The concern sheet
Text extracted from the PDF.
Revised 1/24/02 Airworthiness Concern Sheet
Full Name Vince Massey Title Aerospace Engineer Organization SACO Department ANM-130S Address 1601 Lind Ave., S.W.
City State ZIP Renton, WA 98057 Telephone Number 425-917-6475 E-mail vince.massey@faa.gov Make: Twin Commander Models: 690, 690A & 690B Serial No.: All except 11195, 11279, 11361, 11383, 11527 & 11536 Reason for Airworthiness Concern: Corrosion has been found between the surfaces of the upper wing skins and the engine mount beam support straps. These straps carry engine loads from the beams to the wing structure.
Date: 12/16/2005 FAA Description of Airworthiness Concern (Who, What, Where, When, How? Attachments: RA and appropriate data) Twin Commander Aircraft LLC, Arlington, WA, has been informed by the Twin Commander Service Centers that corrosion has been found between the mating surfaces of the upper wing skins (p/n’s 170141-1/-501) surface and the engine mount beam support straps (p/n’s 170196-1 & 170197-1 LH wing and 170196-2 & 171197-2 RH wing).
These straps carry engine loads from the support beams into the upper skin and wing internal support structure. Twin Commander, LLC issued their Service Bulletin Number 237 to address the corrosion issue.
Request for Information (Proposed Alternate Inspection/Repair Procedures, Cost Impact, Etc. Note: Any comments or replies to the FAA need to be as specific as possible. Please provide specific examples to illustrate your comments/concerns.): To help the FAA determine the most appropriate airworthiness action, we request information on this subject. Please be specific to any experience in corrosion in this area you have experienced. Include any proposed corrective action you have to address the issue.
Attachments: *SDR(s) *A/IDS *S/B(s) *SAIB *FAASR/*NTSBSR *AD *AMOC *RA
Notification: FAA *AOPA *EAA Type Club *TC Holder O t h e r :
Response Requested: Emergency (10 days) Alert (30 days) Information (90 days) (Space Bar Adds “X” to Check Boxes) *Service Difficulty Reports (SDRs); Accident/Incident Data System (A/IDS); Service Letter (SL); Special Airworthiness Information Bulletin (SAIB);
Federal Aviation Administration (FAA)/National Transportation Safety Board (NTSB) Safety Recommendation (FAASR/NTSBSR); Airworthiness Directive (AD); Alternate Method of Compliance (AMOC); Risk Assessment (RA); Aircraft Owners & Pilots Association (AOPA);
Experimental Aircraft Association (EAA); Type Certificate (TC) This Airworthiness Concern Sheet (ACS) is intended as a means for FAA Aviation Safety Engineers to coordinate airworthiness concerns with aircraft owner/operators through associations and type clubs. At this time, the FAA has not made a determination on what type of corrective action (if any) should be taken. The resolution of this airworthiness concern could involve an AD action or an SAIB, or the FAA could determine that no action is needed at this time. The FAA’s final determination will depend in part on the information received in response to this ACS.
The FAA endorses dissemination of this technical information to all manufacturers and requests association and type clubs comments.