Aspen Slope 2% ???

[LegacyDriver]

First this...

If you operate under FAR 121 or 135, a VFR departure does NOT relieve you from meeting your one-engine inoperative requirements under 121.189(d) or 135.379(d). For example, electing to depart KASE and flying VFR "down the valley" doesn't make you legal in this sense.

Now this...

This is an excerpt from the 8400.10, FAA Inspectors Handbook, Volume 4, Ch 3:


"(2) The criteria for TERPS does not take into account whether or not the aircraft is operating on all engines. Operators must either show compliance with TERPS criteria with an engine out or have an alternate routing available for use in case of an engine failure…."

Great! Just when I thought I had a handle on all of this I am COMPLETELY LOST!!!!!!!!!!!!!!!!!!!!

 

[some_dude]

My understanding, and apparently Lead and I disagree on some of this, is the following:

1) Part 91: You need to meet the climb gradient with all engines operating. If an engine fails and you crash into the hill, you will probably be found negligent and "careless and reckless" but up until you actually crash you will be legal.

2) Part 135: You need to meet the climb gradient on the DP, up to the altitude specified in the DP. If it states that you need 300 ft/mile to 11,000 feet, you need to average 300 feet/mile to 11,000 feet. This means that your calculated second segment climb needs to be greater than 300 feet/mile immediately after takeoff. If you have an escape maneuver and are authorized to use it, then I suppose that would reduce the climb requirements.

3) Typically (and I believe the ASE DPs do this, although it's been a while since I've looked), the DP will specify a weather minimum *or* the climb gradient. If the weather is better than the minimum, you need only the basic climb requirements for your aircraft.

Ultranav will compute all this for you, if you have it. It makes it so much easier!

 

[JumpJetter]

Ultranav will compute all this for you, if you have it. It makes it so much easier!

I'm sure glad you brought that up. Ultranav only caculates your Max TO weight up to 400' above the airport!

Dont believe me? Do this; start with what ever airport elevation you want and enter a climb gradient of 300'/nm up to 1000' above the airport elevation.

Then try 500' above airport elevation....Wow! it's the same weight!

Now try 400' above airport elevation....Wow! it's still the same weight!!!

Now try 300 feet above airport elevation...finally!, the TO weight increased!!!

Even the ultranav guys will tell you this....(although they BLATENTLY advertised in magazines like Pro Pilot and such with a screen that calculates SIDs!) Why is it likes this??? Cause just as Lead Sled is professing, the manufactures have not provided us single engine climb charts to determine if we can comply with a particular SID and gradient. So how can Ultranav calculate it?????

PLEASE try this with your ultranav program so you can see how you are being fooled by the SID gradient portion. Don't get me wrong, I can't tell you how many times Ultranav has helped me make decisions on how much fuel i can leave ASE, TEX, DRO etc with. It's a great tool for W&B and MAX TO weight, but don't use it for SIDs!.

JJ

p.s.

And this from www.ultranav.com




Performance Computations

[font=Tahoma, Arial, Verdana, Helvetica]From sea level airports with long runways to high and hot airports with runways that are not as long as you would like, ULTRA-NAV Performance Software will compute and display performance numbers derived from your aircraft's AFM with ease, speed and accuracy. The ULTRA-NAV Performance Software will compute maximum allowable takeoff weight based on ALL limiting factors - field length, climb limitations, brake energy, etc. The ULTRA-NAV Performance Software will then compute and display takeoff distance, all "V speeds", 2nd segment climb gradient, takeoff thrust setting, and other pertinent takeoff parameters dependent on aircraft type.[/font]



[font=Tahoma, Arial, Verdana, Helvetica]For landing data, Ultra-Nav computes and displays all "V" speeds, landing distance, landing field length, approach climb gradient and landing climb gradient.[/font]

[font=Tahoma, Arial, Verdana, Helvetica]Ultra-Nav can also customize weight and balance to your aircraft's exact seating configuration. Software will compute weight, %MAC and C.G. Limits for Zero fuel, Ramp, Takeoff and Landing conditions of your aircraft.[/font]

I don't see anything about SIDs in there?

JJ


​

 

[Lead Sled]

My understanding, and apparently Lead and I disagree on some of this, is the following:

1) Part 91: You need to meet the climb gradient with all engines operating. If an engine fails and you crash into the hill, you will probably be found negligent and "careless and reckless" but up until you actually crash you will be legal.

2) Part 135: You need to meet the climb gradient on the DP, up to the altitude specified in the DP. If it states that you need 300 ft/mile to 11,000 feet, you need to average 300 feet/mile to 11,000 feet. This means that your calculated second segment climb needs to be greater than 300 feet/mile immediately after takeoff. If you have an escape maneuver and are authorized to use it, then I suppose that would reduce the climb requirements.

3) Typically (and I believe the ASE DPs do this, although it's been a while since I've looked), the DP will specify a weather minimum *or* the climb gradient. If the weather is better than the minimum, you need only the basic climb requirements for your aircraft.

Ultranav will compute all this for you, if you have it. It makes it so much easier!

I'm not going do any retyping, just reread my posts. Ultra-Nav is a very handy tool, we have it and use it; but it will not "compute it for you" as jumpsetter pointed out. I hope you're not trying to use the 2nd segment climb charts above 400' agl or the other takeoff charts above 1,500' agl. If you're relying on certain charts to derive your performance data, but you're not complying with the conditions (including configurations and power settings) listed on the charts I would consider that "dangerous and wreckless" operation. Again, reread my posts.

One more time S - L - O - W - L - Y, DP gradients are and alway have been predicated upon "all" engine performance. Period. (As per one of the other guy's posts on this thread, get a hold of a new Gulfstream AFM and read the notes.) The 121 and most knowledgable 135 operaters have the alternate procedure issued to them and is carried in the cockpit.

'Sled

 

[BuddhaJ]

DP gradients are and alway have been predicated upon "all" engine performance. Period.
'Sled

I understand what you are trying to say but your statement is a little misleading. DP gradients are not based on any engine performance data. They are only meant to do one thing. They give you a minimum climb gradient that will keep you clear of any obstacles that may lie within the departure path of a runway.

When they develop the DPs, they do it because there is an obstacle out there. the gradient assigned changes depending on the height of the obstacle. The people who calculate these gradients don't care less how many engines you have operating, 1, 2, 3, 4, all or none. All this info tells you is that this is the minimum performance that your aircraft has to meet when departing.

It is the pilots responsibility to dtermine the performance of their aircraft. The aircraft that I have flown, Falcon, Citations, Global, only give you climb performance with one engine out. This becomes the limiting factor. You can only use charts that are from the AFM.

Point of all this is that dp's are not dependant on "all" engines operating. It is not a factor. The obstacle doesn't care what whether you are Pt. 121/91 or 135...if you can't see it and avoid it, you must fly over it. The DP gives you the minimum climb gradient required to do that and it doesn't care how many engines it takes to do it...thats our responsibility

 

[Lead Sled]

Let me restate it one more time. A transport category aircraft suffering an engine failure on takeoff will likely NOT meet TERP's climbs requirements and isn’t required to do so. The AIM alludes to this in 5-2-6(e)(4) by stating that the pilot should "consider the effects of degraded performance and the actions to take in the event of an engine loss during the departure." The Canadian supplement and ICAO PAN-OPS state it more clearly that IFR SID's and departure procedures are based on normal, read all-engine performance, and not one-engine out performance.

As you mentioned, TERP's climb requirements for DP's are based on a 40:1 obstacle identification surface (OIS) beginning no higher than 35 above the departure end of runway and continuing to the minimum altitude for enroute operations. If no obstructions penetrate the 40:1 OIS then the standard IFR climb gradient of 200 ft/NM applies. This provides at least 48 feet per nautical mile of obstacle clearance. If obstacles penetrate the OIS, then the DP climb gradient will be raised a sufficient amount to regain the 48 ft/NM clearance. Careful note must be given here. There could be obstacle which would require higher than standard climbs but only to heights less than 200 feet above the runway. In this case, higher than standard climb gradients are NOT provided

Like you said, Part 25 aircraft do not provide all engine climb performance data in the AFM. When the performance rules were first written for the first jet transport aircraft, one engine-out performance was considered more restrictive than all engine performance data. This engine out performance data was used to develop the takeoff flight path concept discussed above. The climb gradient data from the AFM is used ONLY to construct the net takeoff flight path as described above and cannot be used in meeting TERP's criteria. Any attempt to use the climb gradient charts from a Part 25 AFM in determining TERP's obstacle clearance would be using this data in a manner for which it was never intended and never approved for.

There are several reasons you cannot use AFM 2nd segment climb data in meeting TERP's criteria. First, all the one engine-out climb flight path data (1st, 2nd, and final segment climb charts) are only good to 1,500 above the runway and CANNOT be used to the heights demanded of certain DP's such as is the case of KASE, 7,800 ft to 14,000 ft. 2nd segment climb data is generally only valid to 400 ft above runway, the point where 2nd segment ends. Second, the differences in climb terminology. Most 2nd segment climb gradient charts in AFM's give the available NET climb gradient so that when you apply this to the flight path charts or computer program you get a resulting NET flight path. TERP's climb requirements are based on actual performance, NOT an already an already reduced NET climb gradient. There's the consideration of 5 minute limitation on takeoff thrust. Many DP's require climb gradients to significantly high altitudes that would exceed the limitation on takeoff thrust, not to mention a shallowing climb gradient due to density altitude changes as you climb. Remember if you try to use 2nd segment climb, you'll only meet that climb gradient if you keep V2, takeoff flaps, and takeoff thrust and that climb gradient is generally valid only at 400 ft above the runway. Finally, as we said above, TERP's performance is stricly considering normal aircraft performance, not an emergency situation such as engine out climb.

FAR 25.121 does not specify a minimum certification (gross) climb gradient for the enroute configuration beyond 1,500 feet AGL (end of the takeoff path under FAR 25.111). However, FAR 25.123 does require the determination of the one-engine inoperative and two-engine inoperative (for 3-engine or 4-engine aircraft) enroute flight paths. These enroute flight paths must be determined at each weight, temperature, and pressure altitude within the aircraft's operating limits and will have a gradient reduction applied.

Typically, the AFM will state that the net enroute climb gradient chart(s) are presented for pilot reference, FAR 25 requires their inclusion in the AFM for use in determining obstacle clearance for the net enroute flight path as required under FAR 121.191 (one-engine inoperative) & 121.193 (two engine inoperative) or FAR 135.381 (one-engine inoperative) & 135.383 (two engine inoperative).

So the two big questions are as follows:

1. How does one compute climb requirements above 1500 AGL when no data is available from the manufacturer?

The net enroute climb gradient chart(s) will provide you with the available net enroute climb gradient for your current weight, temperature, and pressure altitude. With this information, you can 1) review the entire route and ensure you have a positive net enroute climb gradient clearing all obstacles by 1,000 ft, 5 SM either side of the intended route, or 2) pick the most critical point on the route, assume the engine fails at that point, and continue with a net enroute flight path that clears obstacles by 2,000 ft, 5 SM either side of track. You may assume normal fuel consumption using either method. Using method 2, you must also designate as an alternate airport the airport you use after the engine fails. That airport must meet the required alternate weather minimums. You may break up the route into a series of segments with the most advantageous drift down route and alternate for each segment.

So where do you find the obstacle data for the planned route? United Airlines has a world wide computer obstacle database and dispatch program this purpose. For us, sectional charts, Grid MORA's MEA's, MOCA's, would be good starting points. This is a dispatch function only. If the engine fails, you're still expected to land at the nearest suitable airport.

2. How in the world can any aircraft legally depart Aspen under any circumstances? How do the BAC 146's, Dash 8's, and other commuter aircraft types legally depart from ASE? The BAC 146 might meet the DP if it lost an engine if was going to DEN, but how about to ORD? The Dash 8's and other prop commuters? It's inconceivable to me that they'd meet the DP with an engine out. I just can't see them outperforming a Lear 31A on one engine. These are all FAR 121 air carriers with extensive FAA oversight. Yet they takeoff every day from ASE and in bad weather. The same could be said for other airports like Reno.

The DP is a normal performance procedure only. Even the AIM alludes to this by specifying that the pilot consider the effects of reduced performance following an engine failure on a DP and have alternative actions available.

In answer to this specific question, using a sample airport analysis for ASE runway 33 and for a Lear 35 the climb limit weight at 80 degrees F is 16,030 lbs. This weight limit meets 1st, 2nd, and final segment certification (gross) climb requirements. The runway 33 limit weight is 14,770 lbs. The runway limit weight meets the requirements for takeoff distance (all engine & one engine inoperative), accelerate stop distance, brake energy limit, and net takeoff flight path obstacle clearance utilizing a special engine out departure procedure. This procedure does follow the valley out to a holding pattern on the DBL R-244 at 15.0 DME, essentially in the valley over Carbondale, CO. At this weight, 14.770 lbs., you will not meet the DP climb gradient to 14,000 feet with one engine inoperative. The 2nd segment net gradient about 4%. Still, an FAR 121 or 135 operator of this Lear 35 would be perfectly legal departing Aspen at this weight and temperature, assuming that no other Subpart I dispatch requirements are more restrictive.

'Sled

 

[BuddhaJ]

Let me restate it one more time. A transport category aircraft suffering an engine failure on takeoff will likely NOT meet TERP's climbs requirements and isn’t required to do so. The AIM alludes to this in 5-2-6(e)(4) by stating that the pilot should "consider the effects of degraded performance and the actions to take in the event of an engine loss during the departure." The Canadian supplement and ICAO PAN-OPS state it more clearly that IFR SID's and departure procedures are based on normal, read all-engine performance, and not one-engine out performance.

As you mentioned, TERP's climb requirements for DP's are based on a 40:1 obstacle identification surface (OIS) beginning no higher than 35 above the departure end of runway and continuing to the minimum altitude for enroute operations. If no obstructions penetrate the 40:1 OIS then the standard IFR climb gradient of 200 ft/NM applies. This provides at least 48 feet per nautical mile of obstacle clearance. If obstacles penetrate the OIS, then the DP climb gradient will be raised a sufficient amount to regain the 48 ft/NM clearance. Careful note must be given here. There could be obstacle which would require higher than standard climbs but only to heights less than 200 feet above the runway. In this case, higher than standard climb gradients are NOT provided

Like you said, Part 25 aircraft do not provide all engine climb performance data in the AFM. When the performance rules were first written for the first jet transport aircraft, one engine-out performance was considered more restrictive than all engine performance data. This engine out performance data was used to develop the takeoff flight path concept discussed above. The climb gradient data from the AFM is used ONLY to construct the net takeoff flight path as described above and cannot be used in meeting TERP's criteria. Any attempt to use the climb gradient charts from a Part 25 AFM in determining TERP's obstacle clearance would be using this data in a manner for which it was never intended and never approved for.

There are several reasons you cannot use AFM 2nd segment climb data in meeting TERP's criteria. First, all the one engine-out climb flight path data (1st, 2nd, and final segment climb charts) are only good to 1,500 above the runway and CANNOT be used to the heights demanded of certain DP's such as is the case of KASE, 7,800 ft to 14,000 ft. 2nd segment climb data is generally only valid to 400 ft above runway, the point where 2nd segment ends. Second, the differences in climb terminology. Most 2nd segment climb gradient charts in AFM's give the available NET climb gradient so that when you apply this to the flight path charts or computer program you get a resulting NET flight path. TERP's climb requirements are based on actual performance, NOT an already an already reduced NET climb gradient. There's the consideration of 5 minute limitation on takeoff thrust. Many DP's require climb gradients to significantly high altitudes that would exceed the limitation on takeoff thrust, not to mention a shallowing climb gradient due to density altitude changes as you climb. Remember if you try to use 2nd segment climb, you'll only meet that climb gradient if you keep V2, takeoff flaps, and takeoff thrust and that climb gradient is generally valid only at 400 ft above the runway. Finally, as we said above, TERP's performance is stricly considering normal aircraft performance, not an emergency situation such as engine out climb.

FAR 25.121 does not specify a minimum certification (gross) climb gradient for the enroute configuration beyond 1,500 feet AGL (end of the takeoff path under FAR 25.111). However, FAR 25.123 does require the determination of the one-engine inoperative and two-engine inoperative (for 3-engine or 4-engine aircraft) enroute flight paths. These enroute flight paths must be determined at each weight, temperature, and pressure altitude within the aircraft's operating limits and will have a gradient reduction applied.

Typically, the AFM will state that the net enroute climb gradient chart(s) are presented for pilot reference, FAR 25 requires their inclusion in the AFM for use in determining obstacle clearance for the net enroute flight path as required under FAR 121.191 (one-engine inoperative) & 121.193 (two engine inoperative) or FAR 135.381 (one-engine inoperative) & 135.383 (two engine inoperative).

So the two big questions are as follows:

1. How does one compute climb requirements above 1500 AGL when no data is available from the manufacturer?

The net enroute climb gradient chart(s) will provide you with the available net enroute climb gradient for your current weight, temperature, and pressure altitude. With this information, you can 1) review the entire route and ensure you have a positive net enroute climb gradient clearing all obstacles by 1,000 ft, 5 SM either side of the intended route, or 2) pick the most critical point on the route, assume the engine fails at that point, and continue with a net enroute flight path that clears obstacles by 2,000 ft, 5 SM either side of track. You may assume normal fuel consumption using either method. Using method 2, you must also designate as an alternate airport the airport you use after the engine fails. That airport must meet the required alternate weather minimums. You may break up the route into a series of segments with the most advantageous drift down route and alternate for each segment.

So where do you find the obstacle data for the planned route? United Airlines has a world wide computer obstacle database and dispatch program this purpose. For us, sectional charts, Grid MORA's MEA's, MOCA's, would be good starting points. This is a dispatch function only. If the engine fails, you're still expected to land at the nearest suitable airport.

2. How in the world can any aircraft legally depart Aspen under any circumstances? How do the BAC 146's, Dash 8's, and other commuter aircraft types legally depart from ASE? The BAC 146 might meet the DP if it lost an engine if was going to DEN, but how about to ORD? The Dash 8's and other prop commuters? It's inconceivable to me that they'd meet the DP with an engine out. I just can't see them outperforming a Lear 31A on one engine. These are all FAR 121 air carriers with extensive FAA oversight. Yet they takeoff every day from ASE and in bad weather. The same could be said for other airports like Reno.

The DP is a normal performance procedure only. Even the AIM alludes to this by specifying that the pilot consider the effects of reduced performance following an engine failure on a DP and have alternative actions available.

In answer to this specific question, using a sample airport analysis for ASE runway 33 and for a Lear 35 the climb limit weight at 80 degrees F is 16,030 lbs. This weight limit meets 1st, 2nd, and final segment certification (gross) climb requirements. The runway 33 limit weight is 14,770 lbs. The runway limit weight meets the requirements for takeoff distance (all engine & one engine inoperative), accelerate stop distance, brake energy limit, and net takeoff flight path obstacle clearance utilizing a special engine out departure procedure. This procedure does follow the valley out to a holding pattern on the DBL R-244 at 15.0 DME, essentially in the valley over Carbondale, CO. At this weight, 14.770 lbs., you will not meet the DP climb gradient to 14,000 feet with one engine inoperative. The 2nd segment net gradient about 4%. Still, an FAR 121 or 135 operator of this Lear 35 would be perfectly legal departing Aspen at this weight and temperature, assuming that no other Subpart I dispatch requirements are more restrictive.

'Sled

didn't i just say that, in 1/10 the space?

 

[LegacyDriver]

You guys are killing me. Are we all (except the Falcon 50 drivers) illegal out of Aspen or not??????????????

Also, does my fuzzy memory not recall an atc std/terps std climb gradient of 3.3 percent at all time regardless of engines or far part????

 

[JumpJetter]

No! You just need VMC!

 

[lawndart45]

So...basically...121 or 135 Ops Specs specifically state that for an IFR departure, you must comply with any FAA published departure procedures. (SIDS or obstacle DPs). If you have an engine failure and there are obstacles to consider, the company will most likely have special departure procedures from an aero data source that is approved from the FAA in their ops specs. If the 135 company does not have these special procedures, you are not restricted to fly the DP if you have an engine failure, nor comply with the climb requirements. However, it would be in your best interest to have an alternate plan for an engine failure using your own charts, or better yet, just wait until VMC conditions. Part 91 does not require this, but if you took off IFR, you best have an alternate plan and a way to prove that you could meet minimum climb requirements in the event of an engine failure.

So you see, it is legal to fly out of Aspen IFR and not be in a GV or Falcon 50 as long as you have an approved source by the FAA to figure that you can meet the 121/135 requirements with an engine failure. These will be different from the DPs procedures and requirements. This is how regional carriers get away with it.

Sled....am I close?

 

[some_dude]

Lead, I think we agree on 91-- if you can make it with all engines running and you don't crash if one fails, you are legal (not necessarily smart).

I also think we agree on escape procedures-- sounds like a very good idea, and if I am ever so lucky as to get back into an aircraft that goes to ASE occasionally I am going to look into it.

Finally, you probably are correct on Ultranav. It has been a while since I've used it, and I recall it properly computing obstacle clearance gradients in the 50 (and not doing it properly in the Lear), but I certainly could be wrong.

Where we disagree, then, is 135. Specifically, 135.379. Does being able to comply with the obstacle DP climb gradient with an engine out equal complying with 135.379? I would say it does.

Is there another means of complying with 135.379 other than meeting the DP climb gradient or having an escape procedure?

EDIT: Or are you arguing that 135.379 doesn't require you to clear obstacles with an engine out?

 

[some_dude]

Incidentally, with regard to ASE specifically, my obsolete at-home Jepps state that the Aspen 2 departure requires EITHER weather of 5000/5 OR a climb gradient of 950'/NM (15.8%). The Lindz 4 departure requires EITHER 3100/3 OR 460'/nm (7.7%).

So, if the weather is better than 3100' and 3 miles, and you are doing the Lindz 4, all you need to be legal is the minimum climb gradient required by certification for your aircraft.