RNAV it, she, he didn't decent

[Victoroos 205]

HI all

I recently did a short hop froom LOWW to LOWI, using the RNAv, and it worked perfectly (except that I forgot to flair / disconnect the AP in the end. rookie mistake) (do you btw have to disconnect the auto throttle yourself. because it doesn't retard like it does with ILS does it?)

AH, well, onto the real question:

I did a flight from eham to ehgg yesterday, and I established nicely ontp the rnav. VNAV and LNAV were on, the vertical purple line display on the PFD (that one you get when you press center 2 times) showed the decent path that was programmed.

However, it didn't go down.

DO you need to press APP? Or did I forget something else stupidly?

vkr

victor

[30K 72]

Yes you have to press APP.

It's quite similar to ILS at that point with the difference that you can arm APP before one of the ILS bugs is received. The FMA will then, when you are established, change to Single Channel but in green (as the other AP is not needed nor can both be on at the same time -> not autoland capability).

Normal procedure is to disconnect AP and AT at 400ft RA then handfly the short final.

Edited March 19, 2018 by 30K

[30K 72]

35 minutes ago, Victoroos said:

(that one you get when you press center 2 times)

What do you mean?

[Olympic260 415]

17 minutes ago, 30K said:

What do you mean?

I think he means the VSD

[Victoroos 205]

29 minutes ago, Olympic260 said:

I think he means the VSD

Ah, yeah, that s what I mean.

51 minutes ago, 30K said:

Yes you have to press APP.

It's quite similar to ILS at that point with the difference that you can arm APP before one of the ILS bugs is received. The FMA will then, when you are established, change to Single Channel but in green (as the other AP is not needed nor can both be on at the same time -> not autoland capability).

Normal procedure is to disconnect AP and AT at 400ft RA then handfly the short final.

And thanks! THat explains it all. must have done it during my LOWI approach automatically.

400ft? And what if the minimus / no runway in sight are lower than that?

[Victoroos 205]

Speaking about VSD.. why is only the 737 equipped with one. I use it a lot, but really miss it during my 777 or 747 decents. How do Pilots irl know what Vertical Speed to set?

[Olympic260 415]

3 minutes ago, Victoroos said:

Speaking about VSD.. why is only the 737 equipped with one. I use it a lot, but really miss it during my 777 or 747 decents. How do Pilots irl know what Vertical Speed to set?

As far as I know the 777 and 747 does not have them. The 747-8 however does and we simulate it on the upcoming 748.

IRL vertical speed isn't used very often, though this depends on the airliners, and pilots. If they used is they use the green banana for reference, or if you are old school use the banana and crosscheck with the theory :)

 

 

[Victoroos 205]

33 minutes ago, Olympic260 said:

As far as I know the 777 and 747 does not have them. The 747-8 however does and we simulate it on the upcoming 748.

IRL vertical speed isn't used very often, though this depends on the airliners, and pilots. If they used is they use the green banana for reference, or if you are old school use the banana and crosscheck with the theory :)

 

 

aahh, that makes sense. simply due to technology? But the t7 is newer than the 737? or is it because of the amount of landings.

what would they use.. instead of vertical speed? level change? or vnav always?

nice \o/ 748!

[hvw 381]

Victoroos,

Watch this tutorial and you will see the correct way to perform a RNAV.

Hans

[kevinh 409]

38 minutes ago, Victoroos said:

aahh, that makes sense. simply due to technology? But the t7 is newer than the 737? or is it because of the amount of landings.

what would they use.. instead of vertical speed? level change? or vnav always?

nice \o/ 748!

Actually the 737NG’s first flight was three years after the 777’s first flight. So the NG is a newer design.

[Victoroos 205]

27 minutes ago, hvw said:

Victoroos,

Watch this tutorial and you will see the correct way to perform a RNAV.

Hans

Thanks Hans. Removed the video from the quote for size, but thanks. I will. Love the satellite in the thumbnail!

10 minutes ago, kevinh said:

Actually the 737NG’s first flight was three years after the 777’s first flight. So the NG is a newer design.

Ooh, schnapp. cool! thanks for the trivia :)

[Ephedrin 418]

3 hours ago, Victoroos said:

aahh, that makes sense. simply due to technology? But the t7 is newer than the 737? or is it because of the amount of landings.

what would they use.. instead of vertical speed? level change? or vnav always?

nice \o/ 748!

 

3 hours ago, kevinh said:

Actually the 737NG’s first flight was three years after the 777’s first flight. So the NG is a newer design.

 

and typically  (yes, there are exceptions of course) the airports you fly to with a 777 are equipped completely with all you need... a 777 is treated slightly different from a 737 that can actually land everywhere... a 777 is hugh, heavy (I know, the simulator view doesn't really show it) and requires an airport that can handle it... these airports normally aren't fitted into valleys etc. You fly the STARs, get vectored to the localizer, there's much less to improvise.. so you don't need all those little gimmicks a 737NG has (just compare the FMS) :D

[skelsey 765]

5 hours ago, Victoroos said:

400ft? And what if the minimus / no runway in sight are lower than that?

I'm not sure where 400ft came from. As a general rule, no A/P below MDA on a non-precision approach.

Thus, you can keep the A/P in down to MDA if you wish. At this point, you are either visual = disconnect the A/P and land it, or you are not = go around.

5 hours ago, Victoroos said:

Speaking about VSD.. why is only the 737 equipped with one. I use it a lot, but really miss it during my 777 or 747 decents. How do Pilots irl know what Vertical Speed to set?

A little bit of maths!
 

As mentioned above, V/S is rarely used other than to finesse a descent (e.g. to achieve a CDA) or to reduce an excessive rate of climb (e.g. to prevent setting off a TCAS RA on an aircraft 1000 ft above your cleared level). However, the V/S is simply the number of feet you will climb or descend in a minute; so if you are arriving at a waypoint in 2 minutes and you need to lose 2000 ft then you need a 1000 fpm descent, for example ;).

Other than that; other useful formulas include

• Rate of descent for a 3 degree glidepath = groundspeed x 5 (my brain finds it easier to multiply by 10 and then divide by 2 -- so at 140 kt ground speed on a 3 degree glide path you will need 140 x 10 = 1400 / 2 = 700 fpm rate of descent (roughly)
• Height = 3 x distance (e.g. at 50 nm out you should be at 3 x 50 = FL150) or FL/3 (FL180/3 = should have 60 nm to run). Throughout the descent you should keep a constant note of this and compare where you are vs where you ought to be; some 'gates' at FL200, FL100 and 3000 ft are worthwhile. Obviously if you are using the FMC progress page for your track mileage to run it is essential to ensure that the magenta line reflects accurately what you expect to fly!

[kevinh 409]

2 hours ago, Ephedrin said:

 

 

and typically  (yes, there are exceptions of course) the airports you fly to with a 777 are equipped completely with all you need... a 777 is treated slightly different from a 737 that can actually land everywhere... a 777 is hugh, heavy (I know, the simulator view doesn't really show it) and requires an airport that can handle it... these airports normally aren't fitted into valleys etc. You fly the STARs, get vectored to the localizer, there's much less to improvise.. so you don't need all those little gimmicks a 737NG has (just compare the FMS) :D

If it was about aircraft size the 747-8 wouldn’t need a VSD or IAN but it has them. No doubt the 777X will have it too. Having a VSD improves terrain awareness for any aircraft. So there is no reason not to have improve display features or enhance the navigation system in a new or upgraded design.

Edited March 19, 2018 by kevinh

[kevinh 409]

7 hours ago, Victoroos said:

Speaking about VSD.. why is only the 737 equipped with one. I use it a lot, but really miss it during my 777 or 747 decents. How do Pilots irl know what Vertical Speed to set?

It’s worth knowing Simon’s maths techniques, but there is an easier way.  You adjust vertical speed until the green arc on the ND map is over the position you want to be at when you reach the new cleared altitude.