Hi Bob and Richard

Working through the ppl progress test section 2 on page 1.2.13 i have stumbled on question 5 were it mentions that the slope of the runway is 4% down to the NW. When i was going through the example of that question on page 1.2.16 it has mentioned that instead of going 4% down it actually mentions to go 4% up as you are landing to the SE. Guys can you tell me how i work that out because i am unsure how to get that answer from that stage, then the rest of the answer is quite simple to work out

Kind Regards

Morning!

OK, the first thing to take a look at is the wind: 150 ^o M at 10 kt. 10 kt is too much wind for us to accept as tailwind for landing since the max allowable tailwind on landing is 5 kt. That means we have to land on the most into-wind runway available.

Fortunately the runways available are 15/33. Runway identifiers are the runway heading given to the nearest 10's of degrees with the last "0" trimmed off. Runways 15/33 means if you are lined up on runway 15, your compass will read pretty close to 150^oM and if you are lined up on the oppsite end (runway 33), your compass will read pretty close to 330^oM.

The wind is blowing at 10kt from 150^oM so we will have to use runway 15 because when we are aligned with runway 15, our nose is pointing straight into wind.

We now know we are going to be using runway 15 and we will have a 10kt headwind. However we are also told the runway slopes 4% down to the north west. A slope down to the north west is the same as a slope up to to the south east. 150^oM is pretty much southeast so we must have a 4% up-slope for our landing.

Cheers,

Rich

Good Morning Rich

Thanks so much for your reply, just I seem to be getting lost when You say a slope to the north west is the same as a slope to the south east, so how do we know when you have to go up on the landing chart (%) or down, so when we get questions like that do we always have to choose the runway which will suit our takeoff needs. I am gonna keep reading through your previous reply to see if I can get it around my head while I wait for your reply...

Thanks so much rich for taking the time to help us all out on the forum...

Kind Regards
Mark

Hi Mark,

A slope DOWN to the north west is the same as saying there's a slope UP to the south east.

When you are given a slope such as the one in this example they are simply telling you which end of the runway is lower. A 4% slope down to the north west means the north-western end of the runway is lower than the south eastern end. If you were taking off from the north western end towards the south east, you would be battling an uphill slope. If you were taking off from the south eastern end towards the north west, you would have a downhill slope.

Here's some more examples to help make it clearer:

Runway	Slope	Comment
09/27	2% down to the west	uphill to the east (runway 09), downhill to the west (runway 27)
18/36	2% down to the north	uphill to the south (runway 18), downhill to the north (runway 26)
15/33	3% down to the southeast	uphill to the northwest (runway 33), downhill to the southeast (runway 15)
05/23	4% down to the southwest	uphill to the northeast (runway 05), downhill to the southwest (runway 23)

To help you get your head around it (and no, you're not the first to have troubles) draw a picture of the situation. Draw the runway with the approximate direction, draw an arrow representing the wind direction (remember, the wind direction given is the direction the wind is blowing FROM). Finally put in the slope. To do this, write "UP" at the uphill end and "DOWN" at the downhill end (or use your own words like "Higher" and "Lower" if you like).

So, for this example question, try sketching out something like this:

This sketch will help orient you and ensure you use the right values for the P-chart.

Cheers,

Rich

Hi Richard 

Thanks so much for all of your reply's and examples as the examples have helped me a lot, and I am glad to hear that I am not the only one that has had trouble with these kind of questions...

Well I will have a crack at working on these examples and let you know if I get into any trouble

Thanks again

Kind Regards
Mark

No worries Mark. That's what we're here for