Climb Gradient

New Guy · Post by **New Guy** » Wed Feb 09, 2005 7:00 pm

Here’s hoping someone can clarify this for me.

On a departure SID like the COWBY1 in Las Vegas

http://204.108.4.16/d-tpp/0501/00662COWBY.PDF

The take-off minimums of 300’ per NM to 11000ft for Runways 19L/R & 25L/R does anyone know if this rate of climb needs to be maintained on one engine in the event of an engine failure, or is this an all engine operating climb gradient.

Elliot Moose · Post by **Elliot Moose** » Wed Feb 09, 2005 7:29 pm

Yup. You should have the gradient, unless a special engine out or "obstacle departure" is prescribed (such as KSFO-for aircraft that are unable to make min gradient, or engine out). Under part 121 this would have to be accounted for by runway analysis. Under part 91 in something that can't make the gradient on one fan, things get a bit grey. I believe that technically you wouldn't absolutely need to be able to make it on one fan, but accounting for good airmanship.......

Many debates rage on the specific legalities of this one, and especially where the gradients exist for some bullshit thing like noise abatement as opposed to the presence of a BFR at the end of the runway. Of course if one can visually avoid the BFR's due to good weather that changes things too.

I for one go with the "net flight path" calculations based on engine failure at V1 from the AFM regardless. For the CRJ this takes some time and practise, but because we operate under 91 in the states and don't carry runway analysis, I have no choice if the minimum gradient is steep. Do I do it for every leg? Not likely, but I do for the short fields etc. where climb capabilities are critical.

.80@410 · Post by **.80@410** » Wed Feb 09, 2005 8:12 pm

We were having this discussion at work the other day.
I think/ feel/ assume that these gradients are based on 1 engine climb.'

Seems many people don't think that the 121 carriers can do the climb gradients in places like Las Vegas, especially on hot days- and that maybe they have approved company procedures? IE Left to 230 degrees and up to 7000 right 330 degrees up to 10000 etc- basically an unwritten obstacle departure ?

I dunno, I gotta look at the plates n see.

rippey · Post by **rippey** » Wed Feb 09, 2005 8:41 pm

does anyone know if this rate of climb needs to be maintained on one engine in the event of an engine failure, or is this an all engine operating climb gradient.

I guess it depends on whether you want to clear the rocks or not...I don't think the mountains around LAS care how many engines are turning! Usually if a SID climb gradient is for noise it specifies on the plate. We advise ATC if we can't make the gradient single engine but that we can accept the obstacle departure if one is published. At least then if the worst happens and you lose an engine on takeoff ATC will have a good idea of what you're up to. Another thing I have always found strange is that SID climb gradients are only published if they exceed 3.3% (I think)....but transport category aircraft only have to demonstrate second segment climb of 2.4% for certification.

peeelot · Post by **peeelot** » Wed Feb 09, 2005 9:55 pm

Yes it regards to engine out. Whether you have both engines working or just one you still have to clear everything. That is why at an airport like that take-off charts should be done twice just to make sure.

co-joe · Post by **co-joe** » Thu Feb 10, 2005 12:49 am

As far as I know, SID's in Canadia are based on all engines running. SE performance 'should' be taken into account, but not 'shall'. 300 feet per nm to 11000 ' ? How many aircraft could hold that kind of gradient SE?

At 120 you would have to maintain 600'/min. Could your a/c do it on a hot, and heavy day?

Stearman · Post by **Stearman** » Thu Feb 10, 2005 5:45 am

I am curious to know where you found that it says that the pilot is not responsible for obstacle clearance on that one.

I am pretty sure that if you hit something your responsible.

rigpiggy · Post by **rigpiggy** » Thu Feb 10, 2005 6:40 am

That's why the manufacturer's publish WAT charts. Jepps also has an airfield eval service with engine out procedures if required. ie @ 28c off rwy 29 weight limited to 77,500 for second segment climb etc....

New Guy · Post by **New Guy** » Thu Feb 10, 2005 7:49 am

O.K. so say as a Part 121 carrier you cannot make the 300' per NM to 11000ft on one engine but you can on two.

The airport has an obstacle departure proceedure published, as Vegas does

http://204.108.4.16/d-tpp/0501/SW4TO.PDF

(you have to go down to page 3) can this procedure i.e.

DEPARTURE PROCEDURE: Rwys 1L, 1R, 19L,19R,
climbing right turn direct to BLD VORTAC.

be used instead of runway anaysis or a company escape procedure in the event of an engine failure as this does appear to provide obstacle cleareance and does not publish a required climb gradient.

Co-Joe is also right, how many 1900's, Dash 8's and Jetsreams are going to 11000ft on one engine period never mind at 600ft per min.

Great info so far guys keep it coming.

Elliot Moose · Post by **Elliot Moose** » Thu Feb 10, 2005 8:55 am

In the case where 121 carriers can't make gradients, their take off/landing reports or runway analysis (whichever form their dispatch subscribes to) will have alternate engine out procedures. In a case like "300'/mile to 11000'" which is likely a noise/traffic control thing, one would declare "engine out departure" and follow the company prescribed procedure. Under 91, declaring an emergency will generally do it.

In the case of a BFR at the end of the runway, 121 ops would have a similar procedure, or a restriction such as a higher ceiling and vis requirement coupled with a VFR climb to a certain point.

pimper · Post by **pimper** » Thu Feb 10, 2005 12:17 pm

The SID's you speak of are for two engine climb gradients. There is an escape maneuvre also published in case of engine out. As a side note there are also escape maneuvre's for one engine go arounds into LAS that turn the opposite direction as the published missed approach.

SpeedWeasel · Post by **SpeedWeasel** » Thu Feb 10, 2005 12:47 pm

Pimper, do you know if the published escape maneuvres can be used by Part 121 (CAR 704) operators if the SID climb gradient can't be met on one engine or is it only available to Part 91 (Car 604).

Also has anyone ever seen any documentation on this subject from Transport Canada ofr the FAA?

Elliot Moose · Post by **Elliot Moose** » Thu Feb 10, 2005 3:23 pm

There is very little published along this line for 91 ops. Hence my comment about "grey areas". If the alternate departure is published in the Jepps, then everybody is expected to use it if unable to make the gradient. If it's not published, and you accept the departure, YOU are responsible for making the gradient, regardless of whether a fan quits or not.
I would disagree with Pimper's assertion on this. You accept it, you are compelled to fly it, or declare an emergency and follow whatever ATC can give you under the circumstances. No rocks is likely no problem, but if there's a BFR at the end of the runway and you can't make the gradient because you lost a fan, ATC can't issue a waiver for you--they may be able to help though. Many places don't have "special procedures" as pimper asserts, and there you're on your own to comply.

pimper · Post by **pimper** » Thu Feb 10, 2005 3:26 pm

This is more of a guess then anything. In LAS for example off of runway 25R the SID altitude/minimum climb gradients seem to be more for noise abatement over the city as well as the arrival/departure corridor. The arrivals pass under the departures.

As far as the escape maneuvre's that will be airplane specific based off the aircraft meeting the 9 performance factors. SG uses AirCanada charts and the missed approach prodecure for Air Canada is completely different then for the MD. The MD would suck out their on one engine.

As far as your aircraft you would have to do the calculations to find out if it met the performance limitations.

Elliot Moose · Post by **Elliot Moose** » Thu Feb 10, 2005 3:35 pm

You're correct there pimper. But you're talking 121 ops with approved special procedures as I mentioned in my first post. That's how 121 folks get around the sticky spots--by having aircraft specific special procedures.
My second post was of course talking part 91 where we are stuck with Jepp published procedures only.