effect of runway slope on takeoff / landing performance

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Seth.A

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Seth.A
I'm trying to find some figures (or general wisdom) on the effect of runway slope on takeoff and landing performance. Obviously taking off up hill will lengthen your takeoff roll, but by how much exactly. Whats the right way to consider runway slope vs wind when choosing which runway to use.

Take for example a 172S, which offers no guidance in the POH, taking off from ORS which is 2900' with a 0.8% grade. Is the slope even something to consider in this situation? If so, how?
 
I takeoff often uphill at an airport with a .8% slope at 5500’ field elevation. You can tell that you’re going uphill, and it does slow things down a bit, but not enough to worry about much. At KORS at nearly sea-level in a newer 172 I don’t think it’s something you need to be worrying about - in all scenarios I can think of, it will make more sense to just takeoff into the wind.

I do takeoff and land at strips with a lot more slope - like where there’s enough slope that it’s difficult or impossible to taxi uphill. There is definitely is a point where it really starts to make a huge difference, but .8% is pretty minimal.
 
AA5Bman said:
I takeoff often uphill at an airport with a .8% slope at 5500’ field elevation. You can tell that you’re going uphill, and it does slow things down a bit, but not enough to worry about much. At KORS at nearly sea-level in a newer 172 I don’t think it’s something you need to be worrying about - in all scenarios I can think of, it will make more sense to just takeoff into the wind.

I do takeoff and land at strips with a lot more slope - like where there’s enough slope that it’s difficult or impossible to taxi uphill. There is definitely is a point where it really starts to make a huge difference, but .8% is pretty minimal.
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Impossible to taxi uphill?? What kind of plane and what airport? What’s the scope?
 
Taxi uphill is easy. But I'm not fond of taxiing downhill, tailwheel. But again, I'm probably a bit of a baby. It works fine, I just find it "weird".
 
Good question.
When I went into a field with a 1% slope, one of the locals said they typically land uphill and takeoff downhill unless the tailwind is greater than around 20 kts. I haven't done the math on the effect of 20 kts vs up/down hill.
 
100 feet difference in elevation between ends of an 1800 ft strip.

Always land uphill and take off downhill. VSI shows descent at liftoff. Landing uphill very easy.
 
Magman said:
100 feet difference in elevation between ends of an 1800 ft strip.

Always land uphill and take off downhill. VSI shows descent at liftoff. Landing uphill very easy.
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Dang! If I did the math correctly, that's about a 5% grade, or 3.2° - in other words, steeper than most ILSes.

I'd like to land there though, must be fun.
 
There is a road that parallels it. You don’t have ro pedal to go downhill. Twin Otter had no issues; carrying jumpers.
 
Domenick said:
Sporty's Takeoff Performance Computer:
https://www.demonick.com/flying/flying.topcomp.html
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I'm somewhat hazy on computing "Grade." Point me in the right direction.

Ever go into Old Rhinebeck, NY94, up the river near Kingston? Both ends of the rw are on opposite hills. Start your t.o. down hill for a little boost. Those "olde" crates without brakes sometime use the opposite end to stop if they land long. I thought that I was a stud when I was coming out of there in a C 172. Some guy in a Mooney was ahead of me and showed me how its done.
 
Maxnr said:
I'm somewhat hazy on computing "Grade." Point me in the right direction.
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Percent grade is simple: (elevation change/length of runway) x 100. So for the example, 100 ft/1800 ft x 100 = 5.6%.

It's typically published in the A/FD or on airport diagrams if it exceeds a certain value (which I do not remember).

I was on a runway yesterday that has no grade published, but definitely has a grade to it - but it peaks in the middle, and each threshold is at about the same elevation. So no "total" elevation change over the length of the runway means no grade, or slope. Though it is certainly steep enough to affect takeoff performance.
 
upload_2022-5-2_12-11-39.jpeg

Some pilots routinely operate off strips like this. No options: land uphill, takeoff downhill.
 
Dan Thomas said:
View attachment 106544

Some pilots routinely operate off strips like this. No options: land uphill, takeoff downhill.
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Attended presentation by MAF where showing that they routinely operate off strips like this.
They showed the cockpit video of them doing it.

Procedure, touchdown, full power until the top, and that was either 208 Caravan or Kodiak.
If you stop before the top of the hill it "takes the whole village to push/pull the plane to the top"
The abort point on take off is brake release, once you go over the edge you are going fly or crash.

As they showed the take off you could see another almost identical strip on the mountain on the other side of the Valley.
That was their next destination it was 5 minutes away but 3 days by ground transportation.

Brian
 
brcase said:
As they showed the take off you could see another almost identical strip on the mountain on the other side of the Valley.
That was their next destination it was 5 minutes away but 3 days by ground transportation.
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I saw one where they had to do the pre-landing checklist before they took off. The next strip was a 45-second flight away, across a deep ravine. The only other way to get there was to hike it, and it took two days and involved crossing a raging river in the bottom.
 
RussR said:
Percent grade is simple: (elevation change/length of runway) x 100. So for the example, 100 ft/1800 ft x 100 = 5.6%.

It's typically published in the A/FD or on airport diagrams if it exceeds a certain value (which I do not remember).

I was on a runway yesterday that has no grade published, but definitely has a grade to it - but it peaks in the middle, and each threshold is at about the same elevation. So no "total" elevation change over the length of the runway means no grade, or slope. Though it is certainly steep enough to affect takeoff performance.
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Telluride used to be 2 1/2% down to the middle, and 2 1/2% back up to the other end, for a net zero.

I always calculated my performance to make sure I could put climb the runway, in addition to the “legal” requirements. ;)
 
Dan Thomas said:
Some pilots routinely operate off strips like this. No options: land uphill, takeoff downhill.
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Courchevel Altiport in the French Alps is like that. Plenty videos on youtube, both happy and a few sad.

There have been scheduled flights but I don't think there are any now.

Happy:-

Sad (two views of same incident):-
Can't remember the story exactly but it was something like someone pretending to be an airline and getting some passengers. Was pilots first flight into Courchevel on his own after sparse training in a different aircraft.

https://aviation-safety.net/wikibase/wiki.php?id=221641
Link to report here too.

Edit:-
Tyrolean Airways video. What commentary there is is in German. A few landings and takeoffs in Dash 7. Poor quality video by today's standards but there is probably no other source for the images.

 
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S37 -Smoketown in SE Pennsylvania is a fun one. 2700’ with about 2% constant elevation. First time I went in there with my family in the plane I had to go around. Was just high and fast. Screws with your eyes. Launching downhill though feels like you are on an aircraft carrier getting catapulted. Cool place. With bonus of getting to say smoketown all the time on the CTaF.
 
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