34 SA Flyer Magazinesailed off the runway into the grass, while
ATC bleated feebly through the overhead
speaker. Sure, if you have an adjustable
seat you check it is clicked in properly – but
just how far are you meant to check things
before flying? It’s this sort of thing that
encourages one to consider membership of
the famous Live Cowards’ Club.
Actually, it could have been really
embarrassing if this had happened after
takeoff. The rear stick had been removed,
so Ian would have been left with only the
throttle and rudder, and a sack of potatoes
on his lap.
'BW' FOR BEAUFORT WEST AND BERG
WINDS
Two days later my business got
an unexpected boost. A Pommie
seismographic crew had been dumped in
Beaufort West and told to look for oil. They
had lots of spare time and good money in
their pockets – and several of them wanted
to learn to fly. It doesn’t get much better
than that.
I leaped into my faithful little Cherokee
and headed due north across the
Outeniqua Mountains, and over the Little
Karoo. Then over the formidable Swartberg
Mountains and across the desert landscape
of the Great Karoo.
Beaufort West sits up against another
range, the Nuweveldberge. It had one of the
biggest and best gravel runways I have ever
seen – actually three, I think. Flat as a salt
pan, billiard table smooth, and massively
long and wide. They used to run a
passenger service there, using four-engine
Skymasters (DC4s) and Daks.
The weather was perfect for most of
the year. Actually cloudless, but perhaps
not quite perfect. You could get a dust haze
which took away the horizon and forced you
to climb above it to do the early stages of
PPL training, which calls for a clear horizon.
And then you can get a fearsome berg
wind which howls off the mountains and
gives you a tumble-drier flight. A number of
aircraft have become scrap while trying to
land in the gusts and swirls of that northerly
wind.
Before I go on, we need a quick Met
refresher course.
A berg wind is a hot, usually strong
wind, which is caused by a high-pressure
area up-country. The air gets pushed away
from the high, and more air descends from
above to replace it. Of course, the air that
descends into the high pressure area is
heated by compression (adiabatic heating)- like a bicycle pump. As this hot air flows
out towards the coast, it gets heated more
by passing over hot ground, and more still
by further compression as it descends from
the inland plateau to the lower-lying areas
nearer the coast.
The interesting thing about a berg wind
is that as it comes over escarpments and
mountains, it is above the cool night air of
the low-lying regions. This means that you
can take off on a chilly 5°C morning and
climb to 500 or 1,000 ft in beautifully cool,
calm air, and suddenly be battered about in
a 30 kt, 30°C oven blast.
Jets that encounter this after takeoff
from Cape Town literally feel as though
they have lost an engine when they hit this
inversion. This inversion layer – the meeting
of the hot and cold air – is very well defined
and sudden. It normally descends slowly to
ground level during the day.
Okay, I have set the scene for how
a fragile Cub might behave when it
encounters this fire-breathing monster.
I was doing the final PPL test for
someone else’s pupil – a guy I had never
met before. I was squished into the front
seat with a Zane Grey cowboy novel to
while away the slow, boring, triangular
cross-country flight over the semi-desert.
The pupil had more room in the back, but
he needed it to organise his maps, rule,
flight-log and whirly-wheel.
Our route was south-westerly to
Willowmore – 84 miles away – where
we would refuel. Then 55 miles west to
Klaarstroom, and then 65 miles north, back
to Beaufort West. So the whole thing should
take us a bit less than three hours in no
wind. Therein lies the rub.
As we taxied out, the windsock was
as limp as a parson’s pecker, so we
backtracked to the threshold of Runway
11, and – after conforming to the normalControls in the rear seat of a Piper
Cruiser are limited - a problem when
instructing 'slow' students.
Beaufort West Airport sits in the
middle of beautiful flying country ...
except when there are berg winds.Erick Stammcolumns