Photo Report – Life at Lučko, June 2015

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As was the case (nearly) every year so far, the arrival of our continental summer has once again become the trigger for a sudden and rapid reawakening of the light aircraft scene at Lučko :). Even though the flying season itself had already started several months ago, the long hours of daylight, ample public holidays and fine flying conditions of June have given it a much-needed kick, with all operations – private, training and skydive – quickly shifting into high gear (while it all lasts). And while the gear in question is a notch lower than in previous years – with Croatia still knee-deep in the financial crisis – there was nevertheless still quite a bit to see and snap! 🙂

A little airplane that is not often seen at Lučko preparing for a short afternoon flight above Zagreb. Normally based at Varaždin Airfield (LDVA) in the north of the country, DVW is among the best “classic” 172s here on the continent, and has already seen off its fair share of student pilots…

Sporting a new set of clothes, PET gives no indication whatsoever that it is almost half a century old. Still active in skydive circles, it had recently been thoroughly overhauled, and will soon get a purpose-built carbon-fiber skydive door on the right side.

Several of the many bits of local aviation history hiding in plain sight all over the airfield: a replica of the first aircraft designed, built and flown in Croatia, alongside a type that had given wings to entire generations of local pilots – and both inside a hangar that had previously been home to Bf.109s and Fiat G.50s when it was located at Borongaj Airport in the 40s…

The “disintegrating squadron” catching some sun on its temporary parking position in front of the tower. Manufactured in 1967 and 1978 respectively, BDR and DDA had not been off the ground in ages, with the former last noted in the skies in 2003, and the latter sometime in 2006 or 2007…

Always a welcome sight and sound, BKS is seen warming up for a skydive op in the nearby village of Kurilovec. Having to endure continuous operation at both high-power/low-speed and low-power/high-speed regimes, getting the engine’s internal temperatures into the green before flight is of vital importance – not only to preserve its stated service life, but also to prevent seizures and internal damage due to sudden temperature changes.

The newest resident of the airfield snapped after participation in a local precision landing championship. The only DG-300 in Croatia, 1985-vintage D-2871 is also one of the best-equipped gliders in the area, sporting two competition digital VSIs, a GPS unit – and even a FLARM system (a miniature ACAS designed specifically for use in gliders). Interestingly, despite being a German design, the DG-300 line was manufactured in Slovenia by the Elan works, famous locally for their extensive range of high-quality sporting equipment (particularly skis and sailboats).

Photo Report – Life at Lučko, October 2014

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Possibly to compensate for its blatant refusal to play ball for most of the summer, the weather here in continental Croatia has been on its best behavior since my previous post, providing us (mostly) with the same clear blue skies, calm air and pleasant temperatures that we’d expected to see in months past :). Fearing that it may all go terribly wrong at any time and without much warning, out fleet at Lučko has been out and about from sunset to sunrise, getting in as much work as possible without bending any rules. Naturally, the same weather had lured me and my camera out as well, allowing me to present another snapshot of Life at Lučko… 🙂

Back home after an extended leave of absence due to a Cessna-mandated corrosion check, the legend of Lučko is back on the flying circuit. Parked – unusually – outside the hangar following its return from Varaždin (LDVA), BKS easily dominates the apron even in the dark…

Hands down one of the most interesting touring motor gliders (TMGs) in the region, the ungainly Vivat is actually based on the classic Let L-13 Blanik all-metal training glider, to which a 65 HP Walter Mikron III engine, side-by-side seating and a tougher, fully retractable landing gear have been added. Normally based at Sinj Airfield (LDSS) near Split, DSI had on this occasion popped into Lučko for some servicing, having suffered persistent issues with the engine starter.

A peek inside DSI’s clean and pleasant interior. Somewhat more complicated than a modern purpose-built TMG, the L-13SE contains almost as many controls as a standard light piston aircraft, including levers for the throttle, choke, elevator trim, airbrakes, wing flaps, cowl flaps and landing gear.

You could be forgiven for thinking that Lučko was having a helicopter theme day today! As well as HAT, HBA and HBB (the latter of which would later fly a short winch test), we’d soon be joined by Agusta-Bell AB.212 9A-HBM, which had – despite the day’s wind and in true Huey fashion – announced its arrival from miles away. Interestingly, the military side of the airfield was deserted for most of the afternoon, without a single Mi-8/171 to be seen (which in itself is quite unusual).

Definitely the most unusual new arrival into our little fleet, the Sova (“owl”) is an intriguing single-seat motor glider, designed and built by Mr. Marijan Ivanček. Among the many interesting details is the propeller – whirled by a two-stroke Rotax – that folds back under the action of a spring when the engine is not running, thus significantly reducing drag during soaring flight without the need to incur the weight penalty of a fully-retractable prop (of note, while the Sova is a glider with an engine, it does not fall into the same category as the Vivat from two photos above. Due to its ability to fly and operate like a “normal aircraft” during powered flight, the L-13SE is classified as a TOURING motor glider; the Sova however lacks that capability, and is thus labelled as an “engine-assisted glider”).

While for the most part the weather was just as fine as described in the introduction, several mornings – Sunday 19 October included – did let the side down. A common problem during autumn and winter (especially after prolonged rainy seasons such as this summer’s), Lučko, Pleso and indeed the whole of southern Zagreb can be blanketed by thick fog that can reduce visibility down to just 50 meters. While they tend to persist for days or even weeks during the winter, in October and early November they frequently disperse around noon, often leaving behind fantastic anticyclonic weather. On this occasion, a 125 meter visibility and 11 degrees Centigrade were replaced by clear blue skies, 23 Centigrade and just a hint of wind – all within one hour.

Once the fog did clear, flight ops had immediately picked up, including a few flights by the diminutive (and rarely seen) HMB – one of only two R-22s in Croatia and the only one still flying. The first series-produced design to come out of the pen of Frank Robinson – a world-renowned tail rotor expert – the R-22 had first flown way back in 1975 and has persisted in production to this day. HMB itself is an early Mariner version, equipped to carry inflatable floats on the skids for over-water operations and sporting an auxiliary 41 liter / 11 USG fuel tank located right behind the pilot. Interestingly, even though it is registered in Croatia and is operated by a Croatian company – Helimax – it is usually based at Ljubljana (LJLJ) in neighboring Slovenia.

Universally popular primarily due to their low acquisition costs and very agreeable operating economics, all R-22s are powered by variants of Lycoming’s O-320 four-pop – essentially the same engine fitted to the standard Cessna 172N. However, to prevent it from overloading the transmission system (and to assist with longevity), on the R-22 the engine has been de-rated from its nominal 160 HP to just 124. Another important modification – always the eyesore – is the forced cooling fan bolted to the rear of the engine, designed to blow cool, fresh air over the engine block and compensate for the lack of ram cooling in flight.

Photo Report – I have nothing to offer…

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… but sweat, dehydration, sunburn and flight hours 😀 . Okay, Churchill may not have had the spring/summer flying season at Lučko in mind when he uttered his famous phrase back in 1940, but in this custom form it does go a long way to describing events at the field these past few weeks 🙂 . With out traditional summer anticyclone parked very firmly over the entire region, we’ve been graced with fantastic flying weather for days on end, allowing out entire fleet to go out and stretch its wings. And while the temperatures did let the side down – with 40 Centigrade on the apron not even being newsworthy – we’ve nevertheless persevered, allowing me to bring you another photo series of life in Croatian GA (and beyond)… 🙂

The Carryall in its element: on grass under sunny skies on a beautiful spring day. An aircraft with a rich history in the country, BKS was produced back in 1977, entering service with local operator Pan Adria the same year. Used for tailwheel conversion training and crop dusting, it would pass to the Viša zrakoplova škola flight school a few years later, where it would serve as an IFR trainer. Following the school’s collapse in the late 80s, BKS would end up in the fleet of Aeroklub Zagreb, where it was stripped, lightened and turned into a skydive aircraft – a role it fulfills even today. An interesting personal detail is that this aircraft seems to follow my family around, starting with my dad who used to work in Pan Adria, mom who used to work at Viša zrakoplovna škola – and me currently flying it on behalf of AK Zagreb.

Another look at our charismatic fuel-to-noise converter. Powered by an 8.5 liter/520 cu in engine developing 300 HP and whirling a 208 cm/82 in diameter prop – which is well into the transsonic region on take off – BKS is not the most conspicuous machine around, and can – during favorable winds – be heard all the way to the center of Zagreb, some 10 km/5 NM away…

Definitely one of the more interesting aircraft I’ve come across over the years! Sporting an unusual configuration for what is essentially a motorglider, the HB-21 is quite the performer despite its frail looks, easily rivaling the Piper Super Cub in the climb. Indeed, OE-9129 was bought specifically to replace PA-18 9A-DBU in the glider tow role, with trials revealing it’s more than a match even when hauling a heavy glider such as the Let L-13 Blanik…

A scene straight out of WW I as one of Lučko’s most famous residents flies leisurely overhead. Lovingly crafted over a period of several years – mostly out of materials found in hardware stores – XCA is a modern replica of the first proper aircraft built in Croatia: the P-3 of 1910 (designed by inventor Slavoljub Penkala). Not exactly a one-for-one replica, the CA-10 includes a few aerodynamic improvements to make it easier to fly, as well as an 80 HP Rotax 912ULS in place of the extinct Laurin & Klement inline.

The (mostly) fine weather had also lured out the air force, allowing us to play a bit of spot the differences! Even though they are essentially the same aircraft underneath, the legacy Mi-8MTV-1 and the modern Mi-171 do diverge in a number of details – the most obvious being the 171’s flat rear ramp. Other more subtle changes include the additional forward fuselage door – which had necessitated the relocation of the aircon unit to the top of the fuselage – and the Doppler Navigator antenna array moved further back down the tail boom. Intended to also provide at least some of the capability of the country’s long decommissioned Mi-24 fleet, the 171s also sport some additional combat equipment, including bolt-on armor plating around the cockpit, flare dispensers (above the CroAF roundel on the rear fuselage), IR jammers (at the back of the gearbox assembly) and provisions for carrying up to four B8V unguided rocket packs.

Reasons for getting up at 4 AM to go flying: here’s #1… beautifully smooth air, absolute quiet on the frequency, an agreeable 26 Centigrade aloft – and a fantastic view of sleepy Zagorje as I ferry DMG to Varaždin for servicing at 5:30 AM.

Even though it is relatively busy even at the worst of times, on this morning Varaždin appeared to be host to a mini Cessna convention, with seven 172s, one 182 and one 210 lining the main taxiway and apron. The culprits for this threefold increase in Cessna numbers were the seven 172s from Bulgaria and Serbia, in country on a fox immunization contract and for the time being operating out of Varaždin…

Easily mistaken for a brand new Skyhawk SP, this mint 1978 172N is seen rolling gently towards the main hangar for some minor maintenance. Part of the aforementioned Bulgarian-Serbian fleet, AIA is equipped with a bare bones interior and a special pellet dispenser in place of the regular baggage door. In immunization operations, the aircraft is manned by a crew of two, with the second member manually feeding the dispenser with pellets from chilled boxes (kept overnight in a refrigerated truck trailer).

(Aerial) Photo Report – Flight of the Phoenix

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While it is somewhat less exciting than the movie of the same name (even though it involves a similar amount of mechanical ingenuity 😀 ), one event at Lučko back in May certainly gave rise to a bit of optimism, pride – and, not least of all, a fair bit of relief. The occasion in question was the return to flight of our much-loved Cessna A185F 9A-BKS, signalling its eagerly-awaited return to service after five long years on the ground. Covered in part by another post on here, BKS had suffered a prop strike back in 2008 which had seen it confined to the hangar until its prop and engine could be repaired – a process that, through various financial setbacks, took almost four and half years to complete…

Diving for the runway back in happier times
Diving for the runway after a skydive flight back in happier times

However, while the aircraft was airworthy and fully certified as June dawned, one important issue still remained before BKS could be given a clean bill of health and returned to active duty as a skydive platform – the engine break-in period. Like all new and overhauled engines, BKS’ IO-520 needed a 25 hour run-in period during which the piston rings would gradually wear themselves out and begin to lubricate the cylinders properly, boosting the engine’s efficiency and power and generally returning it to “its old self”. This however requires treating the engine with the utmost care, flying it gently and at relatively low power settings, all the while ensuring it is being properly cooled to compensate for the poor oil distribution – not all that easy to do if you’re flogging it at maximum continuous power for half an hour as you haul half a ton’s worth of skydivers to altitude at low speed :).

To avoid making a hash of it, AK Zagreb – the owners of the aircraft – had decided to send it out on a number of extended cross-country flights, which would also have the added benefit of providing long periods of steady cruising and allow the crew to check fuel flows, oil pressures and various temperatures against the operating manual :). Naturally enough, I’d quickly found my way onto several of these flights – and while I was relegated to being the ballast in the tail, I did at least have the time (and cabin space!) to enjoy the scenery outside…

A scene as if it came from the flight levels as we maneuver around some potentially hazardous weather on our way to the Adriatic coast. Moving slowly inland from Kvarner Bay, this storm front was making itself felt even at our 7,000 ft cruise altitude, with the air becoming ever rougher as we closed in

Eventually though, the front had forced us to descent to 3,000 ft and skim around its edge, swapping the soothing cloudscape with some fantastic mountains and shadows

With 300-ish horsepower up front, we managed to outrun the worst of the weather, skimming the edge of the system low among the peaks of the Velebit mountain range. Our 140 knots indicated – the end of the green arc despite flying on only 65% power – meant were were through in mere minutes

Enjoying the crisp and calm weather above Lošinj Island while looking back on the front that had caused us trouble . A beautiful study of convective clouds, the centerpiece of the scene is the impressive altocumulus castellanus, nicknamed the "turret cloud" due to its pronounced vertical development. Alongside another stunning altocumulus type - the altocumulus lenticularis - turret clouds are a sure indication of severe turbulence and icing, making them a handy aid in deciding when to take avoiding action.
Enjoying the crisp and calm weather above Lošinj Island as we look back on the front that had caused us so much trouble. A beautiful study of convective clouds, the centerpiece of the scene is the impressive altocumulus castellanus, nicknamed the “turret cloud” due to its pronounced vertical development. Alongside another stunning altocumulus type – the altocumulus lenticularis – turret clouds are a sure indication of severe turbulence and icing, making them a handy aid in deciding when to take avoiding action.

Enjoying the crisp and calm weather above Lošinj Island while looking back on the front that had caused us trouble . A beautiful study of convective clouds, the centerpiece of the scene is the impressive altocumulus castellanus, nicknamed the "turret cloud" due to its pronounced vertical development. Alongside another stunning altocumulus type - the altocumulus lenticularis - turret clouds are a sure indication of severe turbulence and icing, making them a handy aid in deciding when to take avoiding action.
Challenge accepted! Too good an opportunity to pass up, in a few moments we would be zooming between the peaks at something like 150 knots. How very nice of Mother Nature to place them right on our planned route!

An overflight of what my colleague flying had eloquently termed the "Krbavian Sea" . Neither a man-made nor permanent geographic feature, this temporary lake was created by the abundant rains that had hit the Krbavsko polje area over the past few weeks.
An overflight of what my colleague flying had eloquently termed the “Krbavian Sea”. Neither a man-made nor permanent geographic feature, this temporary lake was created by the abundant rains that had hit the Krbavsko polje (Krbava Field) area over the past few weeks. One of the country’s biggest mountain valleys, Krbavsko polje is also known for its excellent gliding weather, with most Croatian gliding records set not more than five miles to our right

Plane’s Anatomy – Servicing a Cessna 185

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Down for the count pretty much since the time I’ve started this blog, 9A-BKS is the one remaining (and interesting) Lučko resident I’ve never profiled here. A very nice Cessna A185F Skywagon/Carryall, it had suffered a propstrike almost a year ago (if my count is correct), and was in never a presentable enough state to be featured here. However, with the onset of winter and a reduction in flying activities, it was decided to finally fix it up, giving it a complete service and refit along the way. Naturally, I was ready and waiting with my camera when it all started… 🙂

BKS back in happier days. Sporting a very distinctive high-vis paint scheme - and an equally distinctive transsonic prop - it was always an attention-grabber. Manufactured in 1985 and owned by AK Zagreb, it is used exclusively for skydive flights

Our small taildragger air force on a typical Lučko day - skydivers, aerobatic flights, training ops, glider flights...

A bit less glamorous here in the present... though the aircraft itself had suffered no damage during the propstrike, the prop and engine were knackered and needed to be completely refurbished and rebuilt - so BKS had spent a considerable time looking less than dignified

Apparently the locals don't really like BKS flying above their heads :D. Showing just how many access panels there are on the 185's wing... the ones near the leading edge allow for relatively easy inspection of the electrical cabling for the wingtip lights and the wing strut joint, while the those nearer the fuselage give (some) access to the Pitot system, part of the gravity fuel system and the electric flap motors and their cables. The outboard and trailing edge ones give access to the aileron control cable, which was being inspected as part of the service (the aileron being removed first)

Up front, the firewall had to be cleaned and sanded down before the engine could be mounted back on. Among the cables seen are the prop, mixture and throttle controls, as well as control & data cables for various engine instruments (RPM, manifold pressure, oil temp and pressure, EGT, CHT...)

Inside, everything is nice and fluffy :). The sound and thermal insulation - some form of synthetic foam I think - normally hidden away beneath the upholstery (which will incidentally also be changed)

Where the aileron should be. The actual control cable can be seen right by the single access panel

Closeup of the right-hand flap, lowered to give easier access to its guide rails. Like most light Cessnas, the 185 uses Fowler flaps which, in addition to lowering, slide backwards to increase the effective wing area as well as the Angle of Attack

Inside the bare cabin. Configured for skydive flights, BKS usually only has a rear bench, maximizing the number of skydivers that could be carried while reducing weight for better performance

Already featured in my previous piston engine post is BKS's (rebuilt) 8.5 liter six cyl IO-520-D, putting out approx. 300 HP