Arie Egozi/TEL AVIV
THE POSSIBLE Israeli withdrawal from the Golan Heights as part of a peace deal with Syria has put unmanned platforms high on the list of substitutes for the ground-based intelligence sensors, which Israel now operates along this border. Its perceived need to look into surrounding Arab countries has made Israel a world leader in developing and operating intelligence-gathering systems based on unmanned air vehicles (UAVs).
The Israeli air force and intelligence corps operates third-generation UAVs in a variety of missions. One such squadron, operating the Israel Aircraft Industries (IAI) advanced Searcher system from an air force base, has most of the characteristics of an operational squadron. That the flying platforms operated by the squadron are small and unmanned has become a mere technical fact. "We are considered a fully operational squadron and the demand for our services is growing constantly," says the squadron commander.
The short-range, Searcher was procured by the Israeli defence forces in 1992, to replace the Scout UAV. It has an average endurance of 12h, and an optical payload, which enables clear day and night images of the survey area. It has been developed to Israeli defence forces requirement.
The Searcher is 4.07m long and has a wing span of 7.2m. Maximum take-off weight is 318kg, and a 64kg payload can be carried internally and externally. The range of the advanced UAV is 150km (80nm). The maximum speed is 110kt (200km/h).
The optronic payload, is also the result of the vast experience gathered in years of operational use. The payload, the data-link and the ground station all contribute to an excellent result, which is relayed to users in the air force chain of command. During a raid, commanders can make on-the-spot decisions, based on real-time images.
TYPICAL MISSION
The Searcher's SACHS 26kW (35hp) engine is started by an external electrical starter. The small craft is cleared for take-off only after an external operator has completed routine systems checks, and technicians have pushed the UAV to a nearby tarmac strip. The take-off operator stands beside the external operating pedestal and revs up the engine. The pedestal has two parallel, almost identical, control boxes. Both are connected to the main mobile ground-control station parked near the strip.
Using the right control lever, operating the aileron and elevator, and the left one, operating the rudder and the throttle, the operator brings the Searcher to the air, from time to time touching the third lever, which operates the UAV's flaps. After a "safe" altitude of about 1,000ft (300m) is reached, control is handed to the internal operator in an air-conditioned ground control station (GCS). The datalink, which, until that point, uses an omni-directional antenna located on the roof of the mobile GCS, is then switched to a special directional antenna.
The directional antenna is used to control the UAV and its payload during the mission, and to receive the images from the optical sensor. Automatic pilot is used in sections of the flight path, but the internal operator takes over when certain manoeuvres are needed to allow the payload a better angle on the target area.
Normal flight altitude is 7,000-10,000ft. Over the target area, the UAV is placed in loiter mode, enabling the payload to focus on details.
The landing procedure is conducted by the external operator. In case communication with the craft is cut, a special return-home mode in the auto-pilot will bring the Searcher back to the landing area, where the crew can try to renew the up-link and bring it down safely.
The Searcher GCS is manned by three - the internal operator, the payload operator and a technician who keeps the directional antenna locked on the UAV in the mission duration. The Searcher is operated by a new type of GCS and, according to one squadron commander, its systems, and especially the very powerful computers, "...improve the mission quality".
With a 26kW engine, the Searcher is under-powered, and maximum take-off weight is limited. IAI is testing a more powerful UEL (formerly Alvis Engines) rotary engine as a possible replacement. Improved reliability and manoeuvrability have enlarged the flight envelope.
Searcher availability is high, mainly because of the easy maintenance. One squadron technical officer says that the accessibility to each system is easy because the panels are closed with latches. He adds that that the size of the fuselage also improves accessibility. "It is also good when we want to upgrade. There is enough room for more systems," he says.
Source: Flight International
