DOC AIRBUS | AMM A320FLaboratory Analysis of the Engine Oil for Contamination [PW11]
TASK 79-00-00-210-811-A
Laboratory Analysis of the Engine Oil for Contamination
Use this procedure to examine the debris found on the ODM probe, the magnetic chip collectors, the last chance oil strainers and in the main oil filter element. A description and source of the types of debris that can be found is also given. The debris collected can give an early indication of component distress.
2. Job Set-up Information
A. Work Zones and Access Panels
B. Referenced Information
3. Job Set-up
Subtask 79-00-00-860-066-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.01 13:02:02 UTC
Laboratory Analysis of the Engine Oil for Contamination
WARNING:
BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AND THE ADJACENT COMPONENTS AFTER ENGINE SHUTDOWN. THE ENGINE, THE ENGINE OIL AND THE ADJACENT COMPONENTS CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS INSTRUCTION, INJURY CAN OCCUR.
WARNING:
MAKE SURE THAT THE ENGINE SHUTDOWN OCCURRED NOT LESS THAN FIVE MINUTES BEFORE YOU DO THIS PROCEDURE. IF YOU DO NOT OBEY THIS INSTRUCTION, INJURY CAN OCCUR.
WARNING:
REFER TO THE PRODUCT LABEL AND THE MANUFACTURER'S (MATERIAL) SAFETY DATA SHEET (SDS) FOR INSTRUCTIONS ON THE HAZARDS, STORAGE, SAFE HANDLING AND CORRECT USE OF CONSUMABLE PRODUCTS.
ZONE: 400
1. Reason for the JobUse this procedure to examine the debris found on the ODM probe, the magnetic chip collectors, the last chance oil strainers and in the main oil filter element. A description and source of the types of debris that can be found is also given. The debris collected can give an early indication of component distress.
2. Job Set-up Information
A. Work Zones and Access Panels
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 400 | POWER PLANT, NACELLES AND PYLONS |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 71-00-00-860-814-A | Shutdown of the Engine |
| TASK 71-00-00-860-822-A | Start the Engine (Normal Manual Start) |
| TASK 71-00-00-860-823-A | Start the Engine (Normal Automatic Start) |
| TASK 71-00-00-910-803-A | Engine Operation Limits and Guidelines |
| TASK 72-00-00-210-811-A | Inspection of the Engine after Engine Oil Overtemperature |
| TASK 72-61-01-960-804-A | Replacement of the Hydraulic Pump Drive Oil Seal |
| TASK 79-00-00-210-809-A | Visual Inspection of the Main Oil Filter Element for Contamination |
| TASK 79-00-00-210-810-A | Visual Inspection of the Engine Oil System |
| TASK 79-00-00-281-802-A | Inspection of the Magnetic Chip Collectors for Oil Contamination |
| TASK 79-00-00-281-804-A | Sampling of the Engine Oil |
| TASK 79-00-00-610-801-A | Check and Fill the Engine Oil |
| TASK 79-00-00-610-802-A | Change the Engine Oil |
| TASK 79-00-00-680-801-A | Drain the Engine Oil |
| TASK 79-21-06-960-801-A | Replace the Oil Filter Element |
| TASK 79-21-08-000-801-A | Removal of the Fuel/Oil Heat Exchanger |
| TASK 79-21-08-400-801-A | Installation of the Fuel/Oil Heat Exchanger |
| TASK 79-21-18-000-801-A | Removal of the Last Chance Oil Strainer |
| TASK 79-21-18-400-801-A | Installation of the Last-Chance Oil Strainer |
| FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1) | |
| TASK 29-11-51-000-805-A | Removal of the Green Engine Driven Pump |
| TASK 29-11-51-400-805-A | Installation of the Green Engine-Driven Pump |
| FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2) | |
| TASK 29-13-51-000-806-A | Removal of the Yellow Engine Driven Pump |
| TASK 29-13-51-400-806-A | Installation of the Yellow Engine-Driven Pump |
Laboratory Analysis of the Engine Oil for ContaminationSubtask 79-00-00-860-066-A ** ON A/C NOT FOR ALL
A. Not Applicable
4. ProcedureCAUTION:
WIPE CLEAN ALL PARTS AND TOOLS AS NECESSARY TO REMOVE UNWANTED DEBRIS AND PREVENT DAMAGE TO THE ENGINE.
Subtask 79-00-00-210-096-A ** ON A/C NOT FOR ALL A. General
(1) The types and source of debris (contamination) that can be found are as follows:
(a) Metal build debris
1 Description:
Metal build debris collects during the early stages of engine operation after assembly of the engine. Build debris can look like strands of curly steel wool, shavings or burrs. Small quantities are permitted.
2 Source:
This is residual material that is left in or goes into the engine at assembly. Build debris usually comes from machining operations when the components are made or assembled.
(b) Non-metal build debris
1 Description:
Non-Metal build debris also collect during the early stages of engine operation after assembly of the engine. This type of debris can include cloth, paper or plastic accidentally left in the oil system during engine assembly and is not normal. The plastic could be in melted pieces.
2 Source:
This debris usually comes from rags or protective covers, plugs or caps accidentally left in the oil system during assembly or maintenance.
(c) Magnetic fines
1 Description:
These are very small particles. They are less than 0.010 in. (0.25 mm) long and of different widths. They can show as a black or gray sludge or fuzz on the magnetic chip collector (2). When the oil on the chip collector is removed, they show as dull hair-like slivers. This type of magnetic debris is usually found on low time engines and a small amount (quantity) is permitted.
2 Source:
Usual wear debris can have small quantities of fines and can be made by many different engine components. Bearing skid and component part spinning (i.e. spacers, seal plates and shaft plugs) can also make fines and is not a serviceable condition. Fines from these sources are made at a higher rate than fines from usual engine operational wear.
(d) Chips or flakes
1 Description of chips:
These are very thick pieces of metal. Usually one surface is a smooth machined surface, the opposite surface is rough and irregular.
2 Source of chips:
Chips from ball and roller bearings are usually smooth and shiny on one side. This side can have indications of the original honing/grinding process. The opposite side is duller and has a fractured appearance. Chips from gear teeth have a shiny side with machine marks and one side that is smooth and dull.
3 Description of flakes:
Flakes have an irregular shape, but are usually flat and shiny on both sides. You must do an analysis of them to identify their source.
4 Source of flakes:
Flakes come from ball bearings, roller bearings and gear teeth. Flakes from ball and roller bearings are very thin: 0.002 in. (0.05 mm) to 0.010 in. (0.25 mm) thick. They usually have an irregular, plate-like shape and have radial cracks. When the flake is cleaned, it is much brighter than other types of contamination. Flakes from gear teeth are shiny, long and thin, and have an irregular shape. They are usually thicker and not as bright as ball and roller bearing flakes.
(e) Hydraulic fluid (Skydrol) contamination of the oil system
1 Description:
Contamination of the oil system by hydraulic fluid is very serious. At engine operating temperatures, hydraulic fluid reacts with synthetic oils to form a black, thick, gummy substance which can cause a blockage or drastically decrease oil flow through jets, nozzles, fine mesh screens and the main oil filter element.
2 Source:
Incorrect servicing of the engine oil system or a leak by the hydraulic pump seal into the gearbox can cause this type of oil system contamination.
(2) Jet fuel contamination of the oil system
Contamination of the oil system by jet fuel is very serious. The viscosity of engine oil, with fuel contamination, is less than for oil that does not have fuel contamination. Engine symptoms are high oil temperature and over-servicing of (too much oil in) the oil tank. Oil that has fuel in it causes damage to packings (1). Damaged packings (1) cause oil leaks in the gearbox accessory seals. If you operate the engine, for a length of time with oil that has fuel contamination, damage to the bearings can possibly occur.
(b) Source:
An internal leak in the fuel/oil cooler can cause fuel contamination.
Subtask 79-00-00-281-059-A ** ON A/C NOT FOR ALL (1) The types and source of debris (contamination) that can be found are as follows:
(a) Metal build debris
1 Description:
Metal build debris collects during the early stages of engine operation after assembly of the engine. Build debris can look like strands of curly steel wool, shavings or burrs. Small quantities are permitted.
2 Source:
This is residual material that is left in or goes into the engine at assembly. Build debris usually comes from machining operations when the components are made or assembled.
(b) Non-metal build debris
1 Description:
Non-Metal build debris also collect during the early stages of engine operation after assembly of the engine. This type of debris can include cloth, paper or plastic accidentally left in the oil system during engine assembly and is not normal. The plastic could be in melted pieces.
2 Source:
This debris usually comes from rags or protective covers, plugs or caps accidentally left in the oil system during assembly or maintenance.
(c) Magnetic fines
1 Description:
These are very small particles. They are less than 0.010 in. (0.25 mm) long and of different widths. They can show as a black or gray sludge or fuzz on the magnetic chip collector (2). When the oil on the chip collector is removed, they show as dull hair-like slivers. This type of magnetic debris is usually found on low time engines and a small amount (quantity) is permitted.
2 Source:
Usual wear debris can have small quantities of fines and can be made by many different engine components. Bearing skid and component part spinning (i.e. spacers, seal plates and shaft plugs) can also make fines and is not a serviceable condition. Fines from these sources are made at a higher rate than fines from usual engine operational wear.
(d) Chips or flakes
1 Description of chips:
These are very thick pieces of metal. Usually one surface is a smooth machined surface, the opposite surface is rough and irregular.
2 Source of chips:
Chips from ball and roller bearings are usually smooth and shiny on one side. This side can have indications of the original honing/grinding process. The opposite side is duller and has a fractured appearance. Chips from gear teeth have a shiny side with machine marks and one side that is smooth and dull.
3 Description of flakes:
Flakes have an irregular shape, but are usually flat and shiny on both sides. You must do an analysis of them to identify their source.
4 Source of flakes:
Flakes come from ball bearings, roller bearings and gear teeth. Flakes from ball and roller bearings are very thin: 0.002 in. (0.05 mm) to 0.010 in. (0.25 mm) thick. They usually have an irregular, plate-like shape and have radial cracks. When the flake is cleaned, it is much brighter than other types of contamination. Flakes from gear teeth are shiny, long and thin, and have an irregular shape. They are usually thicker and not as bright as ball and roller bearing flakes.
(e) Hydraulic fluid (Skydrol) contamination of the oil system
1 Description:
Contamination of the oil system by hydraulic fluid is very serious. At engine operating temperatures, hydraulic fluid reacts with synthetic oils to form a black, thick, gummy substance which can cause a blockage or drastically decrease oil flow through jets, nozzles, fine mesh screens and the main oil filter element.
2 Source:
Incorrect servicing of the engine oil system or a leak by the hydraulic pump seal into the gearbox can cause this type of oil system contamination.
(2) Jet fuel contamination of the oil system
NOTE: If the oil has fuel in it, you can smell the fuel.
(a) Description: Contamination of the oil system by jet fuel is very serious. The viscosity of engine oil, with fuel contamination, is less than for oil that does not have fuel contamination. Engine symptoms are high oil temperature and over-servicing of (too much oil in) the oil tank. Oil that has fuel in it causes damage to packings (1). Damaged packings (1) cause oil leaks in the gearbox accessory seals. If you operate the engine, for a length of time with oil that has fuel contamination, damage to the bearings can possibly occur.
(b) Source:
An internal leak in the fuel/oil cooler can cause fuel contamination.
B. Oil System Contamination Examination
(1) Examine the oil system for build debris, magnetic fines, chips or flakes (Ref. AMM TASK 79-00-00-210-810).
(a) Do the visual inspection of the magnetic chip collectors (2) for oil contamination (Ref. AMM TASK 79-00-00-281-802).
(b) Do the visual inspection of the main oil-filter element for contamination (Ref. AMM TASK 79-00-00-210-809).
(c) Do the visual inspection of the last chance oil strainers for contamination (Ref. AMM TASK 79-21-18-000-801) and (Ref. AMM TASK 79-21-18-400-801).
(d) If necessary, sample the engine oil (Ref. AMM TASK 79-00-00-281-804).
(2) Examine the oil system for dark oil condition.
1 Does the oil have an unusual smell (burned or equivalent to fuel or hydraulic fluid)?
2 Is the oil thick or gummy?
3 Did an engine oil overtemperature ever occur?
(b) If you answer no to these questions, the engine can continue in service.
(c) If you answer yes to one or more of the above questions, you must continue to check the engine oil system as follows:
2 If necessary, do an inspection of the engine oil system after oil overtemperature operation (Ref. AMM TASK 72-00-00-210-811).
(3) Evaluate the oil system for hydraulic fluid contamination as follows:
(a) Determine if an inspection for contamination from hydraulic fluid is necessary as follows:
1 If black oil is found and the engine has not had and oil overtemperature condition.
2 If there was a failure of an engine hydraulic pump, such that hydraulic fluid was able to go into the oil system.
3 If there is corrosion of metal in the empty space in the pump that is adjacent to the gearbox.
4 If there is a quantity of hydraulic fluid in the empty space in the pump.
5 If other contamination is possible (example, maintenance error).
(b) If necessary, inspect the oil system for hydraulic fluid contamination as follows:
1 Remove the engine driven hydraulic pump:
a FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
(Ref. AMM TASK 29-11-51-000-805).
b FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
(Ref. AMM TASK 29-13-51-000-806).
2 Remove the fluid from the empty space in the pump.
3 Remove the hydraulic pump drive oil seal (Ref. AMM TASK 72-61-01-960-804).
4 Examine the seal and the packings (1) on the seals for deterioration. Deterioration is an indication of contamination.
5 Examine the driveshaft bearing support and bearing. Try to move the driveshaft axially and radially. If the driveshaft is loose, there is a problem with the bearing. Remove the main gearbox immediately and install a new main gearbox.
6 If the gearbox was not replaced, install the hydraulic pump drive oil seal (Ref. AMM TASK 72-61-01-960-804).
7 Install or, if damaged, replace the engine driven hydraulic pump:
a FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
(Ref. AMM TASK 29-11-51-400-805).
b FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
(Ref. AMM TASK 29-13-51-400-806).
(c) If there is an indication of hydraulic fluid contamination, do the steps that follow:
1 Change the engine oil (Ref. AMM TASK 79-00-00-610-802).
2 Replace the main oil filter element (Ref. AMM TASK 79-21-06-960-801).
3 Prepare the engine and the aircraft for engine operation.
4 Do the automatic or manual start procedure (Ref. AMM TASK 71-00-00-860-823) or (Ref. AMM TASK 71-00-00-860-822).
5 Operate the engine at ground idle until the oil is warm for ten minutes (Ref. AMM TASK 71-00-00-910-803).
6 Shutdown the engine (Ref. AMM TASK 71-00-00-860-814).
7 Get a sample of the engine oil (Ref. AMM TASK 79-00-00-281-804).
(d) Make an analysis of the engine oil by one of the two procedures that follow:
2 Examine the oil for phosphorus content. Compare the oil that you think is bad with oil of the same brand that you know is good. Use wet chemical test (ASTM D-1091-64) or spectroscopic oil analysis.
3 If the engine oil is contaminated, change the engine oil, operate the engine and make another sample of the engine oil as previously specified in Para B.(3)(c) and Para. B.(3)(d).
(4) Examine the oil system for water contamination as follows:
(a) Take a 4 oz (113.40 g) sample of engine oil.
(b) Do the SAE ARP 5991 water analysis to find how much water is contained in the oil sample.
(c) If the water content of the oil sample is more than 1000 parts per million by weight or by volume, do the steps that follow:
2 Replace the main oil filter element (Ref. AMM TASK 79-21-06-960-801).
3 Fill the oil system with new oil that is not contaminated (Ref. AMM TASK 79-00-00-610-801).
(5) Make an analysis of the engine oil for acid content by the steps that follow:
(a) Take a 4 oz (113.40 g) sample of engine oil.
(b) Use ASTMD-664 total acid number (titrated to PH 11.0) analysis to compare the acid content of the oil.
1 Find the total acid number for a quantity of new oil which is the same type oil that you use to service engines.
2 Find the total acid number for the oil sample you got before.
4 Change of engine oil:
b If necessary, do an inspection of the engine oil system after oil overtemperature operation (Ref. AMM TASK 72-00-00-210-811).
(6) Examine the oil system for fuel contamination by the steps that follow:
(b) Use wet chemical test (ASTM D-1091-64) or spectroscopic oil analysis to examine the oil for phosphorus content. Compare the oil that you think is bad with oil of the same brand that you know is good.
(c) If there is fuel contamination of the oil system, do the steps that follow:
1 Replace the fuel/oil heat exchanger (Ref. AMM TASK 79-21-08-000-801) and (Ref. AMM TASK 79-21-08-400-801).
2 Change the engine oil (Ref. AMM TASK 79-00-00-610-802).
3 Prepare the engine and the aircraft for engine operation.
4 Do the automatic or manual start procedure (Ref. AMM TASK 71-00-00-860-823) or (Ref. AMM TASK 71-00-00-860-822).
5 Operate the engine at ground idle until the oil is warm for ten minutes (Ref. AMM TASK 71-00-00-910-803).
6 Shutdown the engine (Ref. AMM TASK 71-00-00-860-814).
7 Get a sample of the engine oil (Ref. AMM TASK 79-00-00-281-804).
(d) Make an analysis of the engine oil by one of the two procedures that follow:
2 Use wet chemical test (ASTM D-1091-64) or spectroscopic oil analysis to examine the oil for phosphorus content. Compare the oil that you think is bad with oil of the same brand that you know is good.
3 If the engine oil is contaminated, change the engine oil, operate the engine and make another sample of the engine oil as previously specified in Para. B.(6)(c) and Para. B.(6)(d).
(7) Do a spectroscopic analysis of the chips and flakes as follows (Refer to Table 601 , Table 602 and Table 603):
(a) The function of this analysis is to get a quantitative estimate of the relative concentration of metallic elements in the chips and flakes, a compositional fingerprint that can be compared to elemental profiles of known oil-wetted materials, so that you can find the source of the contamination. One of several spectroscopic methods can be used, depending upon the homogeneity and quantity of the chips and flakes. The methods and advantages/disadvantages of each are given in Table 601.
Table 601 - Spectroscopic Inspection Methods, Advantages/Disadvantages
(b) In all the techniques identified above, you will get the best analysis when you use well-characterized standard materials, similar in composition to the sample, to calibrate the equipment. The stability and relative specificity of modern equipment, however, permits some useful information to be gathered with less rigorous calibration. Interpretation of this type of data is difficult, however, and must be done only by a trained atomic spectroscopist.
Table 602 - Mineral Composition of the Bearing, Gear or Carbon Seal Carrier Materials
Table 603 - Magnetic Probe Location and Material Composition
(1) Examine the oil system for build debris, magnetic fines, chips or flakes (Ref. AMM TASK 79-00-00-210-810).
(a) Do the visual inspection of the magnetic chip collectors (2) for oil contamination (Ref. AMM TASK 79-00-00-281-802).
(b) Do the visual inspection of the main oil-filter element for contamination (Ref. AMM TASK 79-00-00-210-809).
(c) Do the visual inspection of the last chance oil strainers for contamination (Ref. AMM TASK 79-21-18-000-801) and (Ref. AMM TASK 79-21-18-400-801).
(d) If necessary, sample the engine oil (Ref. AMM TASK 79-00-00-281-804).
(2) Examine the oil system for dark oil condition.
NOTE: Dark oil can be an indication of a serious problem or it can be a condition that requires no maintenance action. The dark oil condition "black oil" is the result of some additives in the oil that oxidize as the oil ages. This can cause very fine carbon particulate which darkens the oil without an effect on the properties which lubricate and cool (total acid number and viscosity are not changed).
(a) If you see dark oil, you can determine if maintenance action is necessary as follows: 1 Does the oil have an unusual smell (burned or equivalent to fuel or hydraulic fluid)?
2 Is the oil thick or gummy?
3 Did an engine oil overtemperature ever occur?
(b) If you answer no to these questions, the engine can continue in service.
(c) If you answer yes to one or more of the above questions, you must continue to check the engine oil system as follows:
CAUTION:
BLACK OIL CAN ALSO BE THE RESULT OF OIL OVER-TEMPERATURE. IF THIS CONDITION IS A POSSIBLE CAUSE, REFER TO THE INSPECTION OF THE OIL SYSTEM AFTER OIL OVER-TEMPERATURE. REFER TO 72-00-00 INSPECTION/CHECK-06 (TASK 72-00-00-210-811).
1 Do an inspection of the oil system contamination (analysis and disposition). 2 If necessary, do an inspection of the engine oil system after oil overtemperature operation (Ref. AMM TASK 72-00-00-210-811).
(3) Evaluate the oil system for hydraulic fluid contamination as follows:
(a) Determine if an inspection for contamination from hydraulic fluid is necessary as follows:
1 If black oil is found and the engine has not had and oil overtemperature condition.
2 If there was a failure of an engine hydraulic pump, such that hydraulic fluid was able to go into the oil system.
3 If there is corrosion of metal in the empty space in the pump that is adjacent to the gearbox.
4 If there is a quantity of hydraulic fluid in the empty space in the pump.
5 If other contamination is possible (example, maintenance error).
(b) If necessary, inspect the oil system for hydraulic fluid contamination as follows:
1 Remove the engine driven hydraulic pump:
a FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
(Ref. AMM TASK 29-11-51-000-805).
b FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
(Ref. AMM TASK 29-13-51-000-806).
2 Remove the fluid from the empty space in the pump.
3 Remove the hydraulic pump drive oil seal (Ref. AMM TASK 72-61-01-960-804).
4 Examine the seal and the packings (1) on the seals for deterioration. Deterioration is an indication of contamination.
5 Examine the driveshaft bearing support and bearing. Try to move the driveshaft axially and radially. If the driveshaft is loose, there is a problem with the bearing. Remove the main gearbox immediately and install a new main gearbox.
6 If the gearbox was not replaced, install the hydraulic pump drive oil seal (Ref. AMM TASK 72-61-01-960-804).
7 Install or, if damaged, replace the engine driven hydraulic pump:
a FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
(Ref. AMM TASK 29-11-51-400-805).
b FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
(Ref. AMM TASK 29-13-51-400-806).
(c) If there is an indication of hydraulic fluid contamination, do the steps that follow:
1 Change the engine oil (Ref. AMM TASK 79-00-00-610-802).
2 Replace the main oil filter element (Ref. AMM TASK 79-21-06-960-801).
3 Prepare the engine and the aircraft for engine operation.
4 Do the automatic or manual start procedure (Ref. AMM TASK 71-00-00-860-823) or (Ref. AMM TASK 71-00-00-860-822).
5 Operate the engine at ground idle until the oil is warm for ten minutes (Ref. AMM TASK 71-00-00-910-803).
6 Shutdown the engine (Ref. AMM TASK 71-00-00-860-814).
7 Get a sample of the engine oil (Ref. AMM TASK 79-00-00-281-804).
(d) Make an analysis of the engine oil by one of the two procedures that follow:
NOTE: You can use the engine while you make the analysis of the engine oil.
1 Examine the kinematic viscosity of the oil at 100 deg.F (37.78 deg.C) (ASTM D445). Compare the oil that you think is bad with oil of the same brand that you know is good. A significant difference in viscosity is an indication of contamination by jet fuel or hydraulic fluid. Drain the oil if the viscosity exceeds plus 25 percent, or minus 10 percent from the new oil. 2 Examine the oil for phosphorus content. Compare the oil that you think is bad with oil of the same brand that you know is good. Use wet chemical test (ASTM D-1091-64) or spectroscopic oil analysis.
3 If the engine oil is contaminated, change the engine oil, operate the engine and make another sample of the engine oil as previously specified in Para B.(3)(c) and Para. B.(3)(d).
(4) Examine the oil system for water contamination as follows:
(a) Take a 4 oz (113.40 g) sample of engine oil.
(b) Do the SAE ARP 5991 water analysis to find how much water is contained in the oil sample.
(c) If the water content of the oil sample is more than 1000 parts per million by weight or by volume, do the steps that follow:
NOTE: The maximum permitted quantity of water in new and used Type II synthetic oils in an engine is 1000 parts per million.
1 Drain the oil system (Ref. AMM TASK 79-00-00-680-801). 2 Replace the main oil filter element (Ref. AMM TASK 79-21-06-960-801).
3 Fill the oil system with new oil that is not contaminated (Ref. AMM TASK 79-00-00-610-801).
(5) Make an analysis of the engine oil for acid content by the steps that follow:
(a) Take a 4 oz (113.40 g) sample of engine oil.
(b) Use ASTMD-664 total acid number (titrated to PH 11.0) analysis to compare the acid content of the oil.
1 Find the total acid number for a quantity of new oil which is the same type oil that you use to service engines.
2 Find the total acid number for the oil sample you got before.
NOTE: Type II synthetic oils vary in total acid number by brand and manufacturer.
3 If the total acid number for the oil sample is more than 0.2 above the total acid number found for the quantity of the new oil, then deterioration of the oil has occurred and the engine oil must be replaced with new oil which has the permitted total acid number. 4 Change of engine oil:
CAUTION:
BLACK OIL CAN ALSO BE THE RESULT OF OIL OVER-TEMPERATURE. IF THIS CONDITION IS A POSSIBLE CAUSE, REFER TO THE INSPECTION OF THE OIL SYSTEM AFTER OIL OVER-TEMPERATURE. REFER TO 72-00-00 INSPECTION/CHECK-06 (TASK 72-00-00-210-811).
a Change the engine oil (Ref. AMM TASK 79-00-00-610-802). b If necessary, do an inspection of the engine oil system after oil overtemperature operation (Ref. AMM TASK 72-00-00-210-811).
(6) Examine the oil system for fuel contamination by the steps that follow:
NOTE: If you smell jet fuel in the oil, an inspection for contamination from jet fuel is required.
(a) Examine the kinematic viscosity of the oil at 100 deg.F (37.78 deg.C) (ASTM D445). Compare the oil that you think is bad with oil of the same brand that you know is good. A significant difference in viscosity is an indication of contamination by jet fuel or hydraulic fluid. Drain the oil if kinematic viscosity exceeds plus 25 percent, or minus 10 percent from the new oil. (b) Use wet chemical test (ASTM D-1091-64) or spectroscopic oil analysis to examine the oil for phosphorus content. Compare the oil that you think is bad with oil of the same brand that you know is good.
(c) If there is fuel contamination of the oil system, do the steps that follow:
1 Replace the fuel/oil heat exchanger (Ref. AMM TASK 79-21-08-000-801) and (Ref. AMM TASK 79-21-08-400-801).
2 Change the engine oil (Ref. AMM TASK 79-00-00-610-802).
3 Prepare the engine and the aircraft for engine operation.
4 Do the automatic or manual start procedure (Ref. AMM TASK 71-00-00-860-823) or (Ref. AMM TASK 71-00-00-860-822).
5 Operate the engine at ground idle until the oil is warm for ten minutes (Ref. AMM TASK 71-00-00-910-803).
6 Shutdown the engine (Ref. AMM TASK 71-00-00-860-814).
7 Get a sample of the engine oil (Ref. AMM TASK 79-00-00-281-804).
(d) Make an analysis of the engine oil by one of the two procedures that follow:
NOTE: You can use the engine while you make the analysis of the engine oil.
1 Examine the kinematic viscosity of the oil. Compare the oil that you think is bad with of the same brand that you know is good. A significant difference in viscosity is an indication of contamination by jet fuel or hydraulic fluid. 2 Use wet chemical test (ASTM D-1091-64) or spectroscopic oil analysis to examine the oil for phosphorus content. Compare the oil that you think is bad with oil of the same brand that you know is good.
3 If the engine oil is contaminated, change the engine oil, operate the engine and make another sample of the engine oil as previously specified in Para. B.(6)(c) and Para. B.(6)(d).
(7) Do a spectroscopic analysis of the chips and flakes as follows (Refer to Table 601 , Table 602 and Table 603):
(a) The function of this analysis is to get a quantitative estimate of the relative concentration of metallic elements in the chips and flakes, a compositional fingerprint that can be compared to elemental profiles of known oil-wetted materials, so that you can find the source of the contamination. One of several spectroscopic methods can be used, depending upon the homogeneity and quantity of the chips and flakes. The methods and advantages/disadvantages of each are given in Table 601.
Table 601 - Spectroscopic Inspection Methods, Advantages/Disadvantages
| Spectroscopic Method Spectroscopic Analysis/Estimates | Advantages/Disadvantages |
|---|---|
| Scanning Electron Microcopy/Energy Dispersive X-ray Spectrometry (SEM/EDX) | This technique is especially useful when the chips and flakes are from mixed origin. The small diameter of the electron beam permits special resolution of areas as small as 0.1 micrometers. Care must be taken when you use this technique to sample several areas to prevent the possibility of an unrepresentative analysis. |
| Inductively Couple Plasma/Optical Emission Spectrometry | This technique is highly accurate and useful when a large quantity (several milligrams) of material is available for analysis. This technique, however, is relatively laborious, as the chips and flakes must be digested (dissolved) in an acid solution before the analysis. This method is recommended only when it is necessary to sample a large quantity of material at one time, or if it is the only equipment available. |
| Wavelength Dispersive X-ray Fluorescence Spectrometry | This technique must only be used when a moderate amount of homogenous material is present on the MCD. The advantage of this technique is the great speed with which an analysis can be completed. |
| Spark or Arc-Source Optical Emission Spectrography | This technique is very laborious, and only semi-quantitative. It must only be used when general, non-definitive information is necessary. |
Table 602 - Mineral Composition of the Bearing, Gear or Carbon Seal Carrier Materials
| Element | AMS 6490 PWA-725 (M- 50) PWA-793 (M-50) Min - Max Percent | M50 NIL PWA Min - Max Percent | Gear Material AMS 6265 (AISI 9310) Min - Max Percent | AMS 6308 Pyrowear Alloy 53 Min - Max Percent | Carbon Seal Carrier ASTM F30 Alloy 42 Percent | AISI 52100 AMS 6440 AMS 6444 |
|---|---|---|---|---|---|---|
| Carbon: | 0.77 - 0.85 | 0.11 - 0.15 | 0.07 - 0.13 | 0.07 - 0.13 | 0.05 Maximum | 0.93 - 1.05 |
| Manganese: | 0.00 - 0.35 | 0.15 - 0.35 | 0.40 - 0.70 | 0.25 - 0.50 | 0.80 Maximum | 0.25 - 0.45 |
| Silicon: | 0.00 - 0.25 | 0.10 - 0.25 | 0.20 - 0.35 | 0.60 - 1.20 | 0.30 Maximum | 0.15 - 0.35 |
| Phosphorous: | 0.00 - 0.015 | 0.00 - 0.015 | 0.00 - 0.025 | 0.00 - 0.015 | 0.025 Maximum | 0.025 Maximum |
| Sulphur: | 0.00 - 0.015 | 0.00 - 0.10 | 0.00 - 0.025 | 0.00 - 0.010 | 0.025 Maximum | 0.015 Maximum |
| Chromium: | 3.75 - 4.25 | 4.00 - 4.25 | 1.00 - 1.40 | 0.75 - 1.25 | 0.25 Maximum | 1.35 - 1.60 |
| Nickel: | 0.00 - 0.15 | 3.20 - 3.60 | 3.00 - 3.50 | 1.60 - 2.40 | 41 Nominal | 0.25 Maximum |
| Molybdenum: | 4.00 - 4.50 | 4.00 - 4.50 | 0.08 - 0.15 | 3.00 - 3.50 | - | 0.10 Maximum |
| Copper: | 0.00 - 0.10 | 0.00 - 0.10 | 0.00 - 0.35 | 1.80 - 2.30 | - | 0.3 Maximum |
| Vanadium: | 0.90 - 1.10 | 1.13 - 1.33 | 0.00 - 0.00 | 0.05 - 0.15 | - | - |
| Cobalt: | 0.00 - 0.25 | 0.00 - 0.25 | 0.00 - 0.00 | - | Trace Quantities | - |
| Tungsten: | 0.00 - 0.25 | 0.00 - 0.15 | 0.00 - 0.00 | - | - | - |
| Boron: | - | - | - | - | - | - |
| Aluminum: | - | - | - | - | 0.10 Maximum | - |
| Iron: | Remainder | Remainder | Remainder | Remainder | Remainder | Remainder |
Table 603 - Magnetic Probe Location and Material Composition
| Magnetic Probe | M-50 | M50 NIL | Gear AMS 6265 | AMS 6308 | ASTM F30 | AMS 6444 |
|---|---|---|---|---|---|---|
| No. 1, 1.5, 2 Bearing Compartment | X | X | X | X | | X |
| Angle Gearbox | X | | X | | | |
| No. 3 Bearing Compartment | X | X | X | | X | |
| No. 4 Bearing Compartment | X | | | | | |
| No. 5, No. 6 Bearing Compartment | X | | | | | |
| Main Gearbox | X | | X | | | |