A Spanish Tiger helicopter was forced to perform an emergency landing after hitting a power line near the village of Brestanica, Slovenia.
On May 20, 2021, a Spanish Army Eurocopter Tiger (ET-722) helicopter, taking part in the Adriatic Strike 2021 military exercise, hit a power line near the village of Brestanica in Slovenia. After the impact the pilot managed to land in a meadow a couple of hundred meters away. The helicopter sustained severe damage to at least two blades of the main rotor and to the upper window of the weapon systems operator position.
The wire strike protection system, located just above the damaged window, probably prevented a much worse outcome.
The incident to the Spanish Tiger occurred around 11 AM LT and caused a short power outage to the nearby villages. Moreover, the rail transport near the improvised landing zone was suspended for some hours.
The pilot decided to perform an emergency landing because of the heavy vibrations felt in the cockpit, caused by the damaged rotor blades. Fortunately, the crew was unharmed. More details about the incident will be disclosed once the Slovenian authorities complete the ongoing investigation. For now, what is certain is that the helicopter was flying too low. The power line was marked on the navigation chart.
The landing area was secured by the Slovenian Police and Army.
Spanish Tiger Recovery ops
The recovery operation of the stranded Spanish Army Tiger involved a Spanish CH-47D Chinook (ET-419) that landed in Cerklje ob Krki AB, Slovenia, in the afternoon on Friday May 21. Spanish flight technicians removed the main rotor blades, the horizontal tail and other parts from the Tiger and prepared the helicopter for the airlift which was carried out on Saturday afternoon.
The Spanish Tiger successfully reached Cerklje ob Krki AB, Slovenia, after a short flight, as the air base is located only about 10 km from Brestanica. The helicopter will be carried back to Spain on board of an Airbus A400M of the Spanish Air Force. The incident demonstrated good organisational capabilities of the Spanish Armed Forces, as they successfully recovered the aircraft that was damaged so far from its homebase in another country and great cooperation work with the Slovenian Army.
The one occurred to the Spanish Army Tiger was not the first time that a military helicopter had a close encounter with cables in Slovenia.
An AS532AL Cougar of the Slovenian Army hit with a wheel a wire rope used by loggers while flying over Srpenica on Aug. 23, 2019. Another similar accident happened also in 2019, on Nov. 27, when a Pilatus PC-9M hit a power line with its tail during a low level flight near Dravograd. The pilot performed an emergency landing at Maribor Airport. Also, in 1994, the Let 410 used by the Slovenian Army hit a power cable while landing at Ljubljana Airport. Fortunately, also in this case nobody was wounded and the aircraft landed safely and returned to fly after being repaired.
As explained in detail in a previous article:
“power lines, cableways and any other kind of aerial wires below 500 feet AGL (Above Ground Level) and in mountain regions in any airspace below 500 feet above the highest ridgeline, represent a significant hazard for all kinds of aircraft. Actually, the majority of accidents involving wires occur at or below 50 feet AGL, and are due to the pilot judgement/actions or loss of situational awareness.
Wire strikes have been a matter of concern for both civil and military helicopters. Devices to protect the helicopter in case of wire strikes (such as the cable cutters) have been available for some years. Systems that warn the pilots on the proximity of wires have also been developed. In spite of
these developments, wire strikes occur every now and then. Sometimes with tragic results.
Years ago, the FAA made an analysis of both civil and military accidents involving helicopter wire strikes for the period 1994 through 2004. According to that study, wire strikes accounted for about 5% of all civil and military helicopter accidents.
Wires are dangerous no matter the experience of the pilots flying in their vicinity. A study into the aerial wire hazards published in 2012 highlighted that the average wire accident pilot had 7,225 hrs total, 5,230 FH on rotorcraft and 1,816 FH on that specific helicopter model.
A number of protection systems have been developed and made available to the helicopters all around the world to mitigate the impact, of wire impact. One system that equips most of modern military helicopters offering a degree of protection to the helicopter in frontal impacts is the WSPS (Wire Strike Protection System), whose typical installation consists of a roofmounted cutter and one or more cutters mounted on the fuselage of the helicopter. A deflector running vertically along the middle of the windshield guides the cables into the cutters.”
Adriatic Strike (Jadranski Udar) is a JTAC multinational exercise hosted by Slovenia annually from 2012. This year, the exercise was held from May 17 to 22. Spain sent two Eurocopter EC665 Tigers and one Aerospatiale AS332B Super Puma, supported by a CASA C-295.
The other aerial assets used in the exercise included Slovenian Bell 206, Bell 412, AS532 Cougar helicopters and PC-9M Hudournik advanced trainers, Croatian Pilatus PC-9M, US F-16 and HH-60 from Aviano AB, a Danish Britten-Norman BN-2B Islander, a Montenegrin Bell 412, Austrian PC-7 and OH-58, Italian AMX, Slovakian UH-60B, Romanian IAR 330 Super Puma, an Aero L-39 Albatros of the Dutch company AEC Skyline, Czech and Polish Puma and Fly Eye drones.