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bar_rodoy

RNP, GPS, and Autobrakes

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Hey. I am trying to understand how to fly different types of RNAV approach like a real pilot. I have read about RNP and GPS but I cant really understand the difference when it comes to fly the approach. I read about it in this forum, in the FCTM and several places on Google...I really need someone the make it clear for me. And what is the approach procedure for such approaches? Should I set something in the FMC? I heard that I have to disable DME and VOR location update, is that true?

 

 

Another issue for me is when I land, the Autobrakes goes straight to "Disarm". I dont know why, everything seems fine while I am approaching the runway but when I touchdown, the brakes wont work.....

 

By the way, would you recommend me the purchase AOA 737 videos? is it a good way to learn the aircraft perfectly insead of reading the whole FCOM?

 

Thanks in advance!

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RNAV- decent to the last way point then brought in manually

(ex. Chicago Midways RWY 22L is only a RNAV or Manual approach)

so when you are descending a RNAV arrival set you ALT to the 2nd to last Way point ALT. or even the last one before your T/D. Real World Pilots have ATC to vector them in. Many pilots actually have an advantage so they know what ALT to Descend VIA ATC. Simmers either have Vatsim (which isnt bad unless they are not online in your area you are landing at.) or we have FMC guidance and we have to get creative with ourselves, and vector ourselves in. RNAV approach isnt bad after you get the hang of it, just dont freak out when your last Waypoint on your FMC says for EX. 1200FT you will have plenty of time to manually descend after that. All RNAV approaches do the same thing im still a little confused on the RNAVY, RNAVX. if i had to say RNAVY would be descend for a high ALT airport and then RNAVX would be maybe a crosswind RWY. I hope this helps you out on understanding how  RNAV approaches work. 

 The brakes not working:

  1. check to see if your autobrakes are on.
  2. ​If they are on do not manual brake because then you will override and they wont work after that.
  3. press F2 to put on reverse thrusters and / to put up the spoilers.

I had that problem once it was the weight of the aircraft. Buy PFPX or TOPCAT those wil choose the random weight for you. 

 

hopefully this helps

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Thanks! I do fly on VATSIM a lot with the NGX, I just have to refresh my knowledge (Lont time have passed since I learned it all the first time)     :-)

I do own PFPX + Topcat by the way

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ok yeah dont try to override the breaks if you. you shouldnt have that much weight on the plane anyways, and have fun doing RNAV approaches i still will go for ILS any day if available.

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Should I set something in the FMC?

 

Yes. You must select the approach from the ARR page. You cannot hand-enter the fixes and altitudes on the LEGS page (you can, but if you're going by what is legal in the real world sense, the FAA only allows RNAV approaches to be selected from the unit's database).

 

 

 


I heard that I have to disable DME and VOR location update, is that true?

 

Who told you that? No, this is not true, unless the approach procedure specifically requires it (would be listed on the chart is this were the case). I can't think of an approach that requires this, however. In general, more nav data sources is better to help verify aircraft location.

 

 

 


And what is the approach procedure for such approaches?

 

It's just like every other approach, really, when it comes down to how it's flown and what it is:

It's still an instruction on how to determine your position, and follow a path to the airport. The only difference is that it isn't based on a ground-based nav aid (LOC arrays and GS antennas are both ground-based nav aids - they sit on the ground and aid in help you determine your position along a lateral and vertical line). The RNAV solution moves this position of reference from the ground to satellites above you. That's it.

 

Follow line. Follow altitude instructions (either a step down approach like a LOC approach would be; or a guided vertical path in LNAV/VNAV, similar to an ILS). Land plane (in this case, by hand, since RNAV approaches are not certified to the ground yet).

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Who told you that? No, this is not true, unless the approach procedure specifically requires it (would be listed on the chart is this were the case). I can't think of an approach that requires this, however. In general, more nav data sources is better to help verify aircraft location.

 

Are you sure about this? DME and VOR updating should be turned off for RNP approaches

 

RNAV (RNP): Radios: Inhibit all VOR & DME updating from NAV OPTIONS page 2 prior to IAF

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Guys, thanks for you help. My major question is still what is the differnce between RNP and GPS/GNSS RNAV approaches? is it a matter of equipment on board?

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RNAV RNP just means AR (authorization required)

 

Then you have RNP APCH which is the RNAV GNSS and labelled on approach plates as (GNSS) or (GPS)

 

Both need special types of training and AR - authorization required is a whole different ball game.

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RNAV RNP just means AR (authorization required)

 

Then you have RNP APCH which is the RNAV GNSS and labelled on approach plates as (GNSS) or (GPS)

 

Both need special types of training and AR - authorization required is a whole different ball game.

 

I know I'm being a tiny bit pedantic, here, but I wanted to offer a slight clarification, at least for FAA-land:

 

RNAV(RNP) approaches are assumed to be AR. In the past, this was specifically called out on the chart with "SPECIAL AIRCRAFT AND AIRCRAFT AUTHORIZATION REQUIRED" or SAAAR. Now, it just says "AUTHORIZATION REQUIRED." In theory, one would have RNAV(RNP) as a base (like a CAT I ILS), with RNAV(RNP) AR as a higher qualification (like CAT II/III), but it seems the direction we're headed in is RNAV(GPS) for the base, and RNAV(RNP) for the higher qualification...because we like to confuse people.

 

As far as the labelling on the chart goes, however, RNAV(GPS) requires no training above a basic instrument rating. RNAV(GPS) approaches in the United States occasionally include mins that require WAAS/GRAS (like LPV), but this would only require different equipage in the aircraft, and no extra requirement of the crew. Of course, it would be in the best interest to the crew/pilot to seek additional training, but it is not directly legally required (though someone could make a strong case for FAR 91.103 as a "requirement" for gaining the knowledge somehow - training or otherwise).

 

I can't speak to the RNP APCH / RNAV(GNSS). We do not have those types of approaches here, though the references online do speak to requiring training for them. Additionally, the concept seems pretty confusing to me, since GNSS is supposed to be a term to refer to any nav system that's GPS-like (GPS, GLONASS, Galileo, etc). Alas, I try not to make sense of the odd procedures outside of the US unless I'm being paid to.

 

The rule of thumb for the States is:

If you see "AUTHORIZATION REQUIRED," then there's training for it. If not, then your standard instrument ticket will cover it. As far as which mins to choose, it's up to the equipage in the aircraft.

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Are you sure about this? DME and VOR updating should be turned off for RNP approaches

RNAV (RNP): Radios: Inhibit all VOR & DME updating from NAV OPTIONS page 2 prior to IAF

 

Help me out here, I'm trying to find the source for this information.  All I've found is FCTM 5.68 "inhibiting of navigation radio updating, as needed. VOR/DME updating must always be OFF. DME-DME updating must be inhibited as needed.  Note:In US airspace, and other airspace where DME positioning has been verified to be adequate, DME-DME inhibiting is not required."

 

Are there any other sources? Thanks again.

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