An emergency AD issued Friday requires that before further flight operators perform a “detailed visual inspection to detect repairs, cracking or corrosion” of the wing spars and other structural components in Frakes Aviation turboprop-converted Mallard seaplanes. The directive follows the December 19 fatal crash of a Chalk’s Ocean Airways’ turboprop-converted Mallard when the right wing separated from the fuselage on takeoff. All 18 passengers and two pilots were killed in the accident. Although the cause of the crash has not yet been determined, preliminary indications revealed fatigue cracks in the wing spar and skin and a broken z-stringer that likely led to wing failure. The AD is an “interim action” while Frakes Aviation of Cleburne, Texas, develops a non-destructive inspection procedure that is expected to be required in a superseding AD.