Spring 2006

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• Honeywell SB TFE731-76-5121, F900EX DEEC Upgrade
• F50EX, F900C/EX/DX, & F2000/EX Composite Horizontal Stabilizers
• KHF-950 System

Honeywell SB TFE731-76-5121, F900EX DEEC Upgrade

— Lanny Renshaw

The DEEC upgrade from P/N 211882-2007 to P/N 211882-2009 provides an enhanced fault detection which allows the DEEC to detect the UCA (Uncommanded Acceleration), log fault 9, and then switches the DEEC to Manual Mode. There are several other modifications listed in the SB. The DEEC upgrade from P/N 2118882-2008 to P/N 2118882-2009 allows the DEEC to keep track of the download count correctly since the download count becomes part of the file name. Currently,Windows Software Loader tool (used in other DEEC software upgrade programs) is not approved to upgrade the DEEC software per this SB 76-5121. Per the instructions, you must have a personal laptop computer with Windows 95/98 and restart the computer in MS-DOS mode. Also, when complying with this SB, do not forget to sign-off Dassault SB F900EX-235.

F50EX, F900C/EX/DX, & F2000/EX Composite Horizontal Stabilizers

— Ron Grose

A few years ago, Dassault introduced the composite horizontal stabilizer on the following aircraft models and serial numbers: F50EX-s/n 315 & sub., F900C-s/n 186 to 202, F900EX-s/n 074 & sub., F900DX-all s/n's, F2000-s/n 123, 125, 126, 128 & sub., F2000EX-all s/n’s. If you plan to have one of these aircraft painted, be aware precautions need to be taken during the painting process.

Dassault published MRI procedure 55-00-15 which provides instructions to check the paint thickness and install a CAUTION placard on the composite stabilizer. This is to ensure the lightning strike protection of the stabilizer has not been compromised. Since the MRI is being discontinued, a new procedure is expected to be released in a coming issue of ATA 20-General Procedures. DGAC AD 2002-089(B), US AD 2004-01-05, and F50 SB 396 address this issue on certain serial number aircraft.

Also, precautions need to be exercised during routine maintenance of these stabilizers. Avoid the use of harmful chemicals, dropping of objects, and stepping/walking on the surface to avoid costly repairs or replacement.

KHF-950 System

— Kevin Miesbach

Are you experiencing tuning and/or garbled transmitter problems with your KHF-950 system? Duncan Aviation has seen these issues resolved by installing the following Service Bulletins (SBs). Complying with notes in each SB regarding each of the boxes associated with your HF system can keep you from having further problems (such as failure of high-dollar power amplifiers).

• KTR-953
  • SB 8: To reduce transmit distortion encountered when the KTR-953 is mounted in a different location (> 3 feet) than the KAC-952.
• KAC-952
  • SB 9: To improve common mode rejection encountered when the KAC-952 and the KTR-953 are installed in separate locations.
  • SB 10: To reduce transmitter distortion when the KAC-952 is mounted more that three feet from the KTR-953.
  • SB 11: To prevent the failure of the power amplifier driver and final transistors.
  • SB 13: Mod 13 to improve the tuning reliability of some shunt antennae.
  • Ensure these SBs are installed together to avoid further problems.

NOTE: Remember to pull the HF Coupler circuit breaker before removing or installing your KAC-952 HF Antenna Coupler! Contact Dan Magnus at 402.479.4217 with any questions.

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