Battery Shop Procedures
>> Friday, November 20, 2009
Battery Shop Procedures
1. Purpose
1.1 This procedure defines the maintenance of aircraft batteries (which includes Boost Charge, Capacitance Check, Overhaul and Storage) in the Battery Workshop.
2. Scope and Responsibilities
2.1 It is the responsibility of the approved technician to carry out all Battery Maintenance work in accordance with the approved Data, Manufacturer’s Overhaul Manuals and Operator approved procedure sheet.
2.2 It is responsibility of the authorized staff to take all necessary safety precautions as applicable to the battery maintenance.
2.3 It is responsibility of the Battery Shop Supervisor to check and ensure that all the work accomplished is in compliance with the relevant Approved Data, Battery Manufacturer’s Overhaul Manuals and Instructions.
2.4 Repair/overhaul/modification/testing of aircraft components is restricted to items on the approved capability list in accordance with the approved manufacturer’s manuals, approved technical data and approved procedures and standard of workmanship.
3. Procedures
3.1 Working area temperature should between 70ºF to 80ºF (21.1ºC to 26.7ºC)
3.2 Records and Documents
a) Check the serial number of the battery which is received by the shop and enter in the Battery Inward Shop Register,
b) Check unserviceable tag received with the battery,
c) Check the general condition of the battery,
d) The following records are to be maintained in the Battery Shop:
- Component Worksheet
- Battery Test Result History Card
3.3 Work to be carried out
a) Boost Charge
Boost Charge is the routine service for batteries which have been removed from the “Serviceable Storage Area” in the battery shop due to expiry of validity date after 14 days from release.
b) Capacity Test
- Capacity Test is the routine service required for batteries, which are returned to Battery Shop for servicing.
- For new batteries before their release to service.
c) Overhaul and Repair
Overhaul and repair service for batteries is necessary whenever:
- Battery found in an unsatisfactory general condition
- Battery fails to meet capacity test requirements
- Battery found with excessive leakage current
Note: All the above are to be carried out in accordance with Approved Data
3.4 Storage Service
a) Batteries, which have been serviced and tagged “Serviceable”, shall be stored in the “Serviceable Storage Area” in the Battery Shop
b) The “Serviceable Storage Area” shall be monitored daily. Any battery found with the validity date expired, shall be removed and re-processed through the Battery Shop according to the following procedures
c) Boost Charge
A battery which has exceeded 14 days storage period
d) Capacity Test
A battery is found due for capacity test after four months, (for all Airbus and B747SP aircraft)
3.5 Equipment Required
- Constant current charger
- Constant current discharger
- Digital Multimeter for voltage and leakage current measurement
- Compressed air, clean, dry and 20 PSI maximum
- Liquid level check tube
- Distilled water, Vaseline and lint free cloth
3.6 Re-certification and Serviceable Label
a) Before releasing any battery to service, check the relevant work sheets are satisfactorily completed.
- Component Work Sheet
- Test Result Record sheet
b) Fill out and attach a serviceable label and clear the entry in the Battery Shop Component Register.
c) Endorse the label with the validity period for storage in the Battery Shop. This date shall not exceed 14 days from the certification date. Place the battery in the approved storage area for serviceable batteries.
d) Enter the date of the capacity test due, on a brady aluminum label, and apply the label on the right side of the battery.
e) Enter all outgoing serviceable batteries in outward register kept in the Battery shop.
THIS MATERIAL MUST NOT BE USED FOR FLIGHT OR AS A
MAINTENANCE REFERENCE - IT IS FOR GUIDANCE ONLY
Read more...
Labels:
Aircraft Battery Shop Procedures
Boeing B777 - GE90-115B Engines - Low Pressure Turbine Borescope
>> Monday, November 9, 2009
Boeing B777 - GE90-115B Engines - Low Pressure Turbine Borescope
Background/Reason:
On condition requirement of an engine requires periodical inspection of internal condition of certain critical rotating parts. The exact rate of change of these hardware conditions from the initial condition can be regularly monitored and on a planned basis, the engines can be removed, when these critical parts have reached its maximum life for repair/refurbishment/overhaul/replacement.
Frequency:
Every 500 FC since last inspection.
Material Requirement:
1.Borescope set; Borescope set complete with light, rigid and flexible; Qty 01
2.Plug-Assy P/N 1322M32G08; Qty 01; If require
3.Plug-Assy P/N 1322M32G11; Qty 01; If require
4.Antiseize P/N D50003 or D50017 or D50043; as required
Accomplishment Instructions:
1. Open the following circuit breakers & install safety tags
Row Col Number Name
B 1 C80601 L ENG START VALVE
B 3 C80605 L ENG START SW
B 16 C80600 R ENG START VALVE
B 18 C80606 R ENG START SW
Note: The Circuit breakers listed below are for both engines. Tag & install safety tags depending on engine to be inspected.
2. Retract the leading edge slats as per AMM 27-81-00-860-805.
3. Deactivate the leading edge slats as per AMM 27-81-00-040-801.
4. Deactivate the Thrust Reverser for ground maintenance as per AMM 78-31-00-040-806-H00.
5. Open the fan cowl as per AMM 71-11-04-010-814-H00.
6. Open the thrust reverser cowl as per AMM 78-31-00-010-816-H00.
7. Refer to Fig 1 & Fig 2 and remove the borescope plugs R & S.
8. Insert Borescope Probe through port R or port S as per AMM.
9. Refer to figs 3 to 6 & rotate the Fan Clockwise as per AMM 72-00-00-290-807-H01 & inspect the LPT blades leading edges and trailing edges and complete the Table 1.
10. Remove borescope probe from Ports after completing the borescope inspection as per AMM.
11. Apply Antiseize compound on the borescope plugs R & S.
12. Install the borescope plugs R & S as per AMM 72-00-00-420-001-H01.
Note: Tighten the plugs to 110.0-140.0 pound-inches (12.4-15.8 Newton-meters)
13. Carry out duplicate inspection of installation of the borescope plugs R & S as per AMM 72-00-00-420-001-H01.
14. Close the Thrust Reverser as per AMM Task 78-31-00-410-816-H00.
15. Close the Fan Cowl as per AMM Task 71-11-04-410-814-H00.
16. Activate the Thrust Reverser as per AMM 78-31-00-440-805-H00.
17. Activate the leading edge slat as per AMM 27-81-00-440-801.
18. Remove the safety tags and close these circuit breakers:
Row Col Number Name
B 1 C80601 L ENG START VALVE
B 3 C80605 L ENG START SW
B 16 C80600 R ENG START VALVE
B 18 C80606 R ENG START SW
Note: The Circuit breakers listed below are for both engines. Tag & install safety tags depending on engine to be inspected.
THIS MATERIAL MUST NOT BE USED FOR FLIGHT OR AS A
MAINTENANCE REFERENCE - IT IS FOR GUIDANCE ONLY
Labels:
B777 - GE90-115B Engines
Boeing B727-200F Wiring Inspection
>> Tuesday, November 3, 2009
Boeing B727-200F Wiring Inspection
1.0 FINDINGS OF THE WIRING INSPECTION.
This report details the findings of the wiring visual inspection in the following areas based on Quality Inspection Card (QIC) issued by QA Department. Dated 1st Feb 2006, three (3) B727 acfts have been completed the inspection.
- From Nose to E&E Compartment
- Forward Lower Deck Cargo Compartment
- Aft Lower Deck Cargo Compartment
- Main Wheel Well
- LH Wing (Port & Stbd)
- RH Wing (Port & Stbd)
- Flight Deck Upper (Overhead) to 9G Bulkhead
- 9G Bulkhead to Aft Entry Door (Nain Deck Cabin)
- LH & RH Aft Airstairs Area
- Tail Compartment (including vertical fin and stabilizer)
- Engine 1, 2 & 3 including pylon areas
The overview of the findings for each areas is provided below in para 1.1 to 1.9. However, the details of the findings are provided in the table.
A total of 4898 wires, 65 pressure seals and 752 connectors were visually inspected. It was observed that 21.9 percent of the wires suffered deterioration due to chaffing, kink, hardened and brittle insulation and unauthorised splicing. Also 16.0 percent of the connectors suffered from corrosion at the pin contacts or dialectic insulation and 53.8 percent of the pressure seals are damaged.
It should be emphasized here that wires that showed discoloration at the outer insulation jackets are not included as degraded wires. Similarly, connectors that have corrosion at the outer, shells are also not included in the percentages above.
Connector found with corrosion at the pin contacts are mainly concentrated around the top of the horse collar in front of the firewall and at outer wing pressure break areas. Corrosion of connector pin contacts around this area is significant because most of the connectors have wiring from numerous system passing through it. It addition to corrosion at connectors' pin contacts, the wire's terminating end at the back of the subject connectors also shows sign of discoloration, which indicates that either overheating has occurred or chemical reaction has taken place between the rubberized grommet and bushing material with the wire's insulation, both of the which in time may affect the integrity of the wire's insulation.
The thermal damage may caused by the heat source coming from either the wire's core itself (as in the case of electrical overcurrent) or from external source. Either case may cause the wire's insulation to be gradually discolored and in time may carbonized the insulation material, which turns the insulation material into a conductor. The now conductive insulation may in time become short‑circuited with nearby wires, causing systems failure or in extreme case, an electrical fire. It should be noted that the discoloration found at this area are not due to cable clamps.
Other discrepancies detected on LH Leading Edge wiring includes corrosion at conduit connector (which is not easily observed unless the wiring installation is removed) and illegal splicing close (less than 12 inches) to the connector's end. The illegal splicing are probably due to maintenance insitu repair.
Discoloration of wire ends was also detected at the back of the RH Leading Edge connector's mounting bracket. Since the bracket is similar to the LH Leading Edge's, the affected systems that may be failed due to the discrepancies.
Other discrepancies found on the RH Leading Edge wiring includes deteriorated cable insulation and serious overheating effect that damaged wire's insulation. The overheating of the wires occurred at about 3 feet inboard from the No. 4 engine.
In both cases, should the insulation be exposed to similar effect for a prolonged time, it may cause the wiring to fail and the cores to be shortcircuited, leading to other more catastrophic damaged than just the particular system malfunction, such as electrical spark or even fire.
Of the 5 connectors found with corrosion at pin/socket contacts, two connectors are located at the outer wing pressure break and wiring from multiple system are terminated at these connectors. Wiring for up to 10 systems can be terminated at a connectors. The other two connector are from the emergency valves system for engine bleed air pressure regulation.
1.4.1 LH Trailing Edge
Dump and APU, Trim Tab Position Indicator and Control, formation lights, Engine Fire Extinguisher and paratroop air deflector control. A high percentage (60%) of the wires used in this area a belong to MIL‑W‑5086/2 which has been superseded by MIL‑W‑22759/34.
Degraded wires were mainly from MIL‑W‑5086/2 and MIL‑W‑25038/1 wire specifications. MIL‑W‑25038/1 wires are still valid for use. However 85% (30 out of 35) of this wires type are found to be brittle.
Of the 41 connectors inspected, 3 (7.3%) connectors from the fuel refueling system and paratroop air deflector control system were found with corroded pin/socket contacts. These connectors are also found to be degraded at the RH trailing edge. 21 out of the 41 connectors inspected are for connection to the fuel tank. None of these connectors which are located next to the fuel tanks are degraded. Similar findings were obtain for the fuel tank connector.
The subsystem affected are the fuel system (Boost, Auxiliary,. Tank and External Tank Pumps, Refueling, Crossfeed, Dump and Pressure Indicator, Wing Flap control, Engine Fire Extinguisher, Fuel Quantity Indicator and Hydraulic pumps low pressure warning. Most of the wires used belong to the specifications MIL‑W‑5086/2 and MIL‑W‑25038/1. Similarly most of the degraded wires belong to these two wire types. 100% (33 out of 33) of all wires belonging to MIL‑W‑25038/1 wire specification has superseded to MIL‑W‑25038/3. Of the 41 connectors inspected 3 (7.3%) of the connectors were found with corrosion at pin/socket contacts.
Two of the subsystem affected, the fuel refueling and paratroop air deflector control, are the same as the findings on the LH trailing edge. The other subsystem with degraded connectors are the fuel system boost pump, formation lights, hydraulic pump low pressure warning and fuel system dump. As with the LH trailing edge 21 of the connectors inspected are coaxial enables and are mostly located next to the fuel tank. These connectors, were all found to be in good condition.
The number of degraded connectors i.e. connectors with corrosion at contact pins is 23 (51.1%) of the total 45 connectors inspected. This is very high percentage and it affects 8 out of the 10 subsystem in the dry bay areas. Since this is an unpressurized area, it is subjects to the cyclic environmental condition changes which may explain why we have a relative large number of degraded wires and connectors.
The wiring inside the fuel tanks were found to be in excellent condition. A total of 122 wires and 238 connectors from the wing outboard tanks, wing inboard tanks, auxiliary tanks and external tanks were inspected. 35 out of the 122 wires (28.7%) inspected were found with wiring insulation degradation i.e. insulation hardened, kinked, insulation cracks, contiminated with fluid or brittle. 5 (2.1%) out of 238 connectors were found corroded at outer shell.
A total of 195 wires, 31 connectors and 4 pressure seals were inspected. The wiring looms were from the nose landing gear/wheel well area, the main landing gear (LH and RH) areas and wiring leading to the APU located forward of the LH wheel well area. In general it was found that the wire sleevings were either deteriorated or hardened. 20 (10.3%) wires, 7 (22.6%) connectors were found to be degraded. Wiring around the APU area suffered relatively more degradation due to hardened/brittle insulation. The wires are mainly located between APU compartment fire wall and the APU which is a relative high temperature area.
Only 1 (11.1%) of the 9 connectors at the nose wheel well and the same number of connector for APU area suffered from corrosion of the pin contacts and outer shell. There is only 1 connectors in the LH main landing gear suffered from corrosion of the pin contacts. All pressure seals were found in good condition.
1.8 Empennage Area
1.9 Cockpit
Of the 213 connectors inspected, 52 (24.4%) were found with corrosion at the pin contacts. The instrument system has 25.6% (32 out of 125) of its connectors degraded and the communication/navigation system has 22.7% (20 out of 88) of its connectors degraded.
i) Main Instrument Panel
ii) C‑12 Compass
iii) Autopilot and Flight Director
iv) Oxygen System
v) Air-condition
vi) Fuel Quantity Indication
vii) Hydraulic System
viii) Engine Instrument
Significant degradation of wiring was found on the MIP, Autopilot/Flight Director and the Engine Instruments. Overall 398 (23.3%) out of the 1710 wires inspected were degraded. From the inspection the MIP and autopilot/flight director system also had higher percentage of degraded connectors. The other systems with degraded connectors are the oxygen, compass and engine instrument.
1.9.2 Communications/Navigation System
In section 1, it is stated that about 16 percent of all the connectors inspected were found to be corroded at the pin contacts or at the mating surface. The primary function of a connector is to make good connection and if the contact material is corroded, this most basic function cannot be achieved. The corroded contact will increase the contact resistance which is one of the critical parameters in a connector and typical measured value is in milliohms or a fraction of a milliohm.
Connectors with corrosion found at the mating surface also raises the possibilities that the insulation between the various pin contacts of a connector could be lower than the required value of 10 megaohms stated in CAAIP. It was determined that the dielectric insulation material separating the contacts of connectors are either ceramic or silicone based material.
A insulation resistance check was carried out on 100 connectors. Of the 100 connectors, 62 connectors were good conditions connector i.e. no corrosion were found on the connector mating surface. It was found that all the connector satisfied the requirement in CAMP i.e. insulation resistance between the contacts is greater than 10 megaohms. 29 of the connectors had silicone based insulation material while the other 33 connectors had ceramic based insulation material.
The other 38 connectors are degraded connectors i.e. the connector mating surface were found to be corroded. 30 of these connectors had silicone based insulation and 8 had ceramic based insulation. None of 8 ceramic based insulation showed a breakdown in the insulation connectors, 15 (50%) of the silicon based insulation connector showed an insulation breakdown with connectors having an insulation resistance of below I megaohm.
Apart from the fuel tank connectors, it is estimated that about fifty percent of all connector used in the aircraft are of silicone based insulation. The main concentrations of silicone based insulation are at the trailing edge, leading edge, dry bay, empennage and QEC. These areas also the SWAMP areas where the previous section on visual inspection showed greater degradation of wiring looms.
Table I: Result for the Insulation Resistance Check
Area | Total No of Connectors Inspected | No of Silicone Dielectric Degraded Connector Inspected | No Of Connector with Insulation Breakdown |
Trailing Edge | 15 | 12 | 06 |
Leading Edge | 04 | 02 | 0 |
Landing Gear | 07 | 02 | 01 |
Instrument System Cockpit | 28 | 04 | 01 |
Electrical System Cockpit | 09 | 0 | 0 |
Radio Comm. System Cockpit | 18 | 03 | 03 |
Instrument Panel Cockpit | 14 | 03 | 03 |
QEC | 03 | 03 | 0 |
02 | 01 | 01 | |
TOTAL | 100 | 30 | 15 |
List of SB’s for B727 Wiring Inspection to be incorporated.
No | SB 727 | Description | Action | Remark |
1 | 20-0002 | Prevent personnel from being shocked by 115 volt AC when using the P13 fwd attendant's pnl or the P14 aft attendant's pnl. On P13 fwd attendant's pnl and P14 aft attendant's pnl, install a ground terminal lug over the shaft of the attendant's work light toggle switch so that it contacts the attendant's pnl aluminum faceplate. Install wire from the ground lug to the pnl connector and then to an existing AC groundstud. | O | |
2 | 21-0088 | Reroute air conditioning bay wire bundle to provide more clearance from the hot air duct and reduce the possibility of wire bundle overheat damage. | C | |
3 | 24-0012 | Provides additional insulation for wire terminals to guard against loose metallic objects which can cause short circuit. | C | |
4 | 24-0014 | Eliminates the possibility of damage to the power feeder by installing slotted head fasteners. | C | |
5 | 24-0016 | Prevent wetting of engine power lead wire bundle with engine oil from the oil tank drain by relocating the wire bundle further inboard. | C | |
6 | 24-0040 | Improve short circuit protection for the APU generator and APU starter motor by installing separate ground power. | C | |
7 | 24-0045 | Eliminate the possibility of damage for wire bundle routed with hot battery. Hot battery bus feeder wire will be isolated from the other wire bundle. | C | |
8 | 24-0050 | Reduce the possibility of heat damage to wire bundles in the keel beam area. | C | |
9 | 24-0054 | Provide clearance between airplane structure and a wire bundle that supplies electrical power to the engine fuel pumps. | C | |
10 | 24-0058 | Prevent the APU power feeder wire from contacting the E1-5 pnl door or structure which can result short circuit. | C | |
11 | 24A0072 | Provide instruction for performing inspection and clamping of wire bundle W116 in the E7E comp E1 rack. This is to prevent the wire bundle W116 from chaffing to the APU CB panel cover. | R | TGA & TGB have been incorporated SB 727-24A0072. Recommended SB to be incorporated to all ex-UPS acft. |
12 | 32-0064 | Prevent damage to electrical wiring in the nose gear wheel well by installing the conduit to the existing wire routing. | C | |
13 | 34-0064 | To preclude failure of terminals on the flux valve wire bundle at the flux valve connection. Added clamp to support the wire bundle. | C |
Note:
R – Must be done
O – Optional
C – SB’s have been incorporated by previous operator/Boeing
Read more...
Labels:
B727 Wiring Inspection
Subscribe to:
Posts (Atom)