Things I've noticed with the NGX

[3mta3 14]

Here are a few things I've noticed about the NGX, anyone have any comments?

 

VLO is 270 kts - yet if I put the gear lever down at this speed - nothing happens until 250kts, then gear auto deploys.  Nice it respects the flap speed limits - but hey - sometimes I need those rollers for the big old airbrakes that they are!

 

Fuel Flow reverses when engines are in reverse - yep - you can make fuel going into reverse.  I haven't actually noticed if fuel comes back into the tank - but the FF numbers on engine instruments sure go negative.

 

Manual pressurization - go ahead and close the outflow valve manually, with doors closed and a bleed source cabin should pressurize, in fact mx sometimes does this on the ground to check the pressurization system - however when I tried it - no luck.

 

I also seem to remember to have seen a problem on the PROG pages - if you hit previous page it cycles through other FMC pages - it doesn't go from PROG 4 to 1 like it should.

 

Trim doesn't move to Full nose down with the flaps up.  When you extend the flaps trim moves all the way to full nose down - but with flaps up - trim stops at the green band limit - if I remember correctly.

 

I guess I will put all of this in the log and call mx control ^_^

 

 

[serviceceiling 135]

Regarding your first point - why would you want to put the gear down at 270-250 knots in the first place, as long as you are not doing any sort of steep approach? As long as you always stay ahead of the plane and plan your descent you'll never have to deal with excessive speed.

 

I'll have to check out the reversed fuel flow on my system. Also keep in mind, like with any other software there will always be some bugs that only get noticed by a minority of users. However it's good that even those are being pointed out so they can get ironed out in a future update/SP.

[3mta3 14]

Well the speed brakes are mostly a rumble maker in the jet, not real effective.  The landing gear as speed brakes is the most effective way to slow down and still keep a descent rate going.  As far as staying ahead of the jet, yes, in a perfect world we shouldn't have to do this.  But there are many times when you need to scrub some energy and get configured.  The landing gear - work well for this. 

 

Btw - when was the last time you have NOT seen "drag required" on a VNAV descent in the NGX? 

Anyway - regardless of technique - gear should operate in the NGX at any speed.  It may have doors ripped off real world, but I don't know why it doesn't depoly until 250 knots.

[serviceceiling 135]

The "drag required" message really depends on your weather engine and on how well you feed the FMC with wind data.

On some days everything works out well on other days you have to request a 360 to lose speed and altitude.

[3mta3 14]

Or throw out the gear!

[serviceceiling 135]

Yes, you can do that in some cases but there's no need to put extra stress on the gear by putting it down too early when you are still doing 250kt + 

Certain approaches actually require to configure the aircraft early for landing in order to concentrate on certain procedures such as turns or terrain avoidence.

[mounty 13]

Hi,

 

If you keep having to bleed off speed and use the gear to do so, then it coesn't sound like you are managing the plane very well.  In all the years I have been simming I hardly ever have "Drag Required" coming up.  The limitations are there for a purpose, so that you do not over stress the aircraft and thus safety is the name of the game.

 

Rob

[3mta3 14]

Sorry to disagree but you are not stressing the gear by operating within the certified limits. If it can handle a MGW landing, it sure can handle the low stress of being extended at 270kts. Then you may accelerate with them extended to 320./.82 Mach. All while not stressing the gear the slightest.

 

You can do gear down and pinned ferry flights no problem. Just plan for increased fuel burn - maybe the chart is even in the manual.

 

I manage my vertical profile just fine, but the gear is there when you need it, and it's free. A 360 will cost you time and fuel, and good luck with that on the expressway visual into LGA, or anywhere - someone is always 5 in trail.

 

You guys shouldn't be so fearful of the gear as brakes concept. I bet with 3000 + guppies in the air - right now - somebody is throwing down that big lever to get down at this very moment.

 

Anyway this was about the fact the gear doesn't deploy as it should - whenever the handle is lowered. Regardless of speed.

 

 

Jon Rock

[UAE77W 16]

In the 737s and the 777s you can't use the gear to slow down. Both planes are made to maintain the speed. That means if you're at ~200kts and you want to use the gear to slow down

 

to ~180-190kts it doesn't work because the engines will spool up to maintain your 200kts.

 

 

A good friend of mine, a real world 744 pilot told me that this is a very common technique to slow down the "Queen of the skies". So in the PMDG 747 or the upcoming 747V2 you can handle her like that.

[Alpha Floor 237]

Hello Jon,

 

The gear should never be extended at speeds greater than the maximum landing gear extension speed. However from checking the FCOM, it could be done. If at a speed above the maximum extension speed you pull the gear lever down, the gear should extend, even if that caused damage to the system.

 

I also wanna point out that extending the landing gear in order to slow the aircraft down is a symptom of DEFICIENT ENERGY MANAGEMENT. Maybe on an extremely rare occasion in which wind changes inadvertently, ATC assigns a new runway that's close to the present position etc... then it "might" be justified. But being forced to extending the gear for slowing doing just forecasts that the approach has very high odds of ending up unstabilized.

 

 

Manual pressurization - go ahead and close the outflow valve manually, with doors closed and a bleed source cabin should pressurize, in fact mx sometimes does this on the ground to check the pressurization system - however when I tried it - no luck.

 

 

Every pressurized aircraft has a pressure relief valve which automatically opens should the differential pressure between cabin and exterior exceed a certain limit (I think it's usually around 9 or 10 PSI). So my answer to that is that the cabin will pressurize up to the maximum differential pressure and then start throwing air outboard.

In the 737s and the 777s you can't use the gear to slow down. Both planes are made to maintain the speed. That means if you're at ~200kts and you want to use the gear to slow down

 

to ~180-190kts it doesn't work because the engines will spool up to maintain your 200kts.

 

Well that's only true if autothrottle is engaged to maintain a certain speed and you're trying to slow it down below that speed. I think the OP is saying he's sinking fast at around 250 knots, engines idle, and wants to slow down while keeping the descend rate.

 

Pulling the landing gear out will decelerate the aircraft, most definitely. It's just not meant to be used that way. You should have started your descend earlier.

[3mta3 14]

I guess I'm just along for the ride and can't change the selected speed, hit speed intervention or turn off the auto throttle. Yes you can indeed slow down with the gear.

 

You guys ever hear of "Children of the Magenta"? Google that. Check YouTube, it used to be up there.

 

Often when flying jets, the best solution is "click, click"' auto throttles/autopilot off, and just fly her like the big 182 she is.

"I also wanna point out that extending the landing gear in order to slow the aircraft down is a symptom of DEFICIENT ENERGY MANAGEMENT. Maybe on an extremely rare occasion in which wind changes inadvertently, ATC assigns a new runway that's close to the present position etc... then it "might" be justified. But being forced to extending the gear for slowing doing just forecasts that the approach has very high odds of ending up unstabilized."

 

Actually by configuring early, you have a much greater chance of being stabilized than if you do - I'm guessing here - drag the spoilers - throw out the flaps at limit speeds and the wait until when exactly to extend the gear?

 

Anyway guys. Love the discussion. Very reasoned responses. But yeah, real live airline pilots use the gear when they need to - and don't "save" it to be extended at the last possible second.

[Q_flyer 766]

In the 737s and the 777s you can't use the gear to slow down. Both planes are made to maintain the speed. That means if you're at ~200kts and you want to use the gear to slow down

 

to ~180-190kts it doesn't work because the engines will spool up to maintain your 200kts.

 

The engines will only spool up to compensate, if the speed has not been appropriately reduced in the autothrottle speed window.    If reduced target speed has been selected, and the gear is lowered, then the engines will not fight this or counteract the drag.

 

[EDIT:  Alpha Floor beat me to it, with the same rationale].

 

It seems to me, '3mta3' knows this plane well.  And I agree re the gear and I regularly use it to decellerate in the NGX - far more effective than the spoilers but not in a way that destabilizes the aircraft or causes structural stress.  Although I 've never deployed gear above 250kts, but regularly at that speed.

[Alpha Floor 237]

I'm guessing that what the 744 driver, friend of UAE77W, meant when he said that they use the gear to slow the plane down, is that they use it once the aircraft is leveled at the glideslope intercept altitude, at say 210 knots with some flaps out. Instead of lowering the gear when the GS comes alive (that's when you should ideally do it), they'll extend it a bit farther up the localiser in order to configure the aircraft a little bit earlier. That's perfectly fine.

 

What's not fine is descending at 3.000 fpm, 270 knots within 20nm of the airport and having to extend the gear in order to keep descending at that rate without accelerating any further. That's plain simply bad energy management, and must be avoided.

[RWFeldman 159]

 

 

What's not fine is descending at 3.000 fpm, 270 knots within 20nm of the airport and having to extend the gear in order to keep descending at that rate without accelerating any further. That's plain simply bad energy management, and must be avoided.

 

True. That would be poor descent planning or bad ATC instructions perhaps both.

[3mta3 14]

The way I do plan descents to airports with no vertical STAR, is 30nm at 10000/250kts.

 

Some may recognize this as the 3 to 1 rule.

 

Anyway I always back up my descent planning with a 3 to 1 computation . You will find that the FMC is aggressive. It would rather default to adding drag than adding thrust. Which of course is the most cost effective solution.

 

The spoilers are more effective in the NGX sim than in the jet. Believe me, with the longer wing of the NG vs classic, your first few approaches are scrambles to get down. Hence you reach for the gear which can be deployed at 270 kts, vs the spoilers which aren't all that effective and rumble quite a bit.

 

A heavy 73 at idle 250kts will barely crack 1000fpm in descent, you may get another 150fpm with spoilers. Now you find yourself getting behind the profile and are given a 210 kt restriction by ATC.

 

Guess what, if you don't act quickly you are going to be way high. What do most do? Grab the gear handle.

 

A recent 737 fleet newsletter stated "We all agree that dropping the gear makes a great “speed brake” at times, just make sure the speed is below 270 knots.