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Certification of a glider weighing more than 30 kg

von Jean Lüthi
5

A glider weighing more than 30 kilograms requires certification by the Federal Office of Civil Aviation in Bern. Certification is a two-step process carried out by individuals approved by the aforementioned office: it consists of an electrical certification and a mechanical certification.


Electrical Certification

The radio system is inspected by the importer of Futaba radios in Switzerland. The components used are thoroughly checked, including servos, batteries, wiring, connectors, and receivers. In my case, this initial test was successful; I just need to replace the extension connectors with green Multiplex connectors with a larger cross-section.


Mechanical Certification

Structural integrity checks are performed by a model engineer who inspects and tests the model from every angle. The first elimination test involves assessing the wings’ behavior under load. According to the OFAC, the wings must be able to withstand a load of 5 g (five times the weight of the complete fuselage), which on my model represents a total weight of 122 kg distributed across the wingspan. For this test, I built a special stand to mount my wings upside down so I could place sandbags on them. I first conducted this test at home to get a sense of what it actually entails and, above all, to see if the wings could withstand this load. The wings bend like reeds but do not break. Each one flexes by 24 centimeters, which is perfectly acceptable. Once the weights are removed, a measurement is taken



from the ground to the salmon position to check for any permanent deformation. This test is performed because the spars are not designed to withstand the same loads as those on full-scale gliders. All control surfaces are then inspected for structural integrity, control response, and servo strength. The wing and horizontal stabilizer are also inspected and certified as compliant. The bonded joints are also tested for tensile strength and deformation, particularly at the fin root. Let’s not forget that this test is conducted by a modeler who is thoroughly familiar with the field and its challenges. During the test, you really wonder when something is going to break, but in my case, everything held up perfectly.



Certification

One month after these inspections, I received a flight logbook at my home along with authorization from the Federal Office of Aviation in Bern to conduct my first flights. Special liability insurance for the model must also be purchased, with coverage of at least 1,000,000 francs. The flight logbook is very comprehensive in its sections, which include the number of flights, the location, the takeoff and landing times, and the pilot’s observations during the flight. All maintenance work performed on the model must be recorded in it. For more significant changes, such as modifications to the radio system or other components, a notification must be submitted to the OFAC. A serious approach is required to prevent accidents and to set limits to avoid excesses and reckless behavior. A flight log can also demonstrate the modeler’s professionalism and the condition of the aircraft, allowing the insurance company to cover the modeler in the event of a mishap. However, these procedures can seem surprising the first time you go through them.


IIIIIIIVVVI–VIIVIIIIX
Calum
Date
Date
Flight
No. No. vol
No. volo
Pilot's
Name Nom du Pilote
Nome di Pilot
Airport

Aeroporto
Type
of Flight Genere del volo
Departure
Time Time of Departure
Time of Landing
Time
of Landing Time of Arrival
Time of Arrival
Flight

Duration Flight Duration
Total Flight Time
Tempo du vol
Tempo di volo
April 16, 2008Stephane DriandCantelony4:05
p.m. 4:10 p.m.
April 16, 2008Stephane DriandCantelony4:30
PM 4:40 PM
April 16, 2008Stephane DriandCantelony5:30
PM 5:20 PM

Recording the first flight in the flight log.



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