Category Archives: F900 Troubleshooting

Holds Falcon 900 specific troubleshooting information

F900ex N900HG aspen mx








1.  IAC2 FWC  fail. Verified. Fault history. Also IAC2  will not enter maintenance mode. Flight fault shows FWC2-DAU2B.

 New IAC 2 fixed it. Need to load ACDB  in fms.
2. Passenger temp control failed. Verified . Needle  stays exactly mid scale unless breaker is pulled. 23HG plug was loose.

Pin U pushed back on the Cabin Temp controlle not used


Problem turns out to be 24HC Duct temp sensor below rear lab basin



3. DU5 failed. Not verified.
Pilots incoming items:
4.IRS 1 takes a long time to align.  Verified. No align in Denver. Verified.  Stays at 4 min to align, while other two go to 1 min to align.  Then fast flash for 30 seconds . Init number 1 fms a second time.  Then 2 min to align. Then it aligns. Current faults 8903 and (  ). Nav sensor page shows drift 4.7 miles in 15 min ground run.
United 5947

39834756 airbill

Thanks gerry

5. Radar fail after Denver. (Related to #1 IRU) ? Radar works, but shows DAU1B  fail? shows fault code “SERIAL BUS WX3 IAN INTERFACE 4301-01.
6. Pilot reports RH baro select jumps several hundredths  when you touch the knob.
Also, jumps to HPA  even when you don’t touch the HPA  button.
Other items:
Check pulse lights.
Antiskid meneco red. Will check nose Tach resistance.
BASC control meneco red. Could be switchology.

IRU number 3 cooling fan sounds like rocks in a blender.  Remember not to unholy the rack while accessing the fan.

VQ-BYT squawks at PBI



1. Number 1 hyd qty reads zero all the time.

2. Occasional AUTO SLAT light, clicking noise from behind panel.

3. APU uncommadded shutdown after start.

4. #2 fuel bypass menelco occurred 1 time, no reoccur since. CND.

On site:

1. Failed number 1 gage verified. Gage due in at midnight. Friday night. Ops test 29-20-00-720-801. New gage S/N 1034 has knarly  pinged prints inside the front glass.

2. Suspect WOW Prox  going to ground while ac is in flight.  Could the clicking noise be the gear handle safety pin?  Evaluate Prox detectors. Checked voltage and sensitivity of all 6 Prox detectors.

3. Interestingly, the APU OVERSPEED Menelco was dark when I got to the airplane.  Every subsequent shutdown pops it yellow , which is normal.  All starts were normal for me.

4. EMERG LIGHTS one bulb out. APU MASTER 2 bulbs out. Replaced bulbs.

5. Crew temp amp motor is making a grinding noise. Goes quieter after 10 min. Info only.

6. Cabin pressure triple gage altitude needle hangs at 3000ft. Tapping panel resets it. Triple gage mount screws loose.1483199000798-708599262

Info only

6. Ron said Mr. Burnes keeps asking about the AFIS Printer paper jamb.  Fixed it.  It is old and grouchy, like me. Manual print select does not work.  Use NAV>AFIS INDEX>NEXT>AFIS CONFIG>NEXT>NEXT>OR>AUTO>ON then choose the services you want.

It will print any of the incoming stuff you want.

7.Minor fuel residue forward of RH ADF antenna inside belly faring.
Outboard of the inboard fuel sump, right wing root.

It is a screw or two. the number 10 to 20 screw outboard.

The guys left the tanks pressurized, so I am sure that made it worse.

It dribbles into the belly faring and made a puddle on the ground.  Looked dramatic, no problem.

If it is OK with you, I will brief Ron to vent the tanks each stop until we get to look at it.
8. Tire pressure gage needs cal.