"...the FAA is strongly recommending that owners and
operators of Zodiac CH601XL and CH650 aircraft comply with actions
outlined in a forthcoming safety directive/alert to address those
concerns. The FAA is urging that the aircraft not be flown until
the maintenance is completed."
Source: From the FAA's SAIB
issued in the aftermath of several accidents since April 2009
involving those particular Zodiac models of aircraft. The agency's
investigation, done in cooperation with the aircraft manufacturer,
uncovered areas of concern related to wing structure, airspeed
calibration, stick-force characteristics, among other items...