Topics in Category: Model 750 Citation X - Rotate.Aero Sat, 19 Jan 2019 08:52:37 +0000 MYOB /media/kunena/images/icons/rss.png Topics in Category: Model 750 Citation X - Rotate.Aero en-gb ATA 33-40, Nose Taxi Lights - by: Mark

Light removed. Power was verified good on one of the two wires. The ground was intermittent, but moving the leads just outside the bulb housing would give a reading to ground (not a solid ground).

With the suspect area cut out...... no ground at all. What???

Working the wire bundle aft and up from the light assemblies takes you to what appears to be a junction box.

Just a wire guide assembly. At no point was a ground indicated when moving the bundle in this area.

While moving up the bundle into the nose gear well, the meter had to have the ohm's "buzzer" turned on as it was impossible to watch the meter and shake wires at the same time.

At the top of the gear the open was found. I should of guessed as the harness had been previously worked on as evident by electrical tape being wrapped around it.

Upon gutting the harness two wires were found broken. The taxi light ground wire had an environmental splice that had snapped in half (although I was pleased to see someone actually went through the hassle of installing one there). The other wire probably broke when I was opening up the bundle.

A repair was completed on both wires, but I suspect that more will break over time. This area is where the wire bundle moves and bends in response to gear retraction/extension. I'm not sure if any plausible solution is available other than changing placement and slack of the bundle itself. There is a pronounced bend aft of the lower adel clamp.

If wires continue to break in this area, the complete bundle can be replaced as an assembly. A part number is located on the bundle at the gear well wall feed through plug.]]>
ATA 33 Lights Wed, 17 Jan 2018 22:31:22 +0000
ATA 78, Thrust Reverser - by: Mark

The system has a control card mounted on the forward wall of the baggage pit. A breakout box used to aid troubleshooting can be installed. The breakout is useful in verifying the proper grounds (supplied via the various switches) in both the stow and deploy positions.

There are 6 possible switches (3 on each side) that can cause this warning. Two unlock switches and one unlatch switch are used on the T/R rails.

The upper and lower unlock switches show hydraulic pressure is present and that the locks are in the deploy position. The unlatch switch located on the back of the rail is activated at the end of T/R deployment. (This is an incorrect statement. The unlatch switch(s) is located between the two unlock switches on the forward side of the rail. The fully deployed switch, shown in the lower picture is used to indicate T/R deployment.)

For a problem as this, one of the four unlock switches would be the most likely culprit. If switch failure has been ruled out, switch rigging should be checked. The outboard set is easily reached..... the inboard set...... are going to take some gutting to access.

Cessna recommended working the throttle laterally to verify if the quadrant switches are not faulted.

As a final recommendation, Cessna stated the hydraulic control valves could be swapped for troubleshooting. (Although, I'd exhaust all other troubleshooting steps before swapping the valves.)

Cessna Model 750 WDM 78-30-01]]>
ATA 78 Engine Exhaust and Thrust Reverser Tue, 16 Jan 2018 02:33:36 +0000