From Beechcraft Service Bulletin # MTB-52-01

Date: April 12, 2018

Doors – Inside Airstair Door Handle Snap Ring Modification

Effectivity: Model C90GTi, Serial Numbers LJ-1 through LJ-2150; Model B200GT, Serial Numbers BY-1 through BY-323; Model B200CGT, Serial Number BZ-1; Model B300C, Serial Numbers FM-1 through FM-76; Model B300, Serial Numbers FL-1 through FL-1145.

Reason: This service document is being issued to modify the inside airstair door handle installation.

Description: This service document provides parts and instructions to install an improved snap ring in the inside airstair door handle.

Compliance – Recommended: This service document should be accomplished at a scheduled maintenance period or inspection.

A service document published by Textron Aviation may be recorded as completed in an aircraft log only when the following requirements are satisfied:

1) The mechanic must complete all the instructions in the service document, including the intent therein.

2) The mechanic must correctly use and install all applicable parts supplied with the service document kit. Only with written authorization from Textron Aviation can substitute parts or rebuilt parts be used to replace new parts.

3) The mechanic or airplane owner must use the technical data in the service document only as approved and published.

4) The mechanic or airplane owner must apply the information in the service document only to aircraft serial numbers identified in the Effectivity section of the document.

5) The mechanic or airplane owner must use maintenance practices that are identified as acceptable standard practices in the aviation industry and governmental regulations.

No individual or corporate organization other than Textron Aviation is authorized to make or apply any changes to a Textron Aviation-issued service document or flight manual supplement without prior written consent from Textron Aviation.

Textron Aviation is not responsible for the quality of maintenance performed to comply with this document unless the maintenance is accomplished at a Textron Aviation-owned Service Center.

From Multi-Engine Truboprop Communiqué # ME-TP-008

Date: April

ATA 31 – Pro Line Fusion AFD 3700 Connector Knurled Knobs and Set Screws

Some customers have reported finding loose or missing AFD 3700 connector backshell knurled knobs and/or set screws. We have found that this is due to the knob set screws working loose during aircraft operation. All aircraft harnesses delivered to Textron in 2018 and on will have a thread lock compound applied to the set screws during harness buildup to prevent future occurrences. If you should find either item missing, the replacement part numbers are shown on the Communiqué in its entirety online. There are two sizes of this backshell type used on the AFDs, however, both use the same part number knob and set screw. These are Rockwell Collins part numbers and can be ordered through Textron Aviation Parts and Distribution or directly from Collins. If a maintenance action requires the AFDs to be removed on earlier Fusion-equipped aircraft, we recommend checking the security of all the AFD connector knobs and set screws applying a thread lock compound as needed.

ATA 33 – Emergency Exit Sign Battery Getting Hot (Rev. 1)

King Air Communiqué 2016-10 provided some information regarding the batteries on the Emergency Exit Sign getting hot. The initial issue of the Communiqué mentioned the part number and the size of the battery which were incorrect. The batteries used in Emergency Exit Sign are “C” size batteries with the part number of 14A.

ATA 34 – Pro Line 21 Equipped B200 and B300 Airplanes with Rockwell Collins 3.5 Disk Database Unit (DBU) 4100

In 2017 Rockwell Collins announced that starting January 2019 (AIRAC cycle 1901), they would discontinue distribution of Navigation databases via 3.5 floppy disks. Databases after December 2018 will only be distributed in USB format. They will also discontinue guaranteed repair and support of the associated DBU 4100 which was installed in Pro Line 21 King Airs prior to BB-2001, BL-154, BY-61, FL-600, and FM-67. Any operators still utilizing this format are reminded that the discontinuance date is rapidly approaching. Current DBU 4100 users have several upgrade options and for a limited time. Collins is offering special pricing to their dealers on some of those options. Please contact your regional service center to get additional details and pricing.

ATA 52 – Medeco Door Handle Cylinder Maintenance and Lubrication

Aircraft Security is the manufacturer of the Medeco cabin door handle assembly used in the current production King Air and King Airs that have replaced them as spares. Aircraft Security recommends that the Medeco cylinder be lubricated with FLUID FILM®. This lubricant is available commercially or from Textron Aviation Parts. For more maintenance information about the Medeco Locks, visit their web site at

The above information may be abbreviated for space purposes. For the entire document, go to

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