NEW European rules for 600 kg ULM...
Since the introduction of new rules in many EU countries that allow ULM aircraft to have a max gross weight of 600 kg (instead of 450 kg), owners of 450 kg (472.5 kg w. parachute) Zenair ultralights regularly contact us to see if they can just increase the declared Gross Weight on their aircraft's documentation to 600 kg, and then fly the aircraft up to the higher Gross Weight.
It must be understood that the structure of all older ULM aircraft (i.e CH 601-UL, CH 650E, CH 701, etc.) was reduced as much as possible so that the design could fit the required weight limits, safety margins and performance specifications of the 450 kg ULM category.
Clearly, you do not just increase the load-carrying capabilities of an aircraft by simply changing the regulations - or the aircraft's documentation. To safely increase the Gross Weight, you would have to upgrade the primary structure of the ULM to approximately match that of a 600 kg Light Sport Aircraft (LSA).
For Zenair owners, this means that:
1) the structure of a CH 601-UL would need to match the structure of a CH 601-HD;
2) the structure of a CH 601XL-UL would need to match the structure of a CH 601XL-B;
3) the structure of a CH 650E/Ei would need to match the structure of a CH 650 (LSA);
4) the structure of a CH 701-SP would need to match the structure of a CH 701 (Ed.5).
These upgrades are complex, time-consuming and expensive procedures and Zenair does NOT provide instructions or kits on how to do this. One more point to consider: If you modify a certified ULM model without updating the type certificate (datasheet), it will also make the ULM's certification null and void.
To register a Zenair model from the sporty Zodiac series or from the remarkable STOL series as a 600 kg. ULM, we recommend you order the LSA version of the aircraft, and restrict the design to a MTOM of 600 kg when you register the aircraft. For more information on how to do this, please contact your nearest Zenair distributor.