Aspen Slope 2% ???

[Lead Sled]

DP climb gradients are not dependent upon the number of operating engines and should not be confused with FAR 25.111 takeoff path or 25.115 takeoff flight path obstacle clearance requirements. Rather, the IFR DP climb requirements represent a "plane" below which an aircraft should not penetrate while conducting a normal ("all engine") IFR departure. There was never an intention of making this a one-engine inoperative requirement as this was already addressed by the operating regulations, Subpart I, FAR 121 &135.

An FAR 121 or 135 operator should have performed an analysis for obstacle clearance with a continued takeoff with one engine inoperative after V1 as required by 121.189(d) or 135.379(d). You can have a contractor like Jeppesen Op's Data compute the analysis for you, or if performance data in not available in Jeppesen's computer database for your aircraft, you can receive the "raw" obstacle data and do the computations yourself using the climb gradient and takeoff flight path charts provided in the AFM. You will find, in many instances, that a special engine out departure procedure is provided as an escape route for a continued takeoff with one engine inoperative. This may or may not follow the ground track of the published DP.

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.

There are no one engine inoperative obstacle requirements specified in 91.605 for FAR 91 operators. The only requirement is comply with the minimum one-engine inoperative climb gradient for certification (2.4% gross gradient 2nd segment, etc).

Engine-out obstacle clearance doesn't end at 1,500 ft either. FAR 121 &135 operators also have a requirement for enroute obstacle clearance. It is for this purpose that the net enroute climb gradient charts are provided in the AFM. These operators must demonstrate either a positive net enroute flight path that clear all terrain & obstacles 5 SM either side of track by 1,000 ft, or that the net enroute flight path allows for a continued flight from cruising altitude, following an engine failure, to an alternate airport (as specified under the applicable rules, such as 135.387) which clears all terrain and obstacles by 2,000 feet 5 SM either side of track. In this instance, the engine is assumed to fail at the most critical point enroute.

In both instances, the aircraft must demonstrate a positive slope 1,500 ft above the airport of intended landing following an engine failure. If the second method is used, the operator must designate the airport(s) used as an alternate in the flight plan and that (those) airport(s) must meet the minimum weather requirements for an alternate. This does not relieve a pilot from landing at the nearest suitable airport following an engine failure. This is merely a dispatch requirement.

'Sled

 

[falconpilot]

With a down hill slope brake energy may be a concern . I do agree with one thing is that your take-off roll is shorter but how about accelerate and stop distance they don't print numbers in the afm for more than -1% so is it legal.??

If you are limited by VMBE (brake energy) this problem can be solved by reducing V1 to VMBE... This is called "unbalancing the field"... This technique is used when your V1 comes out to be greater than VMBE... HOWEVER.... This can only be done if your accelerate stop distance is not greater than runway available... (OBVIOUSLY)... Bottom line.... KASE is a pain in the arse if your not in a powerful airplane... The climb gradient out of KASE is obviously for obstacle clearance. In VMC you see and avoid... But in IMC you better be on top of your game if something goes wrong...

 

[cherokee]

OK sled,

So what limits most operators is not so much the fact that you have accepted the DP since that is based on 2 engines but the fact that 121 and 135 guys have to meet single-engine obstacle requirements. How about when a DP has a minimum climb gradient published on the chart such as a runway requiring 400'/nm up to a certain altitude say for an obstacle. Does this change things in terms of requirements that you meet it single engine or does it not matter... all DP's assume 2 engine?

Also, I always thought that you couldn't use "see and avoid' in VFR to allow you to avoid the 121 and 135 obstacle requirements. Sounds like Falcon disagrees...or is is he talking 91 only? I think you ALWAYS have to clear obstacles regardless of wx 121 or 135.

Thanks

 

[Kingairrick]

Shouldn't all this be on the "legal, but stupid" thread?

 

[AZ Typed]

So help a FNG 135 fella out and put it in practical language:


1. can you depart IFR in VMC without getting nailed by the Feds if you cannot meet the climb gradient (I think the answer is no based on this post)

2. under 135 you must meet the climb gradient under all conditions (I think the answer is yes, again based on this discussion)

3. if you cannot meet the climb gradient, no matter what the wx, you must lighten the fuel load (to meet the gradient) and get gas somewhere, correct? (I think the answer is yes)

4. the whole second segment climb gradient as a % is new to me. I have always been taught the get a rate of climb out of the aircraft based on groundspeed. In the 121 world it was done for us. Now in the 135 world I'm tossed into the % concept. How do you determine the % second segment climb for the airport? Rise over Run? Can you give an example at say, ASE? FS did a terrible job covering this and I knew one day I'd be heading to ASE.

Thanks for the help!

AZT

 

[cherokee]

Shouldn't all this be on the "legal, but stupid" thread?

Yes, exactly, I'll tell my clients and boss that it's "stupid" to go in and out of Aspen. What was I thinking? Perhaps you don't fly in and out of there, but a lot of us do and it is actually not very "stupid" to know performance in great detail when you operate there.

 

[Kingairrick]

Actually, I do. I'm lucky now to be in 3 hole Falcons. I used to do it in the King Air regularly, and come non-stop back to FL. I wasn't being condecending. We all have to do things sometimes that aren't exactly ideal, just the best option...every time I think to myself; "This is pretty f'ing stupid, how can I minimize the risk?"

This is an interesting discussion though. Typical of the FAA, the regs are so convoluted that you can have so many different opinions, all by highly experienced professional pilots. I have always believed that the DP had to be met with one engine inop. Sled is pretty convincing, and now I'm not sure. The ex Lear guys I fly with all say that ASE is not technically legal in the older Lears because of the max slope thing. Once again, different opinions from different highly qualified people.

Oh yeah, one more thing; depending on which model HS-125 that is in your profile, it might really be "stupid." No, really...

 

[prpjt]

. How about when a DP has a minimum climb gradient published on the chart such as a runway requiring 400'/nm up to a certain altitude say for an obstacle. Does this change things in terms of requirements that you meet it single engine or does it not matter... all DP's assume 2 engine?

This is a cut of a draft of AC 120-OBS-11. Looks like the fed's are trying to clear up this matter. I don't know if this has been relased as an AC. I highlighted some of the pertinent language.

TERPS CRITERIA VS. ENGINE-OUT REQUIREMENTS:

Standard Instrument Departures (SIDS) or departure procedures (DPs) based on U.S. Standards for Terminal Instrument Procedures (TERPS) or ICAO Pans-Ops are based on normal (all-engine) operations. Thus, engine-out obstacle clearance requirements and the all-engine TERPS requirements are independent. Engine-out procedures do not need to meet TERPS requirements. Further, compliance with TERPS climb gradient requirements do not necessarily assure that engine-out obstacle clearance requirements are met. Terminal instrument procedures typically use specified all-engine climb gradients to an altitude, rather than certified engine-out airplane performance. Terminal instrument procedures typically assume a climb gradient of 200 feet per nautical mile (nm) unless a greater gradient is specified. For the purposes of analyzing performance on procedures developed under TERPS or Pans-Ops, it is understood that any gradient requirement, specified or unspecified, will be treated as a plane which must not be penetrated from above until reaching the stated height, rather than as a gradient which must be exceeded at all points in the path. Operators must comply with FAR requirements for the development of takeoff performance data and procedures. There are differences between TERPS and engine-out criteria, including the lateral and vertical obstacle clearance requirements. An engine failure during takeoff is a non-normal condition, and therefore, takes precedence over noise abatement, air traffic, SID’s, DPs, and other normal operating considerations.

 

[LJ45]

Stupid?

Stupid! we all do things that are "calculated risk". I think you have a bigger chance of something else happing on your trip to ASE besides the engine quitting at V1.

By the way, has a corporate Jet ever lost an engine out of ASE, or another airport like ASE and couldn't climb thus crashed?

I was told at my last Citation recurrent that the whole Citation fleet has never had an actually V1 failure.

I tend to go with Lead Sled and his info being practical, logical and most consistent info over the last several years from the industry

 

[SabreFlyR]

I was told at my last Citation recurrent that the whole Citation fleet has never had an actually V1 failure.

This is not true. I have a very good friend who on takeoff in a Citation 500 left most of the turbine section of one of the engines on the runway a few years back.