EASA today issued a revised AD
on Dassault Falcon 7X horizontal stabilizers, detailing new OEM instructions that get the rest of the fleet airborne.
The AD includes instructions for clearing planes equipped with the specific horizontal stabilizer electronic control unit (HSECU), p/n 051244-04, that was involved in the event that triggered the grounding. Previously, Dassault and EASA issued instructions covering planes equipped with a similar HSECU, p/n 051244-02.
Explains EASA in the latest AD:
The initial results of the investigations show that there was a production defect in the Horizontal Stabilizer Electronic Control Unit (HSECU) which could have contributed to the cause of the event. There are two different HSECU part numbers (P/N) in use: P/N 051244-02 is not affected by this production defect and P/N 051244-04 is potentially affected by this production defect. The aeroplane that experienced the uncontrolled pitch trim runaway event was equipped with a HSECU P/N 051244-04. Investigations are continuing to confirm this cause.
The May 26 grounding affected planes with both HSECUs installed. On June 16, EASA issued a directive
clearing planes equipped with the -02 HSECU, provided certain criteria were met.