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7 Answers

When to decsend using Jepp plates..

Asked by: 6413 views Instrument Rating

On Jeppesen approach plates, with a non-precision approach. When can you descend to the initial altitude on the approach plate if you are cleared for the approach? I know the NOS charts depict the 10NM ring around either the final approach fix or the initial approach fix and you can descend when established inbound and remain within 10NM... However the Jepp plates do not have this ring. Is there a way to know when you can descend to that initial approach altitude when cleared for the approach using Jepp plates? Thanks.

7 Answers

  1. Matthew Hammer on Sep 18, 2010

    I may be misunderstanding your question, but as far as I know the 10NM ring has nothing to do with when you descend for an approach. In support of this I could point out plenty of non-precision approaches where the IAF is located *outside* the 10NM ring (for example, the VOR/DME approach into W99). When you are cleared for an approach, maintain the altitude ATC assigned you until you are located on a portion of that approach, then make your descent to the appropriate altitude.

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  2. Pete on Sep 18, 2010

    i completed my instrument rating back in April of this year using Jepp plates. Please someone correct me if I’m wrong for any of this:
    First off, the 10nm ring you see on NOS plates i think is for procedure turns which should be completed within 10nm of the primary navaid. i’m shaky on that, so double check. keep in mind the navaid is usually not on the field either.
    part 91(.175(c)) talks about adhering to the MDA and what allows you to descend below it, but as for descending TO the MDA, once you are cleared for the approach, you fly the approach and all the altitudes that are applicable to the section you are on. this means that the MDA; whether it’s part of a segment, or a sector (as in a GPS approach) you are cleared down to that altitude – HOWEVER, in the case where an MDA (and i might need correcting on this) is part of a segment, i.e. the thick black line on a chart, you must be ESTABLISHED on that course before descending to it’s MDA from your last assigned altitude – neither part 1 of the FARs, or the two FAA instrument handbooks define “established” but my CFII taught it as less than 2/3 deflection of the needle (GPS or VOR). ATC will usually get you established before clearing you as well though – provided you are in radar coverage. not a problem here in the boston area.
    finally – Jepp non-precision plates give you a descent angle usually. this is nice and impressive in a lesson under the hood, but in the real world – dive and drive! maintain the MDA instead of dividing your time perfecting an imaginary glideslope! in addition, the MDA might be below the deck. it’ll give you time to stabilize your approach and keep you above the pointy things on the ground.
    best of luck

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  3. Matthew Waugh on Sep 18, 2010

    The original poster is very confused about when they can descend without a specific ATC instruction – and this confusion will kill them one day, so I suggest they do more than look to this bulletin board for their instruction.

    However – you may only descend to without a specific ATC instruction when you are established on published segment of an approach and have been cleared for the approach. Some RNAV approaches establish sectors with a published altitude and, if you are cleared for the approach, and in that sector, you may descend to that altitude.

    It can’t be emphasized enough – randomly descending because you are close to an airport will kill you. As somebody else pointed out the 10NM ring defines a range that you may not exceed in a procedure turn, but unless you carefully map out the TERPs clearances within that procedure turn you don’t know the protected area, and descending to the procedure turn altitude because you are inside the 10NM ring is not a good idea because, at risk of repeating myself, it will kill you.

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  4. Matthew Hammer on Sep 18, 2010

    As I understand it the ring simply indicates that everything within it is drawn to scale. It certainly does not mean you are safe within 10 NM to perform a procedure turn, since many approaches have the ring but also require you to be at less than 10 NM for the entire procedure. A perfect example of this would be the VOR-A approach into 12N. It clearly has a 10NM ring in the plan view, yet the profile view says to “remain within 5 NM.”

    As a reference I would refer you to the Instrument Flying Handbook. Particularly pages 8-18 and 8-20. (Available for free here: http://www.faa.gov/library/manuals/aviation/instrument_flying_handbook/ )

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  5. Joe on Sep 23, 2010

    Guys, I really appreciate the responses!
    What I am really asking here (and it has yet to be answered), is when can you descend to an altitude on the initial segment on the approach if you are doing a course reversal OR if you are being vectored onto the approach and then cleared for the approach, but still a bit far from the FAF?…
    To make myself a bit more clear…. suppose you are shooting the VOR 29 into Millinocket Muni (MLT)… You are vectored onto the final approach course (319 degrees) at 4,000ft. You intercept (are established) but you are 20 miles from MLT. When would you descend to 3,000ft?
    Another example would be when the facility is on the field…
    Suppose you were shooting the VOR 24 at Brigeport, CT (BRD) and you were vectored onto the final approach course (234 degrees) from the north at 3,000 Ft. but you are on a long final, say 18 miles. When would you descend to the published 1,800 Ft. on the initial approach segment…
    Thanks for your insights, don’t worry I’m just a new instrument student!

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  6. Best Answer

    Eric Gideon on Sep 28, 2010

    Jeppesen charts have a “Remain within 10 NM” label printed within the profile view if a limitation applies. This is the equivalent of the plan view ring that appears on the government format.

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  7. M Gallagher on Nov 22, 2010

    “Suppose you were shooting the VOR 24 at Brigeport, CT (BRD) and you were vectored onto the final approach course (234 degrees) from the north at 3,000 Ft. but you are on a long final, say 18 miles. When would you descend to the published 1,800 Ft. on the initial approach segment…
    You should have been given an altitude with your approach clearance (ie “cross XXXXX @ ZZZZ; cleared for RWY24 approach”) At any rate, you CANNOT leave your last assigned altitude until you’re established on a segment of the approach, which in this case looks like BAYYS intxn. Thus, you’d maintain last assigned until BAYYS, then descend to 2600 as listed. From there you’d simply follow the profile view to MDA (2600 to KNELL;then 1800 to MILLUM).
    Hope this helps clarify what I think you’re asking.

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