The GEnx engines of a Boeing 787 Dreamliner accelerate to up to 945 km/h on take-off. To ensure the safety of the engines, they must be serviced and overhauled after 2,500 to 15,000 take-offs and landings. GE Aviation maintains various service locations for the maintenance of its engines, including GE Celma in Brazil. Over 300 aircraft turbines are serviced each year in Petropolis, GE Celma's main location. The engines are dismantled, checked, cleaned, repaired if necessary and then reassembled. Each jet engine is tested under simulated flight conditions in a special test cell before it is put back into service. The new large GEnx engines require larger maintenance areas and more powerful test cells. For this reason, a new facility was built in Três Rios with one of the largest and most modern test cells in the world.

Low headroom as a challenge
The crane and lifting technology at the plant was supplied by Stahl CraneSystems and installed by the certified partner in Brazil, Stahl Talhas. The engineers and technicians at Stahl Talhas developed and implemented a customized transport system with a high degree of automation, which takes care of the entire handling of the turbines - from unloading on arrival to transport to the maintenance stands and safe suspension in the turbine test room. "The complexity of the system required a high level of technical sophistication," explains Sandro Galtieri, Managing Director of Stahl Talhas. "On the one hand, the development of the structural and mechanical design was a particular challenge due to the low construction heights in the plant. Secondly, the entire operating logic, including the electrical design and software, placed high demands on our engineers. The hoists and cranes are in constant communication with each other to ensure that everything runs smoothly in the plant."

Precise track positions thanks to camera system
The transport system built by Stahl Talhas consists of a central aisle, eight maintenance areas and a test area. The engines have to be transported from the central aisle to the maintenance bays on the right and left and into the inspection area. A double girder overhead crane handles the turbines in the center aisle. Stahl Talhas also installed a single girder overhead crane for transporting turbine parts. The maintenance areas are equipped with monorails. The crane runways are connected with an interlock system for crane interlocking: A camera-based system records the position of the tracks using barcodes and automatically aligns them with a positioning accuracy of ± 1 millimeter. This ensures that the transition between the crane runways runs smoothly. The cranes and hoists are operated independently by radio remote control. "A special crane construction was required to transport the turbines into the test cell," says Galtieri. A monorail with a curved section was installed here.

A total of four frequency-controlled SHF 60 wire rope hoists and two frequency-controlled SHF 50 wire rope hoists from Stahl CraneSystems are used. All hoists are equipped with bogie trolleys for entering the test cell. As the height of the monorail in the test room is reduced from 400 to 245 millimetres and the internal ceiling height is only 201 millimetres, a bogie trolley had to be designed for the SHF 60 wire rope hoists. When entering the test cell, communication between the hoists and the test cell's locking system is particularly important. A motorized section of the monorail that can be rotated through 90° is located in the passageway to the test room. The section has its own control panel. The hoists can only enter the section if the section of the monorail is not rotated. The track section is released via sensors.

Engine correctly positioned and ready for testing
During the test, the engine must be carried by the test cell's holding device. The control system recognizes the correct positioning of the drive unit by means of the slack rope monitoring. If this is the case, the support pins between the hoist and the suspension device are released, the weight rests on the holding structure and the test can begin.

After two years of construction, the new plant was inaugurated on October 17, 2018. In future, the facility will test an average of 700 engines per year and prepare up to twelve engines for testing in parallel. One more step is needed for the plant to reach its full capacity. "The engines have to be moved into the maintenance bays with the rear section first. This makes it necessary to turn the engines 180° in the center aisle to enter the left-hand maintenance bays. So far, only the maintenance bays on the right-hand side can be used - a slewing trolley will therefore soon be installed on the double girder bridge crane to complete the system," explains Galtieri and sums up: "Communication and coordination with GE Celma were very good and perfectly coordinated despite the many companies involved in the construction of the plant. With the expertise and components from Stahl CraneSystems, we have developed and built a state-of-the-art system for one of the world's leading aviation companies."