Photo File – Domesticated Dornier: The Croatian AF’s Do-28 9A-ISC

By Josip Miljenko Džoja and myself
Photos as credited, copyrighted

While there has always been an abundance of easily-accessible abandoned and disused aircraft to be found in Croatia, one place in particular has always been the local holy grail of “wreck photography” – the Zrakoplovno-tehnički centar (ZTC, Aeronautical-Technical Center) maintenance facility in the town of Velika Gorica, just a few kilometers south of Zagreb. Formerly a military depot with a long and illustrious history, it is now home to what remains of the Croatian Air Force’s earliest machinery, littered chocked full of rusting, disintegrating hulls that had in the war-torn early 90s formed the backbone of the country’s first aerial capabilities.

Even though each and every aircraft there has an interesting and often gripping story, the one I was always most interested in was 9A-ISC, a Dornier Do-28D Skyservant sitting alone and unloved at the edge of the apron. Unfortunately, the facility’s current status in the military hierarchy had always made “unannounced” photography perilous and complicated, making getting up close and personal an impossible task.

Thankfully, as part of the military’s ever-increasing drive for good PR, the ZTC had been selected as the prime venue for Air VG, Velika Gorica’s first aviation theme day scheduled to be held on 13 May 2017 – thus allowing for ample opportunity to sneak a (legal) peek at what’s really hiding behind that fence. However, since I had already reserved that date for snooping around hangars at small airfields in neighboring Bosnia, I’d decided to call on the help of Mr. Josip Miljenko Džoja, a fellow aviation photographer (Flickr gallery here) and keen Croatian military aviation buff who was sure attend no matter what 🙂 . Under our arrangement, he would be tasked with piecing together ISC’s life story and providing both current and past photo material – while I would weave everything together and add the inevitable nerdy bits about the Do-28 design 😀 . Despite not being able to peek inside and make a proper Achtung, Skyhawk! photo report, we both felt that an aircraft of its rarity needed its tale told however possible, so we pooled all of our resources together and got to work…

Despite not being easy on the eye, the Do-28 was – in all versions – a supremely capable aircraft. A direct development of West Germany’s first post-WW2 design – the six-seat Do-27 – the original A and B model 28s were simply straight twin-engine conversions that retained a majority of the 27’s parts. The significantly larger D model – able to accommodate 13 passengers and now named Skyservant – was however a much more thorough redesign that sacrificed almost all of its commonality with the 27 for increased cabin space and hauling capability. Despite this, it still boasted the impressive STOL performance and handling that had made the original 28 such a hit (photo copyright: Josip Miljenko Džoja)

Diaspora-28

But first, a bit of trivia! Like the majority of surviving Do-28s, ISC is a Do-28D-2* model, at 172 examples produced the most common of all the Skyservants. Developed in 1972 specifically to the requirements of the German army following its experiences with the earlier D-1 (the default production model that had introduced a 50 cm wingspan increase and higher take-off mass over the basic D), the D-2 had included:

  • a reworked internal layout to give an additional 15 cm of usable cabin length
  • a further 200 kg increase in maximum take-off mass
  • a higher fuel capacity adding nearly 700 km to the range
  • redesigned flaps and ailerons for better low-speed handling, as well as the removal of the D-1’s wing fences
  • fixed leading-edge slots along the outer sections of the wing to improve STOL performance

and fuselage mounting points for sensors such as mapping cameras and side-scanning radar (as well as equipment for oil spill monitoring on aircraft operated by the German Navy under the designation Do-28D-2/OC).

* in 1980, the Do-28D-2 designation would be dropped in favor of Do-128-2.

ISC itself would turn out to be an early production model, completed in February 1974 with the serial number 4178. Soon after delivery on the 13th of the same month, it would be allocated to the German Air Force’s Government Flight – the easily pronounceable Flugbereitschaft des Bundesministerium der Verteidigung, or FlgBMVg – based at Köln/Bonn Airport (EDDK), where it would receive the code 59+03.

ISC in its GAF guise at Airliners.net

According to the information available, its service life with the FlgBMVg would be fairly uneventful – mostly hauling officials in a semi-VIP passenger interior – right up until early September 1992 when it would be parked at Leipheim Airbase (EDSD) near Ulm as part of the type’s general withdrawal from service.

At this point however, its story starts to become interesting. At some time in 1993, the aircraft had been bought by the Croatian Government – at the time fighting in the first of the 90s Yugoslav Wars – reportedly through intermediaries in the (sizable) Croatian diaspora in Germany. Apparently serviced and made airworthy again in the mean time, it would eventually make its way to Finow Airbase (EDAV) in the former GDR – from where it would be flown to Split Airport (LDSP) in Croatia on the night of 11-12 March 1994. Interestingly, the flight would be made under the reg 9A-NDH, a fictitious identity that had never appeared on the Croatian register before or since. The choice would prove controversial later, since in its most commonly-used form NDH stands for Neovisna država Hrvatska (Independent State of Croatia), a Nazi puppet state that had existed in the western Balkans between 1941 and 1945.

Upon arrival at Split on the morning of 12 March, the reg had immediately been changed into the no less ominous – and equally fictitious – 9A-ISC, under which it would continue to fly until its ultimate withdrawal from use**. Its life in wartime service with the Samostalni zrakoplovni vod (Independent Aviation Corps) of the Air Force’s 4th Brigade is still clouded in confusion and a fair bit of secrecy – and knowing full well the complicated political and military situation that had existed in Croatia in the early 90s, both Josip and myself had quickly decided against digging into the matter any further 🙂 .

** this reg would be formally used for the first time only in 2013 – and on a restored Polikarpov Po-2. Of interest, even though it had always had a dedicated military registry, the Air Force kept some of its transport and utility aircraft – including the Do-28 – on the 9A civil register until the early 2000s, when all active machines were allocated bespoke military codes.

Following the end of hostilities in 1995, ISC would continue to serve in the Croatian Air Force in various (but only occasional) transport roles until a throttle cable failure and burnt cylinder valves on one engine – coupled with a lack of spares and expensive upkeep – grounded it for good in 1999 with around 4300 hours on the clock. As was the case with virtually all aircraft acquired and used during the early stages of the war, ISC was relegated to the corrosion corner at ZTC (then still a fully-military facility known as the Zrakoplovno-tehnički zavod “Zmaj” – the Aeronautical-Technical Institute “Dragon”), where it has remained ever since…***

*** another interesting tidbit was that the MoD had actually been offered the opportunity to restore the aircraft to airworthy state by a private contractor – and even convert it to turboprop power along the way. The engine proposed for the job was the Czech-built Walter M601 – most commonly seen on the Let L-410 Turbolet – which would have resulted in something similar to the factory-standard, PT6A-110-powered Do-28D-6 / Do-128-6 of 1978. However, the MoD had never taken up this offer.

By far the type’s most distinctive feature is the location of the twin 380 HP six-cylinder geared and fuel injected Lycoming IGSO-540-A1E engines. Since the original Do-28 was produced on a tight budget, this solution was likely chosen to avoid an expensive redesign and strengthening of the wing required for high-mounted engines – while at the same time still providing adequate propeller ground clearance for operation on rough strips (photo copyright: Josip Miljenko Džoja)

In common with many similar aircraft acquired in a similar manner during the war, ISC had been hastily prepared and renamed, likely with whatever paint and/or stencils were available. More than 15 years of constant exposure to the elements have taken its toll, with its previous identity slowly coming to the surface… (photo copyright: Josip Miljenko Džoja)

It’s overblown, dirty, and not even from the same aircraft – but since there are so few detail shots of the Do-28 cockpit, I had to improvise. Like in many comparable aircraft of the period, the Skyservant’s cockpit is a mass of dials, buttons and levers; however, the layout is quite intuitive and everything is within easy reach from both sides of the cockpit. And despite the tailwheel layout, visibility over the nose is excellent – though the view out the side is understandably quite poor (photo copyright: Boran Pivčić)

And finally, the only interior shot of ISC we could lay our hands on. The main differences are a different radio fit, more modern IFR instrumentation (two Course Deviation Indicators (CDI) for the pilot, and an Automatic Direction Finder (ADF) for the copilot) – and a simple weather radar (photo copyright: author, name withheld on request)

Sources:

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