The concern sheet
Text extracted from the PDF.
Revised 1/24/02 Airworthiness Concern Sheet
Full Name Andrew McAnaul Title Aerospace Engineer Organization ASW-150 Department Address 10100 Reunion Place, Ste. 650 City State ZIP San Antonio, TX 78216 Telephone Number 210-308-3365 E-mail andrew.mcanaul@faa.gov Make, Model, Series, Serial No.: Air Tractor Models AT-250, AT-301, AT-302, AT-400/400A/401/401A/402/402A/402B serial numbers - 0001 thru -1196 AT-501/502/502A/502B serial numbers -0001 thru -2620 AT-602 serial numbers -0001 thru -1153 AT-802A serial numbers -0001 thru -0282 Reason for Airworthiness Concern:
Overturn Skid Plate Failure Date: 12/17/2007 FAA Description of Airworthiness Concern
The FAA issued AD 2002-25-09 to install an overturn skid plate in the cockpit on Air Tractor AT-250/300/400/500 series airplanes following Snow Engineering Co. Service Letter #97. This was the result of reports of foreign material entering the cockpit during an overturn skid of the affected airplanes. At that time the manufacturer also incorporated overturn skid plates in production models including AT-602 and AT-802A airplanes.
The manufacturer has since revised Service Letter #97 to install wider clamps and larger attach bolts to strengthen the front and rear connections of the skid plate to the airframe structure. This is the result of a recent case of the bolts attaching the forward end of the original design overturn skid plate to the airframe breaking in an overturn accident. This allowed the skid plate to rotate about the rear attach point, and the forward end of the skid plate to enter the cockpit area.
The FAA requests any information from aircraft owners, operators, or repair facilities regarding any service history experience involving the overturn skid plate in Air Tractor airplanes. You may also propose Alternate Methods or Procedures to the Service Letter #97, comment on 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).
The resolution of this airworthiness concern could involve AD action or SAIB, or the FAA could determine that no further action is needed at this time. A risk assessment accomplished in accordance with the Small Airplane Directorate Airworthiness Concern Process guide for the potential condition is attached. 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 owners/operators and requests association and type club comments.
Attachments: *SDR(s) *A/IDS *SL(s) *SAIB *FAASR/*NTSBSR *AD *AMOC *RA
Notification: FAA *AOPA *EAA Type Club *TC Holder Other: NAAA
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)