African Pilot - January 2010 - XSTOL 750 Surveillance Platform - Text and photography by Athol Franz

If ever there was an ideal short take-off and landing (STOL) turboprop platform which can fly remarkably slowly to perform aerial surveillance day and night then it has to be the New Zealand Pacific Aerospace XSTOL 750 single engined aircraft. On Tuesday 24 November taking off into a beautiful South African sunset on board a Cessna 207 with the cargo door removed, a group of four photographers had the privilege to watch Chris Briers demonstrate the attributes of this incredible airplane.

Flying from Wonderboom airport north of Pretoria, we flew to the north at about 1 000 feet AGL with the XSTOL 750 formating close alongside the right side of the Cessna 207. This was a rather difficult photographic assignment due to the fact that the sun was setting and therefore the light level was decreasing. In addition the 'chase plane' was rather cramped with each of the photographers trying to capture that 'special picture.' Speaking to Chris Briers about the concept of the 'eye in the sky' loitering as a platform he explained that he was contacted by a foreign company to supply a marine patrol aircraft. His thoughts gravitated towards the XSTOL 750 due to the type's STOL capability. At the same time the Botswana Defence Force had been looking for an aircraft to monitor Botswana's borders as well as to provide nature conservation with an anti-poaching surveillance platform. The time taken for consideration of the project to final test flying was a mere three months. Since Zeiss Optics was already supplying equipment to the Botswana police, the idea of installing the system into a specially designed cargo pod slung underneath the XSTOL 750 was born. National Airways Corporation (NAC) agreed to supply the aircraft, Global Composite Solutions designed and built the surveillance pod and Zeiss Optics supplied the LEO-II-A5-EP enhanced performance airborne observation unit, which was installed within the cargo pod and the aircraft's cabin.

This type of project is usually reserved for helicopters and I understand that the system has never been installed together with a search-light into a fixed wing aircraft before. The unique feature is that both the 50 million candle power light and the camera system are retracted into the cargo pod which is sealed with doors when the plane is on the ground. The XSTOL 750 operates at one third of the cost, is 40 knots faster in the cruise and has three times the range of a comparable turbine powered helicopter. The pod also has an additional fuel tank installed, which provides for up to eight hours flying time. This unique concept combining a retractable airborne observation system and search-light combination on a fixed wing aircraft that can fly at very slow speeds provides an ideal platform for covert aerial surveillance with long endurance at low operating costs.

Carl Zeiss Optronics

Up to four high-performance optical sensors with ultra-long focal lengths and an eye safe laser pointer are available simultaneously in the turret. This combination provides the operator with the best picture performance during all operational conditions and high-altitude, long-slant distance operation, therefore enhancing safety, extended into video downlink coverage and covert surveillance. The Zeiss Optics Leo-IIA5-EP airborne observation system is the system of choice for police support units worldwide and includes high definition real-time television as well as infra red recording, which includes a gyro stabilised laser target designator. The aircraft can fly up to three kilometres beyond the target and the laser designator will provide the co-ordinates of the target. There are already many helicopters flying with the system, but the XSTOL 750 provides a unique platform for this specific application because the plane can loiter at 75 knots utilising 15 degrees of flap. In the cruise the XSTOL will fly at 160 knots when the equipment has been retracted specifically for travelling to a designated area. The XSTOL 750 pictured in this article is the first prototype of the new system and costs US$1.75 million. The cargo pod fully equipped with surveillance system costs a further US$1.4 million, but the price can be higher depending on the client's equipment needs. Although the Zeiss Optics equipment is the same for helicopter use the acquisition cost of a suitable turbine helicopter will be three times the cost of the XSTOL 750.

Global Composite Solutions have designed a cargo pod that has its own battery which will run off a separate alternator drawing power off a separate alternator mounted on the accessory gearbox on the Pratt and Whitney PT-6-34 turbine engine. This means that the aircraft systems and the surveillance systems will be separate at all times. However, the system is wired in such a way that the aircraft can utilise the cargo pod's power and battery if required, but not the other way around. Power drawn by the surveillance equipment is in the region of 40 amps for the Xenon lamp resulting in a total power requirement of between 47 and 50 amps for the pod's operation.

It would appear that the combined system of a stable economical fixedwing platform with the superior optics of the Zeiss LEO-II-A5-EP suite may have been launched just in time for the soccer world cup scheduled for the middle of this year. Certainly it would make economical sense to utilise platforms such as this one to ensure safety in the vicinity of the stadiums where the games are to be played as well as 'fan parks' which will accommodate thousands of fans.