The best of both worlds

When the Super Star entered service in 1957 it was regarded as the most advanced airliner of the era. As a high-tech product made by the famous Lockheed aircraft company, the L-1649A was flying higher, faster and further than any other piston engine powered long-distance airliner manufactured in the late 1950’s. 

Over the last six decades, the technical standard of aircraft manufacturing has developed in a dramatic way. This primarily concerns the areas of propulsion techniques, materials used for the manufacturing of aircraft and the technical standard of flightdeck instrumentation. 

All these advancements resulted in the aircraft being the safest of all means of transportation on a global scale!

Although the Lufthansa Super Star has its roots in 1957, the year of construction, it was overhauled and equipped by Lufthansa Technik AG according to the highest current safety standards applicable to aircraft manufacturing and overhaul in the 21st century.  

Thereby the Super Star project in a remarkable way was building the bridge way between six decades of aviation technology. 

During this metamorphosis the L-1649A transformed from a pure analog aircraft of the 1950’s to a unique combination of an analog and digital high-tech product of the present.

This was enabled by Lufthansa Technik’s status as an approved design organization in combination with the outstanding know-how of its global workforce.

This unique expertise offered by the leading company in the fields of aircraft overhaul, repair and maintenance was required in many areas of the Super Star restoration. 

Technological world premiere!

The Lockheed L-1649A project was filled with an array of superlatives and extraordinary achievements. Like the fusion of the best of both worlds, not only in a proverbial sense, presented by the example of the Super Star cabin door overhaul. 

As a technological world premiere it has been possible for the very first time to unite ultra modern and historical aluminium alloys by the means of resistance spot welding. Needless to say all safety requirements imposed by the surveying authorities as well as the LSSG and Lufthansa Technik teams have been met.

The reason for this venture was door “one right”, which is constructed in a sandwich form as are all Super Star doors. The outer door skin is welded with a deep drawn corpus, giving the door the necessary strength to withstand the artificial cabin pressure at high altitudes. In the course of the overhaul process taking place at the Lufthansa Technik workshops in Hamburg, the inner and outer door segments were separated, revealing irreparable cracks and signs of corrosion on the inside of the corpus. The only way was to rebuild the corpus with modern aluminum alloys and weld it again to the original outer skin. This demanding process was meticulously planned by the project engineering, members of the FAA and the team of experts supplied by Lufthansa Technik. The welding process itself was executed by a partner company, to the full satisfaction of everyone involved.

As there was no literature or experience available how to connect vintage aluminium alloy with modern alloys, the Super Star project team had to pioneer the process. Before risking working with the original material, the welding experts produced 154 standardized test plates consisting of different materials and welding techniques. By means of this test series the resistance spot welding turned out to be the preferred choice. 

After the successful combination of the structural elements, door “one right” was equipped with the opening mechanism and shipped to Auburn for installation to the Super Star. 

Installed a while ago, today nothing reminds us of the world premiere associated with this door. This instantly successful repair is another example of the unique know-how to be found in the Lufthansa Group!

Reverse Engineering

Only the best in the business had been chosen to work on the Super Star. But sometimes, even the greatest personal experience and most sophisticated technical devices, needed to ensure a safe component overhaul, are unable to deliver immediate answers. Leaving nothing to chance, in these rare cases the Super Star component team trusts in ‘reverse engineering’.

The Super Star team was determined to seek a solution for even the biggest challenges. Like the rebuild of eight jackscrews, driving the wing flap mechanism. As all of them were out of limit, only a new fabrication of these flight safety relevant parts was deemed possible. 

It was essential for the technical team to understand the production method applied by Lockheed in the 50’s, which isn’t described in the original technical documentation. The only way to gather this crucial information was a metallurgical examination by electron microscope of the parts in question. Only this insight view, down to the molecular level, delivered the desperately needed answers in terms of safety margins, expected lifetime, applicable flight cycles, weight and rigidity. 

Based on these scientific examinations, Lufthansa Technik, in cooperation with a partner company, ‘reverse engineered’ replacement jackscrews being at least as good as the original parts when leaving the factory in the 1950’s. Though only eight new jackscrews are needed for installation on the aircraft, two further samples have been ordered for qualification tests. Again, nothing was left to chance, as the meticulously calculated and fabricated parts had to prove the correctness of the theoretical calculations in exactly defined qualification tests. The gathered calculations and test results were finally presented to the FAA as certification agency.