The concern sheetOCR
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Airworthiness FAA Concern Sheet Date: 7 October 2009 Full Name Kevin Schwemmer Title Aerospace Engineer (electrical) Organization FAA Department ACE-119W Address 1801 Airport Rd, Room 100 City State ZIP Wichita, KS 67209 Telephone Number 316-946-4174 E-mail kevin.schwemmer@faa.gov Make, Model, Series, Serial No.:
Beechcraft, Model 390, Premier I/IA, Serials RB-4 through RB-248 Reason for Airworthiness Concern: The FAA has received reports of the wiring for the Spark Gap and MOV being swapped. This configuration could result in the loss of equipment on the essential bus.
There is a concern that the wiring for the Spark Gap and MOV may have been swapped where these two devices are colocated. The Spark Gap has a higher current carrying capability than the MOV and is designed to carry direct currents caused by a lightning strike that attaches to the Wingtip Position Lights. In the event of a lightning strike that attaches to the Wingtip Position Lights the potential exists to overload the MOV protection and allow an electrical spike to pass through to the essential bus. The electrical spike could disable any or all systems that receive power from the essential bus. The systems on this bus include: Autopilot. Anti-skid system, Hydraulic indicator, Spoiler system, Pilot PFD, Audio Panel and the #I ADC.
This condition could result in a loss of information and significant increased pilot workload during adverse operating 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.): We are currently evaluating what corrective action would be appropriate. The airplane manufacturer has released a mandatory service bulletin (SB24-3995, September 2009 Initial Release). The airplane manufacturer has requested this be enforced with an Airworthiness Directive which mandates the service bulletin.
Please direct all comments/input to Kevin Schwemmer at the Wichita Aircraft Certification Office no later than November 9.
2009. (Contact information above) This Airworthiness Concer Sheet (ACS) is intended as a means for FAA Aviation Safety Engineers to coordinate airworthiness concerns with aireraft 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.
Attachments: *SDR(s) *A/IDSL | *SL(S) *SAIBL _ *FAASR/*NTSBSR *AD *AMOC_ *RAL Notification: FAA _ *AOPA • *EAA _ Type Club L | *TC Holder _ Other:
Response Requested_/: Emergency (10 days) L | 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): Airworthines Directive (AD); Alternate Method of Compliance (AMOC); Risk Assessment (RA); Aircraft Owners & Pilots Association (AOPA):
Experimental Aircraft Association (EAA): Type Certificate (TC) Revised 1/24/02