By Boran Pivčić
All photos author

When you get invited to participate in an airshow, you usually don’t ask too many questions. When you’re asked to participate in one in formation with two other aircraft, you don’t ask any, but promptly kick the tires and light the fires :).

Back in the summer of ’08 (not ’69), the aeroclub I’m part of was asked whether we’d have any objections to flying a short display at an aviation happening near Trakošćan castle in northern Cro. There were none of course, but – in line with the above – to this day I have no idea what it was we were asked to fly over. But there was flying and photography afoot, so I was there, no questions asked.

1. The aircraft

Our formation was to consist of two Cessna 150Ms mismatched with a Reims FR172F Rocket sporting more power than the two 150s combined. To add to the difficulties, it was +37 outside and my photo ship just had a new engine installed, which meant we couldn’t floor it as much as we would have liked. But undaunted, we got down to preparing, making up a plan as we went along.

Registration: 9A-DMJ (ECOS Pilot School)
Type: Reims FR172F Rocket
Mfd: 1970.
Engine: Continental IO-360, 6-cylinder, normally aspirated @ 210 HP, driving a three-blade constant speed prop

Registration: 9A-DMM (ECOS Pilot School)
Type: Cessna 150M
Mfd: 1975.
Engine: Continental O-200, 4-cylinder, normally aspirated @ 100 HP, driving a two-blade fixed pitch prop

Registration: 9A-DMI (private)
Type: Cessna 150M
Mfd: 1976.
Engine: Continental O-200, 4-cylinder, normally aspirated @ 100 HP, driving a two-blade fixed pitch prop

DMI was to be my photo ship, while DMM was nominated as the lead aircraft – being the slowest of the remaining two and dictating the pace.

2. The flight

With takeoff being scheduled broadly around 12:30, I arrived at the field about an hour earlier, hoping to make myself useful and help prepare the planes for the epic 45 minute flight. While DMJ sat ready and waiting, DMM was getting a wash – though I don’t know whether it actually needed it, or the guys were looking for a fun way to cool down on one of the hottest days of the month.

Once fresh & clean, we got down to the serious business of checking the bird out before the flight. As a regular maintenance check had been done a couple of days prior, we were mostly left with the preflight check and throwing out everything not necessary for the flight to save weight. After briefly thinking about losing the seats, we settled for more conventional stuff like emptying the baggage hold of various miscellaneous stuff, boxes, tiedown cables, oil canisters and the like.

With the weight-saving measures completed, we settled back and waited for everybody to assemble. The impromptu crew roster required six members, two young PPL pilots and two instructors in DMM and DMJ, and my photopilot and me in DMI. Wanting to blunt DMJ’s power advantage, we found two more willing PPLs who were to be the ballast in the back.

Finally ready, we fired up our engines at around 12:20 and taxied out to RWY 28. The plan was for all three of us to take off in formation: DMJ from the front, (since it could out-accelerate the 150s) and DMM and DMI in the back. However, the tight apron of the club – and a momentary breakdown in coordination – meant that at the RWY 28 threshold the 150s ended up first, with DMJ bringing up the rear. As there was quite a lot of traffic at that time, we decided not to complicate things any further and taxied out onto the runway as it was.

Flooring the throttles – not an impressive spectacle at +37 Centigrade – we took of in pair with DMM, while DMJ started rolling about 30 seconds later. Once airborne – barely – we spread out a bit and turned toward the town of Zaprešić some 6 km away.

Our route took us:

N point (Zaprešić, CTR Lučko exit point) – Krapina – Trakošćan – Krapina – N point

a route all of us knew well from our student days. Navigation on this bit is very easy and boils down to simply following the Zagreb – Macelj highway which runs up almost to the castle itself. Being in formation, we kept our heads down at around 1,500 ft, giving us a 1,000 feet of terrain clearance most of the way.

We actually made it halfway to Zaprešić before the first problems started  to appear. Careful not to force DMI’s new engine, my photopilot Ivan kept it at a maximum 2400 RPM, 200 short of its declared maximum. Doesn’t sound like much, but on aircraft with fixed pitch propellers most of the real power is found in the top 100s. Consequently, with a climb speed of barely 200 fpm, we started falling behind. Mind you, with a temperature of 35 C at this level, DMM wasn’t doing much better either, while our measures for levelling the playing field didn’t seem to be working, as DMJ had to throttle back in order to keep up with us.

However, a couple of kilometers downrange we finally reached our 1,500 ft and set about trying to fall into a proper formation for some photo ops. Once out of the climb, DMI picked up speed and we soon caught up with DMM.

Eventually – after some coming and going – all three of us were holding something resembling a stable formation. As DMM and DMJ tightened together for their photo shoot, we in DMI crawled ahead and a bit up to give me a clear view, away from the wing struts and landing gear.

I must admit this was quite enjoyable, shooting through the open window. Last time I did that four months earlier, it was -15 outside and the experience was not quite so pleasant (more on that in one later post). With the big fan up front throwing some welcome fresh air into the cabin, we actually left the window up most of the way.

After having my fun, we tightened back together, as the terrain was getting progressively hillier. The leg from Zaprešić to Krapina takes just under 20 minutes and ends in some 3,000 ft high mountains, so with a good 10-15 minutes gone, we needed to start actually flying, not just joking around. The approach to Trakošćan isn’t all that easy, so now was the time to coordinate. Meanwhile, between transmissions on my handheld radio station, I snapped a few additional photos.

Soon enough, we were nearing the mountain Ivanščica, right around Krapina. To jump over its lowest part, we needed to climb another 1,000 ft, which – given our appaling climb performance earlier – required some forethought.

Trakošćan itself is surrounded by the foothills of Ivanščica, so we needed to be very careful. More than once, DMM and DMI had to take a slight detour around a peak because we judged our climb rate wasn’t going to get us over it in time. DMJ, bless her six cyl engine and constant speed prop, had no such problems.

When we finally crossed the hills, found the castle and positioned ourselves, we broke into what could maybe be described as a line-astern formation, chasing each other toward the castle grounds. Our plan – drawn up with the organizers – was to make a series of low passes, trying to nail one in formation. However, the restrictive terrain around meant we had to go at it alone, so we floored all three planes and dove gently toward the valley floor.

After the first high pass, we made several more, each lower than the last. Given the aforementioned terrain around the castle – and the heat – we thought it best not to fool around, so we didn’t attempt the formation one.

With four passes completed and our job done, we turned for home and flew back the way we came in, in pretty much the same wide formation, since the hills hadn’t moved appreciably in the mean time.

By now it was around 1 PM and the sun was sliding to the west. Because the Zaprešić-Krapina-Zaprešić leg runs pretty much north-south, I would now have to shoot into the sun, which I presumed wouldn’t give me many photo opportunities – but the forming up delay on the way out meant I was willing to try at least and end the day with a lot of good photos.

This time we chose to fly higher, at around 2,000 ft. Because all our photo ops were done, we flew most of the way to Zaprešić in a clean, tight formation, giving everybody a chance to practice holding station off each other’s wing.

But, in a fit of playfulness, a few miles before Zaprešić our formation finally broke up for good and turned into an all out race to Lučko. DMJ, having 110 unfair advantages, quickly pulled ahead, while DMM fell a couple of hundred meters behind us, despite our 200 RPM handicap. Apart from being quite good fun, it also served to separate and sequence us for landing, so we wouldn’t come in all bunched up.

Passing Zaprešić, we were still a few minutes out from Lučko, so we coordinated our landing sequence via radio. The crew of Juliet, already far ahead, decided to continue  on a panorama flight above Zagreb, leaving us in DMI as number one. Since the wind was calm and there was no more traffic in the circuit, we chose RWY 10 and slid into left base over castle Kerestinec, a convenient turn point.

Landing just after the threshold, we hit the brakes and pulled off to the side so DMM, close behind us, could land. Gunning the throttle to not get stuck in the grass on the taxiway, we rolled of to the ECOS apron at the other side of the field and shut the birds down.

Total flight time: 1h 5 minutes