General aviation is widely accepted to be in somewhat of a decline in South Africa. Thus it is quite exciting when an exhibition aimed primarily at the general aviation sector is scheduled – look, it’s not Oshkosh or Sun ‘n Fun but this is about as good as it gets for us locals. It is also quite unusual in that there was no airshow scheduled – only static and trade exhibits. The exhibition is Aero South Africa and it was billed as an offshoot of Aero Friedrichshafen
The other day I offered to help one of our club members to move his aircraft to another airport for its MPI/Annual. No problem, right? Except it’s a controlled airport I’ve never landed at before (at least during the day – I did a touch and go there on my night cross country but the tower was closed).
This did give me some room for pause – it’s an easy airport, 2 runways, wide runways but there are some issues. Firstly, the airspace is busy – there are a lot of flying schools on the field and a fair number of commercial GA operations. Secondly, the airport is crammed tightly against the Class B (TMA) airspace of O. R. Tambo international airport (FAOR) and they don’t take kindly to bugsmasher’s violating their territory.
It is a year since I passed my initial flight test for my PPL. According to South African air law, after one year, you need to revalidate your PPL (and thereafter every two years). This is done via a ground briefing/exam and a flight test.
In the year since I got my PPL I have flown about 70 hours, 11 of that as dual instruction for my night rating and 5 odd hours in the sim. The rest, apart from a few jaunts in the SR20 with family, has been in my Sling 4 ZU-IBM. There have been a lot of local flights – practicing stuff, keeping current and proficient, and the odd long trip – most memorable being the flight to Cape Town and back in November last year, with a few family day trips thrown in here and there.
My airplane needed to go to the AMO to have some work done. This, as most aircraft owners will appreciate, is a real pain. To achieve this 10nm flight requires two adults, at least one car and a fair bit of patience from the non flying adult.
The usual rigmarole – drive to Baragwanath airfield. Drop off flying adult at Baragwanath. Non flying adult drives (usually in rush hour traffic) to Tedderfield while flying adult preflights and flies the aircraft to Tedderfield. Both adults then drive home. Understandably, this plan is not too popular with the non flying partner because it can be a 2.5h exercise when we have better things to do.
It’s a public holiday – Worker’s Day and those of us who work are restless to get some air between us and the ground. There is some discussion in the club WhatsApp group about a suitable location for breakfast – some guys want to go to Thabazimbi for the NGK Meifees (May fest) but many of us are a little twitchy about flying to a town airfield and leaving our aircraft there, being transported to the festival ground and having to rely on folk to bring us back to the planes again.
My brother-in-law’s family have a place in a game reserve called Zebula – we have driven up with them a couple of times before for the weekend – the house is great with a pool and a jacuzzi and it is good to hang out with family. The reserve has an airstrip which is well frequented with breakfast runners – the lodge will pick you up from the airstrip, deliver you to the buffet breakfast and return you later to your waiting aircraft.
Every time we have been before I’ve looked at the airstrip and thought – “this would be a great fly-in spot.” The strip has a bit of a reputation for being difficult – mostly because it gets very hot in the Limpopo Bushveld and the gradient on the airstrip almost requires a one-way in, one way out philosophy.
On Friday my sister suggested that we fly in and join them for the day on Saturday or Sunday, so we rustled up some cold meats and drinks and I started to have a close look at the trip. Zebula has a 1400m/4500ft , 13metre wide runway which is at 4300ft elevation and slopes fairly steeply from the midway point of runway 08 to the threshold of runway 26. My major concern was density altitude – I knew we’d get in just fine but it was the flying out that had me concerned – more on that later.
Of course, having a trip planned for a Saturday morning was bound to annoy the weather gods and Saturday dawned with a 400-600foot overcast; OK, it was reported as BKN but to all intents and purposes it was overcast. Very occasionally there was a slight break in the cloud and I could see it wasn’t very thick – so we were almost tempted to try and blast through it. This would have been a mistake. After making hourly determinations I decided it was best to delay for 24h. Which, as it turned out, was very much the correct decision. Sunday was clear and the flight was on.
Baragwanath to Zebula is a leisurely 105nm – of course cannot be flown straight line as there are TMA’s to be avoided. We loaded the cooler bags, swimming kit and ourselves and set off. Today I was expecting the slightly longer takeoff run but IBM shot up enthusiastically and it was sad to have to stop the climb at 7500ft. We cruised over the west of Soweto, over Orient Glider airfield (where not even one glider was out of a hangar yet) and then through the Magaliesberg flight training area – where I did the majority of my PPL training. Entering the GFA, we were out from under the TMA so we climbed up to FL95, above the scattered cumulus which was starting to develop and into some cool, smooth air.
30 minutes later we were top of descent for Zebula – the windsock was essentially indicating mostly crosswind with a slight tailwind component – I elected to land with the mild tailwind to make use of the uphill slope. Unfortunately we floated quite a bit on roundout and I ended up landing at the top of the hill (with plenty of room to spare) – I think the wind shifted a bit more towards the tailwind – as we were securing the aircraft someone landed a 182 downhill into the wind. The tailwind component could not have been more than 5knots and my MAUW landing roll is 400m so yes, I had some wiggle room.
As we arrived at the lodge, some cumulus was starting to develop – one large one in particular to the north of us. I called up the weather radar feed – sure enough this was developing into something. I spent the rest of the morning checking the feed every 30min to keep an eye. At the mercy of the weather, with no ability to stay late if need be, it is important to keep a close watch. Unfortunately having to worry about the weather does detract somewhat from the relaxation aspect of a morning in the bush – I would be more relaxed if it wasn’t the whole family.
Fortunately, the weather didn’t develop into anything more than clear sky cumulus. When time came to leave the bases were at FL100 with 4/8 cover. Leaving Zebula presented a bit of a quandary. The wind had shifted so it was now aligned with the runway. The uphill runway. Additionally my daughter decided she wanted to sit up front so I needed to do a quick recalculation of the weight and balance – which still came in within the envelope. The wind was of sufficient strength that I didn’t believe I could justify a downwind takeoff – especially with an air temp of 36 Celsius and a calculated DA of over 8000ft.
The Sling will clear a 50ft obstacle at MAUW at 7500ft DA in 690m so I reckoned if we added 10% for the elevated DA and another 20% for the slope we would be clear of 50ft obstacle (the trees at the end of the runway) in 900m, well short of the 1400m available. The wind was about 10kts which would give us back another 5% so in my mind we’d be fine. In fact, we lifted off marginally short of halfway (just at the top of the sloping section) and climbed strongly at Vx to the extent that I was turning on course as we passed the far threshold. I’m continually amazed by the takeoff perfomance delivered by the little Rotax 914.
I had hoped to climb to FL105 or FL125 for the trip home to get some cool air but the cloud bases were around FL100 so we stayed at FL85 – which was a lot bumpier than the family have experienced – precipitating some nausea on the part of one member. Again we routed over the glider airfield (OK, about 3miles to the west thereof) – it is lovely to see the gliders below and the guys launching with the winch.
Landing at Bara was very enjoyable – with the very rear C/G we did a wheelie for ages after the mains touched down – there is incredible elevator authority down as far as about 38kts – in fact on a proper short field takeoff the nose will unstick at 40kts.
Another new airport into the logbook, another family trip living the Sling lifestyle. The only negative aspect is that the pitch part of the autopilot is STILL not working properly, which is proving to be somewhat annoying. I need to look at that again this week.
The next trip is to Middelburg (FAMB) for the EAA aviation week. Can’t wait.
I have been looking for an opportunity to take some family members flying in ZU-IBM. There is a heck of a lot going on at the moment with year end functions, prize-givings, concerts and the like and there simply isn’t a lot of time. When the Springs airport fly-in came up though we decided to make a morning of it. Some family members preferred their beds to an early flight so it was only myself and my son braving the trip to the East Rand.
I tend to overthink trips to unfamiliar airspace. I’ve only been east of OR Tambo Johannesburg International Airport (FAOR) once and that was a long way wide of the airspace doing my night Nav exercise – this route would call for a very close skirting of the airspace around this large international airport.
Undaunted though we planned to route from Tedderfield to Springs via Suikerbosrand Nature reserve (incidentally I have not been there since I was about 12y old) – I thought it would give me a chance to do some radial intercepts onto the HGV VOR using the “virtual VOR” feature on my MGL iEFIS – it creates radials based on the GPS position, so one can navigate using VORs without having a Nav radio per se (this will have to be fixed if I’m ever going to use this aircraft for IFR though)
Saturday morning’s weather was fairly typical for a Saturday morning at this time of year – beautiful at 04h45, and overcast by 06h30. Fortunately the stuff was thin, was clearing from the east (good news since this was the direction of flight) and it looked like a good day to commit aviation.
24 November 2018
FATA – FASI
I try to involve my kids in the preflight process as I think that the more eyes there are scanning the aircraft, the greater the chance of picking up something – but we both had to stop and gawk as a flight of 4 motor gliders taxied past and departed to Springs – they’re quite elegant and looked like they had some pretty impressive initial climb performance.
Then it was time to set sail – in the video below one can see the smile on my son’s face as we accelerated down Runway 29. The routing was easier than I imagined it would be – and much quicker too – by road Springs is a good 90min drive – took us about 24min all told. Being total newbies to the fly-in scene we were impressed by the number of aircraft joining the pattern from all directions – generally professional piloting meant that we were able to build some good situational awareness and no surprises appeared (apart from the unexpectedly strong crosswind on the downwind leg)!
There is a bit of pressure landing at a busy field when you know everyone is watching your landing – fortunately we didn’t need a broom to taxi the aircraft off the runway so we retained some credibility. Which I lost for us by asking where we could park…. “Um… in any open spot?” So we pulled up next to a very pretty RV8 (ZU-RVA) and shut down.
Then it was time to wander around and have a look at the aircraft – there was a good representation of general aviation in SA – everything from a Trike to a Cherokee 140, to C210 on the type certified side and lots of Vans Aircraft (Mostly RV7A’s with a spattering of RV-6/a’s and two RV-10’s – not to forget the aforementioned RV-8), A couple of Slings, Jabirus and some Kitfox aircraft on the NTCA side. A Robbie R44 and an Alo II kept the motor gliders company too.
Sadly we were not taking part in the navigation rally and we didn’t have time to stay and watch the departing traffic so it was back to Tedderfield for us.
24 November 2018
FASI – FASY – FATA
We wanted to stay well clear of the busy corridor between springs and Rand Airport so I decided to head south until passing over Heidelberg airport and then route for Baragwanath (FASY) airport – which is to be the new home of ZU-IBM for a touch and go before returning to Tedderfield.
As we were doing run ups at the hold for RWY 03 at Springs there was some commotion on the airport frequency – apparently one of the motor gliders based at Springs had had an engine problem on departure from the grass runway and had completed a safe off field landing – I guess this is bread-and-butter stuff for glider pilots?
We had an uneventful trip back to Tedderfield- did one (average) touch and go at BaraG and then perhaps my best landing to date in the Sling at Tedderfield. I discovered an unexpected advantage of having my son with me – he could hop out and open the hangar, avoiding a shut down and hot start ! – Kids have their uses sometimes…
We’ll be looking for more fly-ins to attend in future.
All good things must come to an end and this includes congresses – well, OK, being at a congress (even one dedicated to anaesthetising small people) is not as good as not being at a congress when in Cape Town, but it was still worthwhile.
There was a huge amount going on from a social point of view but was able to have dinner with an old friend and her family and also to have the most expensive cocktails I have ever drunk – I know it’s Cape Town but R130 for a Mojito is somewhat excessive – it is one of the trendiest spots in town though and the views and architecture made up for the cost of the drinks (almost!)
I’d deliberately left an extra day to get back – my plan was, if the weather looked at all dubious on the Monday, I’d aim to fly halfway back on Sunday afternoon, use the night rating to land late in Bloemfontein and sleep over and hop home on the Monday. My weather guy seemed confident that weather would be excellent on the Monday – with the proviso I left early ( 0600 local). This seemed to me like an excellent plan – despite the logistical problems of accessing the airfield at that time (beyond the scope of this piece).
I was surprised to wake up to a thin layer of cloud, which got thicker as I descended down from Rondebosch to the peninsula and headed north to Morningstar. The logistical issues of accessing the airfield at 06h00 were left by the wayside as conditions were low IMC with 1000m visibility but, annoyingly the clouds would break up every few minutes to reveal that the layer was temptingly thin. I could feel the get-home-itis starting to build. It would be very easy to blast through a hole in the clouds, but what if I needed to return? I doubted I’d be able to find the field again, so in consultation with the weather briefer we decided to wait 2hours. This allowed ample time for a very thorough preflight, at least 2 pre departure visits to the bathroom and sorting out returning the hired car to the AMO/FBO.
At 8h30 there was much more blue sky than low cloud and I decided the time was now. I taxied out, did my run up and launched off of 02. Climbing through 300ft the EGTs all climbed rapidly through 1100deg – well into the red. It took me about 3 seconds to decide that I was not continuing with this – reported returning to the circuit and got IBM onto the ground as soon and as safely as I could – I will confess that my circuit was not textbook but I was keeping it tight in case the engine quit. Bizarrely the power output felt ok and there was no roughness at all.
I had the AMO check it out – they ground ran it, and then we test flew the plane again – we were unable to replicate the problem. A possible theory was carburettor icing (there is no carb heat on the Sling and conditions were favourable for development of carb ice) but there was no discernible power loss so I’m sceptical of that. Another theory is that I didn’t put the mags completely back to BOTH but again, I don’t believe this and once again no issue with power. So I’m at a loss as to what happened, but there have been no abnormal indications since then.
Date of Flight
12 November 2018
Morningstar to FATA(Tedderfield)
The nett result of all of this is that it was 10h15 local when I departed, a good 4 hours later than I had wanted. I was hoping for a smoother ride than coming down but was to be disappointed. Initially the air was fantastic and I was settling in for an easy trip but as I approached Sutherland the thermal activity started with a vengeance, as it had on the trip down. I climbed to FL95, where the density altitude was 12750ft – I didn’t believe I could justify a climb to FL115 without supplemental oxygen, so I was properly stuck.
It may be something I need to get used to and there may well be a technique to riding the thermals to get maximum efficiency. I think it may be easier in an aircraft that cruises below Va – the Sling will easily cruise in the yellow band – I was having episodes where I was 5-7.5deg nose down, climbing at 700fpm and rapidly approaching Vne, so I would pull throttle to idle, ride out the thermal and then try to time reapplication of throttle to not end up on the back side of the power curve – occasionally I needed to put the prop into climb and once had to put the throttle though the ‘gate’ to 115% power to not sink. This suggested to me that I was not only contending with updrafts but downdrafts as well.
This continued for the rest of the trip – to say it was tiring is an understatement. I was again fortunate to be cleared through the Kimberly (FAKM) TMA which cut about 30miles off the trip. Most worryingly for me and the primary reason why I chose not to stop and take a break was the possibility of thunderstorm development. I was overhead Kimberley at about 13h45 local and had planned to already be in my car driving home from the airport by that stage.
Looking at the radar download I could see that there were some cells starting up so I elected to continue. Approaching Potchefstroom there were definitely cells but they were isolated so was able to manoeuvre my way around them – it is so tempting to fly underneath them but there was a lot of Virga about and I know well that that implies severe downdrafts – best avoided. So we picked our way through the cells. Typically I was unable to raise any cell signal to download the current radar pictures – man I wish we had a decent ADS-B in solution provided here. ATC was fairly noncommittal, “yes there are some buildups but they don’t look too hectic” – easy to say sitting in a comfortable chair.
Finally I was able to call overhead Tedderfield – had a bit of a fiddly landing as the gusts were starting up prior to a storm arriving but safely down and then the big job of unloading the aircraft.
5.9hours in a single leg is a long flight – it would have been better with less turbulence. I learned some important lessons though – leave as early as possible if possible, and rather leave a day earlier if there is any doubt about the weather. If I was to do this trip again (I’m sure I will), I will land at Cape Town international (FACT), suck up the higher landing fees and then be able to (a) access the aircraft whenever needed and (b) be able to depart before sunrise (Morningstar has no airfield lighting).
For a first long cross country trip I think it went really well. It had moments of frustration and times when I was quite anxious about the effects of the turbulence on continued flight. But that feeling when your destination comes into view after a long trip and you know you’ve made it? It’s fantastic.
So I have a new type on my license – and some endorsements to go with it! I recently spent two days at Wonderboom Airport (FAWB) getting rated on the Sling 2.
The Sling is a locally (South African) designed and built aircraft. It’s nominally a light sport aircraft but as configured it requires a PPL to fly as the maximum takeoff weight is over 600kg. Interestingly the same aircraft, with one wing tank removed will have a MTOW < 600kg and can be flown on a recreational pilot license as a light sport airplane.
It’s also quite different from the Cirrus I have done all my training on to date. Of course, it’s much lighter, all metal and has a significantly different engine? How different? Well, it’s a Rotax 914 – a 1.2l 4 cylinder producing 115hp compared to the Continental 0-360 6 banger on the Cirrus. It’s also turbocharged and the prop is a variable pitch constant speed unit (Yes, the Cirrus had a variable speed CSU but with no direct pilot control). Importantly, it burns MUCH less fuel – 20litres per hour compared to the 50-65litres per hour on the Cirrus. And it will burn MoGas happily too.
To obtain the conversion onto the Sling was not an easy matter. Firstly, there are a lot of flight schools operating Sling 2s. There are only 2 in the country that have the Sling 2 914 Turbo on their ATO. Thus I had to travel to Wonderboom, which is a great airport. Unfortunately it is 90km from my house. Not so good. I did the conversion through FliteCare who were fantastic – they could accommodate me at short notice, and their desk staff were amazing.
I first needed to have briefings on the Sling aircraft itself – concentrating on the many differences between it and the Cirrus – this took about an hour, then it was time to dive into the nitty gritty of turbochargers and variable pitch propellers. Turbochargers are easy to understand – once you figure out how the wastegate works and the differences between the hot and cold sections. The variable pitch propeller on the other hand I found to be a lot more complicated. It’s bloody brilliant engineering but seems very complex. My biggest problem is remembering the difference between fine and coarse pitch which I find counterintuitive.
As it turns out, the intricacies of the variable pitch prop are moot in the Sling because it has a very clever system to adjust prop pitch. Firstly, instead of being controlled by oil pressure and springs, the pitch is adjusted electrically by servos in the hub. And there is no pitch lever as would be suspected, but a pitch control instrument on the panel which has a knob to select T/O, Climb, cruise, hold, and Feather. One can also bypass the selector and adjust pitch manually should the control unit fail – this is done with a rocker switch. Once a setting is selected, the CSU adjusts pitch to maintain the required RPM on the prop. Because the Rotax is a geared engine, engine RPM does not directly reflect prop RPM – so prop rpm is not set, but the CSU will indirectly control engine RPM.
Speaking about engine RPM – this is high! A regular aviation mill will turn at about 2500-2700RPM. The Rotax idles at 2000 and will go all day at 5500. An interesting feature about the 914 is that full power is actually 100hp with an additional 15hp available when you push the throttle through the gate – allows 115hp for up to 5min – would primarily be used for takeoff and initial climb to 300ft AGL and obviously for the go-around. In the gate position the engine is turning at 5800rpm.
After the briefings, it was time to fly. The conversion requires upper air work, simulated engine failure and at least 5 landings. Preflight is fairly standard with the addition of a prop control unit check – cycle from full fine to coarse with the engine off (remember those electric servos?). The other very different aspect is the dry sump oil system – oil is stored in the oil tank – so in order to check the oil one needs to ensure all the oil is in the tank and not in the crankcase. This involves turning the prop by hand (check mags off, key out master off first!) until the telltale gurgle from the tank indicates that the oil has returned.
Dragging the plane out of the hangar is a one man affair – really a pleasure. Startup is a non event – fuel pumps on, fuel on and crank. It literally starts like a car engine. Run at 2000 until oil pressure settles then warmup is at 2500 until oil temp reaches 50C. Operating temps are much lower than conventional engine due to the hybrid air/water cooling system.
Taxiing is much simpler than the Cirrus due to the direct nosewheel steering – so much nicer than the free castoring nosewheel. She’ll roll 2 up at 2500 so the engine can warm nicely en route to the run up bay. Most pre takeoff checks are done on the taxi as they have a reputation of getting quite hot while idling stationary. In the bay it’s final checks, run up at 4000RPM checking the mags (<300drop and <115between), takeoff briefing and then it’s time to fly.
The best word to describe takeoff is “sporty”. Stabilise at 5500RPM and 100hp then through the gate to 115/5800. Lots of right rudder is required and before you know it, we’re at 48kts and the rotate call. Liftoff at 55kts and best rate at 75 has her climbing away comfortably at about 1200fpm. After takeoff checklist includes setting prop to climb, coming back out through the gate and cleaning up the flaps.
For the conversion we set off to the general flying area – steep turns are a non event – very easy to keep the nose up. Stalls are reasonably benign but I did detect a slight tendency to drop the wing and not a huge amount of buffet. The (brilliant) MGL Avionics iEFIS unit has an AOA indicator too which is helpful.
Then we did some circuits at Freeway airfield – which has a massive runway which is gravel. Also a non event for the Sling. I may think twice about taking an aircraft I owned onto a gravel strip but certainly it wasn’t an issue on this plane.
Back to Wonderboom with me having no idea at all of where I was – fortunately the instructor was at home in the airspace. The plan was to do a couple of circuits, but this was foiled by a medium sized Cb cell which decided to discharge itself over the airfield. Conditions on landing were challenging to say the least – significant wind shear and gusts from about 15degrees off the front of up to 25kts. The Sling handled this with admirable aplomb.
Sadly this meant I had to make the pilgrimage to FAWB again to finish the rating. We banged off 4 circuits easily in the mid morning this week – 2 normal landings (Flap 20), 1 flaps up landing (would really rather not do those….) and 1 short field stop and go. The procedure for landing the Sling is similar i believe to the C172 – cut power just short of the threshold and glide it in. You can’t do that in a Cirrus.. The short field landing we did just to demonstrate it – in the POH it says “short field landings as per normal landing” since the landing distance is about 270m. However, we did a short field approach – flaps 30 and standard piloting, stopped on the runway, and then did max performance short field takeoff – full throttle, brakes off, through the gate and full back pressure on the stick from the moment rolling starts. The nose wheel lifted of at 20kts and we broke contact at 48kts. Lower nose to Vx (75) and then up and away. Very impressive, especially when you look at the airport diagram and see how short the distance was – we landed on 29.
It’s really nice to have excess power available. So I’m now rated on the Sling2 and have endorsements for turbocharged engines and variable pitch propellers. Onward and upward!