Story ID: 
Emergency AD on Otters Follows Fatal Accident
By: Gordon Gilbert
Caption: The FAA has issued an emergency AD for visual inspections of the left-hand elevator auxiliary spars on DHC-3 Turbine Otters.
Word Count: 308
On October 4, exactly one month after a fatal crash of a de Havilland DHC-3 Turbine Otter, the FAA issued an emergency airworthiness directive (AD) requiring immediate visual inspections of the entire left-hand elevator auxiliary spar for cracks, corrosion, and previous repairs. According to the FAA, “This emergency AD was prompted by multiple recent reports of cracks in the left-hand elevator auxiliary spar on DHC-3 airplanes.”
Transport Canada addressed this issue more than four years ago. On Jan. 19, 2018, that agency published an AD requiring inspections of DHC-3 elevator assemblies for corrosion. In response, the FAA didn't issue a proposed AD to require such inspections until Feb. 8, 2022, and said it is currently addressing comments. In the proposed AD, the FAA wrote: "Corrosion and cracking, if not addressed, could lead to structural failure with consequent loss of control of the airplane." 
The proposed AD also cited a de Havilland service bulletin, VS/0010, Revision NC, dated March 19, 2020, which "provides a list of new inspection tasks that have been added to the DHC-3 maintenance program as a supplemental corrosion prevention manual, Viking Product Support Manual (PSM) 1-3-5 DHC-3 Otter Supplemental Inspection and Corrosion Control Manual, Revision IR, dated December 21, 2017 (Viking PSM 1-3-5, Revision IR)." 
As an interim action, the FAA issued the emergency AD to mandate an inspection of the left-hand elevator auxiliary spar and replacement if necessary. The agency also said, “structural reinforcements are not considered previous repairs.” All model DHC-3 airplanes, all serial numbers, certificated in any category are covered in the AD.
The emergency AD did not specifically refer to the September 4 accident in which a float-equipped single-engine DHC-3T Turbine Otter plunged into Puget Sound, Washington, during a Part 135 sightseeing flight. The pilot and all nine passengers died in that crash.