3. Fault Confirmation
__________________
A. Test
(1) Not applicable.
NOTE : In flight, air friction causes static electricity to occur on
____ the surface of the aircraft. Static is discharged through static dischargers installed at the trailing edges and tips of the wings and the tail of the aircraft. Static is increased when the aircraft goes through cloud, rain or dust and, if not correctly discharged, it can cause radio noise. An increase in static can occur after an aircraft has been repainted, or had a skin repair (Ref. SIL 23-027). There are two typical types of radio noise caused by static electricity:
- a continuous low frequency noise, which can be caused by static at the radome, antennas or composite panels
- an irregular click or crackle noise, which can be caused by static at the static dischargers or metal panels.
「一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一1 EFF : ALL ∞∞23-61-00∞∞∞∞∞∞∞∞∞∞Page 201
Nov 01/99 CES
4. Fault Isolation
_______________
A. Procedure
(1) Do a check of the aircraft technical log for repair work which can be related to this fault.
(2) Do the steps that follow in an order applicable to the type of radio noise and any related repair work.
(3) Do a visual check of the applicable radio antenna and make sure that:
- it is correctly bonded to the aircraft structure (Ref. AMM TASK 20-28-00-912-005)
- the external paint is in good condition.
(4) Do a check of the static dischargers (Ref. AMM TASK 23-61-00-200-001) and make sure that:
- they are not defective or missing
- they are correctly bonded to their retainers
- their retainers are correctly bonded to the aircraft structure.
(5) Do a check of the radome (Ref. AMM TASK 53-15-11-200-001) and make sure that:
- there are no missing or defective metallic strips
- the correct type of paint was used to paint the radome.
(6) Do a check of repaired panels and make sure that:
- the surface conductivity of composite panels is correct (Ref. AMM TASK 20-28-00-720-010) and (Ref. AMM TASK 20-28-00-720-011)
- metal panels are correctly bonded to the aircraft structure (Ref. AMM TASK 20-28-00-720-004)
- bonding leads are not missing or defective
- all panels are painted with the correct low-ohmic paint.
(7) Do a check of the thickness of new paint (Ref. NTM 51-10-00).
NOTE : If the paint is too thick, compared to the standard specified,
____ electrostatic charges are isolated from the aircraft metal structure and may not discharge satisfactorily.
(8) Make an entry in the aircraft technical log of the work done.
(9) Make an entry in the aircraft flight log to do a check (after the next flight in cloud, rain or dust) that the radio noise caused by static has decreased to a satisfactory level.
COCKPIT VOICE RECORDER - FAULT ISOLATION PROCEDURES
___________________________________________________
TASK 23-71-00-810-801
Loss of the Audio Feedback in the Loud Speakers
1. Possible Causes
_______________
- RELAY-RCDR/CVR TEST (20RK)
- RELAY-PARKING BRK CTLD (14RK)
- P/B SW-RCDR/CVR TEST (5RK)
- wiring
2. Job Set-up Information
______________________
A. Referenced Information
-------------------------------------------------------------------------------
REFERENCE DESIGNATION
-------------------------------------------------------------------------------
AMM 23-71-00-710-001 Operational Test of the CVR and the CVR Channel
Recording
ASM 23-71/01
ASM 23-71/02
3. Fault Confirmation
__________________
A. Test
(1) Do the operational test of the CVR and the CVR channel recording (Ref. AMM TASK 23-71-00-710-001).
4. Fault Isolation
_______________
A. If during the operational test you do not hear the audio feedback in the loud speakers:
- do a check for continuity at the RELAY-RCDR/CVR TEST (20RK) (between pin A and pin 2, pins B and 4, pins C and 6) with the RCDR/CVR TEST pushbutton switch (5RK) pushed (Ref. ASM 23-71/02)
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