Photo File – A Tale of Three (and a bit) Utvas

By me
All photos me too, copyrighted

A manly man’s stick with a guarded weapon release switch, and a 70s green ergonomic mess of a panel… who could honestly say no?

The twins. While the most complicated part of the entire airplane – the powerplant – may be as generic as it gets (a 180 HP Lycoming IO-360 whirling a two-blade Hartzell HC-series constant speed prop), the rest of the airplane is pretty much bespoke. This inevitably became an issue once the spares pool had started to dry out – and was further exacerbated by the type’s withdrawal from the Serbian Air Force in 2016-2017, ending any meaningful official support. Remaining operators are increasingly left with few choices but to cannibalize non-flying examples, a fate that likely awaits E7-PDB as well…

Despite its seemingly compact appearance (accentuated by the short 9.73 m wingspan), the U-75 is a proper chonk of an airplane – which becomes particularly obvious when parked next to something else. The wing root alone is approx. 80 cm off the deck, while the wingtip itself has a very generous 1.1 m ground clearance – both far in excess of many other low-wing two-seaters (E7-PDH would, sadly, be lost with both on board barely six months after this was taken)

As iconic a cockpit view as there can be on the Balkans! True to its role as an everyday workhorse, E7-PDC has a few add-ons not normally found in other U-75s: a Garmin Aera 500 GPS unit, an ICOM IC-A210E com radio, and a Trig TT31 Mode S transponder (the King KR 85 ADF doesn’t count; that was part of the factory standard fit). Other new bits include more modern seats with modern harnesses, and outside there’s a full suite of LED navigation and strobe lights

In addition to the panel layout, another thing to get used to inside are the very lines of the cockpit itself. The heavy frame and low door sills mean that looking forward initially feels like you’re peering out of a post box, while glancing over the sides you’d think you’re in an observation airplane. However, once you get a bit more comfortable with it all, it doesn’t feel even remotely as unnatural as it looks; the short downward sloping nose – plus the extensive glazing and generally airy feel to the cabin – mean that visibility is actually borderline excellent in all direction except backwards

1 among the many specifics of Yugoslavia’s aviation industry was the often confusing interplay of civilian and military interests in the design and manufacture of light aircraft. A perfect example, the U-75 itself was conceived to cater for the needs of both the civilian Vazduhoplovni savez Jugoslavije (VSJ, Aviation Federation of Yugoslavia) and the Yugoslav Air Force (Ratno vazduhoplovstvo, RV). It included very nearly equal amounts of input from both of them – a tow hook for the VSJ, underwing hardpoints for the RV for example – and both were intended to split the bill of its development. However, due to the military’s higher position in the state apparatus (not to mention having eventually ended up covering most of the expenses), all of the aircraft would actually be owned by the RV, with an agreed-upon number made available to the VSJ through a lease agreement. The VSJ would, in turn, distribute these aircraft to flying clubs across the land according to its own internal schedule. This meant that in peacetime, the RV could recall aircraft from civilian service to cover its own operational needs (such as replacement of losses) – and in wartime press them into use as nuisance raiders armed with two of either 120 kg dumb bombs, 12-round 57 mm rocket packs, twin-tube 128 mm rocket launchers, or 7.62 mm machine gun pods.

As an upshot of this “ownership structure”, all of the U-75s used by the VSJ would also carry the RV’s standardized five-digit ID (evidencijski broj, record number) alongside their normal civilian registrations. Here, the first two digits would denote the aircraft type, and the last three a particular aircraft’s position in the production sequence (with the 0xx block reserved for prototypes and pre-production examples, and 101 onward for series machines). With the U-75 having been assigned the type code 53 – and the two production batches being 53101-53124 and 53151-53261 – PDC’s ID of 53238, for example, works out to being the 111th production-standard 75 made. These IDs were sufficiently big a thing in fact that they became the stand-in for serial numbers when identifying individual airframes – so much so that many forgot the aircraft even HAD factory/line numbers to begin with.

To complicate matters even further, the RV also used custom type designations for many aircraft in its service, usually a combination of the aircraft’s role and its two-digit type code. The U-75 so became the V-53 (višenamjenski, multipurpose), though this tended to be rarely used outside of official documents and manuals; thus, U-75 YU-DJS of “the civilians” and V-53 53238 of the military would actually be the very same airplane.

But wait, there’s more! “According to its own internal schedule” is just an abridged, diplomatic way of saying the bureaucracy didn’t end there – not even remotely. Subordinate to the VSJ proper were the aviation federations of the individual Yugoslav republics and autonomous regions – much of the same really, but with a more tactical, hands-on approach. In the case of the U-75, the VSJ, as the “head office”, would split the 86 aircraft it had received (later upped to 114) into lots deemed sufficient for the needs of each republic/region – and then sit back and let the individual federations do the heavy lifting of allocating them to individual clubs. I mention this because anybody not from around here trying to make sense of the whole arrangement will inevitably run into a myriad of acronyms for the various organizations involved – VS, ZS, ZLOS, … – all of which may seem different and confusing… but all essentially denoting the very same thing. The main culprit here is linguistics – and to avoid setting off a firestorm, suffice to say that there were two dominant languages in use back then: Serbo-Croatian (Yugoslavia’s lingua franca) and Slovenian. You can probably see where this is going:

  • VS: vazduhoplovni savez … “aviation federation” in Serbo-
  • ZS: zrakoplovni savez … “aviation federation” in -Croatian
  • ZLOS: zveza letalskih organizacija Slovenije … “the union of aviation organizations of Slovenia”, a long-winded way of saying “aviation federation” in Slovenian

The last place you could see 1991-1994 Slovenian Air Force colors out in the wild. Serving out its third consecutive year in the hangar at the time of writing, there is a possibility (albeit not a definite one) that DCI might eventually join the ever-growing collection of airplanes at the fantastic Park vojaške zgodovine (Park of Military History)… note also the prominent fairing under the wing just outboard of the main gear; this covers up the fuel level sensor and fuel tank drain port – and NOT the pylon attachments as some seem to claim (these were located further out roughly half way towards the wingtip)

Hopping around tight grass strips on the edges of forests, a green panel inside and beautiful green landscapes outside… happy place, happy place!

A cockpit study… in banging my head against the overhead frame while trying to find a good angle. Unlike PDC, DCI’s interior is entirely stock, the only additions being the King KT76A transponder and Trig TY96 com radio

It’s hard to appreciate just how thicc the U-75 really is until you stand behind it. The vertical stabilizer tops out at approx. 3.2 m, while the trailing edge of the horizontal is at something like 1.7. Note also the tow hook under the tail, a VSJ requirement as stated previously

2 since they actually represent a national radio communication identity rather than just plain nationality, registration prefixes are regulated by an industry-spanning multinational body called the International Telecommunications Union (ITU). Since the ITU is a big thing with its own processes, meetings, committees and all the accompanying inertia, it takes awhile to get anything major done – particularly creating and allocating an entirely new prefix. To expedite abandonment of the now no-no YU-, both Slovenia and Croatia adopted temporary non-kosher prefixes of their own choosing that would be considered “legal tender” until the ITU decided on a permanent solution. Slovenia thus went with SL-, while Croatia opted for RC- (Republic of Croatia). By the mid-to-late 1992, all the required processes were complete, allowing for today’s S5- and 9A- to come into use…

And if anybody’s wondering what was wrong with SL- and RC-: as far as I can work out (and I reserve the right to be wrong), SL- had previously been used between 1947 and 1959 for the Saar Protectorate – a bit of Germany that France likes to occupy after every world war – and likely the ITU didn’t want to reuse it so soon. To dial up the irony in this to 11, Somaliland – an unrecognized breakaway territory of Somalia – is nowadays using the same SL- prefix for itself (apparently illegally), and on U-75s of unknown origin to boot! On the other hand, R + the earlier letters appear to be reserved by Russia for future expansion of its registry (such as the RF- regs used by its military hardware), while HR- (from Croatia’s native name, Hrvatska) was already taken up by Honduras

3 upon their formation, both the Slovenian and Croatian air forces existed pretty much in name only. With no proper combat aircraft and few left to capture (most RV units having been withdrawn to bases in Serbia and Bosnia on the eve of war), both forces had to take whatever they could get their hands on – hence the impressment of civilian aircraft from flying clubs. By virtue of its distance from the actual shooting, the Slovenian Air Force could afford to use its U-75s in the training role only; in Croatia however, the reality of BEING the front line meant that the Utvas actually had to go to war as designed – for the first and only time – hastily armed with Yugoslav M79 and M80 shoulder-launched anti-tank systems strapped to the wings in lieu of proper air-dropped munitions.

While this was (and remains) a masterclass in ad-hoc field improvisation and lateral thinking, the fact that it was organized so quickly and successfully owes something – ironically – to a Yugoslav “institution” called TO. Short for teritorijalna odbrana (Serbian) / teritorijalna obrana (Slovenian and Croatian) – meaning simply “territorial defense” – these were archetypal socialist paramilitary defense organizations, in essence irregular units that could be quickly raised from the civilian population in time of war. With their “biggest selling point” being the speed and geographical extent in which they could be activated, their primary goal was to harass and slow down the enemy using unconventional tactics, giving the regular army time to fully mobilize. A key component of this approach was using off-the-shelf “whatever is at hand” equipment, which also included civilian light aircraft. While even Western types were included in the scheme (Yugoslavia having had sizable Cessna and Piper fleets since the 60s), the most common actor in later years was the U-75 itself, since it was literally designed with this in mind. Using aircraft leased from flying clubs (albeit without pylons fitted), the TOs would run a number of exercises through the 70s and 80s, which went a long way to smoothing out kinks in the concept and providing experience to both air and ground crews. Indeed, the TO program as a whole would be wound down at the end of the 80s for fear that it would provide a nucleus for the formation of proper armies and air forces in any breakaway republics… which, in fact, was exactly what had ended up happening in Slovenia and Croatia

4 in this system, the clubs themselves would pretty much be responsible only for the airplane’s day-to-day operational costs and regular maintenance, while the military would do all major servicing and overhauls of its own accord (and out of its own pocket); more than anything else, this helps to explain why the U-75 held on in Slovenia for so long. However, in the early 2020s, the whole fleet would be placed under the jurisdiction of the civilian Letalska zveza Slovenije (LZS, Aeronautical Association of Slovenia), which would in turn transfer full ownership of individual airplanes to the clubs themselves. Included in this deal was a caveat that the airplanes could not be sold onward, which meant that they were now stuck where they were and completely at the mercy of their clubs’ finances. And while for 99% of the 75s this made little difference (having already been grounded and condemned to “hangar arrest” for years), for DCI it spelled a very resounding “game over”…

Push, push, push, I can see the prop! Being a touch under 700 kg empty, pushing the U-75 up any form of slope is a guaranteed workout – especially on a soft surface (and don’t worry, as the youngest present, I did jump in and throw in my lot immediately after this was taken)

Maro says the walkaround is complete, no findings. If you can’t trust the airfield cat, who CAN you trust?!

Stick, rudder, throttle… and outside the sun-kissed slopes of Mt. Plačkovica. Had worse days out to be honest!

I may be biased – having grown up around hills, forests and rivers – but the views out here are a sight for sore eyes! Another sight that fails to escape notice is the 75’s small(ish) wing, which does make for quite a good view down. Despite its lack of span however, the wing area is still significant at 14.63 m2; at the type’s usual7 960 kg Maximum Take Off Mass (MTOM), the resulting wing loading is just 65.3 kg/m2, not that much more than the 64.4 of the average 80s Skyhawk

5 while all the countries that broke away from Yugoslavia outright had sizable fleets of U-75s on the eve of independence (Macedonia 10, Slovenia 15 and Croatia 14), it is the Macedonian fleet in particular that warrants another tangent. By virtue of the country’s peaceful and orderly departure, with none of the fireworks seen up north, its 75s were neither sent to the front, nor pushed to destruction through intensive training and liaison operations; indeed, it took two years from the country’s SEP 1991 independence for them to even be drafted. What’s more, faced with the same lack of spares and support as everybody else, it appears that only two machines would actually be impressed and used: DCF and 53167 YU-DFZ/Z3-DFZ (later renamed Z3-DCE).

Being out of harm’s way also meant that quite a significant number of them had survived to fly another day. Of the 10 in country at the time of independence, eight were operational, and six would eventually live to see the Z3- prefix be introduced. According to available info, three remain flying today, DCE, DCF and 53118 YU-DFB/Z3-DCC/Z3-DAN. While this may not sound like something to write home about, the total sum of operational examples in Slovenia and Croatia is currently… zero

6 try to spot a pattern:

  • Slovenia declares independence… impresses U-75s from flying clubs… replaces them with Zlin Z-242Ls
  • Croatia declares independence… impresses U-75s from flying clubs… replaces them with Zlin Z-242Ls
  • Macedonia declares independence… impresses U-75s from flying clubs… replaces them with Zlin Z-242Ls

Either the Zlin really is that good… or we Balkan people are an unimaginative lot 🤔. Joking aside, there are some notable differences though: while Slovenia and Macedonia had ditched their fleets already in the mid-90s, Croatia held on to them until all the way until 2007. Croatia too would be the only one to NOT return the aircraft to their original owners – bar for one, mentioned later

7 I say “usual” because the U-75 actually had two MTOMs – the applicability of which depended, quite literally, on how many times you wanted to use the airplane afterwards. In the “training configuration” (used by the military in peacetime and by civilian operators all the time), the MTOM was capped at the aforementioned 960 kg, which was sufficient for two RV-standard crew and full tanks (2x 75 l). Critically, this was also identical to the Maximum Landing Mass (MLM), keeping things nice and simple, and assuring that the aircraft would (barring “unforeseen circumstances”) survive intact to its expiration date.

In the “combat configuration” however, the MTOM went up to 1,200 kg, which now allowed for two RV-standard crew, full tanks – and, critically, the maximum permissible war load of two 120 kg bombs (960 + 240). Since the aircraft’s role as nuisance raider meant that its expected lifetime in an actual shooting scenario was rather low, the additional stresses imposed on the structure while maneuvering at such masses were not considered limiting – especially since the aircraft would in all probability be lost well before it began to suffer from the strain.

The 1,200 kg limit would have also been pertinent for a proposed “ferry configuration”, in which the aircraft would be fitted with 2x 100 l external tanks, one on each wing hardpoint. With a resulting 350 l of usable fuel, this setup was projected to give a range of almost 2,000 km – but in reality, the aircraft had never been flown even close to that during flight testing, and the whole idea would eventually go nowhere

A gem straight out of the gate: ID 53182, making it Z3-DCF’s immediate older brother. Initially called YU-DGV, it was operated by AK Prijedor since Day 1; however, in the early 90s it would be impressed into the Bosnian Serb army and given the ID 51104 (it is unclear why the Bosnian Serb military used the Yugoslav type designation for the Cessna 185-lookalike Utva U-66). Following the end of the war, it would eventually become T9-PDB and then E7-PDB. Withdrawn from use sometime in the late 2000s, its future is unclear… though it would surprise no one if it became a parts donor to keep PDC running

E7-PDA, kept company by U-66V E7-PDI/51138 and shot across the dorsal fin of U-66 E7-PDJ/51143… what in another time could have been an Utva promo shot has, sadly, become just another reminder of the demise of the region’s aviation sector as a whole. Manufactured in 1983 with the serial 53219, its history mirrors that of PDB: from being YU-DIZ with AK Prijedor, through 51105 in the military, to T9-PDA & E7-PDA

’tis but a scratch! Born in 1981 with the serial 53187, this sad mess was initially known as YU-DHB, first of AK Banja Luka, and then later AK Bihać. One of the few machines to end up in the hands of the newly-established Bosnian Army, it would become known for its 15 JUN 1992 dash from Cazin to Zagreb (100 knots, at night, through unfriendly skies), intended to open up an air bridge between the Bihać area and the Croatian capital. Having stayed at Zagreb (a return flight at that moment likely being deemed too risky), it would be used to train the upcoming generation of Bosnian military pilots, gaining a camo paint scheme and the reg T9-CLM sometime in 1993. It has been reported by some sources that it had actually made a few runs back to Bihać once the military situation had stabilized; be that as it may, the end of hostilities in 1995 would find it back at Zagreb undergoing heavy maintenance. Through a chain of events that’s not entirely clear, it would end up staying here forever, being slowly stripped of parts to keep the Croatian Air Force’s own fleet flying…

Forming with T9-CLM the second of two “sequential ID” pairs in my collection, 53188 was delivered new to AK Celje as YU-DHC, and would stay with them all the way until its impressment in 1991. Its history immediately after joining the military has some gaps to it, and I could not confirm whether it had ever carried the temporary SL- prefix; what I can confirm is that it became S5-DCJ while there, before rejoining its old alma mater after the introduction of the Zlins. It would serve there primarily as a glider tug, before being replaced by more manageable Western types – including Piper Pawnee HA-TNC, previously a Lučko native called 9A-BLF… and before that YU-BLF, one of a number of PA-25s operated by Privredna avijacija Zagreb

Caught between a trike and a hard place, the 1979 vintage 53122 is the second oldest U-75 I have on file. Originally known as YU-DKT, it would be allocated to AK Novo Mesto, based at the Slovenian airfield of the same name (nowadays LJNM) – ironically today home to world’s sole remaining four-seat U-75A. As was the case with DCJ, I could find no definitive proof that it had carried the SL- prefix in military service, only that it would return to civilian life under the reg S5-DCD. At some unknown point in time (but apparently quite a while ago), it would be withdrawn from use and chucked in the back of the hangar at nearby Metlika Airfield

The first U-75 I have on digital… but not the first one I’ve ever photographed, the honor going to DCI on film in 2002. 53233 from 1983, new to AK Murska Sobota as YU-DJH, all the 1991-1994 stuff as before, renamed into S5-DCN. Don’t really know what had happened to it since, saw it last in 2010 when it was still airworthy…

What could easily pass as an 80s flight line is, in fact, just part of the decommissioned U-75 fleet of the Croatian Air Force (10 strong at its peak). Leading the pack is 009 (1981 53177YU-DGH of AK Split > 001 of the CroAF (not to be confused with the later 001 of the CroAF) > 9A-DCH of the CroAF > 009 (despite still carrying the civilian reg) … then there’s 002 (1980 53169YU-DGB of AK Rijeka > 169 of the CroAF > 9A-DGB of the CroAF > 002) … further on, we have 010 (1981 53191YU-DHF of AK Slavonski Brod > 9A-DHF of the CroAF > 010) … and finally 011 (1983 53215YU-DJD of AK Vrsar > 9A-DJD of the CroAF > 011)

Crap photo, but featuring by far the oldest U-75 I have: 004. Just the seventh ever made (being 53107 of 1979), it would be operated by AK Osijek as YU-DED, before becoming 9A-DED of the Croatian Air Force and assuming its current military identity in 1995. Behind it is 003, 53179 from 1981, originally YU-DGS of AK Kila Like, then briefly 179 of the Croatian Air Force – and then 9A-DGS and finally 003 (UPDATE: as on June 2025, 003 is in the process of being returned to AK Otočac, the successor of AK Krila Like; it is unknown at this time whether it will be just a static example, or will it be returned to airworthy state)

The One That Made It Home – sort of. 53206 of 1982 and initially YU-DIH of AK Čakovec, wartime would find it without a temporary military ID8, and apparently without an RC- reg as well (despite having been QUITE active back then); it would appear in the registers only slightly later as 9A-DIH, before taking up its definitive Croatian Air Force ID, 008. The only U-75 to have been returned to its original owners following the type’s withdrawal from service, it would briefly become know as 9A-DIR (according to some sources), before finally reverting to its new-old identity. Seen here in 2016 during the final stages of a wheels-up restoration, it was supposed to become the first civilian-owned U-75 to fly in Croatia since 1991; unfortunately, a series of events (including the death of the mechanic doing all the work) meant that the project stalled at some 95% complete – and apart from a fast taxi down the runway, it had never actually made it out of the hangar. A couple of years later though, it would be sold to the Delić family of Medulin (LDPM) – well known locally for undertaking such restoration work on a regular basis, and whose members had been very active on the U-75 scene in Yugoslav times – with plans to finally finish it and get it back into the air after nearly 20 years9

8 because the U-75s had joined the fight during the utter chaos of the first days of the war, it is of no surprise that their new Croatian identities had ended up being all over the shop. Most of the units operating light aircraft had sprung up essentially where and when they could, formed almost entirely through self-initiative and without much in the way of standardization from a central military authority. Thus, each unit had adopted a different way of identifying its aircraft, including:

  • the last three letters of their original Yugoslav registration, with the YU- completely or partially removed or covered (e.g. DED, U-DHF and -DIH)
  • the last three digits of their original Yugoslav military ID (such as 169 for YU-DGB, 179 for YU-DGS and 227 for YU-DJL/53227)
  • and the sequence of joining the unit (001 for YU-DGH or 002 for YU-DLD/53239 for example)

Once the “early days” had passed and the Air Force had managed to bring everything together under one roof, the U-75s would begin to receive civilian registrations – in essence just their old Yugoslav regs, but with RC- and later 9A- prefixes. The reasons for this are not entirely clear, but it has been suggested that this was a means to pass them off as non-military aircraft, thus bypassing the arms embargo imposed on the whole of former Yugoslavia, and allowing for the import of Western-made spare parts (particularly engines and propellers). Only around the end of the war in 1995 would the markings finally be put right with the standardized system used by the air force at large, the U-75s (as the OG air units) being allocated the 0xx block.

Mind you, things were not that straightforward even after the latter was adopted; 9A-DGH (which was 001 in its original unit) would now become 009, whereas 001 would go to a U-75 captured in 1995 during Operation Storm (ex. 53255, a military original with no prior civilian usage or reg)

9 something similar is afoot in Slovenia as well, with AK Slovenske Konjice well on its way to bringing its own 75 back into service. Reported to be as much as 90% done and just waiting on its engine, the aircraft in question is a 1983‘s 53216; interestingly, this is not a Slovenian native, having originally been operated by AK Kumanovo of Macedonia as YU-DJE. Heavily damaged in 1993 during a period of upheaval among the country’s Albanian population, it would be shipped off to Serbia for a complete rebuild in 2001 – and then sold on to AK Slovenske Konjice the same year to become S5-DPM. Having (again) not flown for some years, it is now back in the hands of the people who had rebuilt it the first time round, with a projected (third?) first flight due sometime in the summer of 2025… so watch this space!

Sources:

  • Istorija vazduhoplovstva Pančeva: Utva 75 (printed book by Dragan Kolundžić & Dragoslav Dimić)
  • Utva 75 – album VSJ (printed book by Dragan Kolundžić)
  • Utva: fabrika aviona 1937-2022 (printed book by Dragan Kolundžić)
  • Tango Six – U-75 article (in Serbian)
  • sources used in the past two articles, most notably of all Mr. Dragan Kolundžić himself

Rare Aircraft – 2+2: The Four Seat UTVA 75

By me
Photos as credited

While the very mention of its name often invokes fond nostalgia and strong apprehension in equal measure, there’s no denying that the pudgy little UTVA 75 remains one of the most famous, significant – and perhaps maligned – aircraft ever produced by the Yugoslav aviation industry. One of a number of piston props conceived, designed and built solely in-country, it had left a lasting mark on the local aeronautical landscape, having over the years seen off generation after generation of young pilots, service in a bewildering number of roles in every nook and cranny of the land – and the occasional appearance in the odd accident column…

But for all its past ubiquity, the type has become somewhat of a rare sight today, with most of the airworthy civilian examples nowadays confined to flying clubs in Serbia, Bosnia and Herzegovina and Macedonia. Outside military dumps, finding one elsewhere requires a bit of luck – so much so that even the locals (many of which had flown them extensively in the 80s and 90s) raise an eyebrow when one happens to rumble by.

So imagine my surprise when – having so far only five examples under my camera’s belt – I became aware of a beautifully curious four-seat example parked just 70 km away at Novo Mesto Airfield (LJNM) in southeastern Slovenia. Having only seen such a “quad” in one 80s photo, I was through the roof even before I found out it was the only such example in existence – a fact that (as if any further persuasion was necessary!) had seen me grab my car keys and set off across the border to see what’s what… 🙂

It may be fully white and featureless – making it particularly unsuitable for photography in direct sunlight – but being the only survivor of its kind had meant that I just had to have a crack at it whatever the conditions…

Wings of the nation

But, before we cover this prime example of Achtung, Skyhawk! material, a bit of history to introduce this compact little type to readers who may have never seen one in the metal 🙂 . Flying for the first time on 19 May 1976, the UTVA 75 – known under the factory designation U-75 – was designed to be a simple, straightforward basic trainer1 that could be efficiently used both in civilian and military roles. Even though the Yugoslav aviation industry had always put much stock in this segment, its offering of such aircraft was next to abysmal at the time, with the late 40s Ikarus Aero 2 and mid-50s Aero 3 being the only machines widely available for the role. Despite having given wings to post-WW2 Yugoslavia, they were both very much outdated designs, sporting wood & fabric structures, tandem cockpits, narrow-track tailwheel landing gear, basic instrument fits – and flight characteristics that often did not inspire much confidence in the student.

1 interestingly, the project had originally envisaged a whole family of aircraft stemming from one basic design, including a four-cylinder two-seat utility machine dubbed the M-10, and – most interesting for us 🙂 – a six-cylinder touring four-seater called the M-11. Eventually though, financial difficulties (which had also seen the temporary inclusion of Polish aircraft manufacturers in the design between 1973 and 1975) had left the M-10 as the sole survivor, paving the way for its development into the U-75

Designed around more modern principles, the U-75 had a lot going for it in the trainer role: it was robust, simple, easy to maintain and had just enough power to pull a few basic aerobatic maneuvers – but not enough to allow the student to correct every mistake with liberal application of the throttle. Additionally, it had a side-by-side seat configuration, a large instrument panel suitable for more advanced avionics (including blind-flying gear) – and, most importantly, was built entirely of metal (prolonging its service life in the aerobatic role) and used a wide-track tricycle gear with low pressure tires that made it safe and relaxing to operate even on poor airstrips. Other features had included a tailhook for towing gliders or banners, while the military could be content with a removable pylon under each wing, which could accommodate jettisonable fuel tanks, cargo drop containers (carrying 100 kg (220 lbs) each), light bombs of 50 kg (110 lbs) – and even unguided 12-tube 57 mm rocket packs and twin 7.62 mm machine gun pods.

One of the Croatian AF’s post-1991 examples (now decommissioned) doing what it was designed for during low-level training near Zadar (LDZD). Of interest, the fleet would in the mid 1990s be repainted into a mint CroAF scheme and be transferred to a bespoke military register (photo from: www.aeroflight.co.uk).

Designed from Day 1 to meet the requirements of the FAA’s FAR Part 23 regulations concerning UTILITY category aircraft, the U-75 can also boast a +6/-3 load limit – and was found in actual operations to be rather crash-worthy, since its wing and wing box were strengthened to cope with the rigors of “external cargo” 🙂 . Despite hailing from “the East”, under the hood the U-75 sports quite a bit of Western hardware, including a four-cylinder, fuel-injected 180 HP Lycoming IO-360-B1F whirling a Hartzell HC-C2YK-1 BF/F 7666A two-blade constant speed propeller.

With a MTOM of 960 kg, this package is responsible for a maximum level-flight speed of 215 km/h (116 kts), a maximum ceiling of 4,000 m (13,100 ft) and – combined with a wing profile suitable for low speed maneuvering – take-off and landing runs of only 125 m (410 ft) and 100 m (328 ft) respectively. The efficiency of the constant speed prop also means that the U-75 can be relatively frugal in a stable cruise, registering a range of 800 km (432 NM) on 150 liters (40 USG) of internal fuel. When fitted with two 100 liter (26 USG) drop tanks however, the U-75 was supposed to be able to reach an impressive 2,000 km (1,080 NM) – though this was a theoretical calculation only, since the aircraft had never been test flown to this extreme (the tanks themselves were never used in actual training operations).

Equipment-wise, the standard 75 was provided with the usual VFR instrument setup, including everything from the Basic 6 with the addition of an ADF receiver (all of which were powered from a simple and unremarkable 14 V electrical system). The armed versions used by the Air Force would also be provided with a simple optical aiming sight on the left side, while all models could be additionally equipped for night VFR operations. Interestingly, the instruments used were an unusual East-West mix, with the artificial horizon, turn and bank indicator, ADF, manifold pressure/fuel flow gauge and the tachometer all sourced from the US, with the rest of the instrumentation either indigenous or acquired from other European states that had used the metric system.

In service, the U-75 was always much blighted by a popular reputation for violent spinning (sometimes fatally), which bred some distrust in the design. However, while it could indeed be thrown into a serious spin if the pilot was determined enough, most of the type’s spinning accidents were due to it being flown contrary to manufacturer recommendation. Even before it had entered series production in 1978, official flight tests had concluded that the U-75 had no abnormal tendencies to spin if flown by the book – a fact also testified to by numerous operators who had never had any such problems, despite regularly putting their machines through various aerobatic and near-aerobatic routines2.

2 one of the main causes of the 75’s willingness to spin if pushed was the location of the (rather heavy) battery. Initially, it was to be located immediately behind the cabin; however, it was calculated that this would shift the CG too far forward, making the aircraft too stable and docile for its intended training role. To combat this issue, the battery was relocated to the extreme of the aircraft – the tail cone – thus moving the CG backwards and making the aircraft less stable and more maneuverable (but still well within accepted limits).

Interestingly, the U-75’s public perception parallels another love-hate civil aircraft, the sporty Mitsubishi MU-2 twin turboprop. From a purely statistical viewpoint one of the unsafest designs around, the MU-2 had gained its unenviable reputation mostly due its users’ inexperience with turboprop hot ships, coupled with poor and insufficient training (especially in the US). Once these issues are surmounted, owners swear on them to no end, with numerous examples having clocked up accident-free flight time that runs well beyond 15,000 hours

By the time production had ended in 1985, the U-75 had become one of the most produced indigenous Yugoslav designs, with 138 examples made (including the prototypes) – though not coming close to the country’s other notable aviation product, the Soko G-2 Galeb jet trainer, of which 248 were made 🙂 . Being a wee little piston prop had also meant that the U-75 was very usable outside military and training circles, with a good number eventually making it into various civilian flying clubs and to various private owners following Yugoslavia’s collapse. Despite 20 years of attrition still a common sight in Serbia, Bosnia, Macedonia and (very occasionally) Slovenia, the type is – as noted previously – sadly absent from Croatian skies, with the only examples operated after 1991 having flown with the Croatian Air Force. Used initially for limited combat operations during the war, the type would continue to soldier on in the basic training role until 2007, when it was withdrawn and replaced by the Zlin Z-242L…

The only CroAF U-75 to return to civilian life, 9A-DIH - formerly known as 008 - is unfortunately not airworthy... though major steps are being taken in that direction.

The only CroAF U-75 to return to civilian life, 9A-DIH – formerly known as 008 – is unfortunately not airworthy… though major steps are being taken in that direction.

2+2=78

The story of the four-seat U-75 would, however, begin not long after the first of the standard machines had started rolling off the production line. For all the variety produced by the Yugoslav aviation industry, no manufacturer of the time had a modern touring machine on offer, with most of their light aircraft output catering to utility and training needs – leaving various imported Cessnas and Pipers to fill the gap. Having been the newest indigenous design available when the industry had finally turned more of its attention to this segment – not to mention its connection to the stillborn M-11 – the U-75 had seemed to be a good place to start, its basic design offering a low-risk opportunity to quickly (and cheaply) produce a suitable aircraft for the role. From the very outset, the design goal had been to create something of a home-grown PA-28 that could be used both for personal flying and IFR training – as well as potentially exported abroad3.

3 even though the international public’s unfavorable perception of Yugoslavia’s engineering capability (in part well earned) might have put off people from buying its hardware, several of its aircraft were in fact highly regarded in Western aeronautical circles. Most notably, in a USAF fly-off competition in the 80s, the Soko G-4 Super Galeb jet trainer was judged superior in a number of respects to the visually similar BAe Hawk – however, the implications of a major Western power buying military hardware from a Socialist state (never mind its alliance) had sealed the aircraft’s international sales prospects well before it had even been flown

However, since the whole project had had “cheap and cheerful” as its premise, the changes necessary to turn the standard 75 into a four-seater had to be kept minimal (in part to also reduce disruption on the production line). To this end, the design team had taken the second pre-production two-seater (53004/YU-DRJ) and reconfigured its capacious cargo bay to give a bit more room, slotted in two additional seats – and then fitted a longer, extensively-glazed two-piece canopy to make entry into the back easier.

For visual reference, a bog-standard two-seater… (from Cavok Aviation Photos)

... and then DRJ, post modification. Pretty much the only dead giveaway at a glance is the new canopy (equipped with shades) (author: unknown, photo kindly provided by Mr. Dragan Kolundžić).

… and then, post modification. Pretty much the only dead giveaway at a glance is the new canopy (equipped with shades) (author: unknown, photo kindly provided by Mr. Dragan Kolundžić).

Dubbed the U-78, the new aircraft had in other respects remained identical to the stock 754 (retaining even the towing hook under the tail). Even though it had also retained the original’s spartan mil-spec cockpit, production models were envisaged to sport a comprehensive IFR suite, sourced in full from Bendix-King and including the:

4 there were indications in some sources that flush-headed rivets were used in lieu of the dome rivets of the standard model; available photo evidence however shows dome rivets on the fuselage, though it is not possible to discern their type on the wing. Informed opinion from a UTVA engineer is that it is highly unlikely (on a cost/benefit basis alone) that flush rivets were used anywhere on the aircraft

However, back in the actual world, many of the finer details of both the design and DRJ’s service life remain a mystery; according to people in the know, the production documentation for the U-78 had always been scant at best, and what little was widely known was further lost during Yugoslavia’s violent dissolution in the early 90s. Furthermore, the aircraft had never been formally tested by the Vazduhoplovni opitni centar, or VOC – the state flight test center which was required to sign off each indigenous design – so no accurate or official performance numbers exists. Pretty much not even the people who had worked on the basic U-75 at the time have a complete and definitive picture of its capabilities…

What is known for certain is that DRJ – as the U-78 – had flown for the first time on 23 March 1979. Following standard factory testing, it would be transferred to the VOC at Batajnica Airbase (LYBT) just outside Belgrade, where it would continue to fly informally until 14 August 1981, when it had suffered an unspecified accident and was written off.

The loss of the only prototype – and the continued desire to press ahead with the project – had meant that the UTVA works would eventually need to produce a replacement. Interestingly, this would occur only in 1986, a year after production of the standard 75 had come to an end. This had meant that the new aircraft would not be manufactured outright in the classical sense, but rather assembled from the ground up using replacement parts (manufactured in advance to support the fleet in the future) and DRJ’s vertical stabilizer (which had survived the accident). Given serial 53263 – denoting it as the first of the post-production modifications – this new aircraft would officially be designated the U-75A-41 (though always shortened to just U-75A), and would initially carry the reg YU-XAC. Despite the different name though, XAC would not differ from DRJ (apart from dome rivets definitely being used throughout 🙂 ).

Flying for the first time on 14 May 1986, XAC would also initially pass to the VOC – again informally – before ending up with UTVA’s own flying club (AK UTVA Pančevo) as YU-BRJ. Sadly though, it would be completely destroyed on 24 March 1999 when the factory and its facilities were severely damaged in a NATO air strike.

I’m leaving on a container ship…

Even though XAC would – as proof of the design – go on to fly for a good number of years, forewarning of Yugoslavia’s 1991 implosion had quickly dashed many hopes of continuing development beyond the prototype stage. However, just before the country’s whole aviation industry would grind to a halt, the UTVA works had managed to cobble together one final aircraft, the lucky No. 3 that would lure me to Slovenia 🙂 .

Like XAC, this new machine could only come about in an unusual manner. Despite not having produced any new aircraft since 1985, the factory was still busy repairing, overhauling and scrapping in-service 75s – activities that would continue right up until the start of hostilities. At one point in the very late 80s, the company had come into possession of YU-DJO – a stock 75 manufactured in 1983 with the serial 53230 – which had been written off following an accident. Seeing their last chance at keeping at least something of the four-seater dream alive, the factory had decided to take what remained of the aircraft and rebuild it into an XAC-like model using any available spares and parts of other demobbed 75s.

What happens next, however, requires a short digression. The consensus among online sources and forums dedicated to Yugoslav aviation is that the aircraft had never actually been completed prior to the war, and that only an empty shell had been produced. Much doubt is also cast on the extent to which it would have conformed to the U-78/75A standard, especially since it was a rebuild of an existing 75 (using its basic fuselage), rather than a bespoke four-seat model.

These sources also state that the aircraft had remained at the factory until 2003, when it was sold – along with a regular 75 – to a buyer in the US. However, the buyer was said to have been unable to register the four-seater due to issues with its paperwork, with specific reasons given including missing/discarded documents, the aircraft being a composite of several different serial numbers and “unassigned parts” – as well as available documentation pertaining only to the bits belonging to DJO. Having thus sat around for a while, it was said to have returned to Serbia in 2008, to be restored, re-certified and sold on to a buyer in Slovenia shortly afterwards.

But, having had the great opportunity to personally interview the buyer in question, the story I was made aware of was quite different. It transpires that the aircraft had actually been fully completed and outfitted by spring of 1991 – and that its paperwork was, in fact, clean and in good order. Possibly intended for export right from the outset5, the machine would soon be dismantled, crated up and – in the company of the aforementioned two-seater – shipped by sea to Mr. John Wallace of Oshkosh, Wisconsin, who had recently become the official distributor for UTVA aircraft in the US.

5 whether this export was just a fluke or planned from day one is not known with certainty. Given the ad-hoc nature of the build – with Yugoslavia already disintegrating – the project documentation was not diligently kept, so even UTVA employees are in the dark on this issue

53230 nearing completion in early 1991, with a stock two-seater visible behind (author: unknown, photo kindly provided by Mr. Dragan Kolundžić).

Two of Yugoslavia’s best-known people movers, the U-75 (aptly in its four-seat guise) and the Zastava 101 family sedan (author: unknown, photo kindly provided by Mr. Dragan Kolundžić).

Interestingly, Mr. Wallace had specifically requested both versions of the aircraft, since he was interested in marketing both its military and civilian potential (that is, having a single design fulfill the training, light attack and touring roles). However, to be able to actively offer them on the market, Mr. Wallace had first needed to make some changes to comply with FAA regulations, most notably swapping the existing Yugoslav instruments and avionics for a US-spec cockpit suite sporting imperial measurements (in another point of contention, there is some doubt that US instruments had already been fitted in Yugoslavia – though this is believed to be incorrect).

But, by the time the changes had been made and the aircraft were ready for re-assembly, open hostilities in now ex-Yugoslavia had already started, leading to the introduction of a wide-ranging UN embargo against all of its former states. For Mr. Wallace this had meant that he could no longer import any new aircraft from Serbia, making both of his current examples – worthless.

Faced now with a whole new set of financial problems, he had immediately decided to sell the engines of both aircraft in order to try and recoup at least some of the funds invested in setting up the dealership and shipping the machines across the Pond. This had made the already unwanted machines even more useless, with both examples eventually consigned to languish around in Mr. Wallace’s garage, still packed up in their original shipping crates. Having absolutely no use for two engine-less jigsaw puzzles whose market value had been steadily decreasing, he had in 2007 decided to put the aircraft up for sale, going so far as listing them on – eBay 🙂 .

As it is often stated online, “if it looks stupid and it works, it’s not stupid” – which fully applied here, since the aircraft were quickly spotted on that very site by Mr. Leon Pogelšek of Ljubljana, Slovenia. Having recently completed his PPL, he had expressed a desire for his first aircraft to be indigenous, with the four-seater seeming like the perfect ticket for the job. However, since both aircraft were being sold as a single item, there was no other option but to buy the lot and possibly use the two-seater for spares.

With the sale finalized, the aircraft – complete with all papers and US instruments, as provided by Mr. Wallace – were once again loaded up into a container and shipped to Slovenia’s main port in the city of Koper. However, once they had arrived, they would immediately be launched into a world of legal issues, which even today – nine years on – conspire to keep the four-seater grounded. Despite the U-75 having been as common as trees in ex-Yugoslavia, no certified mechanics or service centers had remained in Slovenia by 2007, making the aircraft impossible to assemble and fly within the country’s existing regulatory framework (being a one-of uncertified example didn’t help the four-seater either).

Pretty soon though, a workable solution was found, whereby the assembly and overhaul of the quad would be contracted out to a company based at Lisičji jarak Airfield (LYBJ) in Serbia – and headed by a former UTVA executive and engineer – with the two-seater used as payment for the work done (being a low-timer with prime potential for resale)6.

6 unfortunately, the identity of this aircraft is virtually impossible to determine today, since its documentation had been handed over during overhaul. However, it is known that it was one of reportedly six examples sent to Sudan around 2008/2009, where they had resurfaced under the designation SAFAT 03. Interestingly, that designation had initially been used for an upgraded, Sudan-built version of the U-75, which had failed to gain any meaningful orders and progress beyond the prototype stage…

In the event however, the work would drag on for four years – having even been handed over to a third party at one point – during which only the wings would be attached and a new engine and propeller from another U-75 fitted (both of which with only eight hours on the clock). Dissatisfied with the pace of the work so far, Mr. Pogelšek would in early 2013 ship the aircraft over to an official UTVA service center in Sremska Mitrovica – a road trip of 80 km that had, once again, seen the aircraft disassembled into its original state.

Here, the aircraft would be fully completed, outfitted with the type’s original instrumentation and test flown, making it finally suitable for delivery and operation. Wary of the legal requirements that had prevented it from being assembled in Slovenia, Mr. Pogelšek had originally wanted to register it in Serbia – but was informed by the Slovenian CAA that it was also possible to have it on the Slovenian register. Being a unique, uncertified example, it was initially allocated to the country’s experimental register, becoming S5-MZT the same year (M – experimental/homebuilt). However, it was soon decided that – given its commonality to the stock U-75 – the aircraft could even be added to the standard register (prefixed with D like in all former Yugoslav states), becoming S5-DZT in the process. Under this registration, it would be flown to Slovenia sometime in June 2013 (the exact date eluding Mr. Pogelšek’s recollection), making this the longest time it had been airborne in its entire life – for a grand total of just 7 hours and 13 minutes accumulated by the airframe.

The future is now

Unfortunately, soon after its arrival at Novo Mesto, the Slovenian CAA had withdrawn its approval for registration, effectively grounding the aircraft then and there (the exact reasons for this change of heart appear to fall into a domain I wish to steer clear of 🙂 ). Given that the issue was still not resolved at the time of writing, the aircraft had remained immobile for the next three years, though Mr. Pogelšek has made overtones to eventually register it in Hungary and potentially return it to airworthy state. Being employed in the art world, Mr. Podelšek plans on eventually turning the aircraft into a “mobile canvas” (more precisely, an “aero art” flying installation), and repainting it with stylized images of themes from Yugoslavia’s industry – thus paying homage to both the cultural and technical aspects for former Yugoslavia.

In the mean time, it remains the perfect “poster aircraft” for Achtung, Skyhawk! – and provides an almost unparalleled glimpse into a bit of left-field aeronautical thinking that I hope my readers will enjoy! 🙂

Something’s rotten in the Kingdom of Denmark… and the UTVA factory at Pančevo. A decidedly odd sight for the locals… four people in an UTVA 75…

Unlike similar aircraft, the 75A sports two individual seats in place of a one-piece bench. But, while this may sound like a nice touch, the space and structural constraints in the cabin mean that none of the four seats can recline even one inch.

DZT’s only external difference from both the U-78 and XAC is the shape of the canopy, which has a slanted as opposed to a straight rear edge. The reasons for this change are unknown; however, it is possible that this was a concession to ease of production, since this shape avoided the need to modify the fuselage and rear cabin frame (interestingly, straight-edge version had afforded less visibility to the rear passengers).

Having descended from what was primarily a military trainer, the A is naturally quite airy and full of light, with good view afforded in pretty much every direction except below and aft.

The same logic applies to the cockpit as well, which means that the pilot is spoiled for choice in terms of throttle and prop controls, with one set (the yellow level) on the left sidewall, and one in the traditional place in the throttle quadrant. Combined with an ambidexterous stick, this means the aircraft can be easily flown with both left and right hands, appealing to civilian and military pilots alike. However, like DRJ and XAC, DZT and had retained the basic setup of the standard trainer.

While the instrument panel itself is pretty conventional – reminiscent in layout to a 60s Cessna – the UTVA-75’s traditionally quirky central pedestal gives the cockpit an unusual feel. From top to bottom, the quadrant features the prop control (blue lever) and throttle (leverless… lever), with dual heating/ventilation on each side of the engine controls; the mixture is the first blue-red plunger below the throttle, with the brake block and elevator trimmer below (whose indicator – barely visible – is horizontal as opposed to vertical). To the right is the parking brake plunger and the injector air intake lever, which is a fancy name for an alternate air source. Finally, the small metal lever at the bottom of the pedestal is the fuel selector.

Always a relevant test of any light aircraft: how will I – with my 1.91 m / 6ft 3in frame – fit inside! Sadly though, the crossbeam near my knees (another remnant of an aircraft always designed to have two seats) makes sitting in the back somewhat uncomfortable. Likewise, the rear fuselage being relatively low, closing the canopy and sitting upright was a challenge…

Customarily, I would once again like to extend my sincerest thanks for their time and assistance to:

Sources:

  • Istorija vazduhoplovstva Pančeva: UTVA 75 (The History of Aviation in Pančevo: UTVA 75) by Dragoslav Dimić & Dragan Kolundžić
  • UTVA-75 factory catalogue from the mid-80s
  • Safat Aviation Complex – SAFAT 03 product page
  • My City Military Forum – U-75 discussion (in Serbian)
  • Paluba.info – U-75 discussion (in Serbian)