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MattS

777 Step Climbs

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People need to understand that Flight plan tools like PFPX and SimBrief do calculations based on a static wind/weather data and payload estimates. It's the reason pilots go over weight and balance and enter/downlink whatever you wanna call it "final numbers" into their FMC... There are a number of other things that occur in real world between the time a flight plan is accepted and actual takeoff but

The flightplan is your base, the "best case" scenario, wind and weather is ever changing and this makes the flightplan become a reference tool. Your aircraft will use different fuel with these changes, thus changing your weight, giving you different climb and cruise profiles. Even before takeoff, if temperature goes from 28C to 31C, past o below estimations done in the FP, your performance changes drastically...Step climbs are important because they can change so many variables of the flight...and again, its up to the PIC to decide whats best, performance, comfort and safety wise based off of the dynamic conditions and airspace restrictions.

Oh and 777 and 747 have very different systems on board, don't use data from the 777 for the 747 and vice-versa.

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4 minutes ago, CaptainGabe said:

People need to understand that Flight plan tools like PFPX and SimBrief do calculations based on a static wind/weather data and payload estimates. It's the reason pilots go over weight and balance and enter/downlink whatever you wanna call it "final numbers" into their FMC... There are a number of other things that occur in real world between the time a flight plan is accepted and actual takeoff but

The flightplan is your base, the "best case" scenario, wind and weather is ever changing and this makes the flightplan become a reference tool. Your aircraft will use different fuel with these changes, thus changing your weight, giving you different climb and cruise profiles. Even before takeoff, if temperature goes from 28C to 31C, past o below estimations done in the FP, your performance changes drastically...Step climbs are important because they can change so many variables of the flight...and again, its up to the PIC to decide whats best, performance, comfort and safety wise based off of the dynamic conditions and airspace restrictions.

Oh and 777 and 747 have very different systems on board, don't use data from the 777 for the 747 and vice-versa.

Well stated.

Definitely a reminder that flying isn't about just passively entering data in and going along for the ride. The dispatch is a framework, but the flight itself is down to you.


Kyle Rodgers

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Thanks for the advice Gabe. It's always good to hear from people with real world experience, and since the topic is mostly about flight planning your input is valued. My expertise lies in another aspect of aviation, outside of the cockpit, so I welcome any help that will make me a better sim pilot.

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9 hours ago, scandinavian13 said:

Not correct.

In practice a pilot will stick to one aircraft (or perhaps a couple, if they hold a common type cert) in normal airline ops. This is not a regulatory requirement. Rather, it's one of safety and familiarity.

I've been driving a rental car all week. It's automatic. My personal car is manual. I can tell you that I have, on a number of occasions, stomped down with my left foot out of habit when going to start the rental. This is why they keep you to one. That level of habit and familiarity adds some safety to the whole operation.

UAL just dropped the 744. If their 744 drivers are all flying other planes and they suddenly need a 744 driver for some reason, it's not like they're going to have to get someone to swap out their type ratings. They might throw the person in a sim session if it's been a while, but they'll just pull someone off the other line and put them on that plane for the need.

Wow don't I feel dumb. Here I was all this time thinking you could only hold one type rating, based on some little nugget I read on the internet (maybe even AVSIM forums) at some point in time. I always thought that if it's on the internet then it must be true. I guess I'm wrong about that too....lol.

That's why I like coming to this forum. Aside from the bull word not allowed that flies around here from time to time, the PMDG forums really are a good place to find accurate information. You just have to listen to the right people.

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On 9/27/2017 at 11:42 AM, CaptainGabe said:

People need to understand that Flight plan tools like PFPX and SimBrief do calculations based on a static wind/weather data and payload estimates. It's the reason pilots go over weight and balance and enter/downlink whatever you wanna call it "final numbers" into their FMC... There are a number of other things that occur in real world between the time a flight plan is accepted and actual takeoff but

The flightplan is your base, the "best case" scenario, wind and weather is ever changing and this makes the flightplan become a reference tool. Your aircraft will use different fuel with these changes, thus changing your weight, giving you different climb and cruise profiles. Even before takeoff, if temperature goes from 28C to 31C, past o below estimations done in the FP, your performance changes drastically...Step climbs are important because they can change so many variables of the flight...and again, its up to the PIC to decide whats best, performance, comfort and safety wise based off of the dynamic conditions and airspace restrictions.

Oh and 777 and 747 have very different systems on board, don't use data from the 777 for the 747 and vice-versa.

Gabe, while I have your attention may I ask a question?  In my search for realism, I often struggle with what a typical loadout would be in the 77W. From your real world experience, what do you often see in regards to cargo load, passengers, and baggage? Do airlines often or routinely max out the aircraft?  I would also like to hear the different variables that are involved. Thanks in advance. 

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You can get a good idea of how heavy they are by looking at their initial cruise altitudes.  Right now CX885 B77W KLAX-VHHH has just reached FL300 according to FlightAware.  Given that it is a 11 hr trip you can play with PFPX and see what kind of ZFW limit initial altitudes to FL300.


Dan Downs KCRP

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29 minutes ago, MattS said:

Gabe, while I have your attention may I ask a question?  In my search for realism, I often struggle with what a typical loadout would be in the 77W. From your real world experience, what do you often see in regards to cargo load, passengers, and baggage? Do airlines often or routinely max out the aircraft?  I would also like to hear the different variables that are involved. Thanks in advance. 

Ultimately, it all comes down to the different airlines, seating configurations, and routes they fly. As you can imagine, each airline has their own seating configurations, and some airlines have multiple seating configurations even for one type. Then you have the routes they fly, which can dictate how much cargo goes out depending on what cargo is out there. So that being the case, it might not necessarily be easy to get a concrete answer to that question.


Captain Kevin

nGsKmfi.jpg

Air Kevin 124 heavy, wind calm, runway 4 left, cleared for take-off.

Live streams of my flights here.

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1 hour ago, downscc said:

You can get a good idea of how heavy they are by looking at their initial cruise altitudes.  Right now CX885 B77W KLAX-VHHH has just reached FL300 according to FlightAware.  Given that it is a 11 hr trip you can play with PFPX and see what kind of ZFW limit initial altitudes to FL300.

For me, the lightest I could get the aircraft was a ZFW around 478,400 to get an initial FL of 300. Max ZFW for the flight is 492,427. 

I used current weather, CI85, PFPX generated flight plan, 15 min hold time, and auto-redispatch. 

Any changes or setting you would suggest? 

Great idea Dan. 

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LAX-HKG has never been an 11hour flight, this is more like LAX-Tokyo flying time. 

The quickest I have ever seen was at the late 13hours somewhere like 13:40. In the middle of winter the record so far is 15:45-16:00.

And yes, quite often the flight is longer than a typical JFK - HKG flight which goes over the pole 90% of the time. 

CX885 departed recently had a flying time of 14:04, ZFW of around ~207tons and fuel load of ~122tons. Which is considered to be quite "light" for this trip. And they could have used 24L for take off to reduce taxi time. 

it is quite common for any of the HKG bound flight out of LA to take off with 340-350 tons.  

 

In addition, the initial cruise altitude out of LAX to HKG should not be regarded as solely dependent on weight, because the flight planning software will deliberately choose a lower crusing level to avoid the strongest part of the headwind in a jet stream. Therefore quite often they stay low until the last 3-4 hours of the flight then zoom back up to FL360 / FL380 as final level. 

 

 

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On 9/29/2017 at 3:27 PM, MattS said:

From your real world experience, what do you often see in regards to cargo load, passengers, and baggage?

I'll use the flight I work as an example NRT-IAH 77W

As the Dispatcher, I receive the estimate payload for the flight from the load controller.
Remember, payload is the weight that is added to the OEW, the basic weight of the aircraft with the required fluids, and materials for the flight but MINUS the fuel for the trip. Priority of the Payload in order left to right: Fuel + Passenger/Pax bags + cargo.= Estimate payload. It changes and varies daily based on season and how well the airlines handle business. 
Use this for calculations [Pax + Bags (PAX x 1.5) + cargo = Payload]
Remember! Fuel is more important than cargo!

On 9/29/2017 at 3:27 PM, MattS said:

Do airlines often or routinely max out the aircraft? 

Some airlines fly certain routes with many passengers AND payload or, much cargo and less pax, or a balance of both. I can tell you that our 77W estimates takes 20 tons and up of cargo in addition to 200-260 PAX, limited by config daily. So for us, we TRY and utilize our 77W as much as we can. But as stated in the beginning, cargo is least priority, so, in the next question, I'll answer what I do with these estimates.

However, there is another airline that operates the same aircraft, has 300 PAX yet takes sometimes no more than 10 tons of cargo. So, on the sim, change it up sometimes ;)

If you ever wondered why airlines have so many seating configurations, there is your answer...what is in demand for them.
 

On 9/29/2017 at 3:27 PM, MattS said:

 I would like to hear the different variables that are involved. 

Once the dispatcher has the estimate payload, he does his magic and calculates the best route...BUT this is where the important part comes in. Takeoff and landing performance calculations are made before hand to make sure that the estimate payload does not exceed flight parameters.

Many times, Takeoff performance is what restricts payload…and it does vary from station to station and airline to airline. All of this is calculated just with weather! The next problem is airfield limitations. IAH has 12,000ft runway…great right?! Wrong! We get pretty warm here, summer-35-37C…this heat makes performance suffer and even though, on a cool day we could depart at MTOW 760,000 lbs, with a 12,000ft runway, we are sometimes restricted down to 744.8 etc. In comparison to NRT which as a 14,000ft in cooler climate, they can almost always depart at MTOW. (Kind of wish we had a longer runway for our warm runway to compensate for the heat) 
Size matters!


Excellent questions, this is something Dispatchers don't really talk about and the explanations can be much more detailed.

Please excuse any typos...did this in a rush.
#MakePACOTSgreatagain

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Amazing explanation, Gabe. thank you a lot, the work of the dispatchers is sth nobody knows about but everyone asks himself, how all this is calculated. 

 

PS sry for calling you Gabe, I can‘t see your real name on the mobile layout :laugh:

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22 minutes ago, Ephedrin said:

Amazing explanation, Gabe. thank you a lot, the work of the dispatchers is sth nobody knows about but everyone asks himself, how all this is calculated. 

 

PS sry for calling you Gabe, I can‘t see your real name on the mobile layout :laugh:

Gabe be short for Gabriel anyhow.

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Captain Kevin

nGsKmfi.jpg

Air Kevin 124 heavy, wind calm, runway 4 left, cleared for take-off.

Live streams of my flights here.

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On October 1, 2017 at 3:55 PM, CaptainGabe said:

Use this for calculations [Pax + Bags (PAX x 1.5) + cargo = Payload]
Remember! Fuel is more important than cargo!

Thanks Gabe! Awesome info!

2 questions for you.

Are you saying for bags you use total passenger weight x 1.5 and that is what you use for baggage weight? Is this an initial estimate, later updated once check-in is completed (is the data from the scales at checkin used in your calculations, or are they only used to make sure passengers don't exceed the allotment?)

Do you dispatch / plan the NRT-IAH leg from IAH, or is there a company dispatcher at that station?

Good stuff Gabe!!!

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16 hours ago, MattS said:

Are you saying for bags you use total passenger weight x 1.5 and that is what you use for baggage weight? Is this an initial estimate, later updated once check-in is completed (is the data from the scales at checkin used in your calculations, or are they only used to make sure passengers don't exceed the allotment?)

Sorry I should have been more specific...
Booked Passenger number Say (233) X 1.5 + estimate baggage number (349). You can times that by whatever you want, its usually 50lbs/32kg.

Add that to your planned payload weight with the cargo (25,000-30,000KG) and that's your estimate . Again it is all estimates, and yes it does change by the time boarding is complete...maybe  500Kg less sometimes its marginal with the planned. 

Since PMDG added the option to just input pax number into the FMC, that part is easy...the bags and cargo are not necessary but a "for fun/realism" thing.

This is simplified for the sim...there are more things you need to add and consider such as tare weights for bag cans etc...

16 hours ago, MattS said:

Do you dispatch / plan the NRT-IAH leg from IAH, or is there a company dispatcher at that station?

The full plan is created in HQ HND by a Dispatcher, but I send them all latest info and forecasts for US/local weather conditions,as well as my takeoff performance predictions beforehand. We also speak via satcom to discuss any suggested changes or additions to the ETOPS alts, airways etc. Once I receive the "final" plan, I go over it myself and verify everything is within company minima, no typos etc..once that's done, I brief the flight crew upon arrival at the terminal and they have the final word of accepting or not .Keep in mind there is a +9hr UTC difference between IAH and NRT/HND.

This has gone greatly off topic lol

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