Sunday, 23 March 2014

Appearances can be deceiving

The hills of Karamoja, the most north-easterly region of the Pearl of Africa - Uganda, they look so beautiful in the bright morning light, as I bank steeply over the delightfully named airstrip called Kaabong 5180ft up in the highlands. I can see a Landcruiser acting as a useful marker parked on a clearing on the side of the airstrip.  My two passengers and their driver gaze up at me, as I zip overhead, usually there is a flag fluttering in the breeze from the large aerials these vehicles usually sport, always a useful aid as to the winds strength and and direction but today nothing but it is not difficult to work out today! The sun glitters on the quartz covered runway and all seems peaceful. Excepting it had been such a rough, slow ride as we pushed our way north at 114kts*, into exceptionally strong winds that tore across Karamoja, despite the tranquil scene that lay below me, as the aircraft bounced with enthusiasm from aerial pothole to pothole.

It's warm sunny day in Africa and you wonder what events this airstrip has seen as in it's heyday it was a lot longer! Lining up on finals I held the aircraft steady as the runway desperately tries to dance it's own rythmless quickstep, left, left, left, right, up, up, down, down and down. Somedays airstrips really do not behave and today it seems particularly eager to discourage a visit. It is a strong quartering headwind from the right but I soon get the airstrip to behave itself and come into line. Need to add lots of power descending through the last 200 feet, as a sudden rush of air** seems particularly keen to push one into the ground for an early 'arrival' but I out guess the downdraft and so cross the threshold in a firm, secure and very short-field landing. Definately a nine (my daughter always used to mark my landings out of 10), there is a certain pleasure in the challenge.  The runway has been shut for nearly 2 years and has only recently been re-opened after some remedial work but it is rather narrow now and turning on the runway needs caution as the slope of the drainage ditches is not ideal.

In the old days I used to always pull off the runway but now the drainage 'dip' need more of a 4x4 if one was to negotiate them, so wisdom says stay on the strip. I taxi to the end of the runway which has a convenient turning point, avoiding a rather hefty piece of quartz I park and hop out, quickly chock the wheels. I have decided I will take-off into the slight upslope with gently rising ground, as with todays strong headwinds and my light take-off weight this will be the way to go.  I've dropped off all my up country passengers en-route and just have a lone return passenger, who I picked up at Kotido, she  is very pleased to have some fresh air. The other two passengers walk down to me with their bags.

I do a quick walk around the aircraft to get ready for departure again, I find a couple of small nicks in the prop from a stone or two either kicked up on the brief burst of reverse thrust which helps slow the aircraft down on landing or on the turn, engineering will be able to file those out easily when I get back, props have quite a hard life!

The aircraft rocks gently in the breeze and I think about Karamoja over the years so many cattle raids, fights that have become battles. Almost unreported the tribal warfare has cost many a young man's life. The nomadic lifestyle paints a romantic freedom to the westerner tied up by rules and expectations but the good and bad rain cycle creates a hard hard life and the mobile life takes its toll on the women and children of the region. Interesting how some may say let them be but if you talk with a few of the mothers you find they want for their children exactly what we want for ours, to have health living beyond 5, they want peace and for their children to go to school.

Perhaps appearances can be deceiving...

as I look at the photo , I think what a lovely day, so peaceful but appearances can be so deceiving, in so many ways.

Full power and I am off in no time as I turn into wind and climb away. Next stop Soroti where I pick up 4 more people but we have an extended stay for 20 minutes whilst my 3 passengers change their complexions back from green to white. Actually in all my years I have had very few passengers who have been sick - honest.

 *we would expect a groundspeed generally around 140-160kts
** downdraft

If interested their is a video on youtube bigglesgsy you should be able to find a clip of landing at Kaabong a couple of years ago.

Friday, 7 March 2014

The BVLGARI of the air? Jet A-1 the way to go

As a 'part time' mission bush pilot who is not based in one particular country but has the privilege of helping out on several programs, when they are short of crew. I usually travel between assignments  el cheapo!' But I have to confess that I have received several times from BA and Emirates the  occasional up grade or the chance to use my air miles to move up and get a good nights sleep on a bed and Emirates are the bees knees at providing a very comfortable bivouac and they also give you a great overnight bag containing various men smells by BVGARI which are excellent.

There is nothing, absolutely nothing, quite like catching the scent of a turbine engine's exhaust fumes drifting on the the early morning air, of what is to become a glorious summers day. So I can but recommend, if you ever get a chance to stand downwind of a turboprop as it starts it's engine, seize the day, stand fast, stop, listen, sniff as you are in for a real treat, especially if it is a PT-6.  The sound of the engine spooling up as bursts into life and struggles to get the prop spinning, the engine notes move through the octaves, from a reverberating low growl to a high pitched whine followed by that delicious fragrance, oh so sweet, with perhaps caramel overtones.

Author with the magic liquor and his mount in the background in Pala, Chad
Jet A-1 is wonderful stuff, the fuel of choice for civilian commercial jets and also for an increasing number of Mission Aviation Fellowship's (MAF) fleet of over 130 aircraft. Whilst av-gas, a form of 100LL petrol is used in the piston powered Cessna 206 and Gippsland Airvan's and the last few 185 floatplanes, some of the the 206s are being phased out to either be replaced by piston Airvans or by our increasing fleet of turbine powered aircraft. This is made up of the incredibly kapable  Kodiak, consistent Caravan and somewhat surprisingly the small 4 seat diesel engined 182. We also fly the Twin Otter, King Air & PC-12.

Jet A-1 is much cheaper than the petrol equivalent, more readily available and safer. It is clear to straw coloured liquid, that unburnt smells pretty disgusting, makes your hands smell and tastes little better, no don't suck Jet fuel out with your mouth if you wish to syphon off the tanks of your 747. Though the fuel burns well in your hurricane lamp. It has a flash point of 38C, freezes at -47C and if you burn it out in the open the flames are about 300C but is essentially quality paraffin or kerosene.

In fact according to St .Wikapedia, the fount of all generally reliable info, this is for all you chemists out there, suggests the combustion reaction can be approximated as follows, with the molecular formula C12H26 (dodecane):
2 C12H26(l) + 37 O2(g) → 24 CO2(g) + 26 H2O(g); ∆H˚ = -7513 kJ

If you burn 5* Jet A-1 (RP-1) with liquid oxygen you can put your friendly Saturn V rocket into orbit! But my Jet A-1 does nicely in my 675shp PT-6 and drive sit along at abut 150kts and gets me in an rout of some tricky places with some amazing people making a real difference... bringing help hope and healing to many very remote communities around the world.

Leaving fuel in Bol for the very frugal diesel 182
However I use natural oxygen to power my Cessna 208 and the higher the better (usually around 9-12000ft) and it powers my chariot reliably. We burn about 300lb's an hour so you have 1000 litres in the 5 barrels in the photo above. Which will keep going for about 6hrs or 900 miles!

These donkeys would need to bring me about 8 jerry cans an hour! Actually I was dropping off fuel for the 182 in Bol, western Chad by the shores of Lake Chad.
 This 1979 Cessna 182 had it's old petrol/av-gas engine removed and a new diesel engine put in it's place, this SMA diesel burns paraffin and consumes a very frugal 35 litres of cheap Jet A-1. Cessna now do a brand new aircraft with the SMA installed at the factory, lovely machine but it is not cheap!