Be it known I can walk and chew gum at the same time - or so the theory goes ;)>

Wow Randy. You can handle more tasks simultaneously than most of us ordinary men! Cheers,

Be it known I can walk and chew gum at the same time - or so the theory goes ;)>

But can you fly a 737 800 properly ? Frederic.

Hi there, The point about "energy management' is a compelling one, since in the commercial world that equates to fuel/cost management although in that respect Speedbrakes are probably the least favourable option. I wonder how these methods would look with an RNP approach? cheers,Chris

Hey Chris. On an RNP approach I wold try and use flaps to slow myself down if needed. On an RNP approach we HAVE to be in VNAV PATH but a fixed point on the approach so its vital to be set up and ready vertically before you begin the approach. But all said and done I would use speedbrakes if I had to. Dont get me wrong, i am not saying never use speedbrakes but just pointing out there is other ways of getting set up without having to resort to speedbrakes.

Question because I was just trying to program one into the navdata - RNP approach and IAN are mutually exclusive I take it? Would be only logical as there is not "one" track to fly. Except you get a lateral deviation scale for every leg (which I don't know)

No prob Robert. If anyone has any questions shoot away!

HI Jack, I know this is a bit off topice, can you give a hint how you would input on the ngx fmc legs page the following waypint : 3700N 13600W. Read the manual and didn't work.

HI Jack, I know this is a bit off topice, can you give a hint how you would input on the ngx fmc legs page the following waypint : 3700N 13600W. Read the manual and didn't work.

Eduardo, you enter that as 37N36 I believe. I just checked in the NGX, and the NGX did accept that format

Eduardo, you enter that as 37N36 I believe. I just checked in the NGX, and the NGX did accept that format

Thanks for your reply Mike. What happened to the first digit(1)? Do you just ignore it?

Thanks again Jack, for the instruction. It is really appreciated. Bob

Hi Jack, Yeah, I'm probably guilty of viewing Speedbrakes as a 'last resort'. I usually use the FSX ATC and on a straight-in arrival clearances seems to keep us higher than the published procedures, so efficient descent/drag is a v. useful technique. My old man was a skipper on 200s, 300s and 400s and sometimes referred to "throwing the gear out early" if say ATC were late giving decent clearances and to avoid any chance of a high/fast approach. Cheers,Chris.

Somebody please school me... But shouldn't an 800 model slow down faster than a smaller 700 model in level flight, considering that biggest difference between the two models is that the 800 has a longer fuselage, thus heavier, thus higher level of induced drag on the same wing at the same airspeed? Jack mentions that he would expect the 800 to take longer to slow than the 700? I would think it would be the opposite? Although the 800 has more mass. Maybe the extra drag and extra mass would cancel each other out? JB

I believe this would be down to momentum. If you have two aircraft traveling at the same speed one heavier than the other. The heavier one will take longer to slow as it is carrying more momentum (energy). Elfyn Hanks

There is a small test you can try, I would try it, but I'm at work. Pick a test altitude, lets say 10000 ft. Clear all weather, take the 738 up to the test altitude. Set speed at 250kias then maintain level flight and chop the throttle. Time how long it takes to slow to 200 kias. Do this same test with the 738 loaded to MTW and then also do this test with it unloaded with just enough fuel to fly. Which load takes longer to slow in completely level flight? JB

Unfortunately I gotta work again today so no fun time on the NGX, but I did just get up extra early before work to give this test a try... Looks like Mass trumps Induced Drag... Executing the test above and here are the results. 10k feet, level flight with standard atmospheric conditions......@ 105300 lbs time to slow from 250 to 200 is 54.3 sec@ 170000 lbs time to slow from 250 to 200 is 1 min 14.2 sec. So it seems that Mass has a much bigger influence in level flight than induced drag.PS. The above test was done with the original install and no applied hotfixes. JB

Wait, so does the above results mean that at 10k feet and between 200 and 250 kts while in level flight that the 737 800 NG is more fuel efficient while heavy than light?JB

Wait, so does the above results mean that at 10k feet and between 200 and 250 kts while in level flight that the 737 800 NG is more fuel efficient while heavy than light?

I don't think your little experiment can shed any light on fuel efficiency. And oh, btw, you could repeat this experiment and observe the fuel flow - that should tell you the fuel efficiency story....