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7 Answers

RNAV SID Altitudes

Asked by: 2041 views Airspace, FAA Regulations

Why do some RNAV SIDs have MEAs/MOCAs and some RNAV SIDs do not have any MEAs/ MOCAs? Example: KMIA Deeep One RNAV SID contains MEAs/MOCAs. ┬áKMIA Hedly One RNAV SID does not contain any MEAs/MOCAs. Thanks for the feedback.    

7 Answers



  1. Mark Kolber on Apr 19, 2015

    Most likely because the designers of the SIDs simply did not have a need for a series of minimum segment step-up altitudes for the procedure. The general altitudes for the procedure in the absence of ATC-assigned altitudes for HEDLY ONE – 5,000 and filed altitude 10 minutes after departure are probably all they felt they needed for this procedure.

    If you’ll recall from prior discussions, the “MEAs” on a SID or STAR aren’t MEAs in the en route sense of providing minimum altitudes for acceptable navigational signal coverage and obstacle clearance requirements. They are more related to traffic requirements.

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  2. John D Collins on Apr 19, 2015

    Mark,

    I think MEA’s are defined by TERPS criteria including assuring obstacle and Com reception. If ATC wants to specify minimum or maximum altitudes on the chart, they may do so, but use a line over or under or both over and under to indicate this. There are some SID charts that inappropriately indicate an MEA when an ATC restriction is really what is intended, but these charts are not following the order for DP construction, HUGO 2 in the Charlotte area comes to mind. I think the reason for the MEA on the DEEEP One include the higher MEA may be related to Com reception out over the Atlantic.

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  3. Mark Kolber on Apr 20, 2015

    John, compare the “MEAs” on the DRONE arrival into Notfolk VA with the MEAs for the exact same routing on the enroute chart. So, is the TERPS defined MEA between, say RDU and TYI FL190 or 2500′?

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  4. John D Collins on Apr 20, 2015

    Great example. The MEA is the one on the low enroute chart for V194 and V1. The STAR chart shows a bogus MEA and is not charted correctly IMHO. I opened an issue at the Aeronautical Charting Forum on this topic, see the minutes below. If you have any more examples, it would be appreciated if you send them to me.

    VI. New Charting Topics

    14-02-280 MEA Usage on SIDs
    John Collins, GA Pilot, briefed the issue. John stated that the Legend within the TPPs says that altitudes depicted on SIDs are MEAs, yet many SIDS have altitudes specified that are of little or no operational significance. He noted that a comparison of the MEAs published on the IFR Enroute Charts to those that appear on the SIDS, shows that the altitudes often do not match and in some cases the MEA depicted on the SID is higher than the one published on the Enroute Chart.

    Valerie Watson, AJV-344, stated that from a charting perspective, the MEAs that appear on the SID are published on the procedure source document, FAA Form 8260.15B and are charted accordingly. The charting offices, of either the FAA or non-government, will chart what is on the source document.

    Tom Schneider, AFS-420, commented that the FAA Form 8260.46 provides for altitudes for the transitions, MOCA and MEA. Tom surmised that ATC devises the altitudes appearing on SIDs for their operational needs.

    It was agreed that the issue is not one of charting but of source. Tom stated that he would put a statement into the 8260.46 that MEAs should not be raised to support ATC altitudes and that if ATC needs an altitude for operational requirements, crossing altitudes should be used.

    STATUS: OPEN

    ACTION: Tom Schneider, AFS-420, to report on revision of the 8260.46 guidance on use of MEAs and Crossing Altitudes on SIDs.

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  5. Mark Kolber on Apr 20, 2015

    I know of that one because I’ve been assigned it, so I looked at the chart and noticed the discrepancy. If you come from the southwest of RDU heading to the Norfolk area, it will be typically be assigned as a matter of course.

    I would be interested in seeing the result of the discussion, one of which is, of course, establishing crossing altitudes and other restrictions rather than MEAs.

    Another, leaving the current box, is to treat them as a different type of minimum altitude. That’s why I think of them a “minimum segment altitudes” or “minimum procedure altitudes” subject to change by ATC instruction, established primarily for traffic control but with area minimum IFR altitudes (en route/OROCA) as a minimum base rather than “minimum en route altitudes.”

    They are, after all, minimums altitudes associated with departure and arrival procedures which are created for traffic control purposes, and are more akin to the procedures on approach charts than they are to en route charts.

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  6. Dan Chitty on Apr 21, 2015

    Thanks for the feedback. Nice discussion.

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  7. Dan Chitty on Jul 22, 2015

    Furthermore:—Hedly One for example

    Since DME/DME RNAV can be utilized, a pilot should want to know the MEA/MOCA so that one can determine optimal ground based navaid (VOR) reception along the entire SID route since radar vectors will only be utilized for a portion of the route.Once “resume own navigation” is applied, a pilot needs to understand which altitude will provide safe obstacle clearance and navaid reception. Per the SID note 5000 ft., and assuming my cruise altitude is only 5,000 ft, will 5,000 ft. provide terrain cleance and proper navaid reception for the entire rout of this SID?

    Even if utilizing GPS, a pilot does not need to be concerned with ground based navaid reception but does need to be concerned if 5,000 ft. will provide obstacle clearance assuming 5,000 ft. is the cruise altitude.

    Feedback appreciated.

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