This is an awesome discussion! Thanks for bringing up the question Birdie. This is important real world stuff that we should all keep striving to stay on top of.

I do not have access to APG. I'd call them directly. Good question. They must have data points that are not accessible to non-subscribers to their program(s).

I would suggest the ODP, in this case, would be for departing VFR traffic.

And no, I do not think you can assume a 3.3 degree gradient will keep you clear of obstacles if there is a published non-standard gradient for a SID.

When a SID or DP is created it uses the TERPs requirments which surveys a corridor that starts at 300ft and expands to 8900 ft on either side of the flight path. A few years ago the FAA released AC 120-91 which is more in line with IACO terrain clearance. It widens from 300ft at the airport boundry to 2000 ft either side with a 16:1 splay.

APG applies the AC 120-91 corridor and thus can exclude alot of obsticles that are off the flight path. The FARs only require 300ft a side so APG is still legal and does not require FAA approval to use, rather it is accepted by the POI. APG has a good video on their website that explains how it works.

Last week we were able to leave KEGE with 3000lbs more than what we would have using the book alone.

bookmarked for intriguing discussion.

Birde ... some thoughts ... it is important to read all of the documents I reference in order to help understand my answer. I'm not a TERPs expert ... so I throw that out there for anyone who has better information for which I am receptive to hearing/reading.

1. Yes, TERPs procedures are designed using ALL ENGINES. They don't build procedures for one engine inoperative (OEI). But as pilots / operators, we must plan for the what-if.

2. TERPs looks at a 40:1 plane ... or I guess "splay" is the new buzzword, to determine if any obstacle penetrates this surface. If an obstacle does not, an aircraft must meet at least 200'/NM or 3.3% with ALL ENGINES. Otherwise, a higher climb gradient is published.

Are you with me so far? Ok.

It is my understanding that prior to current procedures in place (I will mention these shortly), operators were using TERPs required gradients to clear obstacles with OEI. This meant that operators had to greatly reduce the grossweights to ensure compliance. This is when engine out procedures (EOPs) were developed. Part 121 and 135 operators submit packages to the FAA for EOP approval. They must demonstrate that these in-house or commercially generated EOPs are safe and clear obstacles by 35 feet and 200'/300' horizontally. This allows for Part 121 and 135 operators to siginificantly increase the grossweights on their aircraft.

Recently, the FAA published Advisory Circular AC-120-91 which clarified acceptable procedures and methods to construct EOPs. http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/55a6248632ed6e8d86257184005a2188/$FILE/AC120-91.pdf

Additionally, there is a video available by the FAA which explains into detail why this AC was published. The information presented is relevant and interesting. You can fast forward to about 12:00. </Title> <Author></Author> <Copyright></Copyright> <Banner></Banner> </entry> <Title>

However, what if you aren't Part 121 or 135? Then I assert that you must meet a 200'/NM or 3.3% climb gradient or as published, in order to clear obstacles. Not only is this the policy of the DOD (something that I'm very familiar with), but it is also stated here http://www.faa.gov/library/manuals/a...edia/CH-02.pdf The last paragraphs of page 2-18 has some VERY interesting information. The Yellow paragraph on page 2-27 is good as well. The US Air Force's requirement is to meet 200'/NM unless there is an SDP (the Air Force's term for EOP) which is produced by Jeppesen.

Your original post asked "No published ODP, SID with non-standard minimums, will a 200'/NM or 3.3% keep me safe from obstacles?" My answer is still, yes as long as there isn't a Trouble T posted anywhere. However, as highlighted in yellow in the FAA Instrument Handbook, if you can't meet the SID climb gradient, you can't fly it. (Note, in the US Air Force, we have flown SIDs where we couldn't meet the CG but we always asked first). Which is why I say to you, if you do indeed find yourself without an ODP and a Trouble T, and you want to fly the SID, I would call ATC and ask the question. They may approve you, or they may not. They may give you an approved DP that isn't published. Finally, in the situation you provided, I would be doing a very good terrain study to ensure that I wasn't making a huge mistake. And trust me, this is very difficult. The Air Force for years flew the KC-10 this way. Every airfield we went to we had to do thorough terrain studies. Ironically, there is no way of knowing all the obstacles or which obstacle is controlling unless you TERPs the airfield yourself.

That's the best answer I can give. This post and NFL has wasted my Sunday. Good luck.

If you like to ask questions to only disagree with the answer...



Click Here

That was damn hilarious! :)