Welcome Guest. Sign in or Signup

7 Answers

Approach Plate Terminology

Asked by: 2481 views General Aviation

1. What is the menaing of "ATC climb" when published on a SID?

Example: Runway 8--- 220' per NM to 2200, ATC climb of 300' per NM to 4500".


2. What is the meaning of " NA-ATC" found on certain SIDs. Specifically, what does the ATC portion mean? (I understand NA means not authorized).

Example found under the "standard minimuns section": Rwy. 8 / 9/ 10 NA-ATC

 

 

Thank you for the feedback.

 

Dan

 

 

7 Answers



  1. Mark Kolber on Mar 31, 2013

    “ATC Climb” and its meaning are discussed in AIM 5-2-8, the AIM section on Departure Procedures.

    It’s a term generally associated with obstacle departure procedures and just means that the climb gradient is for traffic control or airspace purposes and not for obstacle clearance. It’s also letting you know (since it’s a traffic and not obstacle issue)ATC can change it as part of your clearance and you don’t have to worry about following the revised instruction.

    I’m fairly certain “NA-ATC” (which is not described in the AIM) has a similar meaning – the “ATC” means it’s for air traffic control purposes (is the one you looked at near a restricted area) rather than for obstacle clearance.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  2. Dan Chitty on Mar 31, 2013

    Mark,

    Thank you for the feedback.

    If ATC decided that the “ATC climb” of 300′ per NM is not needed, what verbiage would ATC use to notify the pilot?

    Why not just make 300′ per NM the minimum climb gradient instead of having 2 separate climb gradients?

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  3. Mark Kolber on Apr 01, 2013

    Dan,

    I’d be guessing about the “why not?”: The purpose of an ODP is to guarantee obstacle clearance. The “ATC Climb” information is not really part of it. It’s like some of the information on approach charts (like communication frequencies) – not really part of the regulatory IAP created by TERPS standards.

    If a non-standard gradient of 220 FNM is sufficient, there’s no reason to publish a higher one from an obstacle clearance perspective. The 220 is not a big deal, but as you get to higher terrain at higher density altitudes, you reach a point where the needed climb gradient is beyond the capabilities of some aircraft. That will also be true of airspace-based gradients, but would you rather ask ATC for a shallower climb where the issue is other traffic or use a shallower climb rate where the issue is rocks?

    If ATC decided the 300 FNM were not “needed” they probably wouldn’t say anything unless you asked for a shallower climb rate; no reason to. OTOH, if ATC needed a different climb rate, they’d simply give you a different profile – just as they do with the altitudes on SIDs and STARs or when asking you to adjust your speed on an IAP. “Cessna 1234X. Maintain at or below 400 feet per minute in the climb.” The “ATC Climb” is your signal that you won’t hit rocks if you comply.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  4. John D. Collins on Apr 01, 2013

    ATC needs you to have the 300 ft/NM capability to fly the procedure. If you can’t climb at that rate, you need to negotiate with ATC prior to accepting the clearance. If you can’t climb at 220 ft/NM, negotiation is over as there is no way you can safely follow the procedure. ATC can reduce their climb requirement down to but not below the minimum. That information may be necessary for some operators.

    +1 Votes Thumb up 1 Votes Thumb down 0 Votes



  5. Dan Chitty on Apr 02, 2013

    John,

    Per your comment above, I found the “NA-ATC” notation on the BLZZR TWO SID at KBOS. Notation is listed under the “Takeoff Mins.” section and applies to several runways at KBOS.

    What I do not understand is why this SID is acceptable/approved for some of the runways but not for others?

    I greatly appreciate any feedback.

    Dan

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  6. Mark Kolber on Apr 03, 2013

    Dan, step back for a moment and think in terms of what a SID is – it’s shorthand method for what would otherwise be a lengthy clearance from ATC repeated again and again at a busy hub airport with many, many operations a day.

    So your question is roughly equivalent to asking why ATC vectored you in a certain direction or cleared you along a certain route.

    If I would guess on the reasons in this case, I would go with:

    1. If the other runways used that routing, it would cause traffic conflicts.
    2. Since the note on the graphic refers to noise sensitive locations, the SID routing might cause a problem if used on the other runways.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  7. Dan Chitty on Apr 03, 2013

    Mark,

    You make a great point and what you mention makes perfect sense. Thank you for the always great feedback.

    Regards,

    Dan

    0 Votes Thumb up 0 Votes Thumb down 0 Votes


Answer Question

Our sincere thanks to all who contribute constructively to this forum in answering flight training questions. If you are a flight instructor or represent a flight school / FBO offering flight instruction, you are welcome to include links to your site and related contact information as it pertains to offering local flight instruction in a specific geographic area. Additionally, direct links to FAA and related official government sources of information are welcome. However we thank you for your understanding that links to other sites or text that may be construed as explicit or implicit advertising of other business, sites, or goods/services are not permitted even if such links nominally are relevant to the question asked.