Techinically …

Techinically …

From Mandatory Service Letter
MTL-32-01, Rev. 1

Landing Gear – Inspect the Steering Support Bracket for Incorrect Bolts

Original Date: May 30, 2019
Revision Date: July 24, 2019

Reason for Revision:

Updates the Effectivity as follows: Adds defined King Air B300 airplanes.

NOTE: This revision replaces the original issue of MTL-32-01 in its entirety.

Revision Compliance: NO EFFECT. Airplanes previously modified by this service letter are not affected by this revision.

Effectivity: King Air 90 (applicable variants within defined LJ serial range), Serial Numbers LJ-1964 through LJ-2139; King Air B200GT, Serial Numbers BY-75 through BY-298; King Air 200C/B200C, Serial Numbers BL-154 through BL-170; King Air 200/B200, Serial Numbers BB-2004 through BB-2018; King Air B300, FL-601 thru FL-1100; King Air B300C, Serial Numbers FM-27 through FM-69.

Description: Inspect the steering support bracket for the presence of incorrect bolts. If found, replace incorrect bolts.

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 of the in-structions 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.
  6. 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 Turboprop Communiqué # ME-TP-0015

Date: August 2019

ATA 34 L-3 ACSS TAWS+ Computer Database Memory Limitation Update

[Textron Aviation] has been notified by Aviation Communications and Surveillance Systems (ACSS) that database size has grown significantly in recent years. The 9000000-85006 TAWS+ computer installed in many Pro Line 21 and Fusion-equipped King Airs is nearing its memory capacity. ACSS recently notified us that the next obstacle database update 045 will exceed the memory limitation of the current unit. This update released at the end of June 2019 and the ACSS technical newsletter announcing the release states that it cannot be loaded into the 9000000-85006 part number unit. The TAWS system will continue to operate normally on the last database loaded, however obstacles and airport data would not be up to date in the unit. TACSS released optional service bulletin (SB) 9000000-34-6037 to upgrade the memory in fielded units from 128MB to 256MB and converts the unit to part number 9000000-85010. Textron approved the upgraded unit as a spares replacement allowing fielded aircraft to upgrade their units through ACSS and reinstall the new part number without the need of an additional kit or other approval. The spares notes should be added to the related model illustrated parts catalogs as future revisions are released. In the interim, we have placed technical manual deviation approvals (TMDAs) in 1View to provide the approval documentation. The TMDAs can be accessed by going to the IPC section detailing the TAWS computer and clicking on the TMDA tab at the top of the screen, see illustration above. Please contact your local service center in advance for a quote and to coordinate the upgrade as the unit will have to be sent to ACSS for modification. The SB requests a minimum two-week lead time to schedule units in for modification to avoid delays getting the unit returned.

The computer was factory installed in the aircraft listed below:

LJ-1847 and LJ-1853 to LJ-2128; BB-2001 and after; BY-42 and BY-58 to BY-276; BZ-1; FL-600 to FL-611, FL-613 to FL-617 and FL-619 to FL-1080; FM-25 to FM 70.

ATA-77 Collins Pro Line 21 and Pro Line Fusion Fuel Flow Indication


There have been sporadic reports of the electronic engine indication system (EIS) fuel flow readings dashing out (Pro Line 21) or showing XXX (Pro Line Fusion) a few minutes after engine start but returning to normal as the aircraft climbs to colder temperatures.

The common conditions for these reports were ramp temperatures are above 32° C (90° F), and the cause was traced back to a stuck thermal element in the oil to fuel heater.

When this element sticks in the open position, it allows oil to continually heat the fuel. The fuel flow transmitter receives fuel temperature as an input and uses it for compensation in the resulting fuel flow signal. If the fuel temperature exceeds approximately 70° C, the fuel flow transmitter will consider the input to be invalid, triggering the dashes or Xs on the display.

To isolate a stuck thermal element, both engines can be run until the fault occurs then shut down. An infrared thermometer can then be used to check the fuel line temperature at the outlet of the fuel heater or the inlet to the fuel flow transmitter. Comparing left and right temperature readings will compensate for local conditions. A temperature split of as much as 20° C will indicate a stuck thermal unit. This condition was not seen on legacy analog systems as they did not monitor the validity of the temperature compensation from the transmitter.

The information provided in this column may be abbreviated for space purposes. For the entire communication, go to

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