Aircraft 2436 ready for flight awaiting the arrival of its pilot. It carries a non-traditional, relatively large payload of two 350l (92 gal) droptanks and a pair of CP-100-70AM practice bombs. The air intake bears a remnant marking from the airplane’s service with the 11th slp in Zatec. The pilot’s helmet is hanging on the left pitot tube.
….2003 – 2013 timeframe from the point of view of an aircraft armorer
Text: Tomáš Dedera
Photo: unless otherwise stated, author's archive
Time flies like water in a raging river. In 2016, we commemorated the 60th anniversary of the establishment of the aviation units later operating at Náměšť nad Oslavou Air Base, and this year, in October 2023, it will be exactly 10 years since fixed-wing aircraft permanently left the local facility. From the MiG-15s, through the Su-7BM, BKL, U, the Su-22M4 and the UM-3K series of supersonic aircraft, and on to the Su-25K, UBK attack aircraft and L-29 Delfín trainers, plus transport and liaison Mi-1, Mi-2 and Mi -17 helicopters, the unit's main equipment for a decade was also the globally known and proven L-39ZA Albatros, produced by the domestic manufacturer Aero Vodochody. Aircraft of this series began to operate from Náměšt in 1994 with the disbanding of the former 30th bilp at Pardubice Airport. In the fall of that year, Su-25K and UBK aircraft, together with four Albatroses (coded 3903, 5015, 5017 and 5019) moved to their new location at Náměšť as part of the 1st TL (Technical Flight), then the 32 .zTL (Tactical Air Force Base), at Náměšť nad Oslavou.
Aero L-39ZA Albatros, coded 5017 on the apron of the 1st Technical Flight during the winter months. Worth noting is the symbol of the 1st Technical Flight above the nose landing gear (at that time the squadron operated the Su-25K as its bread and butter and this marking was carried by some birds on their engine nacelles or noses) and the 32nd zTL emblem of Náměšť nad Oslavou on the rudder.
As the Su-25K was gradually phased out of service by the end of 2000 (the last flight was made by aircraft coded 5039 in a flyover from Náměšt to Přerov on December 11th) and replaced by the new L-159A ALCA light attack fighter, more L-39ZA Albatroses were assigned to Náměšt’s 2nd TL (Technical Flight). By the fall of 2003, all L-159s were handed over to Čáslav.
On December 1st, 2003, the 221st TL (Tactical Flight), 22nd zL (Air Force Base) was officially founded in Náměšť nad Oslavou. The squadron operated ten L-39ZA Albatros trainers, coded 2341 (crew chief handle ‘Jára’), 2344 (‘Synek’), 2415 (‘Kája’), 2421 (‘Golem’), 2433 (‘ Sun’), 2436 (‘Fanda’), 3903 (‘Miša’), 5015 (‘Zip’), 5017 (‘Worm’) and 5019 (‘Goat’) plus five reserve aircraft (coded 2347, 2418, 2424, 2427 and 2430). The squadron's technical staff was made up of experienced mechanics and specialists who previously worked on the Russian Su-22 and 25 series of aircraft and later, the Czech L-159A ALCA advanced light combat aircraft. The task of the squadron was to ensure the continued training of young pilots who came from the CLV (Aviation Training Center) in Pardubice, especially in ÚBP (training in the use of weapon systems - combat use tasks) and cooperated with advanced FAC/JTAC aviation instructors. Its first commander was pilot Lt.Col. Ing. Antonín K. and ZV-ILS (Commander of the Technical Staff) Capt., later Maj., Marián M. The Flight did not spend much time warming up on its assigned field, as by 2004, it flew to the airport at Pardubice. It operated from there for seventeen long months, while a major modernization, renovation and construction of new buildings took place in Náměšt. By that time the first experiments with ÚBP began with the use of CP-100-70M practice bombs, popularly called ‘cements’. It should be noted here that this type of training almost stopped for a certain period of time, because the L-159s (operating from Náměšt from the spring of 2001 to the autumn of 2003) did not yet have their weapons systems fully integrated, or were still in development (such as the 20 mm PLAMEN cannon). A greater focus on the use of live aerial ammunition occurred only after the return to Náměšt in July, 2005.
L-159A Alca on the apron of the 1st Technical Flight at Náměšt in the summer of 2003. The airplane is interesting with its inscription on the right air intake, symbolizing the 50th delivered ALCA for the Air Force of the Czech Republic Army
The standard gradually became the use of four aircraft at the ÚBP, if technical conditions and, above all, weather conditions allowed, at least once a month. Monday usually started with preliminary preparation - technicians and specialists performed more extensive maintenance, removed defects that manifested themselves during previous flying, replenished fluid levels and gases, checked important aircraft systems and nodes, or they changed worn tires if signs pointed to that need. Armorers carried out loading of UB-16-57 UMP rocket pods and tested all weapon systems (cannon, bomb and rocket armament) in all modes - not only testing in the standard mode of use, but also, for example, control of the jettisoning of payload under emergency situations, with the help of special preparations and measuring or signaling technology.
From Tuesday to Thursday there were special flying events. They started with a weather survey, when one plane took off with an experienced crew, who evaluated the weather conditions on the flight path to the firing range. If conditions suited, then it was down to business. Aircraft ground crews, R+RTV (radio and radio equipment) and E+ESV (electrical and special electrical equipment) specialists carried out pre-flight preparation, and at the very end, when everyone was finished, the weapons specialists came into the picture. They first checked the rotation of the airplanes in the safe directions, turned off all weapon control elements, the on-board network, the external power source and closed the canopies. They then placed red pylons 5m in front of the aircraft (and in the case of charging unguided rockets, 5m behind the aircraft as well), cordoning off the area as a dangerous zone into which all unauthorized persons and vehicles were strictly prohibited from entering. They then performed their own loading of the machines according to the planned flight schedule. Then it was just a matter of waiting for the crews to arrive at the planes. After the arrival of the pilot, the aircraft crewchief gave a report on readiness for flight and information on the amount of fuel added. The armorer informed the crew of the type and amount of armament the aircraft was equipped with for the flight, or provided additional information, such as fuse timings on any bombs carried. This was followed by strapping the pilot into the VS-1 BRI ejection seat by the crewchief, fitting him into the parachute harness, removing the safety pins from the ejection seat, allowing it’s potential launch. First the SAFÍR APU was set in motion, followed by the AI-25 TL engine itself. After a short engine test and a check of the operation of the flaps and speedbrakes, the aircraft approached the so-called ČPS - Preliminary Start Line, popularly known as ‘the line’. Here, specialists performed the last visual inspection of the aircraft before entering the VPD (takeoff and landing runway). They mainly focused on the perfect closure of all covers and openings, or checked for signs of non-standard leakage of operating fluids - aviation fuel, oil or hydraulics, which could indicate a leak or malfunction of these systems, which could have fatal consequences in the later phase of the flight. After this inspection, if everything was in order, only a raised thumbs up from the inspectors followed – indicating all was good to go, and with the permission of the control tower, the roll-up to the VPD and finally take-off followed. Flights to the firing range usually lasted about 1.5 hours.
Armorers load S-5 K unguided rockets into UB-16-57 UMP rocket pods. Red flags are placed in front and behind the aircraft, external power is disconnected from the aircraft and cockpits are closed for safety reasons.
After landing, the aircraft taxied to a special stand - the so-called ‘holding stand’. There, after guiding the aircraft in a safe manner, the gunners performed a post-flight armament check. If everything was in order, meaning that the cannon operated properly, rocket pods were empty and bombs dropped, the aircraft continued to its own stand. When the occasional problem did crop up, the crew shut down the engine, the armorers disabled the cannon against an unwanted firing, the crewchief secured the seat, the pilot got out, and then the gunners completed the safe discharge of the weapons. Then the whole merry-go-round was repeated, usually at least two or three more times. After the last flight, the airplanes were ‘post flight’ inspected and, with the help of tow trucks and tractors, towed to their hardened aircraft shelters in the squadron's dispersion areas. The entire cycle of flights from the beginning to the end of the working day usually lasted 12-13 hours, in any weather, in freezing cold or sweltering summer heat, in wind and rain. Friday, a non-flying day, was intended for the elimination of possible defects in the airplanes, and above all, for the cleaning of all weapons after having been fired.
As standard, the armament triad was flown - B, R, C (for bombs, rockets, cannon) - four aircraft with a GŠ-23 cannon with, typically, fifty rounds, one hundred as the exception, two additional fuel tanks 150 l on the inboard pylons and either two UB-16-57UMP rocket pods, each with a maximum supply of sixteen S-5 unguided rockets of various types or two CP-100-70M cement practice bombs on the outboard hardpoints. Later, we increased the range of armament carried by including the use of OFAB-100-110TU frafmentation bombs of 100kg (220lb) weight. These were of Czechoslovak manufacture, produced in Vlárské Strojírny Slavičín from the 80s to the 90s. It was a special bomb that could be used at high speed at low level as a brake, thanks to the integrated BZ-5 braking system. An electric head igniter, also of domestic provenance, of the LZEH-3 type, made it possible to set up to five different delays, depending on the nature of the target, from immediate action at impact, two short-term modes in the order of milliseconds (against bunkers and other fortified targets) and two long-term delays (for practice and security reasons). The odd time, it was also possible to see Albatroses carrying a quartet of training cement bombs or even live OFABs. Unlike the Slovak Air Force, we practically did not use L-39M559 dual ejector racks (only for demonstrations). At times, when it was absolutely necessary, from the point of view of range, especially during cooperation with other formations and larger exercises, the 150l (40 gal) outboard tanks were replaced by their bigger 350l (92 gal) brothers.
An aircraft technician removes the arming pins from the VS-1 BRI ejection seat just prior to engine start. In a few minutes, the aircraft will take off, its task will be to fire at ground targets with the GŠ-23 cannon and S-5 unguided rockets.
Specialists having performed a final inspection of the aircraft at the ČPS, give the thumbs up indicaing that everything is in order and there’s nothing preventing further taxiing for takeoff.
For display purposes, loaded armament could include a UB-16-57UMP rocket launcher and an L-39 M559 twin ejector rack with a pair of CP-100-70 M practice bombs.
Aircraft 2415 just before taking off from the stand at the point of no return Underslung are a pair of 150l (40 gallon) drop tanks and two live OFAB-100-110TU fragmentation bombs.
Here, the pilot is taking over aircraft 5019 from the crewchief. It carries two 40 gallon drop tanks and two full UB-16-57UMP rocket pods with 32 S-5KP unguided rockets. A special Praga V-3S SUEZ (Universal Electric Starter Source) vehicle is parked between the planes, serving as a source of electrical power during ground preparation and actual engine start-up.
Frontal view of an aircraft armed with four CP-100-70M practice bombs.
In the case of flying from what used to be Přerov Air Base, the aircraft were loaded up with underwing minitions, without the need to mount drop tanks. This was made possible by the close proximity to VVP (Military Training Area) Libavá with its extensive firing ranges. It was also possible to make six flights per day. At that time you could see Albatroses fully loaded with UB-16-57 UMP rocket pods on the inner pylons and OFAB-100-110TU bombs codenamed JUPITER on the outer units, as they would be in times of actual conflict. At this time, the EKSR-46 signal cartridge ejectors, located in the right rear part of the aircraft, with yellow, red, white and green colors, which were to act as decoys, began to be used again.
For the first 5 years of the squadron's existence, scheduled higher level work and aircraft overhauls were carried out in cooperation with the 217th LOLNT (Supersonic Aircraft Repair Squadron) in Čáslav. Part of the work involved armament and associated systems, and occasionally, it was possible to see our L-39s with four UB-16-57UMP rocket pods, but only ones that were empty.
A pair of CP-100-70M practice bombs under the left wing of an L-39. The aircraft is pictured shortly after it was forced to return and land at its home field after suffering a bird strike. The damage, visible on the leading edge of the wing between the pylons, was repaired by the unit's personnel. The bird was not as lucky.
Aircraft 5019, fully armed with four live OFAB-100-110TU fragmentation bombs, waits for the arrival of the crew on a baking apron in the summer heat.
Human ingenuity sometimes did not escape even the OFAB-100-110TU bombs. A time indication on the sides of the bombs lets the pilot know what delay after impact the LZEH-3 fuzes are set for.
Aircraft 3903 ready for flight in front of a weathered shelter at the then Přerov aAir Base. Interestingly, it carries two full UB-16-57UMP rocket pods with 32 S-5KP missiles and two OFAB-100-110TU fragmentation bombs. Under the cockpit windscreen is a red log book.
A separate chapter is the use of
guided munitions - in our case, this involved exclusively the R-60 AA-8 Aphid
air to air dogfighting missile, carried on UZR-60 rails. These were infrared
(thermally) guided missiles, which, however, were not equipped with a rocket
engine, nor did they carry fins on the rear or rudders on the nose of the
missile. Only the IR warhead was retained, as were the four finlets on the
front, whose purpose was to help increase the effect of the rudders by swirling
the air over them at high angles of attack. This training version of the
missile was equipped with a recording device, which recorded some important
parameters when the missile was fired - for example, the overload on the
aircraft. These parameters were evaluated by the instructor after the flight,
and they could realistically indicate whether the launch strategies were chosen
correctly. The missile was white and had 3 black bands around its body as a
distinctive marking, consistent with the training versions of Soviet/Russian
guided missiles. The bodies were suspended on P-62-1M-ZA rail adapters which
were mounted under the pylons. By default, the unit was suspended under the
left wing, but the adapter had to be suspended under the right side as well to
maintain the plane's symmetry. Originally, the ZA version of the Albatros did
not possess the ability to carry these missiles, and could only carry the older
type infra-red guided R-3S. The work required to adapt the L-39 to the R-60 was
carried out sometime in the mid-1980s by workers of the LOZ (Aircraft Repair
Base) in České Budějovice.
A specialty, seen on the ZA version at Náměšt, is the use of special containers, carried under the putboard pylons. These containers, operated by the crews of the Military Technical Institute of Aviation and PVO (VTÚL and PVO Prague), served as carriers for the newly developed types of pilot parachute. These were tested together with a special weight imitating the human body.
Detail of the above noted loadout. Note the weathering on the UB-16-57UMP rocket pod and the fuse delay of 0.03 seconds written down on the bomb in plain chalk.
Loaded EKSR-46 flare dispenser on the right side of the rear fuselage.
L-39ZA coded 3903 ready for flight under winter conditions at Caslav AB. The plane carries four empty UB-16-57UMP rocket pods.
Same bird from the front.
Beautifully mirrired on the cocrete apron after a spring shower is L-39 2421, loaded with large 350l (92 gallon) drop tanks and a UZR-60 training round under the left outboard pylon.
The photograph shows a cartridge case carrying a maximum of 150 rounds of 23 mm ammunition with fifty rounds of OFZ (fragile - explosive - incendiary) and BZT (piercing - incendiary - luminous) ammunition, in a ratio of 4:2. In the winter, when it was not possible to rehabilitate the impact area of the firing range, instead of OFZ cartridges, BZA (armor piercing - incendiary) were used. Visually, the projectiles are distinguished by the following colours: BZA - black projectile body, with a red and white stripe on the tip, under which the incendiary component is hidden, BZT - again black, sometimes gray (depending on the manufacturer and production block) projectile body with a yellow tip, OFZ - black (grey) body of the projectile (grenade) in which the effective explosive Hexogen is incorporated, the lighter is silver in color with a purple tip. It is unlocked only after a certain distance from the muzzle of the weapon (the so-called ‘mask safety’), so that the aircraft itself is not endangered by the action of axial and radial forces (rotation of the projectile, initiated by the grooved bore of the barrel), created during firing. A specific type of round that are placed at the end of the cartridge belt are copper OFZ rounds, additionally marked with a yellow stripe on the body of the projectile. These have a lead wire attached to the bottom of the round, which creates a mixture with copper residues from the guide rings when fired, and the resulting mixture is literally blown out of the barrel by the following round. These cleaning effects on the barrel have a significant effect on reducing wear, improving accuracy and extending overall service life.
The GŠ-23 cannon is a development of a Soviet weapon with dual barrels and breechblocks. This is how the designers of the weapon, Grjazev and Shipunov, managed to achieve a relatively high muzzle velocity of the weapon - 3200 to 3400 rounds/min. The weapon, which is widespread even to the present day, equipped a whole series of airplanes and helicopters of Soviet origin, either as an integral part of the design or in suspended weapons containers. It is a very effective weapon, whether against air or ground targets, accurate and easy to operate and maintain, with a minimal number of defects.
Detail view of L-39 2436 with a 150l (40 gal) drop tank and UZR-60 training round on a P-62-1M-ZA launch rail.
L-39 5017 carrying a special purpose container carrying a newly developed parachute readied for a test flight.
Detail shot of the pod with the parachute and weight, designed to imitate that of the human body.
Ammunition case with an average of fifty rounds. Photo Petr Soukop
Left to right: GŠ-23 cannon pod 23mm rounds of OFZ, BZA and BZT types
GŠ-23 cannon with a full load of 150 rounds.
There were several types of S-5
unguided air to surface rockets used. First off, there were the older S-5 K and
S-5 Ms. Both had the same type of ignition of the rocket motor, using
electrical wires terminated with a plug. These differed from each other in
their purpose. The K version was intended for use against ground and armored
targets (tanks, armored personnel carriers, etc.), while the M variant was a
more general purpose round used against soft targets and destroyed its target
with a pressure wave created during the explosion. The second, more modern
branch of these rockets was represented by three types: S-5 KO, S-5 MO and S-5
KP. All of them had an innovative way of initiating launch, using contact rings
(faster and safer operation). The warheads of the rockets were also improved:
KO – fragmentation - contained a larger amount of explosive and, in addition,
to increase the effective radius, ten extra rings on the warhead were added.
These were ‘pre-fragmented’ and formed projectiles of about 2g in mass after
the explosion. The MO version had twenty of these additional rings. The last
used was KP and was the same as KO, with the difference that the use of a
piezoelectric igniter, which was supposed to safely initiate the rocket motor
even at very shallow angles to the target.
The first big change came about in 2008. On October 1st, Mi-24V/35 combat helicopters, which were operated by the newly formed 221.Vrl, were moved to 22nd Base in Náměšt. As a result, the squadron operating the L-39 was redisignated 222nd Training Squadron. However, the nature of the tasks remained the same. The squadron continued to successfully fulfill its required tasks, until the fateful day of December 16, 2010, when during take-off of 2341, after an engine replacement, a titanium fire occurred in the high-pressure compressor of the engine near the end of the flight, causing its subsequent shutdown. The experienced two-man crew (Capt. Ing. M.K. and Capt. Ing. S.S.) tried several times in vain to restart the engine, until finally both of them were forced to eject from the silent Albatros close to their home field. This accident had a major impact on the further functioning of the squadron. Of course, a ban on flying followed, as it usually happens in such cases, and the problem with the engines were resolved only after more than a year! Then, on November 1st, 2013, operation of Přerov Air Base was definitively terminated and the Mi-171Š transport helicopters were reassigned. At the same time, the remaining L-39s were transferred to the air base at Čáslav, as part of the newly formed 213.VL (Training Squadron), which jointly operates L-39ZAs and L-159Ts, but that's another chapter. Looking back, I believe that the squadron performed its tasks with honor over the ten years and trained many young pilots who then successfully continued on to fly the L-159A ALCA and JAS-39 Gripen out of Čáslav. Thanks also go to the members of the ILS ground staff, not only the 221.TL (222.VL), but also the 217.LOLNT in Čáslav and later the 223.LOLT in Náměšt, who honestly took care of these machines and maintained them throughout their operation on the airfield at Náměšt nad Oslavou.
Detail view of the GŠ-23 cannon pod under the forward fuselage of the aircraft. Photo: Petr Soukup
Top is the S-5 KP, below the S-5 K. The difference in the length of the rocket motor and the warhead are evident in the newer KP version. There was also a difference in the ignition systém.
A comparison of the S-5 K and S-5 KO (top). There was an increase in the rocket motor size and the warhead of the KO, though the V-5 igniters remained the same
Container with eight S-5 KP rocket projectiles, one with deployed stabilization fins, which would be in flight mode. The others have their fins folded and contained in plastic caps.
S-5 M rockets built under a Polish licence and delivered in boxes of sixteen.