doors (AMM 28-11-11/401).
NOTE: Usually the middle access door is the door where you will go into the fuel tank.
2) Install rubber protectors around the openings of the main tank access doors. 3) Install the access door adapter to the access door (the outboard access door is
the preferred door). 4) Bond the access door adapter to the airplane structure. 5) Make sure there will be a flow of air into the area where you will do the
maintenance.
(c) FOR THE MAIN TANK INBOARD OF W/S 433; Do these steps:
1) Remove the access door where you will do the maintenance
(AMM 28-11-11/401). 2) Install rubber protectors around the openings of the main tank access doors. 3) Put the air duct inside the open access door. 4) Use the pigtail on the end of the air duct to bond the air duct to the airplane
structure. 5) Make sure there will be a flow of air into the area where you will do the maintenance.
(d) FOR THE AUXILIARY FUEL TANK AND CENTER TANKS; Do these steps: 1) Remove all of the auxiliary and/or center tank access doors (AMM 28-11-0/401 and 28-14-11/401) 2) Attach modified fuel cell coverplate (Fig. 207) to intercell access panel opening
(if installed).
3) Put the four inch air duct inside the open access door.
500
May 1/98 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 28-10-0 Page 231
3) Use the pigtail on the end of the air duct to bond the air duct to the airplane structure.
4) Make sure there will be a flow of air into the area where you will do the maintenance.
(e)
FOR CENTER FUEL TANK BLADDER CELLS (IF EQUIPPED; Do these steps: 1) Remove tank access panel (AMM 28-12-21) 2) Remove intercell access panel (AMM 28-12-41) and attach modified center fuel
cell coverplate to intercell access panel opening (Fig. 207). 3) Use the pigtail on the end of the air duct to the airplane structure. 4) Make sure there will be a flow of air into the area where maintenance occurs.
(f)
Put the exhaust hose through the opening in the purge door the maximum possible distance into the fuel tank.
NOTE: The access hole in the purge door must be sufficiently large to hold the air hose without blockage of the flow of air from the outer side of the panel.
(g)
Start the compressor to supply air to the air mover to give a good flow of air to the tank.
(4)
After the air supply has operated for approximately 30 minutes, put the sampling line of the combustible gas indicator (Fig. 205) as far into the fuel tank as possible.
NOTE: It is recommended that you take the combustible gas indicator value regardless of the type of fuel that was contained in the fuel tank. If the fuel tank had contained kerosene only, then the combustible gas indicator should show zero. This shows that the tank atmosphere is in fire-safe and health-safe condition.
(5)
Wait one minute for each foot of sampling line before you take a reading.
(6)
Use Table 202 to convert the values on the combustible gas indicator to the actual levels.
Modified Center Fuel Cell Coverplate 500
28-10-0 Figure 207 May 01/98
Page 232
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
NOTE: If you use a combustible gas indicator that is not listed below, follow the manufacturer's instructions to get the actual values.
COMBUSTIBLE GAS INDICATOR FOR PPM MULTIPLY VALUE BY: FOR LEL, MULTIPLY VALUE BY:
GASTECH 1314 GASTECH 1314SMPN GASTECH GT SERIES 2 2 2 3 3 3
Combustion Gas Calculations Table 202
WARNING: DO NOT USE A HEATER/AIR BLOWER UNTIL THE FUEL VAPOR CONCENTRATION IS 10% OR LESS OF THE LOWER EXPLOSIVE LIMIT AS SHOWN BY A COMBUSTIBLE GAS INDICATOR. IF THE FUEL VAPOR CONCENTRATION IS NOT 10% OR LESS OF THE LOWER EXPLOSIVE LIMIT, IGNITION OF THE FUEL VAPORS COULD OCCUR.
(7)
When the combustible gas indicator shows the fuel vapor concentration is 10% or less of the lower explosive limit, you can put warm or cool air in the fuel tank through the tank access opening with an explosion-proof heater/air blower.
NOTE: The use of warm or cool air is for the comfort of persons in the fuel tank. It is not part of the purging procedure.
(8)
Start the heater/air blower before you put the air duct in the fuel tank.
WARNING: DO NOT STOP OR START THE HEATER/AIR BLOWER WHILE THE AIR DUCT IS IN THE FUEL TANK. THE FUEL VAPOR FROM THE FUEL IS IN THE FUEL TANK. THE FUEL VAPOR FROM THE FUEL TANK COULD CAUSE AN EXPLOSION AT THE HEATER OR BLOWER MOTOR. A FIRE OR EXPLOSION CAN CAUSE SERIOUS INJURY OR DEATH TO PERSONS AND CAN CAUSE DAMAGE TO EQUIPMENT. 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：737 AMM 飞机维护手册 燃油 FUEL(23)
