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Old 15th Jan 2019, 10:24
  #2087 (permalink)  
Luc Lion
Join Date: Mar 2006
Location: Vance, Belgium
Age: 57
Posts: 164
Apologies if this has already been posted above ; I found nothing through a quick search.
Here is the report on a Falcon 7X serious incident in May 2011.

I think that the serious incident of HB-JFN shares several commonalities with the Lion Air accident:
1. In both cases, an uncommanded movement of the THS has led to a catastrophic situation.
2. In both cases, the uncommanded movement has been caused by the failure of a single element in an automation system controlling the THS.
3. In both cases, the automation system was a new design or a redesign.

The report does a good job of showing that the combination of 14 CFR 25.671 and 14 CFR 25.1309 implies that an automation system that has the potential of commanding a THS runaway should be designed as fail-safe, which implies immunity to single element failure, or should provide appropriate warning to alert the crew of the unsafe operating situation. The warnings must be designed to minimize crew errors which could create additional hazards.
That was not adhered to by the Falcon 7X at the time of the serious incident and, obviously, also by the B737 Max at present time.

The report does also a good job of showing that the non-compliance to certification specifications was partially caused by a botched risk analysis process and that the risk analysis failure has systemic causes.
I wouldn't be surprised if similar risk analysis failures would be found at Boeing in the context of the Lion Air accident investigation.

Another thing I noticed in the HB-JFN incident report is that one of the first reactions of Dassault had been to add a button in the cockpit that disables the auto-trim system and enables the electric trim push buttons available to the pilots.


Last edited by Luc Lion; 15th Jan 2019 at 11:47.
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