Challenger Winter 2008

• Challenger Thrust Reverser Maintenance Tips—601/604
• Understanding Aircraft Mode on the Challenger 300

Challenger Thrust Reverser Maintenance Tips—601/604

- Scott Shefke

Removing the thrust reverser (T/R) translating cowl for engine removal/replacement or Chapter Five requirements is a normal part of aircraft maintenance. According to the maintenance manual, the technician is responsible for the following:

• Visual inspection of the T/Rs general structure.
• Adjust/verify main and pylon slider blocks.
• Lube the tracks.
• Verify screw-jacks are set to the stow-dog stops.
• Verify ball screw actuator links line up and slip fit to T/R tracks.
• Install and adjust pylon stops.
• PDU flexshaft rigging.
• Perform stow/deploy and throttle lockout switch rigging and functional tests.
• Perform auto throttle retarder check.
• Perform throttle lock functional tests.

In addition to the prescribed maintenance manual procedures, it is good maintenance and preventative care to do the following:

• Look for any cracks or damage to cascades.
• Look at the S.A.M. panels for damage.
• Inspect T/R pylon fairing panels for cracks.
• Verify diverter fairing /bloker door clearance checks.

After the translating cowl has been removed:

• Inspect the diverter seal for damage.
• Look for migrated bushings at the diverter doors and excessive play in the diverter door bushings.
• Verify the pylon slider blocks and main track slider blocks do not rotate and are rigged properly.
• Put your hands on the diverter door links to verify that the spring tension is present and that the link does not interfere with the link housing. If any of these items fail it is worth investigation and repair.

Understanding Aircraft Mode on the Challenger 300

- Cary Loubert

There are three modes indicated by the Proximity Sensor Electronic Unit (PSEU)—ground, taxi and air.

The aircraft is in Ground Mode if:

• The PSEU is initializing, or
• One WOW sensor from each landing gear shows weight on wheels (total of three) or all four from two landing gear AND the left and right engine are not running or all sensors from the passenger or cargo door show open.

The aircraft is in Taxi Mode if:

• The PSEU is not initializing AND one WOW sensor from each landing gear shows weight on wheels (total of three) or all four from two landing gear AND the left or right engine is running AND one or more sensors from the passenger and cargo door show closed AND not in ground mode.

The aircraft is in Air Mode if:

• The aircraft is not in ground or taxi modes.

One important item relating to aircraft mode is how the Maintenance Diagnostic Computer (MDC) stores faults that are reported to it. The MDC will not retain a fault in its aircraft history at power down if the aircraft is in ground mode.

Scott Shefke and Cary Loubert are Duncan Aviation’s Challenger Tech Reps. Feel free to contact them with any of your Challenger technical needs:

• Scott Shefke, LNK - 800.228.4277
• Cary Loubert, BTL - 800.525.2376

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