The 0-8 is designed to get ORD departures above the corridor for MDW. If you can comply with the climb-via, then great, nothing to worry about from an ATC side. If not, then they need to coordinate the non-compliant ORD departure with the MDW to ensure the separation. I'm hoping Marc Z will be along shortly and correct/confirm my basic understanding here...
I've never been compared to a heavy before...
Didn't realize they had to decline it that often.
Learn something new everyday, thanks.
I've never been compared to a heavy before...
Additionally Mark, how critical is it for you to get the word that we won't make the climb? Obviously 95% of the time we'll know early and let clearance delivery know, but occasionally they'll take us from 28R and we're positive SID climb and last minute switch us to 22L and we're negative. Obviously it was out of our control and we'll let whoever know right away, but just curious what kind of impact that change makes on your side.
I flew yesterday in the 20 degrees F and gusty winds in my Cherokee 235. I could have done climb easily. I had to make an effort to keep the sucka below the Bravo.
I still think what MauleSkinner said was correct: "They're probably multi engine airplanes that can't make the climb gradient with an engine inop."
I've never been compared to a heavy before...
Additionally Mark, how critical is it for you to get the word that we won't make the climb? Obviously 95% of the time we'll know early and let clearance delivery know, but occasionally they'll take us from 28R and we're positive SID climb and last minute switch us to 22L and we're negative. Obviously it was out of our control and we'll let whoever know right away, but just curious what kind of impact that change makes on your side.
IMO, there may be no other reasonable option than to use another procedure or wait for VFR weather.
I was commenting on "Point is SID compliance isn't based on engine out performance." Of course that's a true statement, but if you don't have special OEI procedures developed by an engineering department you can simply plan your departure the normal way assuming engine failure at V1. If a Caravan can't make the gradient at ORD, I'm guessing some multiengine aircraft (on one) can't either.
Different strokes for different folks. Just because you buy some data doesn't mean you have a better plan.
Most of the engine out departure procedures are runway heading, right? If you lose an engine at V1 that could be around 20 miles before you reach 1500', right? (A quick deduction based on 200'/nm being 3.3% and 1.2% being 1/3 of that.) There you are, at pattern altitude a long way from the pattern with no positive course guidance at all. How's that a good thing?
No, that's not the point I want to counter. I agree that SIDs are all-engine. It's a point that I think that's so obvious, in fact, I didn't see the need for an advisory circular (AC 120-91) in the first place. The point I want to counter is your statement that it's "wrong" to plan an IFR departure using OEI performance from the AFM. That's something I and many others had done for years. There's more than one way to skin a cat. My point is the technique in the AC is driven by economic forces, not safety. "My" technique preserves TERPS safety margins, the Advisory Circular compromises it, though you could argue it's still safe if you think TERPS is overly cautious.
I would say, "no." Almost all of the EO DPs I've seen have some sort of turn after departure. The whole idea is that you can't fly runway heading without hitting an obstacle, therefore a turn is required.
It depends. Is the climb gradient published for obstacle avoidance or for ATC climb rate? Flying a multi-engine airplane in the ANG (KC-135R), this is the basic Air Force guidance: All climb gradients that are published for obstacle avoidance have to be able to be met with One Engine Inoperative (OEI). If the climb gradient is published for ATC crossing restrictions, we only have to meet that with All Engines Operating. To me, this makes sense. If the climb is for an obstacle, you can't just tell ATC that you've lost an engine and to move the mountain in front of you.
The constructed EO procedures do assume a failure at V1, and are good until you diverge from the EO routing. Even after airborne, if you are still on the EO routing, you can still fly it. If you have already departed the routing, due to turning on the DP, you're on your own and just have to avoid the rocks using whatever means you can.
They aren't. See above.
I disagree. Any of the published EOPs I've seen at work have some sort of turn after departure. Obviously, if there is no obstacle issue, you'll climb straight out. If you can't go straight out, there will probably be a turn, and a EOP may be published.
You did.
Not true. Those charts are for pilots, that's why they're onboard the airplane in the AFM and required to be there.
Can't you see the irony in this statement?
I think it's annoying for you because you don't understand the issues. I'd suggest getting familiar with basic departure procedure design under TERPS, reading Chapter 4 of any Part 25 airplane and then studying AC 120-91 to see an approved method for shaving TERPS criteria to allow for more payload. "Safer" it is not, IMO.
We're in agreement on everything else and would be on this too if you can accept that a straight-out procedure is an exception to TERPS criteria also. Take a diverse departure under TERPS as an example. A pilot adjusting takeoff weight to meet a 3.3% OEI climb gradient can depart in any direction, but an operator meeting only second segment climb requirements of 2.4% is restricted to runway heading. The lateral buffer is just 2000' either side of centerline too, so it's much less of a safe operation, IMO.
Captain is correct about this. You are not going to design an alternate procedure like those shown in post #32 just by using the spaghetti charts because you also need the surrounding terrain and obstacle information. This is what the engineers do.
TERPS departure procedure design and Part 25 standards use different methods to calculate climb gradient/performance. Here is a good article which explains the whole thing.
Of course not. If diverse departures are allowed and you know from experience the single engine climb gradient is around 5 or 6 % why would you? Planning for a departure off less cut and dried runways, like RWY 25 at KLUK need a bit more thought. But it's quite doable. Figuring the departure fuel load keeps Part 91 pilots from boredom too.
They are "less safe" how? Did you read the article in the link I posted? Is that why the airlines use them? As far as costing money, yes they do. The people who design these things don't work for free.