Category Archives: F50 Troubleshooting

Holds Falcon 50 specific troubleshooting information

F50 Troubleshooting

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.

PRE SB

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.

 

POST-SB 147

 

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 Troubleshooting

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

 

 

May 2022 visit.

Discrepancy:

IRU Failed. Left

 

Left compass squirrely, RH RMI flag dance, Pilot wind vector crazy.

Verified TCAS operates when IRU OFF

Verified EGPWS failed when IRU OFF

F50_Heading Channel Left side

F50_Heading Channel Left side

 

 

F50_Heading Channel Left side

Page two is the VALID conditions for the AHRS.
We have no HORIZON flag, so that leaves only a few things that will cause SERIAL HDG flag (EFIS HDG FLIG IN VIEW)…..and……. PIN 9 LOW. (ANALOG HDG FLAG IN VIEW, RMI.)
The things that are possible are upper left.

COMPENSATION is the one I suspect.
I think we can rule out SLAVING, because we have a flag in SLAVED and in FREE.
We need to swap the compensation modules next.
Todd

 

 

 

F50 Troubleshooting

How could the heat ducts become clogged in a Falcon 50?

 

The foam inside the ducts has deteriorated and fallen onto the outlet registers at the carpet level.

foam20161216_153910

loosefoamf50022heatduct

blocked20161214_100113

 

 

Foam released from some areas inside the ducts

161216_152952

Dime size chunks completely covered some outlets

161216_153140

Smaller pieces

161216_153423

Bosrescope in duct

 

Possibly the situation was made worse because earlier in the year, the airplane had lost a APU seal and put oil residue in the entire condition system. this may have caused the foam to finally release.

 

There is foam sheet mufflers on each register, drilled t match the holes in the register.  Also deteriorated,  but that did not seem to be the worsen problem.

 

the small pieces of loose foam was blown toward the registers, and completely covered a few of them.

 

We used a vacuum and a bore scope to clean out the ducts.

the rest of my notes are here

Why would a Falcon 50 Passenger temp run away from HOT in AUTO mode

 

AircraftTroubleshooting, F50 Troubleshooting

Why would a Falcon 50 Passenger temp run away from HOT in AUTO mode

Complaint:  Cabin cold in flight in auto mode:

EDIT squawk turned out to be : cabin cold in AUTO and in MANUAL.

How could the heat ducts become clogged in a Falcon 50?

I failed to realise early on that the cabin valve backing away from hot was normal operation.  Also, when crew is max hot, the cabin backs down even lower.  This also seems to be normal operation.

 

Observation: Pass Valve position needle will drive full hot, then immediately back down to half scale or lower. In the air and on the ground with APU.

 

EDIT 20/20 hindsight, this is normal operation. Also, it is exaggerated when the crew valve is toward hot. Who knew?

 

At about :40 seconds the valve runs cold on its own.

Reference:

F50 Pass temp electrical:   f50passtempcontrol

Associated:

With the flood duct open, the problem is reduced.

EDIT: with the flood duct open, the cabin will quickly overheat.

With CABIN and CREW valves selected OFF, the problem goes away.

With a SEPARATE temp sensor plugged into 163H, hanging in free air, THE PROBLEM GOES AWAY.   THIS is the ONLY way we have affected the squawk.

 

Troubleshooting so far:

We  have shorted 162H AMP pin A and B together. This takes the temp select system out of the system and commands full hot.  Squawk remains the same.

Crew Bleed or Pass bleed or both yield the same result.  Squawk remains the same.

AMP to 163H wires rung out carefully. M, H, J.

AMPs swapped cabin and crew.  Squawk remains the same.

162H Temp select controllers swapped for a loaner unit,  Squawk remains the same.

Back-pinned v to assure it had a solid ground during operation.

With amp unplugged, Ohm meter on M, H, and J  Both halves of the sensor read ~89  ohms at max cold, ~124  ohms at max hot.

Unrelated?

pulled 5 temp switches for a unrelated bleed oheat light when wing heat switched off, turned out to be a sticking PRV

Unrelated?

Removed  failed seals at upper and lower turbo cooler Best-O-Bell inlet pipes. Installed 4 each  new seals.

PARTS OFF: P/N 460-150 S/N NA.

PARTS ON: P/N 460-150 REV P  LOT# 0110336483.

Performed leak check.

Quoted text from John Taylor:

  1. Leading Particulars.

Type of Control …………………………………………………………………………………………………….. Pulse modulated

Temperature Selector Range ……………………………………………………………. 60°F to 90°F (15.4°C to 31.9°C)

Input Voltage ……………………………………………………………………………………………………………… 18 to 32 VDC

Maximum Output …………………………………………………………………………………………………. 2 amps at 28 VDC

Ambient Temperature Range ………………………………………………………………-65°F to 165°F (-54°C to 72°C)

Deadband ………………………………………………………………………………………………………………….. 3.0°F (1.7°C)

Transient Voltage Protection …………………………………………………………………………………. + 80 volt, -600 volt

Reverse Voltage Protection ………………………………………………………………………………………………………. Yes

Output Protection …………………………………………………………………………………………………………………….. Yes

Hi-Limit Protection ………………………………………………………………………………………………………. 160°F (70°C)

Cabin Sensor …………………………………. Negative Temperature Coefficient Disc Thermistor ( See Figure 1 )

Temperature Readout Sensor ……………………………….. Wire wound positive temperature coefficient 0.2°/F

Construction …………………………………………………………………………………………………………. Repairable Assy.

Connector Type …………………………………………………………………………………… Mates with MS3120A-14-195

Size

Length (max) ……………………………………………………………………………………… 8.400 inches (213.36 mm)

Width (max) ………………………………………………………………………………………….. 3.900 inches (99.06 mm)

Height (max) …………………………………………………………………………………………. 3.225 inches (81.91 mm)

Weight (approx.) ……………………………………………………………………………………….. 18 ounces (510.3 gm)

Temp Amplifier simplified block diagram:

temp-control