Category Archives: F900 Troubleshooting

Holds Falcon 900 specific troubleshooting information

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.

Byt squawks at Portsmouth.

1. Hyd. pressure gage 2 inop. – Number 2 hyd gage dead below the zero peg until it warms up. PN 5502-360-80-10 SN 764, then it started working half way through our troubleshooting. rang wires.

 Number 1 gage will not go to 2100 lbs with the AUX pump,  hangs at 1600 lbs until you tap it. video.  PN5502-360-80-10  SN 765

2. Number 1 engine ignition –  L3KK left ignition switch.  820UN01S1BAOA.  IPC 31-11-30-21 .  SO number 403787. 1 gage only. ref.

3. Printer cockpit jammed – fixed paper jam

4. Look in radome  – visual inspection good

5. Landing LED taxi – provide quote

6. ANTISKID Menelco. – Suspect moisture in nose axle.

7 . Overhead panels loose – resecured

8. Face on entry away light – Reinstalled face.

9. Light check , logo lights – LOGO lights not installed on this AC.

10. reevaluate possibility of repair for overhead panel. –  paper overlay, month long repair removal.

11. change router password 




Why does the door pop on a f900 during climb?

There is a HUGE  amount of pressure that pushes the door outward when the airplane is pressurized.  It causes the feet to lock in place then jump a little as the fuselage grows with pressure.  The feet must be perfectly polished and clean to prevent this.  There must be a SMALL film of grease on each foot.


This is the dome shaped foot on the door.





This is  the flat foot on the air-frame. interestingly it has a slight pattern of vertical lines that are worn away on the contact patch.


the tiny polished spot is the contact patch1474911029365-546824352



The contact patch for each foot is only about a quarter inch around or less in some places



looking at the pressures applied to these feet:

Door is about 34 inches by 80 inches.

2720 square inches, 9.1 psi of pressure,

24752 pounds pushing out on the door.

10 door stops, so about 2400 lbs pushing on each stop.

.25 X. 25 inch contact patch means

2400lbs / .0625 sqin = 38000 psi pushing on each contact patch …….