That Sling Smile

Yesterday I was fortunate enough to be able to take my friend Ari flying. He may not know it but he’s actually my aviation mentor – one heck of a nice guy who has a knack of thinking about general aviation in ways I haven’t thought of. He’s a commercial instrument rated pilot with more than 1500h and he flies a FIKI Cirrus SR22T with his father.

One reason we are buddies is that we have similar outlooks on general aviation safety and doing GA correctly. My feelings on these are borne out of lots of reading – his I suspect are from lessons learned in years of flying. It can be daunting flying with a significantly more experienced pilot in a non instructor/examiner situation (OK, it can be very daunting flying with an examiner) because one feels like one’s skills are on show – this was the first time I was to be PIC in my aircraft with him (I’ve flown in his aircraft many times). You don’t want your first flight with a new passenger to be your last flight with that passenger..

Special Sling preflight pose – lifting the elevators to view the control rod attachment bolt

I must confess to feeling that the Sling was a little shabby compared to the extremely well equipped G5 Cirrus but hey, an airplane is still an airplane – and I’m a proud owner.

We had a secondary objective and that was to test the Aerox system I acquired recently – it seemed prudent to do this with an experienced supplemental oxygen user. We came prepared – he had 2 oximeters and I had 1. Of course, true to form mine was DOA, although after 10years of hard use in my day job meant I shouldn’t be surprised. It is time for a new one anyway as the LCD display isn’t very readable in the bright cockpit. In addition we had an emergency cylinder in case the main cylinder didn’t perform as expected.

For a change the weather was playing along really nicely and although the visibility wasn’t really good, the air was smooth as we climbed energetically away from BaraG – had a good 750-800fpm climb rate which impressed my passenger. There was no other traffic in the training area and we started our climb after exiting from under the Johannesburg TMA. Information approved our climb and handed us over to the area controller (Centre) and I handed control over to Ari. For the last day in March it was still pretty warm – was showing an OAT of 21 Celsius at 10000ft but the Sling trundled on at 400fpm through 11000ft with the Airmaster Prop in Climb and 34” manifold pressure on the throttle.

We routed south as we climbed, out over the Vaal River and Parys, enjoying the views (despite the limited vis) and the smooth air. Climbing through 10000 feet I popped the pulse oximeter on and was quite alarmed to find my sats were 89%. I wasn’t expecting it to have dropped so low at a relatively low altitude. I didn’t feel any adverse effects although I don’t believe time of useful consciousness is an issue at this altitude. However, it seemed like a good idea to get the oxygen on which we did.

Looking silly with a poorly applied Oxysaver

Let it be said that one looks a little ridiculous wearing an oxysaver cannula – but you look a lot less ridiculous with the cannula on than slumped over the controls with two fighter jets on your wing. The oxysaver allows pretty low flows – <1litre per minute at altitude up to 15000ft – by using a small reservoir so it’s relatively economical to run once you’ve forgotten the initial outlay for the equipment!

Above the inversion @11500ft south of the Vaal River

Area control came on asking us to stop our climb at FL125 due to other traffic on the airway above us which was a little disappointing but the density altitude was already well over 14000ft by this time, so I didn’t think with a service ceiling of 16000ft we’d get much higher anyway.

Heading back into the smog…

At this point we noticed that the oil pressure had decreased to 1.6bar from 2.5bar. Lower limit of normal is 2bar on the Rotax 914UL. This was obviously not something to take lightly. Initially we thought it could have been due to the warm conditions – oil temp was normal and CHT’s were within limits. Still, we arrested the climb and throttled back with no improvement. The best call at this point was a 180deg turn and route back to home base keeping a good lookout for potential off airport landing sites.

We had to descend to avoid busting airspace and as we descended below 9500ft the oil pressure recovered to normal and stayed there, going up to 3bar as we leveled off at 7000ft. Given that there was no other indication of abnormality we felt it was reasonable to do some maneuvering while keeping an eagle eye on the engine gauges.

I did two steep turns (PPL standard @ 45deg) and thereafter Ari did 2 at CPL standard (60deg). That man can fly an airplane – made the wake on the second attempt in an unfamiliar aircraft. He was raving about the control responsiveness and the inherent balance of the Sling – I think he was quite impressed – high praise indeed from someone who has hundreds of Cirrus hours. “It feels like I have an RV Grin,” he said as we cruised back for the overhead at Baragwanath. I dubbed it the “Sling Smile”

Steep turns – fun!

One touch and go then a full stop landing and it was time to put the plane away. I did get some constructive criticism of my crosswind landing – I need to try and land upwind of the centreline rather than ON the centreline – this makes sense as it gives one a few more metres to deal with any squirrelly behaviour after touchdown.

All in all a successful morning’s flying. The oil pressure reading remains a concern but I’m waiting on the AMO to comment. We suspect it may be a grounding issue or a problem with the oil breather pipe. We had a good look around the inside of the cowling and there is absolutely no oil leaking anywhere and no oil stain on the belly of the plane. Time will tell – the joys of aircraft ownership…

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