WELLINGTON III, X, XI, XII, XIII AND XIV

HANDLING INSTRUCTIONS

All handling speeds are quoted for aircraft with the static side of the A.S.I, connected to the pressure head. The equivalent speeds in knots are quoted in brackets. The corresponding speeds for aircraft with the A.S.I, connected to the static vent in the side of the fuselage arc given in para. 61.

38. Management of fuel and auxiliary oil systems (i) Use of balance cocks :

(a) The pressure balance cock (A) should be turned ON only when an engine fails due to lack of fuel. It should be kept ON only if the engine cannot be supplied otherwise (i.e. if its pump has failed).

(b) The suction balance cock (B) should always be OFF unless it is necessary to feed either engine from tanks on the opposite side or, in certain cases, when auxiliary tanks are used.

(ii) Normal fuel system

The following recommended procedure ensures the fullest possible use of fuel, and should be studied in conjunction with the Fuel System Diagram (Fig. 4) in Part V.

(a) The nacelle tanks should always be filled, even it it is unnecessary to carry full fuel capacity, and their contents held as a reserve until all main tanks arc exhausted.

(b) The operation of the nacelle tank cocks should be checked after take-off to ensure that the wire controls function correctly in flight. The pre-flight check may have been satisfactory, but the Hexing of the wings in flight may interfere with the movement of the wire controls.

(c) Take off and fly on the main tanks, with both balance cocks closed and the nacelle tank cocks OFF.

(d) When an engine commences to cut through lack of fuel (this will be indicated by the appropriate fuel pressure warning light) open the pressure balance cock (A). This will revive the engine immediately and there is, therefore, no danger in allowing an engine to splutter through lack of fuel, except when coming in to land.

(e) Pull ON both nacelle tanks.

(f) Turn OFF the pressure balance cock (A).

(g) Nacelle tank cocks should not be turned ON until one engine fails due to lack of fuel. This will ensure that the Captain will have a known amount of fuel when the main tank supply is exhausted.

(A) Nacelle tank cocks should, however, always be pulled ON before landing, if the sufficiency of fuel remaining in the wing tanks is. in doubt.

(iii) When auxiliary fuel tanks are fitted.

(a) Fuel in the auxiliary tanks should be used early in flight.

(b) The order of use of the tanks should be so arranged that both engines do not run short of fuel simultaneously (see below). In all cases, when one engine fades for lack of fuel (this will be indicated by the appropriate fuel pressure warning light), open the pressure balance cock (A) which will revive it immediately. This cock should be closed again as soon as the fresh supply has been turned ON.

(c) Recommended order of use of auxiliary tanks:

(i) When an equal amount of furl is available on each side of the suction balance cock: (Two tanks of equal capacity in the outer bomb cells, or a 185-gallon tank in the centre bomb cell connected to cocks Dp and Ds.):

Both balance cocks must be kept OFF.

Shortly before the auxiliary tanks arc due to run out, change over to the main tanks on one side and empty the auxiliary tank on the opposite side. Repeat this procedure for the^ second auxiliary tank. Turn OFF the auxiliary tank(s) when empty.

(2) When a greater amount of auxiliary tank fuel is available on the port side of the suction balance cock:

(A) 185-gallon tank in the centre bomb cell connected to cock Dc, and other auxiliary tanks) :

Both balance cocks must be kept OFF.

If a 140-gallon tank is carried in the starboard bomb cell, empty the rear half of the 185-gallon tank first, and then change over to the front half; this will be done before the 140-gallon tank is empty. When the starboard auxiliary tank is empty, open the suction balance cock (B) and run both engines on the remaining auxiliary fuel. Shortly before the fuel is due to run out, turn ON the starboard main tanks, close the suction balance cock (B) and exhaust the auxiliary tanks on the port engine. Then change over to the port main tanks and turn OFF the auxiliary tanks.

Note.—This will mean that the starboard main tanks will empty first. When they do, boch nacelle tanks remain as a known reserve, plus a small extra quantity in the port main tanks which in the last resort can be used for both engines by opening the suction balance cock (B).

(3) When a greater amount of auxiliary tank fuel is available on the starboard side of the suction balance cock :

(A 140-gallon tank in the starboard bomb evil and two 55-gallon tanks in the port bomb cell):

Both balance cocks must be kept OFF.

When the port auxiliary tanks arc empty, open the suction balance cock (B) and run both engines on the remaining fuel. The procedure detailed in (2) above then applies, but in the reverse sense.

(4) When a 185-gallon tank in the centre bomb cell is connected to cock Dc, or a H)$-gallon tank is connected to cock Ds, and no other auxiliary tanks are carried:

As (2) and (3) above, except that the suction balance cock (B) must be ON from the time of first changing over to the auxiliary tank. Shortly before the auxiliary tank is due to run out, the main tanks on the opposite side should be turned ON, the suction balance cock (B) turned OFF and the auxiliary tank exhausted on one engine. The final residual fuel will then be in the port or starboard main tanks according to the bomb cell in which the auxiliary tank is carried.

(iv) Emergency operation of toing fuel tanks:

In the event of a wing tank being damaged, the following sequence of operations should he carried out :

(a) Turn ON the suction balance cock (B).

(b) If fuel remains in the damaged tank, turn OFF the main tank cock (C) on the good side so as to use up any remaining fuel in the damaged tank.

(c) When the engines cut*:

Turn OFF the main tank cock (C) on the damaged side. Turn ON the main tank cock (C) on the good side.

(d) When the engines cut again*: Pull ON both nacelle tank cocks.

Turn ON the main tank cock (C) on the damaged side. Turn OFF the suction balance cock (B).

(v) Operation of auxiliary oil tank:

After the first two hours of flight and thereafter every hour, the handpump should be operated so as to supply each main oil tank with about one gallon of oil.

39 Preliminaries (i) Check fuel cock settings in fuselage:

Main tank cocks (Cp and Cs) .... On

Nacelle tank cocks ..... Off

Auxiliary tank cocks (Dp, Dc and Ds) .. Off

Suction balance cock (B) ......... Off

(ii) If RotoF electric propellers arc fitted check : Master switches .... ON Feathering switches .. NORMAL

Selector switches .... AUTO

(iii) Check that undercarriage selector lever is locked DOWN.

(iv) Switch on undercarriage and nap indicators and test undercarriage warning horn and light (if fitted).

40. Starting engines and warming up

(i) Set pilot's engine master cocks (Ep and Es) ON and the pressure balance cock (A) OFF.

(ii) Set engine controls as follows :

Throttles ......

Mixture controls (if fitted)

Propeller speed controls ..

Supercharger control ..

Carburettor air-intake control ...

Cowling gills

Oil cooler shutters (Mark III aircraft only) ..... Closed

(iii) Have each engine turned slowly by hand for at least two revolutions of the propeller, in order to ensure that oil will not cause a hydraulic lock of pistons or sleeves.

(iv) It is not necessary to prime the carburettors unless the aircraft has been standing for a week or more. If necessary, this must be done with the pressure balance cock (A) ON.

(v) High volatility fuel (Stores ref. 34A/III) should be used for priming at air temperatures below freezing. Instruct the ground crew to work the induction system priming pump until the suction and delivery pipes arc primed. This may be judged by an increase in resistance..

(vi) Switch ON the ignition and press the starter and booster coil pushbuttons simultaneously for each engine in turn. Turning periods must not exceed 20 seconds, with a 30 seconds wait between each. The ground crew will prime the induction system or each engine while it is being turned, and the engine should start after the following number of strokes if cold:

(vii) Release the starter button as soon as the engine fires. It will probably be necessary to continue priming after the engine has fired and until it picks up on the carburettor.

(viii) As soon as the engine is running satisfactorily, release the booster coil button and get the ground crew to screw down the priming pump, turn OFF the priming cock and close the cowling door.

(ix) Open the engine up slowly to 1,000 r.p.m. and warm up at this speed.

* Or earlier if considered advisable.

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