NDB Approach question

Discussion in 'Cleared for the Approach' started by Walboy, Feb 15, 2018.

  1. Clip4

    Clip4 En-Route

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    I would maintain 5000, crossing the NDB I would turn right to a heading of 345 and slow to 100 KIAS, time out bound 2:00 upon crossing the 305 degree bearing from the station and start descent to 2800 ft. Then a left turn to 170, intercept and descend to MDA.
     
    Last edited: Feb 23, 2018
  2. aterpster

    aterpster Pattern Altitude

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    Just to be clear, the descent to 2,800 can be commenced overhead the NDB as soon as the outbound turn is started. The procedure turn area has an entry zone and a maneuvering zone. The altitude for both is 2,800 in this case. When there is an obstacle in the entry zone that requires a higher altitude until within the maneuvering zone, that entry altitude restriction will be charted in the profile view above the NDB.
    PT Area.jpg
     
  3. MauleSkinner

    MauleSkinner En-Route

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    I think it's important to understand what that protected airspace generally looks like...I've had a couple of jet instructors over the years who thought there was no protected airspace on the "unprotected" side. They considered a parallel entry to be inherently dangerous (I consider them to be inherently too much work ;) ).
     
  4. aterpster

    aterpster Pattern Altitude

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    This is different than the protected airspace for a HILPT.
     
  5. luvflyin

    luvflyin Final Approach

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    They have a lot of space on the other side. FIG 5-3-7 of the AIM has a pretty good picture of it even though it's about slant range correction. The picture of the pattern itself is accurate. Like the PT, there's almost as much space on the 'non holding' side as the holding side.
     
  6. aterpster

    aterpster Pattern Altitude

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    True enough. Having said that there are only three templates for the 10 miles procedure turn, depending on altitude. For the HILPT there are 10 templates, depending on altitude.

    For the conventional procedure turn, there can sometimes be entry maximum altitude (ALW example) and in some cases an entry zone altitude restriction (JAC example):

    KALW ILS.jpg KJAC ILS Y.jpg
     
  7. luvflyin

    luvflyin Final Approach

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    Is 6000 the cutoff point for the lowest template? Theres another approach at Walla Walla that uses the same PT without the no higher than 6000 restriction. It's 'turn' altitude' is 1200 feet higher though, 4900 vs 3700 on the ILS approach. The bigger template probably didnt accomodate having to get down lower to get the glideslope. Wonder if it was the windmills or the terrain itself.
     
  8. aterpster

    aterpster Pattern Altitude

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    Yes, 6,000 is the cutoff for the smallest template. The second goes to 10,000, and the third above 10,000. If they had used the mid template at ALW, they wouldn't have had to chart the restriction. Don't recall the reason, other than it was not necessary. It became a "cultural" thing for the designers that had that area for a time.
     
  9. Clip4

    Clip4 En-Route

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    True, but I was in no hurry to descend and I am a believer that altitude is usually your friend.
     
  10. aterpster

    aterpster Pattern Altitude

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    No disagreement there. But, that's technique rather than procedure.
     
  11. GenAv

    GenAv Filing Flight Plan

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    Very late to the party here, but was surprised to get 42 posts down before it was clearly stated in a response that one could descend down to 2,800 upon crossing the NDB for the outbound. I am guessing others did not state that b/c they would have employed a technique delaying the descent to the procedure turn altitde, but just surprised to see no one clearly stated that until post 42.
     
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  12. MauleSkinner

    MauleSkinner En-Route

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    That's because post 41 was the first to show that there might be some misunderstanding in that area. ;)
     
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  13. Dave S.

    Dave S. Pre-takeoff checklist

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    The key is in the order of the words. The controller, almost certainly, wants you to stay at 5000. The problem is that one the words “cleared for the approach” that cancels the 5000 foot sticker allowing you to descend. But it depends on the clearance. Are you being vectored. If so ATC must give an altitude to maintain until established on the route segment to which you are being vectored and at an altitude that meets the route segment altitude minimum. Such as “maintain 5000 until the ndb ( or procedure turn or pt inbound or established on final ( assuming the final is displayed on the scope)or some such) cleared ndb approach.”

    If on a clearance direct to the ndb ““maintain 5000 until the ndb ( or procedure turn or pt inbound or some such) cleared ndb approach.”

    But when he said “ cleared for the ndb approach” last in the sentence he canceled the 5000 altitude which leaves you with no altitude assignment for the off route to the ndb as required by 7110.65.

    Another classic case of poor non-standard non-book phraseology.

    Tex
     
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  14. aterpster

    aterpster Pattern Altitude

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    The pilot is bound by 91.175(i) not the 7110.65.
     
  15. Dave S.

    Dave S. Pre-takeoff checklist

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    Didn’t say he wasn’t. And exactly what part of 175 is in play here?

    The standard FAA phraseology is “...maintain 5000 U N T I L (fill in the blank) cleared NDB approach”.

    By not doing so ATC removed the 5000 foot assignment (technically) leaving the pilot without an altitude assignment between his position and a subsequent route...TECHNICALlY.

    We all know what he meant...or do we? That’s what standard phraseology is for. We have no way of knowing how far the controller wants the pilot to maintain 5000. Till the NDB? Till the procedure turn? Till established inbound? That’s what the purpose of “until” is.

    “Maintain 5000 until the NDB cleared NDB approach” is quite a bit different from “maintain 5000 until procedure turn outbound cleared NDB approach” or “maintain 5000 ????? Cleared NDB approach”.

    The pilot should question the improper clearance.

    Tex
     
  16. MauleSkinner

    MauleSkinner En-Route

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    The altitude clearance is still 5000 feet until established on the approach, whether the controller says those words or not. If you look at the history of the “maintain xxxx until established” terminology, it was added due to confusion about the proper altitude resulting in an accident after leaving an assigned altitude too early. It didnt change the altitude to be flown, just the way it’s communicated.

    But yes, if there’s any question, it should be clarified.
     
  17. Dave S.

    Dave S. Pre-takeoff checklist

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    Getting back to the question...

    If you assume the controller wants you to maintain 5000 until, let’s say the NDB, then at the NDB you would leave 5000 and descend to the outbound approach altitude and begin the approach.

    Tex
     
  18. luvflyin

    luvflyin Final Approach

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    Yeah. Controllers clearance was wrong. The 7110.65 tells them how to do it right. FAR 91.175(i) tells the pilots what to do when ATC doesn't do it right. FAR. Not AIM or AC. FAR. 91.175(i) is written in blood. http://libraryonline.erau.edu/online-full-text/ntsb/aircraft-accident-reports/AAR75-16.pdf
     
  19. aterpster

    aterpster Pattern Altitude

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  20. aterpster

    aterpster Pattern Altitude

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    91.175(i). Pilot is bound by it whether or not he gets clarification.

    (i)Operations on unpublished routes and use of radar in instrument approach procedures. When radar is approved at certain locations for ATC purposes, it may be used not only for surveillance and precision radar approaches, as applicable, but also may be used in conjunction with instrument approach procedures predicated on other types of radio navigational aids. Radar vectors may be authorized to provide course guidance through the segments of an approach to the final course or fix. When operating on an unpublished route or while being radar vectored, the pilot, when an approach clearance is received, shall, in addition to complying with § 91.177, maintain the last altitude assigned to that pilot until the aircraft is established on a segment of a published route or instrument approach procedure unless a different altitude is assigned by ATC. After the aircraft is so established, published altitudes apply to descent within each succeeding route or approach segment unless a different altitude is assigned by ATC. Upon reaching the final approach course or fix, the pilot may either complete the instrument approach in accordance with a procedure approved for the facility or continue a surveillance or precision radar approach to a landing.
     
  21. Datadriver

    Datadriver Line Up and Wait

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    My understanding is that NDBs are being phased out when they break. Once it breaks, it's gone forever.
     
  22. spiderweb

    spiderweb Final Approach

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    Are you doing this for "fun."

    Way back when it was required, my instructor signed me off for the practical when I was able to perform a PP NDB approach. It wasn't asked for in the practical, I've never had to do one (though I've had to do other PP approaches), and I don't see the point of them, on mainland America, in 2018, except for the challenge.
     
  23. MauleSkinner

    MauleSkinner En-Route

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    Not necessarily...the FAA has determined which of their NDBs will be phased out or kept. Locally-owned NDBs (city, state, county, whatever) May differ in that regard.
    Up until 7 years ago, I was still doing them fairly regularly in real life.
     
  24. spiderweb

    spiderweb Final Approach

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    I was actually asking the OP, but I can also ask you: JOOC did you do them for fun, or because you had no other choice?
     
  25. MauleSkinner

    MauleSkinner En-Route

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    That was the only way to get into those airports.
     
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  26. spiderweb

    spiderweb Final Approach

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    Very cool.
     
  27. aterpster

    aterpster Pattern Altitude

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    When the GPS overlay program was launched in the 1990s, virtually every NDB and VOR approach was made "...or GPS." Then, as an RNAV (GPS) approach was added at a given airport, the "..or GPS" was removed from any NDB or VOR approach at the airport.