Second Segment Climb

[rchcfi]

Guys,

I did a search on this and dived into Part 25 before starting this thread, but I can't seem to find the answer I'm looking for.

I know what the definition of the segments are and requirements to be met, but herein lies my problem. Here's an example:

An airport's DP requires a 12.5% climb gradient to 10500. Field elevation is 6500'. The weather is OVC020. Therefore you are past your second segment requirement in VMC. So when I go into the clouds at 8500' do I have to once again maintain that 12.5% or is there a way to average out the reamining climb. For example, you are doing 16% with 2 engines in VMC. When you get into IMC, can the gradient be averaged so that it can be lower than 12.5% using your initial 16% thru 8500'? I can't see anywhere, where it says that second segment continues past 1500'. Therefore, do all you have to meet is that than just meet the 1.2% requirement. It doesn't seem right, but it would help me get out of this airport.

The reason I'm asking is because I'm going thru my aircraft's second segment climb charts. And even with Engine A/I off, I can't meet that requirement, therefore that would make that airport off limits to me unless it was OVC040 (the top of the DP), 10C or greater, and no visible moisture.

Sorry to be asking, but I'm new to jets and I'm just trying to make sense of it all.

Thanks
RCHCFI

 

[Kingairrick]

It's a good question. I've always assumed that you have to wait for the better weather, or lower the weight by making a fuel stop at a lower elevation airport. If you are talking about EGE or Aspen, that's what I've been taught.

Now the reality...lots of operators just go and hope they don't lose an engine and get dirt in the pitot tubes. I was told that Aspen's runway slope is beyond the Learjet's max slope limit, making every Lear at Aspen in violation.

I'm not condoning the practice. I'm interested to hear other responses to your question.

 

[Ty Webb]

Normal second segment climb requirement (SE) is 2.4% to 400' or until the obstacle is cleared. Then, after the acceleration to Flap Retraction speed, the Final Segment gradient is 1.2%. Compliance with a SID (now a DP) normally requires a minimum climb gradient of 3% to the MEA of the nearest airway. You are required to be able to comply with these basic minimums, period. AIrports that require something above that standard have an Obstacle Departure DP

When you are talking about an Obstacle DP that you can't possibly meet (and you would have to be able to do it SE) then, at least under 135,your other option is to determine that you can maintain the required clearance from obstacles/terrain to the degree specified under 135, which, if memory serves, is something like 50' above the highest obstacle within 250' horizontally while within the airport boundary, and 65' vertically and 500' horizontally thereafter until established on a published route, transition, procedure, etc. Of course, if you were unable to follow a published procedure, you would have to advise ATC.

Most of the time, you can make the procedure with both engines, but would be unable to maintain in the event of an engine failure, in which case you would have to have a Plan B, such as the above, or circling the field and climbing to the min safe altitude in the pattern, which would only be possible in visual conditions, of course.

Sorry I can't be more specific, but it has been too long. As for just departing and hoping, not only NO, but HELL NO. We get paid to make the hard decisions, and sometimes it is to tell the owner or pax that it is not possible to do what they want to do. Sometimes, you can accomodate them by landing with min fuel, then requiring them to depart in the early morning, say, before 9 a.m., when it is still cool out, and stopping for fuel in Pueblo. Whatever you do, do it legal and smart.

 

[rchcfi]

It's a good question. I've always assumed that you have to wait for the better weather, or lower the weight by making a fuel stop at a lower elevation airport. If you are talking about EGE or Aspen, that's what I've been taught.

I am talking about EGE....Funny how airports of this nature are well known. Another thing about my airplane is that it would only make that gradient with a 20kt HW and a temp of -25C with only enough fuel to make it to Rifle (50 miles away) with no pax. Oh yeah, and assuming those conditions are with a low ceiling I would have to use engine A/I....At that point I become just another airplane parked on the ramp.

 

[LJ45]

Learjet

My Learjet 45 AFM has up to +/- 2.4 % gradient. Aspen is 2.0%...So I was not in volation of the AFM.

thank you!

 

[LJ45]

91 vs. 135

My understanding is IFR 135 you must meet the climb requirement. Part 91 you don't have to.

This is a grey area past the 1500' as you mentioned in the charts. You have in most jets a 5 min limit at TO pwr. that can come into play also.

 

[CaSyndrm]

First of all climb gradients in the US are for 2 engines not one. Safe planning would predicate making it on one engine. Secondly there is no requirement to comply with any of them after you declare an emergency. What is done by most with experience at challenging airports is to brief a visual escape maneuver in IMC conditions and a IMC escape maneuver when not IMC. Any of these maneuvers is legal and how to get a plane out of a tight spot.

 

[flyguy75000]

CaSyndrome brings up the point that climb gradients are for two engines not one. I haven't looked it up, but I don't think it is correct and I'm not quite sure I understand your logic behind this. A climb gradient is the required distance climbed per given horizontal distance traveled, regardless of how many engines are working. It is the required rise over run to not hit the obstacle. What does one engine or two have anything to do with being able to clear an obstacle?

Clearing the rocks is clearing the rocks, with all engines working or one or more failed. It may be a legality that once an emergency is declared you no longer have to meet the gradient, but is that really what a "wise, experienced pilot" would go by? Climb gradients are charted because the gov't, believe it or not, is looking out for us. They are't to punish us and keep us from flying, they are keeping us and pax from a granite death. I had a chance once to watch a surveyor at work at a local airport figuring out the climb gradient for a specific runway, and it wasnt until then that I realized why they were in place.

I havent flown an airplane yet that could meet the climb gradient requirements out of Aspen. The Excel is close, but still 2 or so % less than the 7.5% (i think) needed for the LINDZ4. Anyone out there in a bird that can make the gradient with a a full or close to full load out of EGE or ASE? On a side note, did any of you guys (besides AirWhiskey/Mesa/Mesaba) guys know there is a localizer and GPS-Z approach into ASE for special operators. Wasn't aware of this, but you have to jump through a lot of hoops to get approved. We did some training with the Chief pilot over at Aspen Air, he's a retired 727 AA Capt. flying a Lear for them. He knows those airports out there like the back of his hand and for a small fee he'll go out and shoot approaches, circles, go-arounds, etc, and give you all the advice he can. It was definitely worth it, and most owners probably wouldnt think twice if you asked them to do some training out there.

 

[Ty Webb]

First of all climb gradients in the US are for 2 engines not one.

That is not true. If you don't know something for sure, how about looking it up first?

Look at the chart below. . . . it's from Part 25.111 Transport Category Aircraft, which most business jets are certified under.

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2nd Segment Climb Requirement:​

at V2, from 35ft to 400 ft above ground level:​

for engine failure, flaps in takeoff position, landing gear retracted:​

# of engines climb gradient (CGR)​

4 3% ​

3 2.7%​

2 2.4%​

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[CaSyndrm]

Isn't that part 25 for certification. Do we operate under that part? Do I appear to be somebody that would make a statement without having some knowledge on the subject. However, I am frequently wrong. I am more of a stick and rudder kinda person not a book person. That being said refer to my first sentence. I should have however used the letters VMC in the last word of the 4th sentence of my original post. I believe that most discussion points such as the long one above still refer to safe operation and are not regulatory on this matter. If people flying private jets in these scenarios are so concerned and cancelling flights for the above mentioned reasons at KASE and others then these same pilots should be departing KVNY light to get fuel elsewhere also because I don't think many of the corporate jets meet the approximate 7.8% climb gradient out of there (what I think is one of the busiest corporate airports in the world).

I always regret getting involved in these discussions, when will I learn.