Category Archives: F50 Troubleshooting

Holds Falcon 50 specific troubleshooting information

When is the friction check due on a Falcon 50 H stab


For F50 N98DH, the fwd H-Stab, (Normal) motor is P/N 1234-2, S/N 206, monted on Stab Jack P/N 021121-09.    S/N 332.


Normla motor is p/n 1234-2


That means the stab jack is compliant with SB F50-267, and SB F50-247.

So, brake current check and instpect and clean are not due at the 12 month check.


Here is some of the early analysis.


you have Stab Jack P/N 021121-01 or 021121-05 or 021121-05 AND Normal motor P/N 1234.

Brake holding check and Check is due at the 12 month AND check and clean is due at the 12 month.




you have any stab jack with stab normal motor p/n 1234-1.Drop out current check  is not required. inspectand clean  is due at every 12 month check.


POST S/B F50-267

you have any P/N 021121-09 stab jack, with normal motor 1234-2,  Check and cleaning not required, drop out current not required.

F50 items N98DH

pilot report.

HRS 9950.3

CYC  5311

Yellow HDG miscompare at rotate, and sometimes descent.  Both HDG seem identical, even when HDG CMPRTR warn is present.  Verfied. Rplced #1 ahrs.

#2 AHRS CB pops. Previous troubleshooting found a grounded , burned in two, power wire near fwd RH card cage in the nose. Possibly verified.  Slave control free switch contact burned.  Smoke evedence. (Picture). Repaired wire.


Repaired wire at #2 AHRS slaving control panel switch.  #2 AHRS system ops test good I.A.W AMM 34-21-00710


Pilot and copilot tx sidetone very loud, cabin sidetone, ics sidetone normal.  Verfied.


Adjusted pilot  Audio control box P/N M1045-fbaa-hj7f S/N 9010358, and copilot s/n ,  headphone level, speaker sidetone level, ICS level, and ICS sidetone level I.A.W. AMM 23-50-01-820-801.  Crew ICS system ops checks normal.


Ectm 1, needs  download

Number 2 RMI flag flickers into view.  Troubleshot by AHRS swap and STIM. Failure is now pilot RMI.   order AHRS collins AHC85E, P/N 622-6190-204 , failed S/N 726( causes RMI flag to flicker into view.

AHRS swap detail: Units are now swapped to:

#1 unit, Aft. P/N.622-6190-204    S/N 957

#2 unit, Fwd. P/N.622-6190-204    S/N 726 (causes RMI flag to come in view)

Removed failed AHRS computer #1.  Installed overhauled unit.  Unit recieved on Duncan W/O 4K0Y6,  from Regional Avionics Repair WO.    2020-9726.

Parts off:   P/N. 622- 6190-204. S/N 726. (Causes HDG flag to flicker)

Parts on:   P/N. 622- 6190-204. S/N 866.

Unit installed I.A.W. AMM 34-22-01-900-801.  AHRS system #1 ops checks normal.

P.brake bleed down.  Needs troubleshooting.

TERRAIN DISPLAY button inop.

Lh main brace leak, needs troubleshooting.

2 hyd pump bad,2000 psi replace pump. done.

Busstied ann  and other anns , needs bulb.

Crew temp valve resistor dead, passenger has rough spots near full cold. Needs crew dual temp valve.

Wednesday early am.  L ahrs displayfail with original in aft postion, and rh rmi flag in view. R rmi card shakes. Center MFD shows red DRV. This ended up being….AHRS will not STIM with STBY battery breakers in.


MFD Red DRV is a problem.  Rerack MFD solved this.

No ALIGN light on MSU.  Replaced with serviceable.

Parts Off.

MSU p/n CG1042AB03. S/N 1084 (align light inop)


Parts on:

MSU p/n CG1042AB03. S/N 461 (removed from inservice aircraft, see Pollard Spares LLC  SO5857.  Init ops test good refrence AMM 34-21-00-710-801






Ann bulbs

#2 hyd qty

Panels at pylon

Window seal

Cabin floor.

Low fuel light

Number 1 dme ind dead.

Left closet avionics fan loud

Terrain display inop.

Why is number 2 dpu 622-9009-001, #1 is -002



Week starking June 9

New items:

Left pylon leak

Aft compartment leak

Skin temp thetmostat at rh wheelwell not bonded.

Air check valve left side f4 tape

dv window has jumped the rack and pinion, needs reseal.

#1 and 2 mlg tire condition.

Fuel sample bottle clip brocken.

BATT 1 amps blue lamp inop.

Pilot and copilot window shades need rewind, small glue repair.

Low fuel light on

Hyd qty low

Number 2 transfer light will not go out.

Red CABIN light  rigged on the edge,

MED overserviced, upper fwd seal area gap., fwd side mid to fwd upper corner.  Check rigging also.


Dv window jumped off teeth, check stripped bolt.


No terrain display.

Ectm 1





Pilot reports 30 degree heading split.

98dh left alpha, then 13

Copilot seat no springback in seat lock. Also rocks for/aft

IRU will sometime start with FAN FAIL.





July 20, 2020