Lindz Four Departure

[Lead Sled]

The paragraph you quoted refers to CERTIFICATION climb requirements, which have absolutely nothing to do with obstacle clearance requirements. Note that the 2.4% requirement listed is pretty much useless for obstacle clearance in IMC conditions, as obstacles may grow at a 2.5% gradient from the DER without having to publish specific climb requirements for departure.

The quoted reference is simply saying that, unlike light twins that have NO single-engine climb requirement, a 2-engine jet has to be able to make at least a 2.4% gross climb on one engine.

Someone has been paying attention in performance class! Also the certification climb requirements only get you (in most jets) to 1,500' AGL - in other words, pattern altitude. From there, you are expected to be able to fend for yourself and make your way back to a landing runway. In the case of the Lindz4 at ASE, you can not extrapolate the performance charts from 1500' AGL to 14,000' MSL. (Well you could, but you'd be wrong.)

The performance requirements of a SID (DP) are based on TERPS requirements and TERPS requirements are based on all engines operating. No allowance is made for the loss of an engine. If you accept a SID (DP) you must be able to comply with the performance requirements - VFR or IFR, VMC or IMC.

'Sled

 

[MauleSkinner]

Someone has been paying attention in performance class!

Actually, paying attention in performance class had nothing to do with gaining this knowlege...but asking questions that pissed off the instructor and caused him to walk out on me because he didn't want to actually teach the subject DID put me on the right track.

I am making the mental note, however, that you are the person to ask those tough questions when they come up. Sounds like I wouldn't get the usual "I don't know and I don't care" response.

Fly safe!

David

 

[hawkerjet]

Also at ASE, I never accept the Departure procedure. ( say No SID in the remarks section of your flight plan) You will then receive the LINDZ 4 departure procedure in textual format from ATC but no longer binded to the requirements. I still don't depart unless I can see the mountain tops in the departure environment. Our company has done an escape practice in the aircraft. One is a 180 back to the runway in case of fire, the next we practiced was scooting over the first hill on your left then down the valley to MTJ. I can say good luck to anyone who plans the latter in an emergency with celings and vis to deal with.

 

[Correcting]

I have some questions for those more in the know than me. I just want to know what is legal, not launch a discussion about what is smart.

If you accept a SID (DP) you must be able to comply with the performance requirements - VFR or IFR, VMC or IMC.

What if an engine fails and you declare an emergency? Seems like all bets are off in that case.

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I thought the second-segment climb stuff was part 25 and not related to 91 or 135, meaning that every part 25 turbojet that takes off has to be able to meet the second-segment climb requirements of the departure on one engine, whether they are operating 91 or 135. Does this mean when I takeoff part 91, I only must demonstrate a 1.6% (2.4% net) on one engine regardless of what the weather is and what the DP says?

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If the weather is VMC (3100-3 per the DP), I thought only a 1.6% (2.4% net) gradient to a safe altitude was required, regardless of what is published on the DP? This is because you are using see and avoid and therefore only have to meet the 1.6 (2.4 net) gradient.

Again, I'm just looking for what's legal.

 

[Lead Sled]

What if an engine fails and you declare an emergency? Seems like all bets are off in that case.

That's exactly right. You've got a bonafide emergency in progress and, at that point, you can deviate as necessary to insure the safety of the flight. That's where the alternate departure procedure comes into play. It's actually a pretty complicated procedure - a DME arc to a radial with specified bank angles; but it beats sticking your nose into the dirt.

I thought the second-segment climb stuff was part 25 and not related to 91 or 135, meaning that every part 25 turbojet that takes off has to be able to meet the second-segment climb requirements of the departure on one engine, whether they are operating 91 or 135. Does this mean when I takeoff part 91, I only must demonstrate a 1.6% (2.4% net) on one engine regardless of what the weather is and what the DP says?

You're right, it is JUST a certification issue. Second segment (for most aircraft) ends at 400' AGL. Some how people have gotten the idea that it goes on - in the case of Aspen up to 14,000' MSL.

'Sled

 

[simav8r]

Lead and Maule are on the right track.

People often confuse the different climb requirements of FAR 25, 91, 135 and TERPs.

Part 25 is how the aircraft was certified. 2nd segment is what we deal with everyday as a climb requirement i.e. 2.4% gross or 1.6% net. This is reflected in the AFM and with the exception of subpart K, this is what we use when operating part 91. What follows is the second segment requirement. Note: Some aircraft like Hawkers are certified as second segment ending at 1500 AFL or 3.5 minutes….your mileage may vary.

§ 25.121 Climb: One-engine-inoperative.

(b) Takeoff; landing gear retracted. In the takeoff configuration existing at the point of the flight path at which the landing gear is fully retracted, and in the configuration used in §25.111 but without ground effect, the steady gradient of climb may not be less than 2.4 percent for two-engine airplanes, 2.7 percent for three-engine airplanes, and 3.0 percent for four-engine airplanes, at V2 and with—
(1) The critical engine inoperative, the remaining engines at the takeoff power or thrust available at the time the landing gear is fully retracted, determined under §25.111, unless there is a more critical power operating condition existing later along the flight path but before the point where the airplane reaches a height of 400 feet above the takeoff surface; and
(2) The weight equal to the weight existing when the airplane's landing gear is fully retracted, determined under §25.111.


Part 135 says that we have to adhere to the AFM but ads the requirement for an airport analysis that we may comply with however we wish. Some operators are required to have a formal airport analysis done via subscription service just like 121 operators.

§ 135.379 Large transport category airplanes: Turbine engine powered: Takeoff limitations.
(d) No person operating a turbine engine powered large transport category airplane may take off that airplane at a weight greater than that listed in the Airplane Flight Manual—
(2) For an airplane certificated after September 30, 1958 (SR422A, 422B), that allows a net takeoff flight path that clears all obstacles either by a height of at least 35 feet vertically, or by at least 200 feet horizontally within the airport boundaries and by at least 300 feet horizontally after passing the boundaries.
The airport boundaries verbage is the airports analysis requirement for climb.

Terminal Instrument Procedures (TERPS) is the criteria the FAA uses to form DPs, STARs, and IAPs. These are absolute criteria. Not one regulation requires us to conform to the TERPs criteria. TERPs does not know if it is VMC, IMC, or how many engines you have let alone how many are operative. Otherwise how could a C172 ever fly IFR? The only regulation the FAA or court can throw at you is 91.13 careless and reckless as long as all other regulations are complied with.

With regard to special procedures, there are some available for ASE. If you are operating under FAR 135 you must be approved by your POI either by letter, operations manual, or ops spec to use it. FAR 91 has no such requirement.

Bottom line….just because you can do something, doesn’t mean you should. That’s why companies develop SOPs for airports like ASE that have higher minimums than on the approach plate.

 

[LegacyDriver]

Lead Sled is pretty squared away on this.


Without getting technical, my understanding is:

You must meet the DP gradient with either both engines operating or one engine inop (OEI) when IMC under 135.

If you are unable to meet the DP when OEI you must have an approved escape procedure when IMC or a visual escape path VMC.

 

[rice]

That's exactly right. You've got a bonafide emergency in progress and, at that point, you can deviate as necessary to insure the safety of the flight. That's where the alternate departure procedure comes into play. It's actually a pretty complicated procedure - a DME arc to a radial with specified bank angles; but it beats sticking your nose into the dirt.

'Sled

Sled,
Have you seen the alt. departure proc. from APG?
Much simpler than Jepps, basically fly to the DBL 163R/10.0D and turn left to 270deg. Intercept the IPKN BC and climb via the SID and in the hold at Gleno. Not fun but it works in the sim and in the plane (practice) at least for the 900B.

 

[HS125]

Sled,
Have you seen the alt. departure proc. from APG?
Much simpler than Jepps, basically fly to the DBL 163R/10.0D and turn left to 270deg. Intercept the IPKN BC and climb via the SID and in the hold at Gleno. Not fun but it works in the sim and in the plane (practice) at least for the 900B.

Check out the APG Alt Procedures for KEGE, there is one special departure that has you fly a 280 heading right after takeoff and go up the valley to the right of the hill off of rwy 25 and eventually fly outbound the DBL 336 radial. We did that in the Sim (900B) the other day and I think that the DBL 336 radial must be an error (all the other procedures have you fly out the DBL 322 radial). At one point after intercepting the DBL 336 radial, we flew over a ridge with less than 500 feet between us and the dirt . Flying the Gypsum departure using the APG weights (36,000 lbs) and temperature (30 deg C). had us 1500 feet above the ground after turning out of the valley.

Word to the wise, APG has a good product, but pay close attention to the information before you bet you a$$ on it.

 

[Lead Sled]

Check out the APG Alt Procedures for KEGE, there is one special departure that has you fly a 280 heading right after takeoff and go up the valley to the right of the hill off of rwy 25 and eventually fly outbound the DBL 336 radial. We did that in the Sim (900B) the other day and I think that the DBL 336 radial must be an error (all the other procedures have you fly out the DBL 322 radial). At one point after intercepting the DBL 336 radial, we flew over a ridge with less than 500 feet between us and the dirt . Flying the Gypsum departure using the APG weights (36,000 lbs) and temperature (30 deg C). had us 1500 feet above the ground after turning out of the valley.

Word to the wise, APG has a good product, but pay close attention to the information before you bet you a$$ on it.

I haven't seen the APG procedure. (Anyone have a website?) IMHO, you should always try any alternate procedure in the airplane prior to betting your a$$ on it. For some of you it may be difficult - you don't get there all that often. If you have the opportunity (and the weather allows it) just coordinate with ATC and let them know what you want to do. The time to try and figure out that the procedure is telling you to do isn't immediately after shutting one down and you are up to your eyebrows in airplane. The ideal way to handle the situation is to have it standing at the ready in the #2 FMS. (Using a "pilot" SID.) Prior to departure brief you simply review the procedure for the PNF to bring it up for you should the need arise. It's very simple and straight forward.

'Sled