RNAV Approaches

Hi

I'm having real trouble with them. Sometimes they work, sometime not. Really inconsistent.

Has anyone got them to work consistently?

What would be a well-prescribed method?

Thanks

Comments

  • Does this affect different airports or does it affect a particular airport?

  • any airport

  • Fair enough to say that sometimes they and work and other times they do not, but what specifically are you seeing issues with? Have you set everything up correctly for the approach, I do not fly RNAV approaches but if I recall your altimeter setting must be correctly set to the field elevation of landing. If you are experiencing the same issue(s) on each approach, or seeing something specific at a particular airport then kindly be sure to make reference of it when posting so that others can check it out and give possible feedback if needed.

    There are several YouTube user have some good tutorials with useful information on RNAV approaches.

    Keep the Blue side Up!

  • Thanks....I'm going to keep testing and report back.

    Really appreciate the helpful support.

  • edited June 6

    Ok, I think I've figure this out. This may be useful to some of you. Som eof you may know how this done, but here it is.....

    1 - I arm my approach before the IAF in the FMS
    2 - I hit altitude restrictions using ALT, VS, and ALT SEL prior to the FAF
    3 - When you get LNAV APPR in the PFD (Just before the FAF, I think) I go to the VNAV page in the FMS - the vertical guidance will appear in the PFD - this was the problem for me - that page needs to be selected
    4 - I then set ALT at just below the MDA - this needs to be quickly done
    5 - Hit VNAV and APPR on the MCP

    Hey presto.....it works. The plane smoothly follows the vertical and lateral guidance.

    I've just tested this an NZQN on both a GNSS and an RNP approach to RWY 23 (challenging approaches) and what a fantastic experience it has been.

    I also just upgraded to the pro version and the control difference is amazing.

    What a plane.

  • It's also worth noting that a lot of RNAV approaches have no vertical guidance. This is the case with LNAV and LP types, which made up half of US RNAVs in 2016 (can't find more recent data). I've wasted time in the past trying to 'fix' my stubbornly unchanging altitude when the approach actually had no vertical component in it.

    LNAV/VNAV and LPV have vertical guidance and behave more like an ILS.

  • If you are looking for updated approach charts for the USA you have plenty of sites to get them. The FFA site:
    https://www.faa.gov/air_traffic/flight_info/aeronav/digital_products/dtpp/search/

    JP

  • RNAV approaches have been broken since release in the MJC Q400. If an approach has in intermediate course correction or fix in general between the FAF and runway it will fuck the descent profile. I would not have any hopes on it being fixed anytime at this point.

  • Feel free to Express your displeasure with our product but continued use of profanity will have your offensive post(s) deleted. If this was an uncensored forum then fire away....but it is not.

  • LNAV is easy......Getting VNAV PTH and GS was the tricky bit. It just seems to need to be on the VNAV page of the FMS for the vertical guidance to com "alive". I haven't experienced the "messing up" of the descent profile.

  • The technique is simple, we use LNAV\VNAV and go down to DA\MDA and disable autopilot (or earlier if there are visible landmarks)...

    Quite accurately (in accordance with the documentation) can be seen here

  • In my opinion RNAV's are mostly ok on the Q400. I have found some exceptions, the main one being RNP approaches. They sometimes spit the dummy. That's probably not going to be a problem, because I doubt the Q equipment would be certified, in real life, for RNP's anyway. As this is a sim, we want to do everything though. I stand to be corrected about the Q400 RNP certification, as I don't fly airliners in real life.
    Choose an RNAV approach that is suitable for your needs. Check out the charts on the appropriate web pages, then see if the Q400 FMC includes the one you want. Marry your choice to an Arrival which is suitable for your Approach. If you do this correctly the Q400 will mostly fly right down to the field and you won't need to touch the yoke. I know, RNAV's aren't substitutes for ILS coupled landings, but the Majestic Q does a good job anyway. On my computer the Q will easily get me to minimums shown on the charts, using RNAV.

    Good luck
    Dasher

  • The Dash 8-Q400 is certified under the airworthiness regulations of JAR 25 (including
    change 14) and JAR-AWO (change 1 plus orange paper AWO 91/1).
    The nav-equipment meets the requirement for RNP 1 (P-RNAV).

  • edited July 20

    @niksan29

    If you're a real Dash Pilot, you'd like to know what the Majestics Dash is about.
    You have 2 variants, with or without HGS If you write that your Dash is approved for RNP 1, that's sufficient in my view only for the Initial Approach, the Intermediate Approach and the Missed Approach, which have a RNP of 1.0 , The final approach would need 0.5 (RNAV) or 0.3 (RNAV GNSS / GPS). I have not considered RNAV RNP or RNAV AR with RNP <0.3.
    RNAV RNP does not work, because the Majestics does not own RAIM.
    By the way, the Majestics should not fly to EGLC either, as the additional equipment for the Steep Approach is missing, as well as the Dash without HGS is only ILS CAT 1.
    The Majestics work according to FMS Database with the RNP values ​​2.8 (E) / 1.0 (T) / 0.5 (A), whereby you can enter 0.3 manually, if you have not got the approach armed, then it will not work for me anymore. The question, but would that be allowed with the RNP 1 you mentioned?

    By the way, here is an interesting study on the RNAV implementation of the Dash
    http://gf3.myriapyle.net/aero/Fichiers/RNP.pdf

  • edited July 21

    I do not know such details, and is certified for RNP 1 at flybe airline, other companies may have higher limits;)
    But I want to add, that my RNP (majestic dash 8)accuracy is usually around 0.14, which means you can land with high accuracy requirements RNP 0.30;)

    P.S 1) Without hgs, cat 2 landings are allowed, where do you have information that only cat 1?
    2) And what equipment is not enough for steep approaches you can say?

  • Hello, with CAT 2, I have to revise well, goes without HGS.
    But I still believe in the Steep Approach because not all Dash 8 q400 are equipped for it. In particular you can see that in the missing EGPWS STEEP APPROACH MODE SWITCHLIGHT and partly in real images of a dash cockpit with a corresponding sticker.

    That with the personal certification RNP 1 (corresponds to yes RNAV 1 / P-RNAV) I understand so unfortunately not quite. That the Dash of Majestics and then probably the real Dash with a ANP 0.14 flies, can be yes (you can see on the NAV Page), but for the APPR phase are yes 0.3 vorgesenen, or am I wrong? How do I have to understand this in terms of your certification or that of the aircraft?

    Not every plane is allowed to do everything, unfortunately this is not always so obvious in the flight simulator. Of course I can do anything I want in the simulator, but that's not my claim. A friendly A320 pilot was recently unable to take over his plane because it had to fly to an alternative location. The reason, the ILS of the main runway of the airport was waited, for the smaller parallel runway there is only one RNAV (GPS) and one NDB Approach. The Airbus of a large German airline had no GPS (older model), so the RNAV Approach was not allowed to be flown. However, the weather conditions for the remaining NDB approach were no longer sufficient, ie Alternate Airport.

    So I am just interested in a realistic approach as possible. For RNAV RNP procedures, it would indeed require a working RAIM, which is not yet fully implemented in the Majestics (in the training version this comes probably). So RNP Approaches fall away too, especially the question of whether the Dash can really fly RF Legs.
    In sum, a lot of stuff for learning (and misunderstanding), so I think it's good, if real pilots take the time for us - thank you

  • edited July 31

    I've never seen the indicator steep approach in real life, but i have
    the FCOM requirements:

    Steep Approach and Landing
    The following limitations apply to steep approaches and landings.
    • A flap setting of 35° must be used.
    • The EGPWS must be serviceable.
    • A screen height of between 35 ft and 60 ft is applicable.
    • Anti-skid brake control system must be serviceable.
    Flight spoilers must be operative in the Ground mode.
    • Maximum runway slope is ±0.5%.
    • The maximum tailwind component for landing is 5 knots.
    • Maximum landing mass is 26,308 kg.
    • Minimum height for transition to the steep approach is 1000 ft AGL.
    • Landing gear down, flap 35º and Condition levers to MAX, must be selected prior to
    commencing a steep approach.
    • A steep approach must not be commenced or continued with only one engine
    operative.
    • Minimum height for go-around following an engine failure is 300 ft AGL, flap 35º.
    Note: Height loss in the go-around, following an engine failure, is 150 ft.
    • Minimum DH is 300 ft Above Runway Threshold Elevation (ARTE).

    This item has caused me a special interest: Flight spoilers must be operative in the Ground mode ,it means that spoilers should be in taxi mode? :o

    About the RAIM function, I don’t know how to check its activity / work, I think either a real pilot or a developer can tell us here...

  • "Flight spoilers must be operative in the Ground mode"
    It means that the roll spoilers ground mode, must be in working order (not MEL'd) before attempting a steep approach. The spoilers are a part of the pre-flight checks, I do believe.

    From the Q400 MEL list.

    "The Q400 is permitted to fly with the roll spoilers (ground mode system) inoperative, 
    

    provided:
    a) Associated inboard or outboard pair of roll spoilers (ground mode) are deactivated, and
    b) Appropriate CFM performance decrements are applied per AFM Supplement 17 “OPERATION WITH INOPERATIVE FLIGHT SPOILERS IN GROUND MODE”."

    Cheers

  • hmm, it's hard for me to understand. Let's start with the fact that this is a mode roll spoilers ground mode?

  • From what I know, it is another part of the roll spoiler system.
    In flight the roll spoilers act as an assistant to the ailerons in low speed flight (ie, approaches).
    On landing, as the main gear touch the runway, the spoilers deploy to provide braking (ground mode).

    The real Q400 can be flown with the system that deploys the spoilers during landing, inoperative. 
    

    With the spoiler system deactivated, the ailerons would be the only roll control surfaces available. With the ailerons being rather small on the Q400 pilots would probably have to limit their bank angles during take-off and approach maneuvers. There would possibly be limits on the amount of crosswind in which the aircraft would be allowed to make an approach. As in the MEL list, steep approaches would not be permitted.

  • edited July 31

    if try to describe it rather briefly: spoilers must be in working condition and set to flight mode, or did I misunderstand again? :s

  • Yes. For a steep approach, the flight/taxi switch will be in the "flight" position, and the spoilers will be in good working order. In the majestic Q400 it is the same as for a "normal" flaps 35 approach, as spoiler failures are not modeled.

  • Thx!
    Just about complicated :D

  • edited August 2

    I found a little information for the user FraPre and for everyone who did not know this :)

    He asked me above: > and then probably the real Dash with a ANP 0.14 flies, can be yes (you can see on the NAV Page), but for the APPR phase are yes 0.3 vorgesenen.

    I answer: you wanted to say RNP 0.14 and RNP 0.30, not 0.3)))

    Different operators have different certification, Flyby proceeding from the FCOM , can only perform the EN ROUTE and TERMINAL phases(RNP 1 (P-RNAV)
    image-thumb1
    But other operators may have better performance and certification, eg Horizon Air have
    HUD CAT 3 and RNP allowed
    Horizon

    As for our Majestic, I think it is certified to the maximum requirements and performance that are possible for dash 8 q400, such as Horizon Air and the like
    https://youtube.com/watch?v=Yv90kPhT3Z8
    Or at least RNP 0.30 performance, although most of the time, accuracy and performance are higher and equal 0.14 ;)
    dash-doc

    P/S the RAIM will give warnings, if you set the accuracy manually to the 0.14 or lower >:)

  • Thank you @ niksan29, I know the pictures to the RNP yes, it was just missing a clear statement, what the Majestics Dash can or may, say their certification. In the Approach Phase, the Majestics only give an RNP of 0.50 for the Approach, so you always have to enter the 0.30 by hand. I had also bought the FO version of Airline2Sim because of another RNAV question, because the RNP 0.30 was named. But if I read that correctly, the pilots of Flybe, so they are not allowed to fly an RNAV approach, had to inform themselves first as well. In the end, they flew only a standard approach, so as published in the charts. My questions about the approach with Vectoring before (see other thread), the episode has thus not answered.

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