2% Runway slope limitation

[C77MD80]

Taking a type soon and have 2% runway slope limit. Not exactly sure how that is figured. Anyone know? I do know it's not really an issue as our computer/performance won't allow it, but our examiner is asking...

 

[Lead Sled]

Taking a type soon and have 2% runway slope limit. Not exactly sure how that is figured. Anyone know? I do know it's not really an issue as our computer/performance won't allow it, but our examiner is asking...

It's the old rise/run formula put into a percentage. For example, if you have a 5000' runway with a 8' differential it would be 8/5000 or .0016 = .16%. One of the more common examples would be Aspen (KASE). There's a 140' difference in runway elevation spread over a 7006' runway. It would be 140/7006 or .01998 = 1.98% or just under the common 2% limit. Whether the slope is + or - depends, of course, whether you're headed uphill or downhill. It's not always as cut and dried as that however. You guys who have flown out of Telluride will know what I mean. On paper, there's very little slope - about .25%. Yeah right. The runway has a wild depression in it. It one of those airports where a positive rate of climb doesn't necessarily mean that you are increasing your vertical separation from the ground.

'Sled

 

[Clutch_Cargo]

Well you can WAG it by taking a look at your airport diagram...

There is an elevation listed at each end of the runway (at least on Jepps). Take the difference between the two, divide that number by the runway length and muliply by 100. That gives you the % gradient but that also assumes it is constant slope. The actual runway might not be that way. Really the best answer is that someone in your operations should be doing an airport analysis and providing you with the results.

Edit: Yep, just what Sled said. I wasn't fast enough with the reply button. BTW, he's right about TEX too... that's an interesting place to visit.

 

[HMR]

Taking a type soon and have 2% runway slope limit. Not exactly sure how that is figured. Anyone know? I do know it's not really an issue as our computer/performance won't allow it, but our examiner is asking...

I know the formula your examiner is looking for but does it work in the real world? If so, can you ask him what the slope at Telluride is? I've never been able to figure that one out.

Hint: The runway is 6870' long and the ends are only 17' apart in elevation but how you factor in the dip in the middle is beyond me.

 

[HMR]

Lead & Clutch-Dang, you guys are fast! I need to learn how to type with more than one finger.

 

[Lead Sled]

Lead & Clutch-Dang, you guys are fast! I need to learn how to type with more than one finger.

I'm bored.

'Sled

 

[taloft]

So a runway at a 45 degree angle would be 100% slope?
nifty

 

[Clutch_Cargo]

Yeah, I have to jump on the ones I know... usually I'm just sittin' there scratching my head and mumblin' "Hmmmm..."

 

[Lead Sled]

Yeah, I have to jump on the ones I know...

Hey, don't let that stop you. It's never stopped me before.

'Sled

 

[HMR]

While we're talking slope...

I used to fly a PT135 twin in and out of a dirt strip with a 6% grade. Can anyone top that?

 

[HMR]

usually I'm just sittin' there scratching my head and mumblin' "Hmmmm..."

Sheesh, that's me everytime I get behind the yoke.

 

[Clutch_Cargo]

Hey, don't let that stop you. It's never stopped me before.

'Sled

Guess I can't be bashful around here! LOL

Sheesh, that's me everytime I get behind the yoke.

Ha ha... me too... good to have some company!

While we're talking slope...

I used to fly a PT135 twin in and out of a dirt strip with a 6% grade. Can anyone top that?

Holy shnikes! You got me beat. How about this one... Mr. Toad's Wild Ride... Courchevel... http://www.buttonvilleflyingclub.com/photos/courchevel.pps

 

[Daveman]

Yeah, I have to jump on the ones I know... usually I'm just sittin' there scratching my head and mumblin' "Hmmmm..."

That's me. So what would be the case if we flew together???

 

[Clutch_Cargo]

That's me. So what would be the case if we flew together???

Ha ha... well, I think that's the ol' "how many _____ does it take to screw in the bulb" question! Ah, I'm sure it'd be a good time... and that's what counts, right?

 

[Lead Sled]

HMR...
That ski jump, err, runway has to beat anything I've ever seen. How would you like to have been the first guy to fly in there in a -8? Those guys had huevos the size of cantloupes.

'Sled

 

[Daveman]

Yep Clutch Cargo, that's what counts. Good point.

Lead Sled, I've learned a few things from you and the Avbug cat along the way.
Thanks for sharing (in a non-confronting) way. I'm always ready to learn from your type.

Dave.

 

[qmaster3]

That's me. So what would be the case if we flew together???

Me in the back thinking Hmmm what in the hell am I doing here.

 

[Lead Sled]

Lead Sled, I've learned a few things from you and the Avbug cat along the way. Thanks for sharing (in a non-confronting) way. I'm always ready to learn from your type.

So far no one has asked me a question that I couldn't find the answer for in my copy of "Flying for Dummies".

'Sled

 

[Clutch_Cargo]

'Sled, maybe I could use you as a reference for my new book...

"How to Land a Plane in 10 Easy Steps... OR... It Wasn't the Pilot's Fault, It Wasn't the Plane's Fault, It Was the Asphalt!"

What are your rates.

 

[dalegribble]

If you want to know the actual slope, check the afd (green noaa book) published every 56 days, it has the slope everywhere. Your AFM limitations and performance numbers are the limitations when you figure slope and conditions.

 

[Lead Sled]

'Sled, maybe I could use you as a reference for my new book...

"How to Land a Plane in 10 Easy Steps... OR... It Wasn't the Pilot's Fault, It Wasn't the Plane's Fault, It Was the Asphalt!"

Sure, I'll collaborate with you on your book - just as soon as I finish my latest book...
Stupid Things I Have Done In Airplanes Volume III. I'm already doing the research on volume IV.

'Sled

 

[Clutch_Cargo]

Sure, I'll collaborate with you on your book - just as soon as I finish my latest book...
Stupid Things I Have Done In Airplanes Volume III. I'm already doing the research on volume IV.

'Sled

You've got some of those volumes too? I was going to publish mine posthumously... pride 'n all ya know!

 

[Lead Sled]

If you want to know the actual slope, check the afd (green noaa book) published every 56 days, it has the slope everywhere. Your AFM limitations and performance numbers are the limitations when you figure slope and conditions.

Dale...
We probably ought to at least try and keep this thread on topic. Just out of curiosity, what the the AFD show as the gradient for Telluride (KTEX)?

'Sled

 

[MTpilot]

Out of curiousity

Why the 2% limit. I've been on a few runways with slope, works just fine, take off downhill, land uphill, some of them are short enough it would be tougher getting in if it weren't for all that slope.

 

[Lead Sled]

Why the 2% limit. I've been on a few runways with slope, works just fine, take off downhill, land uphill, some of them are short enough it would be tougher getting in if it weren't for all that slope.

As far as I know, it's a certification thing. They had to establish a limit and they chose 2%. Kind of like the 10 knot tailwind limit. I have heard of cases where operators needed greater limits and were able to get waivers.
'Sled

 

[Clutch_Cargo]

Dale...

If you've got an AFD handy I'd also be curious to hear what it lists for a gradient at TEX. What I remember is just like 'Sled said... overall it's about a quarter percent. But that dip in the middle is like 65 ft of elevation change and it has a gradient of 1.9% or something close. I haven't been in there in about 4 yrs so I don't know if things have changed but I remember that they were talking about leveling out the runway.

cc

 

[fly4free]

Lead Sled is not really a pilot...He just stayed at a Holiday Inn Express last night.

Fly

 

[C77MD80]

Thanks all, that was quick! I appreciate it

 

[bafanguy]

Taking a type soon and have 2% runway slope limit. Not exactly sure how that is figured. Anyone know? I do know it's not really an issue as our computer/performance won't allow it, but our examiner is asking...

I suppose it's nice, in terms of general knowledge, to know how to compute it, but in a 121 operation where you better not get caught doing your version of "runway/airport analysis", why would an examiner expect you to be able to demonstrate it ? Show me how to do something I better never catch you doing ? lol

The 2% number is fair game on an oral if it's in the Limitations Section as knowing it shows you have a general awareness of the factors that go into making up runway analysis.

At my former carrier, the pct slope for each runway was published on the airport analysis pages and had been figured in to the allowable weights. And with computer weight & balance, we rarely even used the pages from the 50 lb book.

If I were giving orals, I can think of a whole lot of more important stuff to ask a guy.

 

[Lead Sled]

I suppose it's nice, in terms of general knowledge, to know how to compute it, but in a 121 operation where you better not get caught doing your version of "runway/airport analysis", why would an examiner expect you to be able to demonstrate it ? Show me how to do something I better never catch you doing ?

The problem is that it's only the 121 guys that have someone doing this for them. The rest of us 91 and 135 guys have to fend for ourselves and do "our version of runway/airport analysis". He needs to know how to calculate slope and he needs to know how slope factors into the runway performance calculations. It's a fair question.

'Sled