Minimum Climb? (on a SID)
12-30-2014, 06:14 AM
#1
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Thread Starter
Joined APC: Dec 2011
Position: Captain
Posts: 52
Minimum Climb? (on a SID)
So I'm looking at the EDUKY THREE (RNAV) departure procedure at KRIL. With regards to Runway 8.
http://155.178.201.160/d-tpp/1413/06741EDUKY.PDF
Conventional wisdom indicates that this is a normal SID. It does NOT say "OBSTACLE" with inverted colors.
However, if you look at the Takeoff Minimums, it does say "Rwy 8: Standard with minimum climb of 396’ per NM to 11100". Does this mean that because it says "minimum" that you must maintain this rate to 11,100 ft. or else you may impact terrain?
Incidentally, I was under the impression that 396 ft/nm can be reduced by 48 ft/nm to remove the extra safety buffer and that would leave 0 ft. between you and terrain.
Now, when I look at the front of the Instrument Procedures book:
http://155.178.201.160/d-tpp/1413/SW1TO.PDF
Scroll down to "Rifle, CO". Here's what it says...
"RIFLE, CO
GARFIELD COUNTY RGNL (RIL)
TAKEOFF MINIMUMS AND (OBSTACLE)DEPARTURE PROCEDURES AMDT 10 12320 (FAA)
TAKEOFF MINIMUMS:
Rwy 8, std. w/ min. climb of 400' per NM to 11900 or 5400-3 for climb in visual conditions.
"
The Takeoff Mins section at the front of the book uses the same terminology as the SID page namely, "Min. Climb of xxx". Why are the gradients are different? Which one is for terrain and which one is for ATC?
I'd love to find an official FAA document that explains it all but everything I have found is in piecemeal and it seems like terminology is used very roughly.
Thanks everyone.
http://155.178.201.160/d-tpp/1413/06741EDUKY.PDF
Conventional wisdom indicates that this is a normal SID. It does NOT say "OBSTACLE" with inverted colors.
However, if you look at the Takeoff Minimums, it does say "Rwy 8: Standard with minimum climb of 396’ per NM to 11100". Does this mean that because it says "minimum" that you must maintain this rate to 11,100 ft. or else you may impact terrain?
Incidentally, I was under the impression that 396 ft/nm can be reduced by 48 ft/nm to remove the extra safety buffer and that would leave 0 ft. between you and terrain.
Now, when I look at the front of the Instrument Procedures book:
http://155.178.201.160/d-tpp/1413/SW1TO.PDF
Scroll down to "Rifle, CO". Here's what it says...
"RIFLE, CO
GARFIELD COUNTY RGNL (RIL)
TAKEOFF MINIMUMS AND (OBSTACLE)DEPARTURE PROCEDURES AMDT 10 12320 (FAA)
TAKEOFF MINIMUMS:
Rwy 8, std. w/ min. climb of 400' per NM to 11900 or 5400-3 for climb in visual conditions.
"
The Takeoff Mins section at the front of the book uses the same terminology as the SID page namely, "Min. Climb of xxx". Why are the gradients are different? Which one is for terrain and which one is for ATC?
I'd love to find an official FAA document that explains it all but everything I have found is in piecemeal and it seems like terminology is used very roughly.
Thanks everyone.
12-30-2014, 06:31 AM
#2
Gets Weekends Off
Joined APC: May 2010
Position: Baja Vermont
Posts: 5,177
This subject is without a doubt the most contentious and argued over subject, especially in UPT.
First, Rifle sits in a bowl, so it's not an ATC gradient and, civil airspace, ATC gradients are less common than in the military where lots of special use airspace is nearby.
Second, the gradients differ because the procedures differ. The charted SID is based on RNAV 1 while the text version is VOR/DME based and routes differ. With different navigation, different splays and accuracy standards apply; also the slight differences in routing mean different terrain might affect the climb gradients.
GF
First, Rifle sits in a bowl, so it's not an ATC gradient and, civil airspace, ATC gradients are less common than in the military where lots of special use airspace is nearby.
Second, the gradients differ because the procedures differ. The charted SID is based on RNAV 1 while the text version is VOR/DME based and routes differ. With different navigation, different splays and accuracy standards apply; also the slight differences in routing mean different terrain might affect the climb gradients.
GF
10-30-2015, 02:42 PM
#4
New Hire
Joined APC: Oct 2015
Posts: 2
After reading AIM 5-2-8, read AC120-91. Should answer some of your questions, but will raise even more.
Most likely, it has to do with terrain, but in the end it doesn't matter why, just can you do it.
Rifle is uncontrolled and has an ODP associated with it. In IMC or night conditions, you would be wise to fly the ODP, they do not require a clearance. If you've been given the SID by ATC, you would be expected to fly that SID, not the ODP. You would be required to maintain the 396ft/nm to the altitude specified, and if you could not meet that requirement, you would decline the SID. Part of the requirement is a minimum of 35 feet at the DER, 400 feet before any turns unless otherwise specified and maintains at least 200ft/nm unless a greater gradient is specified (in this case 396). Compliance with SID gradients are mandatory, unless you are OEI or other emergency.
Most likely, it has to do with terrain, but in the end it doesn't matter why, just can you do it.
Rifle is uncontrolled and has an ODP associated with it. In IMC or night conditions, you would be wise to fly the ODP, they do not require a clearance. If you've been given the SID by ATC, you would be expected to fly that SID, not the ODP. You would be required to maintain the 396ft/nm to the altitude specified, and if you could not meet that requirement, you would decline the SID. Part of the requirement is a minimum of 35 feet at the DER, 400 feet before any turns unless otherwise specified and maintains at least 200ft/nm unless a greater gradient is specified (in this case 396). Compliance with SID gradients are mandatory, unless you are OEI or other emergency.
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