yak WElcomE

Coming in from the cold

Yaks and Nanchangs to join the LAA fleet. By Jeremy Diack…

At the 2019 LAA Rally, Rachel Gardner-Poole, head of the UK CAA’s GA Unit, confirmed that the CAA and LAA had reached an agreement on the transfer of regulatory oversight of Russianbuilt Yak light aircraft, including the Yak-50, Yak-52 and Yak-18A (and also the Chinese-built Nanchang CJ-6A by virtue of its

Yak-52 heritage). To mark the occasion, Yak-52 G-YAKX was confirmed as the first Yak to be approved for Permit transfer. Rob Rowe, part owner of G-YAKX and chief test pilot for this regulatory switchover, has recounted his experiences later in this article, but perhaps it’s best to start with some latter-day Yak aircraft history, picking up some 40 years after Alexander Sergeyevich Yakovlev first established his pioneering aircraft design and manufacturing company in the early 1930s.

The WAC and the Yak 50

taking seven of the 10 top positions, including first, second and third places. The same aircraft type was used by all Soviet Bloc team members, the newly launched Yak-50, which had completed its maiden test flight just 13 months earlier in June 1975. Created as a rival for the American bi-plane pocket-rocket, the Pitts S-1S, the Soviets finally had their championship winner. Fast-forward two years to the 1978 World Championships held at Ceske Budejovice in the Czech Republic, and the picture had changed somewhat. Introducing more abrupt manoeuvres into the competition sequences for the first time, the Yak-50 struggled to keep pace with other types, such as the Zlin Z-50 L which, with its full-span ailerons could easily out roll the Yak-50. The highest placing the men’s Soviet team managed that year was fifth place, and not wishing to be outdone on the international stage, it looked like the Yak-50 was officially on notice. Impressively, the Soviet women’s team had still managed to take the top five female positions in their Yak-50s and so the aircraft was used again at the 1982 championships in Sptizerberg, Austria (the Soviets having passed,

Above The Yakovlevs display team with a Super-52 in the foreground, its lighter weight and additional power enabling it to keep pace with the Yak 50s. Photo: Courtesy Yakovlevs

understandably for the times, on the USA-hosted 1980 championships). Soviet aerobat legend Victor Smolin managed to secure the top spot in his Yak-50 but the writing was on the wall, and this was the last time the Soviet team was to use the Yak-50 at the WAC in the unlimited class.

It’s fair to say that the Soviet’s desire to win, rather than just compete, was all-consuming. By 1984 the Soviet team had lost four pilots, including 1976 World Champion Viktor Letsko, because they had been pushing their Yak-50s beyond their limits, resulting in structural failures. A Service Bulletin to strengthen the main spar had been introduced and new life limits of 300 hours for training aircraft and 47 hours total life for team aircraft had been imposed, but it was clear that the Yak-50 had now been overtaken by other types and was no longer the leading aerobat at this unlimited level.

Sukhoi take centre stage

The Soviets went back to the Yakovlev Design Bureau and asked them to build a Zlin-beater and this resulted in the birth of the Yak-55. With fixed undercarriage and powerful, slab wings, the Soviets were presumably expecting great Top left Transition to an LAA Permit will not alter maintenance requirements, Yaks may be ‘agricultural’ but they do require regular attention. Photo: Courtesy Yakovlevs

Top right The Yak 52 is an affordable and capable aerobatic machine, with the plus of the feel of a warbird at a sensible price. Photo: Ed Hicks

Above Modified Super-52 panel, removal of horizon and its inverter alone saves 15kg. Photo: Courtesy Yakovlevs things from the Yak-55 at the 1984 championships in Bekescuba, Hungary, but their top finisher, Victor Smolin, only managed fifth place. Having failed to achieve a repeat of the 1976 clean sweep, the Soviets later switched to the Sukhoi 26M and went on to achieve considerable success with it at the 1986 championships.

Yaks come up for grabs

With the Yak-50 now relegated to the side lines, and with DOSAAF (the sports arm of the Russian military) withdrawing all support for it in 1990, there were significant numbers of them sitting unused and unloved at DOSAAF airfields across the Soviet Union.

Enter UK aerobatic legend Richard Goode. Richard had been competing at the world championships in his Pitts S-1S during the 1970s and 1980s. In 1988 a fellow competitor, Wolfgang Jagle, who flew for the West German national team in his Pitts S-1S, told Richard that the East Germans were interested in off-loading their Yak-50 fleet, and suggested that there was a good business opportunity waiting. Richard agreed, and in partnership with Vic Norman, of AeroSuperbatics fame, they purchased six

Yak-50s, two of which were brought onto the UK register. With a sponsorship deal from UK vodka distillery Valdivar in place at the time, the two aircraft were re-registered as G-VLAD and G-VLAR.

Glasnost

By now, with Glasnost in full swing and the dissolution of the Soviet Union underway, Richard was able to start purchasing those Yak-50s dotted around the Soviet Union at DOSAAF airfields. According to Richard, there were a total of 312 Yak-50s built but most of these were scrapped under DOSAAF orders, leaving only around 70 still surviving today (the UK has 16 of them). They had survived by being ‘hidden’ from the Soviet authorities. Richard’s search for a Yak aircraft dealer put him in contact with some interesting characters, and without wishing to pre-empt his autobiography (out April 2020), suffice it to say that the British security services found Richard’s Soviet Bloc contacts a matter of some interest.

The ‘flag of convenience’ era

It would appear that practicality beat strict regulatory compliance in the early 1990s and through a contact at the FLA (the USSR’s general aviation amateur builders association), Richard was able to register Yak-50s bought in Russia under their banner, and had FLA Certificates of Airworthiness issued. Richard readily admits that the FLA registration was effectively a ‘fudge’, but it was one that worked well for a number of years and UK Yak-50s (excepting G-VLAD and G-VLAR which had come from Germany) could be seen sporting Russian ‘RA’ registrations. The ‘fudge’ was finally brought to an end, however, when the Russian aviation authorities knocked on the UK CAA’s door in 2001 and informed them that the registrations weren’t valid. Richard subsequently discovered that there was a UK statute in place which required the CAA to issue Permits to Fly to any and all ex-military (airworthy) aircraft put forward, and so this was the route chosen to get them onto the UK register. Much discussion ensued between Richard, the CAA and the Yakovlev Design Bureau (YDB) and eventually it was agreed that Dimitri Dratch – head of light aircraft at YDB – would issue an AD to life limit Yak-50s to 100 hours between major overhaul, and the CAA would then allow them to be put on the UK register under a CAA-issued Permit to Fly.

The Yak 52s

At the same time that this was occurring, another UK aerobatic superstar, Mark Jefferies, had started Below The Yak50 is getting on for 45 years of age, but what a stunning looking machine. Under the LAA maintenance regime, its future will hopefully be assured. purchasing Yak-52s from Termikas in Lithuania. These aircraft were imported under Lithuanian registrations (LY) and soon started appearing across the country. Other companies started to get involved and Yaks were suddenly available from a number of sources in Eastern Europe, including Aerostar in Romania (who held the manufacturing rights for the Yak-52) and Anabaras in Lithuania. The Yak-52 is a direct descendent of the Yak-18A, first test flown in 1976 and put into production in 1979. Powered by the same Vedeneyev M14P 360hp ninecylinder radial engine as the Yak-50, the aircraft was designed to serve as a military trainer, sharing design and layout similarities with post war fighters such as the Yak-17 jet fighter trainer.

Heavier than its single-seat cousin at 1,015kg (the Yak-50 is 750kg empty weight) the trainer is nonetheless a very responsive and highly capable aerobat, and also relatively easy to fly and land. With inverted fuel and oil systems, the aircraft can fly inverted for up to two minutes, has a 180˚/second roll rate and is stressed to +7 and -5 G.

As a trainer, the undercarriage was designed so that the two main wheels are still exposed and unlocked when retracted, limiting fuselage and wing damage following a wheels-up landing – which not only military cadet pilots have benefitted from in the past. Like its lighter cousin, the Yak-52’s engine starter, brakes and landing gear (and flaps on the 52) are operated by compressed air, replenished by an engine-driven compressor charging main and emergency air bottles, which can also be manually topped up.

Yak formation teams

Team Yakovlevs owner and lead pilot, Jez Hopkinson, who in the early 1990s operated a one-man aerobatic school out of Compton Abbas airfield using an immaculate Slingbsy T-67M Firefly, was an early adopter of the Yak-52. Purchasing LY-ALJ in 1994, Jez and his fellow syndicate members, John Griffin and Dave Hawkins, soon caught the Yak bug and it wasn’t long before other Yak enthusiasts were knocking on their doors and The European Yak Club was formed. This included the establishment of Yak-specific formation training at The Squadron at North Weald (and at Compton Abbas), where many Yak pilots cut their formation teeth. Out of this came two aerobatic formation teams, The Aerostars and The Yakovlevs, as well as John Griffin’s spectacular solo Yak-50 displays in G-YAKA, under sponsorship from F l y e r magazine.

Getting to know the Yaks

Idiosyncratic is probably the best way to describe the Yak-50. Powered by a supercharged 360hp nine-cylinder radial engine, with a two-blade VP prop, the design belongs firmly in the warbird camp rather than the modern aerobat category. The all-metal airframe (with fabric covered ailerons, rudder and elevator) is tough and agile and boasts exceptionally fine handling characteristics, enhanced by a relatively high power-toweight ratio. Aside from the engine start, which requires thorough pulling through beforehand to prevent hydraulic lock, and also requires more hands than are readily at one’s disposal (one hand to hold the stick-mounted brake lever, one hand to control the throttle, and two extra hands to operate the magnetos and starter button simultaneously), the most notable ‘gotcha’ for first-timers is undoubtedly

taxying the aircraft. The 50’s nose is long (imagine a Yak-52 without the front cockpit) and wide and obscures any forward view when on the ground. By loosening the shoulder straps, it is possible to lean out of the side of the cockpit and gain some forward visibility, but the only real way to see what is ahead is to use a zig-zag style of taxying.

There is then the added gotcha of the locking tailwheel, which no amount of differential braking will overcome and must be fully unlocked before taxying. The method of unlocking the tailwheel is somewhat counterintuitive, as it requires a positive stick forward position which feels both unnatural and precarious. With these idiosyncrasies mastered, the standard manoeuvre is to then jam the tailwheel in the taxiway guttering after having forgotten how much fuselage there is behind you! ‘B e e n t h e r e , b a l l s ’ e d t h a t u p !’ T-shirts are available to order…

In the air

Once in the air, both types handle like the warbirds they emulate and the growl from their radial engines makes them a popular addition to the air show fleet. The Yak-52, while an excellent platform for solo aerobatics and basic formation training, is nonetheless a bit underpowered for dynamic formation aerobatics. The Yakovlevs’ solution to this was to launch a Super-52, a lightened and more powerful version of the factory-built Yak-52. Using an upgraded M14P ‘F’ engine, with in excess of 400hp, and swapping the two-blade Russian propeller with a three-blade replacement from MT in Germany, the other significant change is a weight reduction of around 150kg. Much of this can be achieved through the replacement of the original Russian instruments and avionics with modern equivalents, such as the artificial horizon, which in combination with its power inverter weighs in at a hefty 15kg, compared to the 600g solid-state gyro replacement. With the upgraded engine, three-blade propeller and lightened airframe, the Super-52 now manages to keep pace with its single-seat cousin.

The Yakovlevs

Performing in the UK and across Europe for nearly a decade (the team’s first official display was at Yeovilton in 1999), The Yakovlevs made an inaugural trip to China in 2008 and had to learn the fine art of dismantling and re-building their aircraft. This proved to be a steep (and expensive) learning curve. As the only team in the world able (or sufficiently foolish enough…) to pack two Yaks into one container, the project involved the services of a master carpenter in addition to the team’s engineers.

The dismantling includes removing the aircraft’s wings, tail section and propeller. The wings are packed into upright wooden cradles, which are placed in the container either side of the fuselage, with the rudder and elevator secured above the fuselage on a rig between the two wings, with the propeller on the floor beneath the fuselage. As the main undercarriage on both the Yak-50 and Yak-52 is ‘conveniently’ attached to the wings rather than the fuselage, this meant a dolly had to be constructed to hold the fuselage off the floor (and also for wheeling it in and out of the containers). The prototype version appeared to work OK, and on the journey out it did its job well, but unfortunately the same couldn’t be said for the return journey. Having finished the inaugural display at Dazu in east-central China to spectacular acclaim (the viewing figures were amazing and would make X - F a c t o r blush), there was an Above The ‘Bomb’ – actually the compressed air tank. LAA oversight should enable the use of replacement alternatives made of kevlar. Photo: Courtesy Yakovlevs accident at the shipping port and both of the team’s containers were dropped. The wing cradles held firm but unfortunately damage had been caused to the main spar of three of the four aircraft, due to the dollies bottoming out on the container floor whilst still under heavy load. The damage effectively wrote off three of the four aircraft and it was two seasons before the team could launch again (the five-year court battle over insurance pay-out is a tale for another time…). Gluttons for punishment, the team were back in China in 2010, this time with bomb-proof fuselage dollies, and despite numerous incidences of heavy handling of the containers in ensuing years (G-meters/trackers installed in the containers generally reveal a 20 G+ stress load on each trip), the aircraft have not received any significant damage since the 2008 incident and the team will be returning to China for the ninth time in 2020.

Engineering

One advantage of dismantling and rebuilding aircraft so often – 43 times and counting due to the fact that the Chinese military won’t let GA aircraft transit in-country and require teams to bribe their engineers into dismantling aircraft in between shows for transport by road – is that it means that our engineers have a more comprehensive knowledge of the state of the airframes than is possible under standard maintenance.

While it’s fair to say that Yaks are ‘agricultural’ in build (e.g. the generator is powerful enough to provide light for a small town), they are nonetheless maintenance intensive and require constant vigilance. The air system is one of the most temperamental of the aircraft’s systems – there isn’t a Yak aircraft out there that doesn’t have some minor air leak in it somewhere – and with moisture an unavoidable factor, flap and gear actuators are frequently subject to corrosion. Not unlike their woolly cousins, Yaks are blessed with snot valves, conveniently

located under the engine canopy and just within spray reach of an unsuspecting novice’s foot.

Parts availability

Preventative action is the name of the game, as replacement parts are something of a lottery and are becoming increasingly difficult to source, which of course is one of the key reasons for bringing them over to the LAA. While Minor Mods approved by the CAA have led to non-OEM components being used in certain areas (harnesses, lightweight generators and modern avionics, for example), there are other components that would significantly benefit from a modern replacement, but would require a Major Modification approval under CAA PtF categorisation, and therefore are beyond the budget of a private Yak operator. Yak aircraft’s air bottles are a prime example of this. With the appearance of joke bombs from a Peter Sellers’ movie set, these metal spheres have also behaved as such in the past, with one notable explosion in a Yak-50 15-odd years ago. Luckily the explosion happened when the aircraft was taxying rather than airborne, but it still wrote the aircraft off. An MPD imposing a hydrostatic testing requirement every five years, plus a yearly borescope check, has Below The Yakovlevs regularly visit China to perform and manage to ship two aircraft per container. Experience has taught them they need to be virtually bullet proof! Photo: Courtesy Yakovlevs prevented further bottles giving way so spectacularly, but as soon as these bottles reach their finite life and fail hydrostatic testing then there is a problem, as there are no replacements to be had for love nor money. The Americans, who operate Yaks on their Experimental aircraft category, have no such problem as they are permitted to use replacements made from Kevlar, which as well as being much stronger are a fraction of the weight of the original ‘bombs’. But on this side of the Atlantic, Yak operators have been unable to follow suit and it’s Russian Roulette as normal.

Future-proofing the fleet

The prime reason for the move to the LAA register is therefore one of future-proofing the Yak fleet. There are ex-DOSAAF airfields dotted around Russia which still house spare Yak components, but unless your Russian ‘contacts’ are up to scratch then sourcing these parts has become something of a challenge. The 50 and 52 share many common components (particularly firewall forward), but there do remain some significant differences, and it is Yak-50 parts that are by far the most challenging to source. With the Yak-52 still in production in Romania, and the Chinese producing their own equivalent (the Nanchang CJ-6A), parts are still available, but many of the Yak-50’s replacement parts have now been exhausted, so non-OEM replacements are the only realistic option.

No shortcuts

It is envisaged that the move from CAA to LAA Permit to Fly status will make a significant difference for the future-proofing of these aircraft, but what the change is not about is an opportunity to make cost savings by cutting back on maintenance requirements, and the LAA has been very clear about this from the outset of negotiations with Yak operators and the CAA. Luckily, most of the existing engineers who are qualified to work on Yaks in the UK are also separately LAA inspectors, meaning that not only will the maintenance programmes remain the same as they were under the CAA PtF system, but these same engineers will also be able to continue to work on them and sign them off.

Overflight restrictions

Another key benefit to arise from the change of register is that of overflight restrictions. Until recently, all CAA PtF aircraft were subject to some pretty Draconian overflight restrictions, effectively limiting flights over congested areas to just that ‘for the purposes of taking-off or landing at a government or licensed aerodrome’. Taking this at

Not just Yaks!

As well as the transition of YAKs to LAA oversight, we will also in future be in a position to support owners of an even rarer type, the Nanchang CJ-6. Originally developed as a military trainer for the Chinese People’s Liberation Army Air Force, while it looks superficially similar to its Russian counterpart it is structurally quite different, with a flush-riveted aluminium structure and a distinctive cranked wing. There are currently five aircraft on the UK register.

Nanchang CJ-6A G-BVVG, pictured by Mark Harkin at Prestwick Airport, belongs to the Nanchang CJ6A Group.

Transitioning to an LAA Permit to Fly: What is involved

By Rob Rowe

With G-YAKX being the first YAK-52 to transition, at the point of conducting Annual checks, we realised this was going to involve a learning curve all round. Compounded by simultaneously conducting a 600 hour life extension inspection programme of thorough visual and NDT inspections. So about as complex as it gets, but with this done we’ve covered off the two key procedures to be encountered across the fleet … so a very useful exercise all round.

Annual It makes sense to schedule transferring to the LAA when your aircraft’s Annual is due and this helps spread the LAA’s workload too. The starting point is filling in the LAA/APP-TRANSFER1 ‘Application to Transfer Form’, covering airframe, engine & prop details from the log books and weight and balance schedule, with some aircraft basic history too and the maintenance schedule being used (your maintainer will have this, if you don’t). A list of non-standard features is required that can be found online, from the CAA’s AAN (Airworthiness Approval Notes) for your aircraft when it was first registered, plus any subsequent mods, again your current maintainer can help here. As many of these mods are commonly found across the fleet, we’ll progressively build up a LAA archive of these to make this information more accessible. With the form completed, you’ll need to provide supporting docs consisting of CAA Permit to Fly / Limitations, Certificate of Validity, plus a weight and balance schedule and evidence of compliance with all the required MPDs and service bulletins, plus show that all of the ‘life limited parts’ such as hoses are still ‘in life’. A new yearly activity will be to conduct and document a simple flight test (details can be found on the LAA’s website) to flag any performance issues ahead of Annual maintenance. In the case of G-YAKX we agreed with LAA Engineering that it made sense to hold this over until after the combined Annual and Life Extension had been completed, as a thorough check out of the aircraft was of greater benefit then. With the Annual and paperwork completed, a £350 one-time aircraft transfer fee, and your LAA membership dues paid, you should be good to go when LAA Engineering issue your new Permit to Fly. Above Rob Rowe’s Yak will soon be the first to transition onto the LAA fleet, with the others coming over as their maintenance checks come due.

Life extension This has just been made a whole lot easier by LAA Engineering acquiring the intellectual property (IP) for this process on YAK-52s, and the historic fleet records, thereby bringing it in-house for a single sign-off. The scope of the life extension remains unchanged, but over the next 18 months we’ll work with LAA Engineering to review the fleet records and explore whether there are alternative means of compliance. As for G-YAKX the procedures for this activity are work-inprogress, with an end of January completion envisioned, and I’d certainly like to thank LAA Engineering for their ongoing support in making all this happen, in particular by taking ownership of the IP.

New Parts It is early days for this, and we’ll solicit a prioritised wish-list from the YAK community first, but the objective is to drip feed researched alternative component sources for LAA Engineering approval, to fit in with their fair resource availability. Certainly, an early opportunity would be to source new pneumatic reservoirs made from composite materials, as the original steel sphere variety have now reached ‘unobtainium’ status. We’ll keep you posted on this and other activities in due course.

face value, it meant that basically any flight within UK airspace was questionable, as it was patently impossible to avoid all congested areas, especially when the term is so loosely defined (apparently an empty golf course abutting a settlement is a ‘congested area’, while the M25 on a Friday afternoon when it becomes ‘Europe’s largest car park’, isn’t!). For formation teams in particular, it meant that they couldn’t ask for any form of air traffic control service, for fear of being routed over a congested area, and any short A-to-B flight would invariably involve the rest of the alphabet being used as turning points, routing the formation around all potential habitations. A recent amendment to the overflight restrictions has ameliorated the situation considerably (thank you, CAA), but by moving across to the LAA register the restriction is now non-applicable, and a more sensible (and workable) set of over-flight regulations are in place.

Looking forward to our new relationship

As mentioned at the outset of the article, Rob Rowe’s Yak-52 is the first undergoing CAA-LAA changeover and the Yak community wishes him luck in his venture but have faith that Francis’ team will manage the transition with their usual aplomb. It is envisaged that the rest of the Yak fleet will follow over the next couple of years, to coincide with future maintenance checks, and the Yak community is excited to be making its new home with the LAA. With many thanks and all due respect to the CAA for putting up with us ‘Russians’, it feels great to be coming in from the cold… ■