-MAKE SPARKS OR FIRE
-USE ANY EQUIPMENT WHICH IS NOT APPROVED FOR REFUEL/DEFUEL
PROCEDURES.
AIRCRAFT FUEL IS FLAMMABLE.
1.
Reason for the Job
__________________
Self Explanatory
2.
Job Set-up Information
______________________
A. Fixtures, Tools, Test and Support Equipment
-------------------------------------------------------------------------------REFERENCE QTY DESIGNATION -------------------------------------------------------------------------------
No specific hot air blower No specific safety barriers No specific surface contact thermometer
B. Referenced Information
-------------------------------------------------------------------------------REFERENCE DESIGNATION -------------------------------------------------------------------------------
12-32-28-281-001 Drain Water Content 28-00-00-910-001 Fuel Safety Procedures
3. Job Set-up
__________
Subtask 12-31-28-869-050
A. General Information
This procedure gives the cold weather maintenance practices for the fuel system when an aircraft is operated or stored in conditions with ground temperatures of between 0 deg.C (32 deg.F) and -54 deg.C (-67 deg.F).
The fuel storage and handling conditions can have an important effect on the amount of water in solution with the fuel. In unsatisfactory conditions, each 3785 liters (1000 USgal) of fuel can contain up to 0.76 l (0.2 USgal) of water. Water can get into the tanks in different ways:
-
the fuel supplied to the aircraft contains water
-
the air in the tank contains moisture (water)
-during descent large quantities of moist air can enter the tank
-fuel which is open to dampness or wet atmospheric conditions will contain larger quantities of water than fuel stored in sealed containers.
In cold conditions, much of this water can come out of solution and fall to the bottom of the tank. It then collects at the lowest parts of the tank and can form ice. The formation of ice (and the presence of water) in the fuel tanks can have an effect on the accuracy and/or performance of the quantity indication system. It can also cause engine or corrosion related problems.
Approved anti-ice additive can be added, in the correct proportions, to the fuel which is supplied to the aircraft. This can prevent water in the fuel from freezing and let it be drained from a tank with a fuel temperature below 0 deg.C (32 deg.F). The ice in the fuel tank can be melted through these procedures:
-ambient air heat in a hangar
-a refuel with "warm" fuel
-warm air heat from a blower, until the temperature of the whole of the bottom skin is 1 deg.C (34 deg.F). This procedure is usually done in a hangar, but can be used outside if a hangar is not available
-a combination of these methods.
NOTE : Ice can form on the inside of the fuel tank close to the water
____ drain valve. When you drain fuel from the tank for a water analysis check, fuel flows over the ice and collects water. This can cause incorrect analysis results. The procedure that follows should remove most of the water/ice from the fuel tank. You must do the water drain procedure regularly to make sure that all the water is drained from the tank low points.
Subtask 12-31-28-941-050
B. Safety Precautions
WARNING : OBEY THE FUEL SAFETY PROCEDURES.
_______
(1)
You must obey the fuel safety procedures (Ref. TASK 28-00-00-910-001) when you do work on the fuel system.
(2)
Put the safety barriers in position.
4. Procedure
_________ Subtask 12-31-28-660-050 R A. Water Draining of the Tanks
(1) If a water drain does not open with the usual pressure, find the cause. The valve could be frozen because of the low temperature.
R (2) Water draining of the tanks (aircraft in a hangar):
(a)
If possible, refuel the aircraft with "warm" fuel.
(b)
Use a surface contact thermometer to measure the temperature of the bottom skin of the tank to be drained.
(c)
If necessary, use an approved hot air blower to warm the bottom
skin of the tank to be drained. Make sure the temperature of the R bottom skin does not increase to more than 50 deg.C (122.00 R deg.F).
R NOTE : The temperature of all the bottom skin should be 1 deg.C
____ R (33.80 deg.F) or more measured one minute after the removal of the hot air blower.
(d) Drain accumulated water (Ref. TASK 12-32-28-281-001) 30 minutes R after the aircraft has been refuelled (and before the bottom skin R temperature decreases below 0 deg.C (32.00 deg.F)).
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