Gone are the days when the MiG-21 fighter was stopped in an emergency by "MiGołapka", a plowed piece of field. In 60 years, in Poland, there were tests of the TS-11 Iskra emergency stop system in a network. However, the system did not enter service. But such systems are used in the world.
At the present time (2020), the Polish Army uses a system called BAK-12. BAK-12 stands for Barrier Arresting Kit. BAK-12 was developed by the American company ATECH Inc., and is used in the US armed forces. BAK-12 belongs to the MAAS system, i.e. the mobile aircraft stopping system.
The F-16 multi-role aircraft performs a routine training mission. At one point, the pilot notices that there is something wrong with the plane. The pilot crashes and releases the tail hook of the plane during the rollout. The hook catches on a line stretched across the DS (RWY), which, unrolling from a drum equipped with a brake, safely slows down the plane. Yes, the BAK-12 system works in a simplified way.
One BAK-12 kit costs approximately $ 250,000. The system can be stationary or mobile. The system must be tested at least once a year if it is not used during an actual emergency during that year. In Poland, this system is used only by Lockheed Martin F-16 Jastrząb multirole planes, and in the future it will be used by F-35 planes. Only fighters are allowed to use the BAK-12 as they are the only aircraft with tail hooks.
The BAK-12 slows down the plane with the B-52 Bliss Brakes, which are mounted on both sides of the runway (RWY), connected by a rope running across the runway. The brakes are frictionally pressed by a hydraulic system that slows down the plane at an even pace, keeping it centered on the RWY. The middle element of the system is a rope that has a rubber roller every bit. The roller holds the rope a few centimeters above the ground so that the hook of the plane catches the rope. Outside the runway, the rope is connected to rubber-fabric straps. The belts are wound on drums on both sides of the RWY. As the belt unrolls from the drum, it is braked by the hydraulic system of friction brake discs. The brake is released automatically. After the plane has stopped, the belt is wrapped around the drum by means of the diesel engine and the rope is returned to its place. BAK-12 service soldiers improve the arrangement of the rollers on the rope.
The BAK-12 stationary system is able to stop the Lockheed C-130 transport, because it will brake an aircraft weighing 59,000 kg. It all depends on the weight of the plane and its speed. In the stationary system, the rope is lowered into the groove, and when needed, it rises up a few centimeters. The system can be started automatically when the electronic system, based on photocells, judges that the plane is moving too fast. But the hook of the plane must be released.
The BAK-12 PIV mobile system is a system that can be deployed at any airport within 4-6 hours. Such a system will brake an aircraft weighing about 20,000 kg. The mobile system is anchored to the ground with 2-meter long anchors (such large tent pegs). There are a dozen of these anchors and they are connected with each other with metal clamps. The anchors are driven into the ground with hydraulic hammers. The same hammers are used to pull out these anchors when dismantling (winding up) the system.
The BAK-12 system is resistant to wind, sand, rain, snow and UV radiation.
The BAK-12 stationary system is installed in Poland at the following airports: Świdwin, Mirosławiec, Malbork, Krzesiny, Łask, and Mińsk Mazowiecki. Additionally, the Polish Army has two BAK-12 PIV mobile systems that can be installed at any airport, for example in Radom or Dęblin.
In Poland, BAK-12 systems are serviced by a special unit 1. Regional Logistics Base - Aviation Techniques Workshop in Toruń, 37 Okólna Street.
Written by Karol Placha Hetman