JU-AIR has begun overhauling its three JU-52s from the ground up. The work is carried out by certified specialist companies and should take around two years. To resume flight operations in spring 2021, aircraft maintenance will also be reorganized.
After several months of planning, the major overhaul of JU-AIR's historic JU-52 has begun. First, the aircraft and their individual parts are digitally measured in order to be able to produce three-dimensional, computerized construction plans. The major project is being carried out by JUNKERS Flugzeugwerke, which has engaged numerous specialist companies from Germany and abroad. All work steps are supervised by the Federal Office of Civil Aviation before, during and after implementation.
At the end of the extensive work, the three aircraft will be technically virtually new.
All safety-relevant, load-bearing parts of the wing structure are replaced as a preventive measure due to their age. Since new parts for the eighty-year-old aircraft are no longer available, hundreds of individual parts must be remanufactured by authorized partners. To do this, the original parts are digitally measured first. Components such as wings, stabilizers and control systems are then modeled in the computer. The individual parts are then reproduced using this data. Around 90 percent of the wing parts are replaced in this way.
The wing overhaul will take place in Malters (LU). The fuselage, tail, chassis, control system and all other systems are now being overhauled in Dübendorf. Here, too, the work is carried out by specialists from certified specialist companies.
The project is being closely supported by the Federal Office of Civil Aviation. The individual work steps are described in detail in advance and checked by the Federal Office. Once approved, they are carried out and can be reviewed again by the Federal Office.
Goodbye to BMW engines
The engines of the three aircraft are being replaced. There are no longer any spare parts available for the BMW “132” radial engines used to date, as BMW discontinued construction of this engine type in 1944. The cost of continuing to operate these aircraft engines over the longer term would increase year by year.
JU-AIR has therefore decided to replace them with R-1340 “Wasp” radial engines from Pratt & Whitney. Although the “Wasp” radial engines are no longer being built, they were manufactured in such large quantities that they are still very common all over the world. Completely overhauled engines and replacement parts as good as new are readily available.
Pratt & Whitney engines were regularly present at the JU-52. Some of the aircraft were delivered with the radial engines from the American manufacturer.
The aircraft with HB-HOS registration is the first of three aircraft to be completely overhauled. It was delivered brand-new to the Swiss Air Force in late summer 1939 and remained in army service until 1981. In 1983, it was taken over by JU-AIR and has been part of their active fleet without interruption ever since.
The major overhaul of the other two JU-52s from JU-AIR will begin later. The exact timetable also depends on how work on the first aircraft is progressing. It is planned that HB-HOS will return to flight operations in spring 2021.
With a view to the resumption of flight operations, the maintenance of aircraft and engines is being reorganized. Investigations are ongoing. JU-AIR is also supported by external experts and monitored by the Federal Office of Civil Aviation.
JU-AIR will keep you informed about the progress of the work on its website and on Facebook. In addition, the revision of the fuselage in the Dübendorf Aviation Museum can be viewed on special guided tours. Details will be communicated promptly.
Christian Gartmann supports JU-AIR in crisis management and crisis communication following the JU-52 accident in summer 2018 and serves as spokesperson for JU-AIR.