedure...practice...practice...& more practice!!And finally...use TOPCAT!!!BestSteve Bell


Steve Bell

 

"Wise men talk because they have something to say.  Fools talk because they have to say something." - Plato (latterly attributed to Saul Bellow)

 

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Guest kelvind80

Ok many thanks. Is TOPCAT free?To the mcdonar: my apologies; I'm new to the AVSIM forum (as you may have guessed).To G-CIVA. Thanks for that information; great stuff. Just wondered how you got access to the BA Noise Abatement Procedure? Is it on BA Virtual or speedbird online or something? If so, where on the website? If not, how did you get it?Again, many thanks...Kelvin

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Kelvin,A good friend (RW BA 744 Commander)who kindly lent me his BA Ops Manual to read over a couple of beers one evening...I am afraid I bored him nearly to tears with all my questions!!! Yes TOPCAT is free but to take advantage of all it offers a nice little donation to its designer Mr Christian Grill will unlock its true potential.BestSteve Bell


Steve Bell

 

"Wise men talk because they have something to say.  Fools talk because they have to say something." - Plato (latterly attributed to Saul Bellow)

 

The most useful tool on the AVSIM Fora ... 'Mark forum as read'

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If the procedure tells you to be higher then... at a certain point, why not wait with accelerating and focus on climb?Best Regards.Bert Van Bulck

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Bert-Up to 1000agl its ALL focus on climb (pitch and HOLD IAS). Then Steve's FLAPS10 + 10 technique will result in the emphasis on climb performance NOT acceleration performance that you are asking about. You are getting higher, quicker- and while the noise foot-print reduces, the other important benefit is you have altitude beneath you. It is exactly for this reason that BA utilizes this technique.Keep in mind reaching for PACK 1, checking the EICAS synoptic, then reaching for PACK 2 and PACK 3 can be a fair bit easier with PNF performing the duties- solo it makes for a high workload- try it sometime :)Best-Carl F. Avari-Cooper BAW0225http://online.vatsimindicators.net/980091/523.png| XP Pro SP3 with FS-GS System Unification | 2 x APC UPS | Coolermaster Stacker 830 SE | Asus P5E-Deluxe (X48) | e8500 @ 4gHz | Tuniq Tower 120 | EVGA 8800GT 512MB | Sony 40" Bravia XBR | 2 x 1 GB Corsair XMS2 | 500GB Seagate Barracuda 32MB SATA2 | Corsair HX620W PS | CH Products Yoke-Pedals-Throttle Quadrant | Aerosoft 747MCP-EFIS-EICAS |


Best-

Carl Avari-Cooper

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>Bert->>Up to 1000agl its ALL focus on climb (pitch and HOLD IAS). >Then Steve's FLAPS10 + 10 technique will result in the>emphasis on climb performance NOT acceleration performance>that you are asking about. You are getting higher, quicker->and while the noise foot-print reduces, the other important>benefit is you have altitude beneath you. It is exactly for>this reason that BA utilizes this technique.>>Keep in mind reaching for PACK 1, checking the EICAS synoptic,>then reaching for PACK 2 and PACK 3 can be a fair bit easier>with PNF performing the duties- solo it makes for a high>workload- try it sometime :)>>Best->Carl F. Avari-Cooper BAW0255>http://online.vatsimindicators.net/980091/523.png>| XP Pro SP3 with FS-GS System Unification | 2 x APC UPS |>Coolermaster Stacker 830 SE | Asus P5E-Deluxe (X48) | e8500 @>4gHz | Tuniq Tower 120 | EVGA 8800GT 512MB | Sony 40" Bravia>XBR | 2 x 1 GB Corsair XMS2 | 500GB Seagate Barracuda 32MB>SATA2 | Corsair HX620W PS | CH Products Yoke-Pedals-Throttle>Quadrant | Aerosoft 747MCP-EFIS-EICAS |Hi Carl,Exactly what I mean: don't focus on accelaration but on climb.I dont't fly the 747 but the PMDG 737.Best Regards.Bert Van Bulck

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