Maintenance & fault isolation

Access · Forward cargo / mix bay

Tools & materials · Gloves · Mask · Bags for disposal

Warning · Wear protective mask and gloves when handling used filters.

1. 1.Electrical power off for recirculation fans (open breakers, tag).
2. 2.Remove the filter housing cover and old HEPA filter.
3. 3.Bag the old filter (may contain biological contamination).
4. 4.Install the new filter with arrow in flow direction; close cover; close breakers; run fans.

Ref: B737 AMM 21-25-00

Access · Left fan cowl

Tools & materials · IDG servicing cart · Approved oil

1. 1.Engine shut down 5 min minimum.
2. 2.Open fan cowl; read the IDG sight gauge.
3. 3.Service with pressure fill until oil flows from the overflow.
4. 4.Check filter delta-P indicator; close cowls.

Ref: B737 AMM 24-11-00

Access · Flight deck fire panel

Tools & materials · None

1. 1.Hold FAULT/INOP test switch: check FAULT, APU DET INOP, MASTER CAUTION and OVHT/DET annunciators.
2. 2.Hold OVHT/FIRE test: fire bell, fire handles, wheel well light, MASTER FIRE WARN, ENG OVERHEAT lights.
3. 3.Press EXTINGUISHER TEST 1 and 2: three green squib lights per test.
4. 4.Check bottle pressures (maintenance) against chart.

Ref: B737 AMM 26-11-00 / FCOM SP

Access · Aft equipment area, stabilizer compartment

Tools & materials · Approved grease (e.g. Aeroshell 33) · Grease gun · Torque check tooling

Warning · Lack of lubrication on a stab trim screw has caused fatal accidents (e.g. Alaska 261 on an MD-83).

1. 1.Remove access panels to the jackscrew.
2. 2.Clean old grease from the screw threads.
3. 3.Apply new grease and run the stabilizer full travel to distribute.
4. 4.Check the end play of the ballnut against the limit.
5. 5.Reinstall panels; operational test of main electric and manual trim.

Ref: AMM 12-21-27 / MPD

Access · Under each wing and centre tank

Tools & materials · Drain tool · Sample jar

1. 1.Allow fuel to settle.
2. 2.Drain each main and centre tank sump until clear.
3. 3.Check for water and microbial contamination (dark slime).
4. 4.Close and check for leaks; record.

Ref: B737 AMM 12-11-28

Access · Gear on ground

Tools & materials · Calibrated gauge · Nitrogen

Warning · Never stand in line with the wheel axle.

1. 1.Check cold tyres; correct to placard.
2. 2.Look for cuts, bulges, worn tread to the bottom of a groove.
3. 3.Check thermal fuse plugs and wheel tie bolts.
4. 4.Record and remove per loss limits (same as 5 % / 10 % rule).

Ref: AMM 12-15-31

Access · APU access door (left side tail cone)

Tools & materials · Approved oil

1. 1.APU off (wait as specified).
2. 2.Read the oil sight gauge; LOW OIL QUANTITY indication on the upper display.
3. 3.Service to FULL via gravity fill.
4. 4.Close door; record quantity added (trend monitoring).

Ref: B737 AMM 12-13-49

Access · Borescope ports on core case

Tools & materials · Video borescope · Core rotation tool (N2 drive pad)

1. 1.Engine cooled; install the manual turning tool on the AGB.
2. 2.Insert borescope through the HPT port.
3. 3.Rotate N2 and inspect each blade for burns, cracks, coating loss, tip curl.
4. 4.Measure damage against AMM limits; record images.
5. 5.Remove tools, install port plugs with torque and safety.

Ref: AMM 72-00-00 Inspection/Check

Access · Right side fan cowl oil fill door

Tools & materials · Approved oil · Lint-free cloth

Warning · A cap not locked can cause total oil loss in flight.

1. 1.Service within 30 min of shutdown for an accurate reading (or after motoring the engine).
2. 2.Open the oil filler access; read sight gauge.
3. 3.Remove the cap slowly, fill to FULL.
4. 4.Install cap — check the locking handle is fully down and flush.
5. 5.Record quantity for consumption trend.

Ref: AMM 12-13-11