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?