Message Name:

FLAP RUNAWAY

Message Code:

B3-006688

Associated CAS:

FLAPS FAIL
(Caution)

Flap Control Unit (FCU) detected a runaway in the Flap System. Check mechanical driveline for symmetric disconnect. (If OB Actuator is disconnected or replaced, flaps must be rigged).

• Mechanical Driveline
• Flap Power Unit (FPU) (A123)
• Associated Wiring

Advisory Wire/Service Bulletin:

• AW300-27-0058 - Flap Control Unit - CAS Messages Reset procedure (20501 to 20999)

Forum Articles/Infoservice/Newsletter: None

In the MDC system parameters, an FPU PRESS XDCR SIGNAL showing 3740 PSI indicates the FCU have detected a malfunction in the system and do not send the excitation signal to the FPU pressure transducer.

MDC REPORT: SYSTEM PARAMETERS
FILENAME:
DATE:
...
FLAP SURFACE ANGLE - 3.74 DEG
FPU PRESS XDCR SIGNAL - 3740 PSI
APU HOURS - 1116.75 HRS
…

Source of the problem still has to be found.

2. 1. 1. Perform a General Visual Inspection of the Flap system per AMM (Verify integrity of driveline by pulling and pushing on the flap panel and by attempting to rotate the driveline by hand, verify integrity of AGB, and actuators to ensure that they are not loose or do not have stripped gears.).

         1. Replace any defective component per AMM.
         2. Continue with next step.

      2. Reset the following circuit breakers.

         1. If system checks are good, do close out.
         2. If fault remains, continue with next step.

         FLAP R IND	CB2-B12
         FLAP L IND	CB1-B13
         FLAP CTRL	CB1-B14

      3. Reset the FCU by pressing the FCU reset button on the MAINTENANCE TEST control-panel. If unable to reset, engage the Alternate Flaps button with the left hydraulic system pressurized, and attempt another reset using the Flap Reset switch on the left galley.

         1. If system checks are good, do close out.
         2. If fault remains, continue with next step.

      4. Perform a Flap Power Unit solenoid resistance check as follow.

         1. If values are not within specifications, replace FPU per AMM.
         2. If system checks are good, do close out.

         Connector	Part	Coil Resistance:	Values:
         A123J1	POB Solenoid	Pins 4-5 =	Normally around 58 Ω
         A123J1	Solenoid #2	Pins 1-2 =	Normally around 58 Ω
         A123J1	EHSV	Pins 7-8 =	Normally around 500 Ω
         A123J2	Solenoid #1	Pins 1-2 =	Normally around 58 Ω