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sd75lover

Unable to successfully land

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Hello,

 

It seems that either I am stupid or that there is a bug with the aircraft, whenever I try to land my t7 anywhere, the plane will descend very very fast, even though engines are at like 60% and whenever I do land, it is a very hard landing normally over -800 fpm and it seems like my plane always sinks in approach, I'm always falling below G/S can anybody he explain to me what I'm doing wrong?

I normally do short flights on the t7

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It seems that either I am stupid or that there is a bug with the aircraft, whenever I try to land my t7 anywhere, the plane will descend very very fast, even though engines are at like 60% and whenever I do land, it is a very hard landing normally over -800 fpm and it seems like my plane always sinks in approach, I'm always falling below G/S can anybody he explain to me what I'm doing wrong?
I normally do short flights on the t7

 

Hi Benjamin,

 

It sounds like your final approach speed is decreasing as you get close to landing.  Are you leaving the autotthrottle on and also paying attention to your actual speed as you near landing?  How are you choosing your final approach speed?

 

Mike

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I am leaving auto throttle on,

 

A friend said I might be overweight on landing?

Should I decrease payload?

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Could be a lot of things, but a couple of things spring to mind:

 

How much fuel do you have on board? That can make a big difference to V-Ref (reference approach speed) since one US gallon of jet fuel weighs about 6.84lbs (0.84kg per litre if you're all modern). Now with that in mind, since a Boeing 777-200 can carry about 31,000 US gallons of fuel, that means full tanks weigh about 212,000lbs, which is a little bit less than half the weight of the entire aeroplane itself when empty. Thus if you are trying to land with a lot of fuel, you could be landing an aeroplane which is seriously overweight, and that's not even taking into account passengers and cargo/baggage. Of course in a simulator that means you ain't going to break it, but on the real thing you'd be drilling the undercarriage through the wings landing with that kind of overload, but more importantly for your sim, you're going to have to come in like a rocket sled just to keep the thing airborne, and might not even be able to do that if you've got the flaps out full and the gear down, since both of those increase drag a lot. Add some windshear or gusting and you're going to be arriving at blazing fireball city.

 

The other thing which might be an issue, is incorrect or even no inputs into the CDU (FMC), get those wrong and you are also asking for trouble because the wrong CoG, or fuel weight entered into it, coupled with maybe derated thrust settings or whatever is going to make the autopilot and autothrottle apply the wrong settings. FMCs are only as good as the info you put into them.

 

So, you probably want to find some reference for calculating fuel requirements for various flights and info about what settings you should put into the FMC etc. Have a look on sites such as Simbrief and Smart Cockpit, which will help with all that malarkey. Check out the manual for the PMDG too, particularly the tutorials, or if you prefer something a bit more fun in terms of tutorials, consider buying the excellent 'Flying the Boeing 700 Series Flight Simulators' book (you can find it as a PDF too) by Captain Mike Ray, which is good at demystifying all this kind of stuff as well as being an entertaining read.

 

A decent Flight Calculator is worth getting hold of too, or failing that, check out this link for fuel planning:

 

http://www.fuelplanner.com/

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A friend said I might be overweight on landing?

Should I decrease payload?

 

What is your gross weight just before landing?   How much  fuel do you have remaining?  You should not have to experiment with or guess at your landing weight; the 200LR maximum landing weight (MLF) is 492,000 lbs; 777F is 575,000 lbs and the 300ER is 554,000 lbs, FCOM v1 section L.10.4, pdf page 182.  Generally if your Landing Weight is too high, it is due to too much fuel; for example a max payload aircraft with 30,000 lbs of fuel should be well below MLW.

 

At any rate if you are below MLW, have the FMC Approach Page recommended final approach speed + 5 for flaps 30 set in the MCP speed window, the autothrottle on, and actually have the flaps at 30, you should not have a problem with excessive descent speed, as long as you follow the GS indicator and remember to flare.  

 

Mike

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Just a reminder that the 777 FMS does not dial in approach speeds automatically in the VNAV/LNAV mode. You need to switch to MCP SPD, stick the approach to Vref+5.

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Lots of valid replies above, it could be so many things, plus you might not be selecting enough flaps + are not flying into the wind too. However, I think Dan Downs' post above was my biggest learning point when I first started flying the PMDG 777.

 

If still in a VNAV/LNAV approach (so VNAV & LNAV lights are still on), ensure you get the MCP to display your speed (e.g. IAS 190) and gradually wind it down as you continue your approach (to Vref+5). Speeds can get out of hand quickly (as the PMDG manual says this is one 'slippery' plane!).

 

I hope this helps.

 

Arne

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There are also a load of you tube videos worthy of a watch, (not necsessairly mine as the greatest example) but there are many great tutorials, worth checking out which may shed some light.

​Liam Reynolds

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