Under or over the mountain?

[DarkHelmet]

Do any of you recall the series "Under the Mountain" on TV? A bunch of kids meeting some aliens and then getting "flown" around tubes like a roller coaster thru the innards of a mountain?

My flying career has been a mirror image of that story, filled with thrills and experiences that I find hard to describe.

This Wednesday was one of them. Approximately 3 months ago I undertook an epic two hour journey to fly from Kliprivier to Brits. It scared the heeby jeebies out of me just thinking I had to fly thru controlled airspace and I adopted to fly around it. I opted to fly from Klip to Carletonville and then on to Brits.

Mountains are bad. I was taught you fly OVER them, DON'T try to fly through them. Thus, mountains scare the living crap out of me. They ARE bad. The Magalies ridge is not really a mountain but still to me they are a major obstacle. I respect them, I fear them, I loathe them...

Needless to say I ventured into the void on Wednesday and I took the plunge and I went over the ridge... My pulse was racing, every sense accute and truly waiting for that leeside effect. Nothing happened, smooth as a baby's behind, awesome - glorious... wow - what a damn dam... Green as my lawn, but I made the leap to cross over. I stayed high and quickly went back to safety but I have met my arch nemesis with glee. I feel that I have won the match. But this is not a match between me and the mountain - I fully know that the mountain has stood the test of time, she wins no matter what you throw at her.

Respect.

Trust in your skill. If the conditions outperform your envelope - write mom a letter and admit that the windsock outperformed your experience. Tomorrow is always a better day to fly when the windsock blows as hard as you want it to.

I had two people out here from our UK office and took them flying on Wednesday, 9 August 2006. I took the first one up - took her OVER the Magalies!!! Surely most of you are aware of my enormous fear I have of that "enormous" ridge!

Courage was my middle name. I skimmed the synoptic chart the day before and thought that some cloud and some rather ugly weather was going to prevail, but the front was still a way off and Wednesday afternoon would be a beaut! The pommies knew that I am an aviator extra-ordinaire (cannot sell yourself short now can you?)

To my sad surprise I logged in to weathersa and saw the forecast for that day. Light Northerly wind in the morning - turning to fresh in the afternoon. Fresh? Ouch - NO WAY on earth (or in the sky) would I even think of crossing over that "mountain" with a fresh wind!

Taking the scenic route from Rosebank to Aviators Paradise I was hesitant but still insistent that my prediction was better than that on SA Weather (okay okay - I got lost - but men never get lost, we take the scenic route - UNDERSTOOD?)

Two Brits anxious to go flying, me anxious to take off because the WX Beareau was predicting the weather to turn "south", in a bad way south, not in a southerly direction...

Pre-flighting my aerie I constantly wanted to know if I was doing the right thing, two very important people, one very unimportant aircraft, risk, no reward. The only reward being the smile on their faces when we come down. What am I risking? What do I have to lose? The weather smooth as silk as I can see but still the authority predicts otherwise? My pax (pax = passengers for those that do not know) just wants to fly.

I am a licensed qualified semi experienced pilot but my interpretation and that of the weather predictors clashes. What do you do? WHAT DO YOU DO?

On the ground it looks AWESOME - hang-gliders say it is as smooth as a baby's bottom (or that of a shaved labrador? how do you read it?) You go up and you test it for yourself and you make up your own mind!

Confident enough with my own skill I decide to strap my most daring PAX into the backseat and proceed with my pre-take-off checks. Call on the radio and backtrack to use the most of the runway as I have been taught ad infinitum.

My 582 purrs like a persian cat on heat behind me pushing us up into the air: 1 for the hang-gliders, ZERO for weathersa. I make a slow climbing turn over Miracle Waters and showed my PAX (who is an avid diver) the waters below... "Look, people dive in that pit!"

I see the quarry, I see the gap in the mountain, now or never goes through my head. "NOW" it was the obvious answer and I do not regret one moment heading over the ridge! Constantly I monitor the radio, this is all new to me, I am pretty sure I changed to the right frequency because everyone is calling locations around or over the dam. DAMN. Will they see me?

I skinted around the Western verges of the dam but could not stop worrying because the wind was coming from the north, straight over the mountains!

I was in awe! I stayed rather high and constantly felt that no-one was hearing me on the radio. Not having a wingman to talk to made me even more attuned to the environment and being a newbie to the damn dam made it even worse. I have driven over the wall to see two fixed wings cross over it within 1000ft of each other – that to this day scares the heeby jeebies out of me. Both going opposite directions!

That said - I have also now flown over Hartebeespoort Dam on my own and I want to do it as soon as possible again!

[Morph]

I remember a little flight you and me took, over a saddle between Contemans kloof and Goedverwacht. I recall your nervousness at the time , and with reason. It comes down to understanding the winds. Know the land, the mountains and the valleys. Don't venture too close if you don't. Generally speaking, in no wind conditions (check the high level winds with the weather department) you will be safe. Alternatively, if you have a tail wind and you are approaching mountains and hills you will normally only experiance lift, which can be fun.

[DarkHelmet]

Morph - my post was a work in progress and I have edited it since you read it.

One thing I have to admit that flying in the Cape has broadened my horizons. Wind is not ALWAYS bad.

Wind is DANGEROUS, but not BAD. My experiences in Cape Town flying CLU-less' trike has added a new dimension for me.

A horizontal windsock made me dive for the first beer before I went to visit you guys. Now I dive for the trapeze bar

An understanding of local conditions is imperative, I have come to respect the advice of fellow pilots more than what the WX beaurauauguggg.ggg (word I cannot always spell, never mind understand) says. But if the WXB is the only thing I can rely on in an unknown area - they are my last resort and even if they are wrong - they still predict the worst and save my bacon from becoming a bokwurst...

[DarkHelmet]

Found that out demon - thanks for the tip on the speed.

[skybound®]

if you have a tail wind and you are approaching mountains and hills you will normally only experiance lift, which can be fun.

Until you cross over into the lee, then it is only fun if you like washing machines on spin cycle.

Rule of thumb is cross over at 1.5 times the height of the mountain, and if in the lee of a ridge, remain 1.5 times away from it. This should keep you clear of the rotor area.

[Morph]

Just when you get complacent, pow

Read my section on flying in the Cape

viewtopic.php?t=2464

[Morph]

Rule of thumb is cross over at 1.5 times the height of the mountain, and if in the lee of a ridge, remain 1.5 times away from it. This should keep you clear of the rotor area.

We generally use 1000ft clearance per 10kt of wind

[skybound®]

Morph, it is at least good that you have a rule of thumb - I have found some that know not of rotor or obstacle turbulence. Seems to be left out of some schools sylabi.

Only thing I would mention however, is that the pressure factor increases four times with the doubling of wind speed. Hence it may be an idea to revise that equation a little. It is not a linear graph.

[The Agent]

Mountains and me are not mates.

I am frikken scared of them and treat them wiffff respect, and altitude.

[Morph]

We get to fly mountains more often than many of you, you cannot go east or north of CT without having to cross mountains within one hour. Going west and south you get wet. They are dangerous under the wrong conditions.

However under the right conditions they are absolutely breathtaking, magnificent and nothing to be afraid of. I flew from Cape Town to Plett and back one weekend. Man going east there was no wind, and we routed along the top ridge of the Langeberge 7500ft. Routing back we had a SE so we routed along the Southern side of the Outeniquas below the peaks at about 3500ft. It felt like you could put your hand out and touch them. Awesome

If there is no wind conditions we often fly through a valley called Hells Hoogte, interlinking the Stellenbosch and Franschoek valleys. You have two huge towering mountains either side and a magnificent valley below. Indescribable.

[Morph]

Only thing I would mention however, is that the pressure factor increases four times with the doubling of wind speed. Hence it may be an idea to revise that equation a little. It is not a linear graph.

I hear you, but with your calcs we would have to cross any of the mountain ranges around us at a minimum of 9750ft. (we are surrounded by 6500ft peaks). Climbing that high from sea-level is quite a task.

We are very cautious before attempting crossings.

[Morph]

Here are some pics from the Stanley Island Trip. Page 1, Pics 8 and 9 are to the right and left of a 3500ft saddle (you can see the saddle on the left side of pic 7)above Franschoek. We scooted across here at about 500ft clearance.

We routed along the top of the Langeberge Pic 13. We were heading for that V in the mountains crossing over from the southern side (right) to the northern side of the mountains) At this stage again not even 1000ft clearance. This was at about 6am, and there was no wind whatsoever.

Later on in the day a westerly came up that pushed us along Nicely. We flew over Swellendam and landed at Riversdale. The airport was closed due to a drag event coming up later in the day so we took off and flew low level on to Mosselbay (By now very thermally bumpy). After refueling we flew low-level along the beach to Plett and Stanley Island.

The return trip we flew along the Outeniqua mountains, with a 10kt easterley tail wind. Landed at Swellendam for a leg stretch and fuel and then routed via, worchester, bains kloof, climbing to 6500ft and scooting through the saddle and on to home.

Here is a gpx file. Save it, unzip it and open it in Google Earth, then start at Morning Star. You can tilt the earth down so you get the sense of the flight. Use the mouse to droag yourself along and you'll see the route. Almost like flying it yourself. Great Fun

[Coyote]

If you ever want to understand rotor speak to a paraglider. These guys spend all their time flying near to mountains. I flew paragliders for 5 years and understanding the wind around a mountain becomes second nature. I find that alot of microlight pilots don't take the effects of rotor seriously - this will stuff will slam a microlight into the lee-side of a mountain in strong conditions. Demon is absolutely correct 1.5 x the height of the mountain and same behind. If you can't get that high is strong wind conditions - go around.