Recent Topics - Rotate.Aero Thu, 19 Jul 2018 13:40:00 +0000 MYOB en-gb El Brutus - by: Mark

I've found the cheapest price was from Brown Tool .

We also have this guy named "He Man" running around aviation maintenance. This guy is in corporate aviation as well as commercial. He works for all the airlines and all the business jet operations world wide!!!! He Man loves to over torque everything..... including screws. I seem to see a lot of his previous work. Dragging out El Brutus or a screw knocker always adds that extra "specialness" to a job.

Tools Wed, 18 Jul 2018 00:04:08 +0000
ATA 32-31, Gear Control - by: Mark
Having limited Falcon knowledge, I took a back seat on this aircraft's troubleshooting. We experienced a slightly different issue on several gear swings. The gear doors would not come up after the gear was up and locked.

The cause of both the crew report and our own was one faulty component. In this case, the nose gear up-lock actuator/switch assembly.

All gear activation and indications are derived from proximity switches located on the up-lock, down-lock, and door actuators. Usually there are two switches per unit. One for control and one for indication/warning. For control, the switches are wired in series for each particular type of lock.

In our case, the nose gear up-lock switch was intermittent. When it was failed, the ground path (via nose, R/H main, L/H main up-lock switches) was not present. The gear control circuit card did not see the gear as up and consequently did not allow the doors to actuate.

For the crew..... if the doors don't open, the gear is not coming down. For us, the gear was fully up, but the system didn't see them as up so the doors wouldn't close.

Left main gear up-lock switch with plug hanging off. The proximity switch is located in the silver barrel on the left side of the hook actuator assembly.

We used a small test unit for proximity switch operational checks. I found this box here online. The gear locks themselves can be easily activated or reset with just a finger push.

As with all posts on Rotate.Aero if any system descriptions are incorrect...... please feel free to comment on it.

Falcon 2000 AMM 32-30-00
FIM 32-30-00
WDM's 32-31-00 and 32-61-00
ATA 32 Landing Gear Tue, 17 Jul 2018 01:19:26 +0000
Freon Air Conditioning - by: Mark
The compressor unit is quite the pain to access, much less troubleshoot. It's tucked in the forward right section of the hell hole. It is mounted quite low also. The majority of the electrical components are mounted underneath the unit and are only freely accessible with the whole unit pulled out and laying on a bench. This problem didn't require such drastic measures.

The compressor system uses a control unit to power a large contactor which feeds 28 VDC to a compressor motor. This motor has a large drive belt which spins the actual compressor.

Without access to the maintenance manual, some basic control logic functions can be understood. The controller needs to see the aircraft on ground using external power. It also requires a 28VDC signal from the cockpit switch. There are inputs from the generator system, but their function is unknown. If all the prerequisites are satisfied, the control unit sends an enable signal (28VDC) to the compressor motor contactor.

Initial troubleshooting just required an ear. A noticeable "click" was heard when the cockpit switch was cycled a few times. This of course, required two people. The click was quite faint while listening directly in the hell hole. This was actually a small relay inside the controller which when closed, fed 28VDC out on the "enable" wire.

With that being understood, it was now time to determine if or why not voltage was reaching the contactor coil. An easy way to accomplish this was the hour meter. The red wire feeding the hour meter is tied off of the coil input enable signal. No voltage was found. Just to check the main power feed from the 135 amp breaker was present, it could be checked via the hour meter's white wire. Power was present on the white wire.

This left only two intermediate pressure switches as a possible problem. A barometric switch and a freon pressure switch are wired in series to the contactor coil. I have no clue as to what the baro switch is used for. The freon switch is mounted on top of the receiver-drier in a horizontal direction.

I was very lucky that the wiring was easily accessible to the freon pressure switch. After sliding back the heat shrink, voltage was found on only one of the connectors ( knife splices ). The open pressure switch was bypassed for just a brief second with a jumper wire. The contactor closed and the motor started running.

Switch replacement required a purging of the freon before removal and a re-service after a new one was installed.

Cessna A/C System WDM C30062
ATA 21 Air Conditioning Sat, 07 Jul 2018 02:50:57 +0000