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Title: British Air Ministry Pilot Notes for Fortress
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MINISTRY i Supersedes A.P. 2099 B (Dea.l942j PILOT S NOTESFOR FORTRESS & biii GR.IIA, GR.II & III, BII FOUR CYCI.ONE A. 1820-65 OR R. 182G-97 ENGINES Promulgated by ordei of the Air Council RESTRICTED NOTKS TO UqSHS nets publication is divided into four parte: Descriptive, Handling, Operating Data and emergencies. Part I gives only a brief description of the controls with which the pilot should be acquainted. These Notes are camplanentary to A.P.2095 Pilots Notes General and aseme a thorough knowledge of its contents. All pilots should be in possession of a copy of A.P.2095 (see A.M.O. A93/U3).	\ Words in capital letters Indicate the actual markings on the controls concerned. Amendments to this publication will be issued as necessary and incorporation must be certified on the Certificate on the inside of the back cover. Additional- copies may be obtained fraa A.P.P.3., Pulham Load, 3.W.J. by application anR.A.F, Perm 29UA, in duplicate, quoting the numbar of this publication in full - 2025C Comments and suggestions should be forwarded through the usual channels to the Air Ministry (v.T.P.) AIR MINISTRV	AIR PUBLICATION 2O99B,C,D,E,FtP.N. May 1944	Pilots Notea. Thia supersedes A.P.2O99B Pilots Notes issued December 1942. PORTRESS GR.IIA, OR.II AND III, B.II AND B.III POUR CYCLONE R.1820-65 OR R.1820-97 ENGINES. LIST OF CONTENTS PART I - DESCRIPTIVE Para. INTRODUCTION 		a a a	a a a	1 FUEL AND OIL SYSTEMS Fuel tanks			2 Fuel quantity gauge 		see	e 	5 Fuel cooks		a a e	a e	4 Booster pumps 			a a e	e e	S Fuel transfer system 		sea	e a	6 Priming system 		wee	e a	7 Oil system..	...	...	...	a a 	a e	8 MAIN SERVICES Hydraulic system, Fortress IIA.		9 Hydraulic system, Fortress II and	iii "	10 Pneumatic system		a a a	a a	11 Electrical system		a a a	a a	12 AIRCRAFT CONTROLS Plying controls locking gear...	* * a	a a	15 i1 rimming tabs 		see	 e	14 Tail wheel lock 		a a a	a a	IS Undercarriage 		see	e e	16 Undercarriage indicator		a e 	e e	17 Undercarriage warning horn ...	e  	 	18 Flaps		see	a a	19 Wheel brakes		e e e	 e	20 Fluxgate compass	  ...	a a a	a a	21 Static pressure selector valve.	a  a	 	22 ENGINE CONTROLS Throttle controls			2Z Mixture control 		a a a	a e	24 Air cleaners (Portress II and Hl'			25 Carburettor heat control (intercoc	)ler) ..	26 Cowling gills 		sea	e e	27 Turbo superchargers 		e e 	e e	28 Propeller speed controls. ...	see	 	29 Propeller feathering controls..	OGG	e e	50 Starters	  ...	...	see	e e	51 OPERATIONAL CONTROLS Banb doors... 			* * a	a a	52 Automatic pilot 		 a e	a e	55 Oxygen			 a 	O a	54 R.T.P/2286 500 5/44 F.S/1 > PART II - HANDLING Para. Management of fuel system...................... 35 Operation of turbo supercharger	...	....	36 Preliminaries.................................. 37 Starting engines and warming up...	....	38 Testing; engines and installations............. 39 Before taxying................................. 40 Taxying out ................................    41 Check list for take-off ....................... 42 Take-off.*	...	...	...	...	....	43 Climbing (Fortress II and IIA)	............. 44 Climbing (Fortress III) ....................... 45 General flying................................. 46 St alling...	...	...	...	...	47 Deseent ...	...	...	...	...		48 Check list before	landing..................... 49 Approach speeds..	...	................ 50 Mislanding. .................   ...	....	51 After landing.................................. 52 PART III - OPERATING DATA Engine data, Wright Cyclone R-1820-65 or B-1820-97	53 Position error correction..........  ....	54 Flying limitations..........................    55 Maximum performance............................ 56 Maximum range ...   ............... ....	57 Fuel capacities.............. ...	....	58 PART IV - EMERGENCIES Engine failure	during	take-off ............ 59 Engine failure	during	flight............... 60 Feathering	........................ 61 Unfeathering...............................     62 Failure of Minneapolis-Honeywill turbo- regulator....	63 Undercarriage emergency operation.............. 64 Flaps emergency operation ..................... 65 Brakes emergency operation..................... 66 Jettisoning ball turret ....................... 67 Bomb Jettisoning .............................. 68 Bomb doors emergency operation ................ 69 Parachute exits ............................... 70 Fire extinguishers ............................ 71 Dinghies and ditching ......................... 72 Incendiary bombs ............ -................ 73 Crash axes .................................... 74 From RareAviation.com AIR MINISTRY May 1944 Additional copies may be obtained from A. P. F.S., Fulham Road, S.W. 3., by application on R. A. F. Form 294A in duplicate. AIR PUBLICATION 2099B,C,D,E,F. Pilot's Notes This supersedes A,P. 2099B Pilots Notes issued December 1942 FORTRESS SR. IIA, SR. II and III, B. II and B. Ill FOUR CYCLONE R.1820-65 OR R.1820-97 ENGINES PART I DESCRIPTIVE 1.	INTRODUCTION Fortress IIA (B. 17E), Fortress II (B.17F) and Fortress III (B.17S) aircraft are four-engined aircraft powered by Cyclone R.1820-65 or R.1820-97 engines equipped with. Hamilton Hydromatic propellers and turbo-superchargers. On Fortress II and IIA, SEC turbo-supercharger regulators are installed, whereas on Fortress III Minneapolis Honeywell electronic regulators are fitted. The Fortress III also has extra fuel tanks. The Fortress II and IIA differ mainly in their hydraulic systems. There are other differences in the equipment installed in the three versions and those which affect the pilot will be covered in the following paragraphs. FUEL AND OIL SYSTEMS 2.	Fuel tanks F. 3/2 The fuel system for each engine is independent. The capacities are as follows: Outboard engine tanks 354 Imp.gals each (424 U.S.gals) Inboard engine tanks	177	"	"	"	(208	"	"	) Inboard feeder tanks	177	"	"	"	(808	"	"	) Tne inboard feeder tanks are directly connected to the inboard engine tanks. On Fortress III and on some Fortress II aircraft in addition there are two groups of fuel cells ("Tokio" tanks) in each outer wing, the five outer cells in each wing feeding into the outboard engine tanks and the four inner cells in each wing feeding into the inboard feeder tank. These cells give an increase of 225 Imp.gallons (270 U.S.gallons) of fuel to each engine. A. P, 2099B. C.D.E, F-P. N. In addition on Fortress II and IIA two auxiliary droppable tanks of 341 Imp.gallons (410 U.S. gallons) each may be carried in the bomb bay, one on either side of the walkway. These tanks feed the wing tanks through the fuel transfer system and do not feed the engines direct. 3,	Fuel quantity gauge. Fortress II and III A single fuel gauge is provided with a tank selector which can be turned to select either out- board engine tank, either inboard engine tank, or either inboard feeder tank. As on the Fortress IIA, there is no fuel quantity gauge for the bomb bay tanks. A red warning light above the fuel gauge indicates when the contents of the selected tank has fallen to approximately 40 gallons. 4.	Fuel cocks (1) Four solenoid-operated fuel shut-off valves, one for each engine, allow the fuel supply to any engine to be cut off in emergency. The switches for the fuel shut-off valves, on the central control board, should be kept ON under all normal conditions. NOTE that the master Ignition switch must be ON for operating these valves. (ii) The transfer of fuel from the Tokio tanks (when fitted) is controlled by shut-off valves which are remotely controlled from the rear bulk- head of the bomb bay, either side of the doorway, through hydraulic pipelines. The valves should be opened fully by turning the handles clockwise when the contents in the corresponding main tank has fallen to 100 gallons, and at other times should be kept shut to avoid any tendency .or fuel to be forced from the main tank vents (since the outboard cells are on a higher level). 5 Booster pumps. Electrically driven fuel booster pumps, located at the bottom of each engine fuel tank, are provided to prevent fuel vaporisation at high altitudes in the supply lines to the engine pumps. The booster pump switches are on. the central control board. NOTE: Do not use No.3 booster pump on the ground more than is necessary, as this feeds the priming pump. From RareAviation.com A.p, 2099B. C.D. E. P-P. W. 6.	Fuel transfer system.- Fuel can be transferred from any tank, Including the homb bay tanks, to any tank on the opposite side (excepting the Lokio tanks). The port and starboard selector valves, on the rear wall of the control cabin, each have four positions: the three "on" positions enable either the inboard tank, outboard tank, or auxiliary bomb bay tank (if installed) to be connected with the electrical fuel transfer pump. The switch for the transfer pump is above the transfer selector valves, and should be thrown over in the direction in which the fuel is required to flow. Safety switches at each transfer selector valve prevent the pump operating unless both valves are fully turned to one of the three tank positions. WARNING. Do not set the tank selector valve to the bomb bay position when the bomb bay tanks are not installed. 7.	Priming system.- A priming pump is provided on the starboard side wall to prime any one of the engines. The pump draws fuel from No.3 engine tank (starboard Inboard engine tank) and No.3 booster pump must be ON when the priming pump is used. If any engine other than No.3 is started first, No.3 mixture control lever must be at ENGINE OFF. To operate the primer, push the handle down, turn the handle to the engine position required, then withdraw it and pump the charge to the cylinder head. When priming is complete, return the handle to OFF to avoid overpriming. 8.	Oil system.- Each engine tank has a separate oil tank. It is self-sealing end is mounted in the respective engine nacelle. The capacity is 37^ Imp. gallons of oil and 4 Imp. gallons air space. MAIN SERVICES . 9.	hydraulic system. Fortress IIA The hydraulic system operates Brakes Cowling gills A hydraulic pump driven by No.1 engine (port out- board engine) maintains pressure in the hydraulic accumulator between 600-750 Ib/sq.in. F.S/3 A.P.2099B.C.D.E.F-P.N. 10. A hydraulic handpump is provided on the starboard side of the 2nd pilot's seat. The hydraulic valve on the starboard sidewall has two positions, NORMAL and PRESSURE STORAGE TANK. The valve should always be left at NORMAL for emergency operation of brakes and gills. In.this position hydraulic accumulator pressure is also available, but if the accumulator is flat, it will be necessary to continue hand pumping until the operation of brakes or gills is completed. The hydraulic pressure gauge will not record the handpump pressure when the hydraulic valve is in the NORMAL position, but a pressure of 400 to 800 lb/sq.in. will be available, depending on the force exerted by the 2nd pilot on the pump handle. The hydraulic valve can be set to PRESSURE STORAGE TANK to build up pressure in the hydraulic accumulator. Handpump until the pressure gauge indicates over 450 lb/sq. in. Always return hydraulic valve to ifORMAL. When No. 1 engine is feathered, taxying is not recommended, as releasing the brakes causes the loss of all pressure built up in the brakes system by the handpump. Hydraulic system. Fortress II and III. Hydraulic pressure for operating cowling gills and brakes is provided by an electrically driven pump which maintains pressure in the main hydraulic accumulator between 600-800 lb/sq.in. The switch for the hydraulic pump on the pilots electrical control panel should normally be kept at AUTO. NOTE: The automatic switch will only cut the pump in when hydraulic pressure is above 275 lb/sq, in. Therefore, before flight, check the hydraulic pressure and if it is below 275 lb/sq.in. hold the switch to MANUAL until it builds up. On Fortress II aircraft an emergency hydraulic accumulator is provided for emergency brake opera- tion. This is charged from the main accumulator before flight and is then isolated by a shut-off valve (on the main accumulator at the aft starboard corner of the control cabin) which is wired in the closed position and should not be touched during flight. It is not necessary to open the shut-off valve for emergency brake operation. See para.66 for emergency brake operation. The left-hand hydraulic pressure warning light on the port instrument panel indicates when the pressure in From RareAviation.com A.P.2099B.C.IJ.E.F-P.N, the emergency hydraulic accumulator Is below 700 lb/sq. in. This emergency hydraulic brake system is not fitted to Fortress III aircraft. The right- hand warning light on the port instrument panel indicates when the pressure in the main hydraulic accumulator ia below 600 lb/SA.in. On Fortress III only one hydraulic pressure warning light is fitted. This comes on when the pressure in the hydraulic accumulator falls below 528 Ib/sg. in. A hydraulic handpump is provided which can be used: to operate brakes or gills directly if no accumulator or pump pressure is available. 11.	Pneumatic system.- Two suction pumps driven by the Inboard engines"provide for the operation of the gyro instruments and the surface de-icers. Either pump may be selected to supply vacuum for operating the gyro instruments, by turning the selector valve (VACUUM PUMP) on the port sidewall. The vacuum from the other pump, and the pressure from both pumps operates the Goodrich leading edge de-icHhs. A red warning light on the port side of the instrument panel indicates when the vacuum is less than 3.75 inches. 12.	Electrical system.- Four generators ana three batteries supply D.C. current at 24 volts, which operates:- Electro-hydraulic pump on Fortress II and III Undercarriage Tail wheel Flaps Bomb doors and bomb release gear Fue . shut-off valves Fuel booster pumps Fuel transfer pumps Oil dilution valves Inertia starters Propeller feathering pumps Propeller anti-icer pumps Leading-edge de-icer distributor valves Pressure head heater Landing lights Radio Gun turrets Inverters The master ignition switch must be ON before battery power can be used. The three battery switches should normally be left ON, but should be OFF when using-an external battery supply for starting. The voltmeter on the control panel can be connected to F. 3/4 A.P, 2099B.C.D.E.F-P.M. any one of the generators by the voltmeter selector. Either of two rotary inverters convert D. C. current to L. C. for operating the sutosyn instruments, on Fortress II and IIA, the fluorescent lights, the Minneapolis Honeywell automatic controls, and on Fortress III for operation of the electronic turbo- supercharger regulators. The selector switch is on the electrical control panel; on Fortress IIA the selector switch has no "off" position, so that A. C. current will always be available when battery power is on. On Fortress II and til aircraft the switch has an off position. In flight the normal inverter should always be used and the alternate inverter should be conserved for emergency use. On some aircraft an A.C. voltmeter is fitted; if this does not register within the green band (30 to 36 volts) changeover to ALTERNATE. AIRCRAFT CONTROLS 13.	Flying controls locking gear (i)	The rudder and elevator control locking lever is the port lever recessed into the floor just aft of the control stand. The controls are free with the lever down. To lock, press spring button on end of lever and raise lever. The controls will then lock when the control column is moved fully forward and the rudder pedals centralised. To unlock, press spring button and push lever down. (li) On Fortress IIA the ailerons are locked by a pin which is inserted through a hole in the middle spoke of the left wheel and a hole in the control column. (iii) On Fortress II and III, the ailerons are locked by a spring-loaded pin with a fork end which engages with the middle spoke of the pilots control wheel; the pin is inserted through a hole in the control column; to unlock ailerons, push pin back, and remove- it from the column. A stowage for the pin is provided to the left of the pilot's seat. 14.	Trimming tabs.- The aileron tab control is on the floor panel on the pilots left. The rudder tab control is on the floor aft of the engine control stand. Two elevator tab control wheels (one for each pilot) operating on the same shaft, :ro1*n RareAviation.com A. P. 2099B. C.D. E. F-P. N. are on opposite sides of the control stand. The controls act as follows:- Aileron - clockwise - right wing down Rudder - clockwise - nose right Elevator - in the natural sense 15.	Tail wheel lock.- The tail wheel locking lever is thentarboard lever recessed into the floor aft of the^pontrol stand. The tail wheel is free when the lever is up. To lock, press spring button on end of lever and move lever down. The tail wheel will then lock when centralised. To unlock raise lever. A red tail wheel warning light on the centre instrument panel shows when the tail wheel is unlocked; no light shows that the tail wheel is locked. 16.	Undercarriage.- A switch on the central control board operates the three motors for retracting the undercarriage and tail wheel. The switch has three positions - UP, DOWN and off; the off position is merely a safety feature since the circuit is opened automatically at the end of travel. A hinged plate must be lifted against spring action before the switch can be moved to UP. For emergency operation of undercarriage see Part IV para.64. 17.	Undercarriage indicator. - The undercarriage warning light is on the central instrument panel. Indications are:- Undercarriage DOWN - green light Undercarriage UP or between locks - no light The light may be tested by pressing the push-button marked GLOBE TEST, if fitted. IS. Undercarriage warning horn.- On Fortress IIA and II the horn sounds if any throttle is closed while the undercarriage is not locked down. A switch on the electrical control panel permits the horn to be silenced when it is desired to fly with one or more throttles closed; this will not prevent the horn sounding on subsequent closing of any throttle while the undercarriage is up. On Fortress III no undercarriage warning horn is fitted. F.S/5 A.P. 3099B.C.D.E, F-P, N. 19.	Plana.- The flaps are operated by a switch, on the central control board. The position of the flaps Is shown at all times by the autosyn indicator on the starboard instrument panel. For emergency operation of flaps see Part IV, para.65. 20.	Wheel brakes.- (1) The Independent wheel brakes are operated by tilting forward the rudder pedals. "Spongy" opera- tion of the brakes usually indicates air in the system; to bleed air from the system, apply brakes slowly and release them several times. (ii)	Parking brake.- The pull-handle at the bottom of the instrument panel in front of the 2nd pilot operates the normal braking system through the 2nd pilot's metering valves. It is therefore necessary to have hydraulic system pressure available. To operate parking brake, depress 2nd pilots pedals and pull handle, release the brake pedals, and then release handle. To release parking brake, depress 2nd pilots pedals. 21.	Fluxgate compass.- On Fortress G.E.Ill aircraft a fluxgate compass is installed in the nose compartment. This must be switched on before taxying and left on for 10 minutes before un- caging thS gyro. A remote indicator is fitted at the top of the left-hand instrument panel. On Fortress B.Ill the fluxgate compass is removes and the British E.R. compass is installed. 22.	Static pressure selector valve.- A switch is provided which enables the pilot to select an alternate static source for the altimeter and rate-of-climb indicator, should the normal static tube become iced up. The alternate source will not operate the airspeed indicator. ENGINE CONTROLS Note: Engine controls marked 1,2,3,4 refer respectively to port outer, port inner, starboard inner, and starboard outer engines. 23.	Throttle controls.- Any one lever, or a combina- tion of inboard, outboard, or all four levers, may be operated with one hand by the 1st or 2nd From RareAviation.com a.p.2099b.c.d.e.f-p,n. pilot. A throttle locking lever is on the port side of the control stand. To lock, pull up knob to release spring catch, and move forward to lock all four throttles, or aft to lock the inboard throttles only. 24.	Mixture control.- Stromberg injection carburettors are fitted. The fully forward position of the mixture control levers gives ENGINE OFF aid is used in starting and for stopping the engines; the levers click into the automatic LEAN and HIGH positions by feel. The LEAN position gives a weak mixture automatically cong>ensated for boost pressure temperature and altitude and is used only when cruising below maximim weak continuous boost and rpm (see para.53). The RICH position gives an automatically compensated rich mixture and is used for operating at all engine conditions higher than maximum weak continuous. The FULL RICH position is not compensated for altitude and boost pressure and is used only if the automatic mixture control should stick at high altitude, giving too weak a mixture for operating at lower altitudes; this is not likely to occur. 25.	Air cleaners (Fortress II & III).- A switch for the electrically operated carburettor air cleaners is provided on the lower starboard instrument panel. When the switch is set to OPEN, the cleaners are brought into action; the yellow warning lights indicate when this operation is complete. When the switch is set to CLOSE or OFF, the cleaners are bypassed; the green warning lights show when this operation is complete. It is recommended that the air cleaners are bypassed above 8000 feet. Above 10000 feet, if the air cleaners were still in operation, the turbo-superchargers might overspeed. NOTE: On some aircraft the air cleaners may be wired in the OPEN position. If this is the case, the precaution recontnended in para. 53 when flying above 10,000 feet must be observed. 26.	Carburettor heat control (intercooler).- The control handles latch in any position between HOT and COLD. To operate, lift handle to release catch, and then pull up to HOT, down to COLD. On Fortress II and III carburettor air temperature gauges are fitted on the right-hand side of the instrument panel. Unless flying in icing conditions the intercooler control should be at COLD. F. S/6 A. F. 2099B, ll.v.L. F-P. I'J. Cowling gills.- When operating the gills, the switches should be turned to LOCKED when the desired opening is reached, to guard against loss of emergency oil supply through leaks in the gill actuating mechanism. 28.	Turbo-superchargers (i)	An exhaust-driven turbine wheel drives an impeller which congresses air before it passes to the carburettor; from the carburettor the fuel-air mixture passes through a normal engine-driven supercharger to the engine. The speed at which the impellor is driven, and thus the boost pressure, is regulated by a wastegate in the exhaust system which, when open, discharges exhaust gas and bypasses the turbine; as the gate is closed, exhaust gas is admitted to the turbine and it speeds up. The wastegate opening is controlled by G.E.C. regulators on Fortress IIA and II, and by Minneapolis Honeywell electronic regulators on Fortress III. These two systems are entirely different. (ii)	G. E.C. turbo-supercharger regulators (Fortress IIA and II).The wastegate is operated hydraulically by engine oil pressure, which is controlled by an exhaust-gas bellows to maintain constant exhaust pressure, the pressure being selected by the pilot's control levers; when the levers are fully aft the wastegates are opened and the turbo-superchargers are idling. As the levers are moved forward the regulator mechanism is adjusted to close the wastegate progressively. With the throttle fully open and the turbo- supercharger regulator levers set to give, say, maximum climbing boost on the ground, as the aircraft climbs the back pressure on the turbine falls and so the turbine wheel speeds up more than is necessary to maintain the boost with increasing altitude, and so the boost .will rise. It is therefore necessary to retract the turbo- supercharger controls progressively in order to maintain constant boost on the climb. (ii1) Minneapolis-Honeywell turbo-sunercharger regulators (Fortress III).The turbo wastegate is operated by electric motors which are controlled by the "PRESSURETHOL, in which a boost pressure bellows sends an electric signal through electronic amplifiers to operate the wastegate motor in order to maintain constant boost pressure at the From RareAviation.com A.P.2099B.C.D.E.F-P.N. entry to the carburettor, i.e. before passing the throttle butterfly. The MAUIFOLD PRESSURE SELECTOR, or TURBO-BOOST SELECTOR, selects the desired pressure which the Pressuretrol will then maintain, provided that the throttles and rpm are set correctly. There are ten possible settings: setting B gives take-off boost with the throttles fully open and propeller speed controls set for maximum rpm; a stop is fitted to prevent the control inadvertently being used at higher settings. Setting 10 is used for combat power, with throttles open and maximum rpm. A turbo-speed governor is incorporated (a)	to prevent excessive acceleration of the turbo wheel, (b)	to prevent the turbo wheel overspeeding. 29.	Propeller speed controls.- The propeller speed control levers for the Hamilton Standard Hydramatic propellers move up to high rpm, down to low rpm. The friction lock lever is on the starboard side of the control stand. To lock, pull up knob to release spring catch and move lever up. The words LOCKED LOW PITCH at the top of the speed control lever travel do not mean that the propellers are automatically locked in extreme fine pitch in this position. 30.	Propeller feathering controls.- For feathering and unfeathering procedure, see paras.61 and 62. Practice feathering should not be carried out above 20,000 feet; above this altitude the operation becomes uncertain and should only be attempted in emergency. 31.	Starters (1) Fortress IDA. Eclipse inertia starters are fitted. The electric starter motor for each engine is energised when its starter switch is moved up to START. To engage the flywheel with the engine, the switch is moved down to MESH. This operation also energises the booster coil. (ii)	Fortress II. Eclipse inertia-and-direct cranking starters are fitted. To energise the starter motor, move START switch up or down (according to which engine is being started) and after about 20 seconds move adjacent MESH switch up or down, still holding START switch, to engage F. 3/7 A. F.2099B.C.D.E.F-P.N. flywheel with engine. This also energises the booster coil. The START switch must then be turned off within 30 seconds. (iii)	Fortress III. Jack and Heintz inertia-snd-direct- cranking starters may be fitted instead of Eclipse starters. These operate in the same way as the Eclipse inertia-and-direct-cranking starters with this exception: should the engines have been handcranked and engaged by the manual engaging cable in each nacelle, the brushes will have been lifted from the starter motor; and before the engine can be started electrically, the brushes must be replaced; this is done by momentarily flipping on the MESH switch before energising. On Fortress III aircraft the booster coils have been replaced by induction vibrators. OPERATIONAL CONTROLS 32.	Bomb doors.- The bomb doors are normally operated electrically by a lever in the bomb-aimers compartment. For emergency .operation of bomb doors, see Part IV, paras.68 and 69. 33.	Automatic pilot.- On most aircraft Minneapolis Honeywell 0.1 Automatic pilots are fitted. On some aircraft Norden Stabilised Bombing Approach Equipment is fitted. For operating instructions see A.P.LOSS Part III Notes v and E. 34.	Oxygen.- On Fortress III aircraft, American type oxygen equipment is installed with A.12 demand regulators at all crew stations. To obtain oxygen, it is only necessary to plug in the oxygen mask. As the working of the demand regulator depends upon the suction applied to it, it is essential that the oxygen mask should be a good snug fit. For normal operation, the red emergency khqb on the demand regulator should be OFF and the AUTOMIX control should be ON; then, when the oxygen mask has been plugged in, the regulator is set in operation and regulated by the user's breathing, a mixture of oxygen and air suitable for the altitude being delivered. If the AUTOMIX control is OFF, the air supply is cut out and pure oxygen will flow to the mask through the regulator; at any time when lack of oxygen is suspected, AUTOMIX should be set OFF; but this will reduce the oxygen endurance of the aircraft at heights below 30,000 feet. The AUTOMIX control is to be turned From RareAviation.com A. P, 2099B, C,D, E, F-P. N. off at heights above 30,000 feet, but if adequate oxygen supply is available, it should preferably be turned off at heights above 20,000 feet. Either Alrco or Pioneer demand regulators may be fitted; the endurance at 20,000 feet with AUTOMIX on is approximately 7 hours with the Airco type or 11 hours with the Pioneer type; and with AUTOMIX off, about Si hours on both typos. The emergency control is provided to bypass the regulator mechanism, if this should become faulty, and when the emergency knob is ON pure oxygen will flow at a high fixed rate Irrespective of altitude. This high flow will quickly reduce the oxygen supply available, and therefore the emergency control should only be set on when absolutely necessary and for as short a time as possible. Blinker flow indicators for the pilot and 2nd pilot, on the pilot's instrument panel, show if the regulators are working properly; they are set in motion by the users breathing. A warning light at the bottom of the pilot's instrument panel indicates when the oxygen pressure is dangerously low (100 lb/sq.in.). The normal pressure is 450 lb/sq.in. and a gauge is provided beside the warning light. P. 3/8 AIR PUBLICATION 2099B,C,D,E,F-P.N. Pilot's Notes i PART II HANDLING 35.	MANAGEMENT OF FUEL SYSTEM (i)	Normally:	fuel switches OPEN fuel transfer valves OFF Each engine is fed from its own tank independently and the fuel supply for one engine cannot he used for any other engine except through the fuel transfer system. (ii)	On Fortress III and on certain Fortress II aircraft, if Tokio tanks are filled, set their shut-off cocks FULL ON when about 100 gallons is left in each main tank. About 1 hour is required to transfer all the fuel from the Tokio tanks to the main tanks. (iii)	Fuel transfer system.- To transfer fuel between two tanks on opposite sides of the aircraft centre-line:- (a)	Set the port and starboard fuel transfer valves to the tanks between which fuel is to be transferred. (b)	Throw the fuel transfer motor switch firmly in the direction in which the fuel is required to flow - i.e. over to the right if fuel is to be transferred from port to starboard; and vice versa. Switch off when transfer is coraple te. Fuel can only be transferred directly from a port tank to a starboard tank, or vice versa. To transfer fuel between two port tanks, it must first be transferred to a starboard tank and then back to the desired port tank. (iv)	Long range bomb-bay tanks.- The fuel from these tanks can only be used by transferring it to the opposite inboard or outboard wing tank. See (iii)	above. 36.	OPERATION OF TURBO SUPERCHARGER (i)	At high altitudes the required power should be obtained with the throttles fully open. If the throttles are only partially open, the turbines From RareAviation.com A. P. 2099B, C.D. E. F-P. N. must go faster to produce the required boost; this may lead to overspeeding (on Fortress II and IIA) and will also produce unnecessarily high charge temperatures. (ii)	As the aircraft ascends, in order to maintain a constant boost the turbo has to speed up. The maximum permissible turbo rpm on B2 supercharger is 21300 (23400 for short periods only; and to guard against exceeding these rpm, it is necessary to reduce boost by 1 inch for every 1000 feet above 25000 feet. On Fortress III, B.22 superchargers are fitted with a maximum rpm of 24000 (26400 for short periods). Although the Minneapolis Honeywell turbo regulators fitted on Fortress III have a speed governor, it is still advisable to reduce boost above 25000 feet, as otherwise the turbo will be working for prolonged periods at maximum rpm. (iii)	In cruising flight at high altitudes, if the boost begins to surge and fade, the remedy is to increase rpm. (iv)	The intercooler controls should always be fully open to give lowest possible carburettor air temperature, unless cruising under icing conditions - see para.46(vij. (v)	Shutting down turbo superchargers in flight Turbos should not be shut off suddenly in flight as the rapid cooling which will follow may cause distortion of the turbine rotor. Power should be reduced progressively and over a period of several minutes, if possible. 37.	PHELIMINABIES (1) Flying controls unlocked. (ii)	Check fuel transfer valves OFF. (iii)	Master ignition switch OK. Generator switches OFF. (iv)	Check that undercarriage switch is off. (v)	Fluxgate compass (if fitted).- Switch on amplifier. Leave for 10 minutes before uncaging. F. S/9 A.P.2099B. C.D.E.F-P.N. (vi)	Inverter switch NORMAL (Inverter Bust be ON for operation of turbo regulators on Fortress III, and engine pressure gauges and rpm indicators on Fortress II L IIA). (vii)	Hydraulic pressure (Fortress IIA aircraft): Second pilot sets the HYD.VALVE to PRESSURE STORAGE TANK position, raises hydraulic pressure with the handpump to 450 Ib/sq.in. and then resets the valve to the NORMAL position. (viii)	Hydraulic pressure (Fortress II and III aircraft). Hold hydraulic pump switch to MANUAL and check' that pressure builds up. Minimum hydraulic pressure for AUTOMATIC operation of hydraulic pump is 275 lb/Bq,, in. 38.	STARTING ENGINES AND WARMING UP (1) Switch batteries OFF if using ground batteries, and set controls as follows: Supercharger regulator controls	- OFF, or setting 0 Mixture controls (2nd pilot)	- ENGINE OFF Propellers	- Fully up Intercooler heat control (2nd pilot)	- COLD Gills (2nd pilot)	_ Fully OPEN When the desired position is reached, turn to LOCKED. Air cleaners (if fitted)	CLOSED, or open if necessary. (ii) Have each engine turned by hand for at least three revolutions of the propeller. (iii)	2nd pilot sets fire extinguisher selector valve (if fitted) to engine being started. Auxiliary external extinguishers should be at hand. From RareAviation.com A,P.2099B.C,D.E,F-P. N, (iv)	Switch on booster pump of engine being started. In summer three to four strokes, and in cold weather six to eight strokes, should be given before energising the starter, and additional priming should be given while the engine is turning until it is running smoothly. (No.3 booster pump must be ON and No.3 mixture control set to ENGINE OFF, until No. 3 engine Is running). (v)	Starting engines on Fortress XIA (Eclipse inertia starter) (a)	Switch on ignition. (b)	2nd pilot energises starter for 12-15 seconds. Never exceed 20 seconds. (c)	Heturn starter switch central, pause for a second, and engage starter. Additional priming should be given as soon as the engine starts turning, and continued until it is running. Keep starter engaged until engine is running as it also switches on the booster coil. (d)	When engine begins to fire regularly 2nd pilot moves mixture control slowly to HIGH and stops priming. If engine shows signs of being over rich, return to ENGINE OFF until it is running smoothly. (vi)	Starting engines on Fortress II and III (Eclipse or Jack Heintz direct-cranking inertia starters). (a)	On Fortress II, switch on ignition. On Fortress III, leave ignition off until engine la turning, to avoid backfiring. (b)	If Jack and Heintz starters are fitted flip MESH switch momentarily to ensure that the brushes are lowered on to the starter motor. (c)	Aa the engine starts turning, switch on ignition (Fortress III); continue to prime as the engine is turning until it is running. F. 8/10 L. P. 2099B. C.D. E. F-P. N. (d)	When the engine is firing regularly release starter switches (the START switch must not be held on for more than 30 seconds). Move mixture control to RICH and stop priming. If engine shows signs of being over rich, return to ENGINE OFF until it is running smoothly. (vii)	If engine fails to start (a)	Stop priming and move mixture control to ENGINE OFF. (b)	Wait till propeller stops rotating. (c)	Switch off ignition. (d)	Close the starter switches to engage flywheel with engine to ensure that flywheel stops, then return switches central. (ej Have propeller turned forward by hand half a revolution at least, to disengage the flywheel from the engine. If engine has been over-primed, open throttle slowly and have it turned several revolutions. (f) With Eclipse or Jack and Heintz airect-cranking inertia starters, wait two or three minutes before another attempt. (viii)	When the engine is running satisfactorily, turn off and lock priming pump. (ix)	Open throttles slowly and warmup at 1,000 rpm. (x)	When all engines have been started switch OFF booster pumps and check fuel pressure on engine pumps. (xi)	If fitted, switch DR corpses ON and SETTING. (xii)	If ground battery has been used for starting, switch on aircraft battery switches when the plug has been removed. 39.	TESTING ENGINES AND INSTALLATIONS (i)	Check tenperatures and pressures. (ii)	Switch on each generator separately and check that it is charging, then switch off. From RareAviation.com A. P. 2099B.C.D.E.F-P.N. (ill) Test operation of flaps. After warming up (iv)	At 1500-1600 rpm, check each magneto in turn. The drop should not exceed 100 rpm. (v)	At 1800 rpm check operation of constant speed propellers. Return constant speed lever fully up. While checking operation of constant speed propeller slowly open and close the turbo- supercharger controls two or three times to fill the system full of hot oil. (This is a precaution against irregular turho-operation on takeoff). (vi)	On Portress IIA and II. for each engine in turn (a)	Open throttle fully and see that engine is running smoothly. (b)	Set turbo-supercharger regulator control to give 47J inches manifold pressure. Note that the regulators are sluggish and boost will continue to rise after the operation of the regulators has stopped. (c)	Lock turbo-supercharger regulator in this position. (d)	Close throttle. This adjustment must be made as quickly as possible and must not exceed  minute for each engine. On Portress Hi. open up to full throttle at setting 0 and check that engine is running smoothly. Then set MANIFOLD PRESSURE SELECTOR, or TURBO BOOST SELECTOR to setting 8. Open each engine in turn up to full throttle and check take-of* boost and rpm. 40.	BEFORE TAXYING Battery switches ON Tailwheel unlocked (red light) Hydraulic warning light - Off Hydraulic pressure 600-800 lb/sq.in. - operate brakes and ensure that hydraulic pressure builds up again as soon as it falls to 600 Ib/so.in. Vacuum warning light - off.	' u P.S/11A. ?.2099B.C.2.E.F-P.N. 41.	TAXYING OUT Avoid excessive use of brakes. Assist, turns by using outer engines. 42.	| CHECK LIST -FOB TAKE-OFF Controls Turrets Crew positions T - Trimming tabs M - Mixture P - Propellers Intercoolers Gills Fuel Supercharger s Air cleaners (if fitted) Flaps Auto pilot Gyro horizon Fluxgate compass (if fitted) or 28 compass (if fitted) -	Unlocked -	Locked in central position -	Nose compartment empty -	Elevator 1J divisions nose heavy. Rudder and ailerons neutral. -	RICH )	J . < Locked -	Fully up) -	COLD -	CLOSE. Return valves to LOCKED -	Fuel shut-off switches OPEN Transfer valves OFF Check contents Booster pumps ON. -	As set in para.39. -	CLOSED (or OPEN if necessary). -	UP -	OFF -	ON -	Uncaged -	NORMAL 43.	TAKE-OFF (i)	Generator switches - Turn ON (rpm should be over 1,400). (11) Turn into take-off position; release brakes, taxy forward a little, and lock tailwheel. (ill) Open throttles slowly to full throttle. (iv)	Keep feet off the brake pedals during take-off, as this might cause swing. (v)	There is a slight tendency to swing to the left in the early stages of take-off but it can be held by use of rudder. .From RareAviation.com A. P. 2099B, C, D.E, F-P. N. (vi)	Take-off speed at full load is 115 mph (104 knots) IAS. (vii)	Before raising undercarriage, use the brakes to stop the wheels spinning. (viii)	Safety speed is 180 mph (104 knots) IAS. The recomnended speed for climbing away is 150 mph (130 knots) IAS. 44.	CLIMBING (Fortress II and IIA) (i)	At 1,000 feet close turbo-supercharger regulators slowly. (ii)	Reset rpm to 2,300 and bring in turbo-superchargers when necessary to maintain desired boost. Maximum climbing boost is 41 inches, but 38 inches boost is recommended. (iii)	The turbo superchargers will have to be set every 1,000 - 2,000 feet to prevent overboosting. (iv)	The speed for maximum rate of climb is 150 mph (130 knots) IAS up to 8,000 feet. (v)	If used in tropical climates, air filters should be set to CLOSE above 8,000 feet, but if dust conditions are found above this altitude, they may be left in up to 15,000 feet. Above this altitude they should never be open. 45.	CLIMBING (Fortress III) (i)	At 1,000 feet return TURBO BOOST SELECTOR to setting 0. Reset rpm to 2,300, and adjust TURBO BOOST SELECTOR when necessary to maintain boost. Maximum climbing boost is 41^ inches, but 38 inches boost is recommended. (ii)	The speed for maximum rate of climb is 150 mph (130 knots) IAS up to 8,000 feet. (iii)	If used in tropical climates air filters should be set to CLOSE above 8,000 feet, but if dust conditions are found above this altitude, they may be left in up to 15,000 feet. Above this altitude they should never open. 46.	GENERAL FLYING (i) The aircraft is stable longitudinally, laterally, and directionally. F.S/12 -	A. P. 2099B, C.D.E, F-P. N, (11) Change of trim: Undercarriage up - Slightly tail heavy Flaps half down - Nose up Flaps fully down - Nose down. The aircraft will need retrimming when flaps are fully lowered for landing. When cowling gills are closed on inboard engines, there- is a slight tail-heavy change of trim. (ill) The controls are quick in response and effective; the ailerons are reasonably light, the elevator slightly heavy, and the rudder extremely heavy. (iv)	Turn on booster pumps if fuel pressure falls below 14 lb/sq.in,, and always above 12000 feet. (v)	Flying low in bad visibility.- In bad visibility near the ground flaps should be lowered 20% and propeller set to give 1,900 rpm. Speed may then be reduced to 135 mph (117 knots) ILL. (vi)	Icing conditions. Maintain at least 4 inches of turbo boost, keeping throttle fully open if possible. If insufficient heat is obtained thus, move intercooler controls to full HOT position for a short period to remove ice, then cut back controls to maintain correct degree of heat (above 20C). Do not exceed 38C. Return Intercoolers to COLD when danger of icing is passed. 47.	STALLING (1) The stalling speeds in mph ILS are:- Weight	50,000 lb. Flaps and undercarriage up	102 (89 knots) "	"	" down	90 (71| knots) (il) With flaps and undercarriage up, there is a slight buffeting on all controls about 3 mph above the stall. At the stall either wing and nose drop gently, falling together. Recovery is straight- forward and easy. With flaps and undercarriage down, the buffeting is more pronounced and the wing drops away faster. Recovery is normal. From RareAviation.com A. P. 2099B, C, D, E, F-P. N. 48.	DESCENT (i) Sufficient power should be used to keep the cylinder head temperature between 150 and 305C. (11) The turbo-supercharger regulators should be shut off very slowly when no longer required. 49.	CHECK LIST BEFORE LANDING Trailing antenna Autopilot Intercoolers Gills Hydraulic pressure Hydraulic valve (Fortress ILA only ) Superchargers Tail wheel Reduce speed to U - Undercarriage -	retract (check visually) -	off -	COLD -	slightly open and LOCKED -	600-800 lb/eq.in. (450 lb/sq.in. is minimum pressure at which brakes will work). If pressure is below 450 lb/sq. in., handpump or emergency system (Fortress II only; will Lave to be used - see Part IV para.66. -	set to NORMAL position for emergency brake operation. -	set up to take-off position -	locked - warning light OFF 150 ntph (130 knots) IAS. -	DOWN - green indicator light. Check by horn (if fitted) and visually. On aircraft with the warning horn deleted, check undercarriage down by handcrank. (IMPORTANT - see para.64). -	RICH -	Set for 2,300 rpm -	Booster pump ON -	Billy DOWN -	OFF M - Mixture control P - Propeller F - Fuel F - Flaps Generators 50. APPROACH SPEEDS Recommended speeds in are:- Englne-assisted Glide F. S/13 mph IAS for At 54000 lb. 110 ( 96 knots) 120 (104 knots) the approach At 47000 lb. 100 ( 87 knots) 115 (ICO knots) A. P. LGS9L. C. D. E. F-P. N. 51.	MISLANDING (1) Tile aircraft will climb away with undercarriage and flaps down at climbing power provided that the speed n&s not fallen below 100 mpb IAS, note, however, that if full take-off boost is used with turbos on, rpm must be increased to S500 before boost exceeds 41j inches. Retrimming is not necessary. (ii)	Switch on generators and raise undercarriage immediately. (iii)	Haise the flaps at 500 feet. 52.	APTER LANDING (i) Raise the flaps and open gills before taxying. 2nd pilot unlocks tailwheel. (il) Booster pump switches OPP, and propellers set for maximum rpm. (iii)	Stopping engines.- (a)	Idle engines at approximately 800 rpm until cylinder temperatures drop to 150C. (b)	Before stopping engines, run at 1200 rpm for 30 secohds. (c)	2nd pilot stops engines by moving the mixture controls to ENGINE OFF. (d)	Switch off ignition after engines have stopped. (iv)	Allow time for the brakes to cool before applying parking brakes: brakes should never be left locked when they are hot. Use chocks for parking whenever possible. (v)	Oil dilution. The oil dilution period is 4 minutes; while diluting, on Fortress IIA and II, operate supercharger regulator controls to get diluted oil to the turbo-superchargers. RareAviation.com AIR PUBLICATION 2O99B, C, D, B, FrP.N. Pilots Notes PART III OPERATING DATA 53.	ENGINE DATA, WRIGHT CYCLONE R-1820-65 or R-1820-97 (i)	Riel.- 100 octane only. (il) The principal engine limitations are as follows: MAX.TAKE-OFF TO 1,000 FT.	R.p.m. 2,500	Boost ins. Hg.aba. 47}	Temperature C Cylr. 250	Oil Max. Desired MAX. CLIMBING CONTINUOUS	2,500	41}	220	90	70 MAX. LEVEL CONTINUOUS	2,000	35 	205	90	70 MAX.WEAK CONTINUOUS	1,950	33	205	90	70 COMBAT 5 MINS.LIMIT	2,500	47}*	260	90 NOTE.- In <	>rder to	avoid overspeeding the turbo- supercharger the boost pressure must be reduced by 1 inch per 1000 feet above 25000 feet. If carburettor air filters are in use above 10000 feet, the maximum boost for combat is 41g inches, and combat and climbing boost mist be reduced by 1 inch per 1000 feet above 21000 feet altitude. OIL PRESSURE:	NORMAL: 65/75 lb/so.in. IUNM. FOR IDLING: 25	" MINE. TEMP. FOR TAKE-OFF: OIL: 10C MIN. RISE NOTE: The boost and rpm limits given above are approved, but American operational experience has shown that it is more satisfactory to keep within the recommended limits given in para.57. F. 3/14 A.P.2099B.C.D.E.F-P.N. (iii)	Stopping engine: Maximum cylinder temp: 150C (iv)	Fuel pressure:	14/16' Ib/sq. in. normal 12 lb/sq.in. minimum 54.	POSITION ERROR CORRECTION (i) On Fortress II and I IL From	120 125 130 135 145 150 160 mph IAS To	125 130 135 145 150 160 220 "	" Add	0	1	2	3	4 mph Subtract 21	" (ii) On Fortress III with static vent connected to LSI. From 100	140	160	180	195	210	215	nrph	IAS To	140	160	180	195	210	215	225	" Subtract 0	1	2	3	4	5	6	nph 55.	FLYING LIMITATIONS (i) The aircraft ia designed for manoeuvres appropriate to a heavy bomber and care must be taken to avoid imposing excessive loads with the elevators in recovery from dives and in turns at high speed. Violent use of the rudder at high speeds should be avoided. Spinning and aerobatics are not permitted. At weights above 54000 lb. no manoeuvres other than gentle turns should be attempted. (ii) Maximum weights Take off from hard runways, and straight flying Fortress IIL L II 59000 lb. provided Mod.123 (strengthened undercarriage) is incorporated If not, 57000 lb. Landing and all forms of flying. 52000 lb. Fortress III 60000 lb. to pilots experienced on the type. Outboard wing cells must be filled at weights above 54000 lb. 54000 lb. From RareAviation.com A. P. 2099B.C.D. 2. F-P.N. (ill) Maximum indicated airspeed - mph	Knots Diving	270	245 on Fortress III, and on Fortress II & IIA if Mod.161 is incorporated; if not 220 mph (190 knots) ILS. Flaps down	ISO	130 Undercarriage down	150	130 56.	MAXIMUM PERFORMANCE 150 (130 kts) mph IAS between S.L. and 8,000 ft. 145 (126 kts) mph IAS "	8,000 ft. and 12,000 ft. 140 (122 kts) mph IAS above 12,000 ft. 57.	MAXIMUM RANGE (1) Climbing. Use 2300 rpm and 38 inches boost and the speed for maximum rate of climb - see para.55. (il) Cruising. The recommended speeds in mph IAS are;- Without special radio, or ASV and external loads With special radio, or ASV and external loads Below 20,000 feet	145-150	140-145 Above 20,000	"	135-140	136-140 The recommended power settings (and corresponding total gallons per hour) are as follows:- Boost [ 29 1		Rpm 1400	Total gallons/hour Imperial 104	US 87 LEAN	( 29	1	1700	123	100 1	I 29+	1	2000	150	125 ; 3i+	1	2100	195	163 RICH	> 34	1	2200	245	204 > 36+	1	2250	290	242 . 38	1	2300	325	270 F. .;/ib A.P.2099B.C.B.E.P-P.N. Obtain the recommended airspeed by flying at the reconmended power settings given above. At low and medium altitudes, and at light weight, use LEAN mixture and set 29 1 inches boost (bringing in turbos when boost cannot be obtained on throttles alone) and adjust rpm between 1400 and 2000 to give the recommended airspeed. At higher altitudes and heavy loads, when the recommended speed cannot be obtained at 2000 rpm, use RICH mixture and increase rpm and boost together as shown in the table of power settings. 58.	FUEL CAPACITIES Outboard engine tanka - each 354 Imp.gals.(425 U.S. gals) Inboard "	" each 177 "	"	(213 U.S. gale) feeder "	- each 177 "	"	(212 U.S. ___	gals) 70S "	" per side 1416 Imp. gals (1702 U.S. gals) in all. Outboard wing cells On Fortress III and	450 Imp.gals.per side on some Fortress II aircraft (540 U.S. gals) 2316 Imp. gals. (2772 U.S. gals) in all. Auxiliary bomb bay tanks (Fortress II and IIA only) each 341 Imp.gals, per side (410 U.S. gals.) From RareAviation.com AIR PUBLICATION 2099B, O,D,E,F-P.N. Pilot's Notes PART IV EMERGENCIES 59.	ENGINE FAILURE DURING TAKE-OFF If either outboard engine fails immediately on becoming airborne the resultant swing can be checked by coarse application of rudder and ailerons, assisting by throttling back the opposite engine if necessary. The aircraft will climb away easily on three engines. 60.	ENGINE FAILURE DURING FLIGHT (i) If the failed engine cannot be made to pick up, feather the propeller and switch off. Switch off fuel shut-off valve and fuel booster pump. Switch off generator. (ii)	Handling on three engines. - The aircraft can be trimmed to fly down to 120 mph (105 knots) IAS hands and feet off, at climbing boost and rpm. (ill) Landing on three engines.- A normal approach can be made at the speeds recommended in nara.50. (See A.P.2095 Part IV Note D). (iv)	Handling on two engines.- The aircraft can be trimmed to fly down to 125 mph (119 knots) IAS hands and feet off. Jettison everything droppable. At 44,000 lb. height can be maintained at this speed at low altitudes at climbing power. (v)	Landing on two engines.- The circuit should be made with the good engines on the inside of the turn, and undercarriage and flaps left as late as practicable. Keep extra height in hand, if possible, and lower the undercarriage later than usual, but have it locked down just before the final approach. The approach should be made at 115-120 mph (100-104 knots) IAS in a glide. When certain of getting into the aerodrome, lower flaps for landing. Do not wind off trim until final approach can be made in a glide, as some power may be necessary in the early stages. (See A.P.2095 Part IV, Notes C and D). (vi)	Fuel system.- Transfer the fuel from the dead engine tank to the remaining tanks, when these are sufficiently empty. See Part II, para.55. F.8/16 A.P. 2099B, C.D, E, F-P. N. 61. (11) (Hi) FEATHERING NOTE that when above ,20,OOO feet feathering should only be attempted in emergency. Set propeller control to low rpm and turbo to give a low cruising boost. Hold the button in only long enough to ensure that it stays in by itself; then release it so that it can spring out when feathering is complete. Close throttle immediately, switch off booster pump, and set mixture control to engine off. (iv) Switch off only when engine has stopped. (v)	Note the following: Propeller	Auxiliary power	Equipment feathered	out of action	affected Port outer	Generator	(Fortress.IIA Hydraulic pump	only) (On Fortress IIA (a) Gill controls only)	Brakes Port inner Generator Vacuum pump (b) Gyro instruments Deicer system Glycol pump (c) Cabin heating Starboard inner Generator Vacuum pump (b)	Gyro instru- ments Deicer system Starboard outer Generator Action to be taken (a)	Gills controls and brakes (Fortress IIA only). Turn hydraulic valve to PRESSURE STORAGE TANK and maintain hydraulic accumulator pressure above 450 lb/sq.in. with the handpump. After landing, avoid taxying since releasing the brakes causes the loss of all hydraulic pressure built up by the handpump. From RareAviation.com L.P. 2099B.C.L.E.F-P, N- (b)	Gyro Instruments. Set vacuum pump selector (GYRO INSiR.) valve to VAC. PUMP. R. if port inner propeller feathered; to VAC. PUMP. L if starboard inner propeller feathered. (The deicer pressure will thus be reduced and the deicer system will therefore operate inefficiently). (c)	Cabin heating. If cold air is not desired in cabins, shut off heating and ventilating system by moving control fully aft. 62.	UNFEATHliKIKG NOTE. It is preferable not to unfeather at speeds above normal cruising speed to avoid any risk of overspeeding the propeller. (1) Set throttle closed or slightly open, propeller control fully down (LOW rpm) and ignition on. Leave mixture control at ENGINE OFF. Leave booster pump off. (ii) Hold the button in until rpm reach 1000-1300. Set mixture control RICH. If fuel pressure does not build up, switch on booster pump. (ill) If the propeller does not return to normal constant-speed operation, open throttle slightly. 63.	FAILURE OF MINNEAPOLIS-HONEYWELL TURBO-REGULATOR If one boost gauge indicates erratic functioning of the regulator - e.g. boost gradually building up or diminishing - it is likely that the amplifier has failed. The four amplifiers, one for each engine, are installed In the fuselage in the radio compartment and a spare amplifier is carried. Actions to be taken if boost builds up excessively on one engine!- (1)	Throttle back immediately (2)	Have faulty amplifier replaced by spare amplifier. If boost diminishes, during cruising flight it may be possible to restore power by opening throttle or increasing rpm. Have faulty amplifier replaced by spare amplifier. F.S/17 A. P. 2099B. C.D.E, F-P-Jk 64.	0 NDERCARRIAGE EkLERSENM OPERATION (i)	If the electrical system fails, each wheel may he lowered hy hand. The crank handle sockets lor the main wheels are on the front wall of the bomb bay: the socket for lowering the tailwheel is ait of the tailwheel retracting mechanism, just forward of the rear gunners compartment. The detachable crank handles are stowed on the starboard aide or the rear bulkhead in the wireless compartment. NOTE- On most aircraft the electric operation of the undercarriage is by Eclipse motors, but on some aircraft (built by Vega company) the undercarriage is electrically operated by General Electric motors. This affects the direction of hand cranking thus:- Main wheels	Tail wheel DOWN	DOWN Eclinse	Counter clockwise Clockwise General Electric Clockwise	Counter clockwise The undercarriage electric switch should be left OFF when operating manually, since (with Eclipse motors) it is possible to injure the man on the crank, if the switch is on. (ii)	T.nnrj-incr with the undercarriage retracted If it should be necessary to land with the under- carriage retracted action should be taken as follows:- (a)	Jettison ball turret. (b)	If the aircraft is equipped with a chin turret the landing should be made with the tailwheel retracted to prevent the chin turret digging into the ground and thus causing extensive damage to the fuselage. (c)	If the aircraft is not equipped with a chin turret, land with the tailwheel extended. 65.	FLAPS EMERGENCY OPERATION The flaps may be lowered by hand. The crank handle socket is in the forward ehd of the camera pit. Both camera pit doors must be open for hand operation. The crank handle is on the starboard side of the rear bulkhead of the wireless compartment. From RareAviation.com A. P. 20SSL. C. D. E. F-P. N. NOTE: When operating manually, do not attempt to assist with the electrical system; this might cause injury to the man on the crank. 66.	BRAKES EMERGENCY OPERATION (i)	On Fortress II aircraft only, if the main hydraulic pressure gauge shows less than 450 Ib/sq.in. use the emergency braking system. Pull down the two emergency brake handles on the roof behind the pilot's seats. It is not necessary to operate the brake pedals when using the emergency brake system. (ii)	On Fortress II and IIA, if on the approach the hydraulic pressure gauge shows less than 450 Ib/sq. in., it will be necessary to operate the brakes by handpump. On Fortress IIA, check that hydraulic valve is NORMAL; depress pedals fully and work hydraulic handpump slowly, the speed of operation controlling the degree of braking. 67.	JETTISONING BALL TURRET If it is necessary to land with the undercarriage retracted (see para.64(ii)) the ball turret should be jettisoned when time permits, to prevent extensive damage being caused to the fuselage. To jettison proceed as follows: (a)	Remove the computing sight if possible. (b)	Remove the 4 nuts and the azimuth gear box at the ring gear. (c)	Remove the 4 safety retaining hooks over the ring gear. (d)	Remove the 12 yoke nuts supporting the turret. A vigorous kick on the aft aide of the turret will then free it, but the crew member must be held by a second person during this operation as there is a risk of falling from the aircraft. NOTE: (a) 20-30 minutes will normally be required for 2 crew members to carry /it the jettisoning procedure described above, and the following equipment .will be required. (i) An adjustable spanner (ii) A hammer (iii)	A chisel. F.S/18 A.P. 8099B.C.D.E.F-P.N. (t>) The ball turret weighs in all 1300 lb. and its removal in an emergency will improve the performance of the aircraft. It should be borne in mind, however, that with the ball turret removed the aircrafts ditching qualities are likely to be impaired. 68.	BOMB JETTISONING The piioT's emergency bomb release handle is on the port sidewall. Pulling the handle will first open the bomb doors and then operate the salvo release mechanism. NOTE: To close the bomb doors after opening them by emergency method, the retracting mechanism must be reset. On Fortress IIL and II, open the door in the floor of the pilot's compartment and push on the arrow-like hinge of the link; then fully extend the door retracting screws by putting the bomb door control to OPEN (in bomb aimer's conj>artment). This will re-engage the retracting screws with the doors. Then close doors in normal manner. On Fortress III, the retracting mechanism is reset by operating the bomb-aimer's rewind wheel in the nose compartment. 69.	BOMB DOCKS EMERGENCY OPERATION The bomb doors can be operated manually should the electric motors not function. The handcrank socket is at the forward end of the bomb bay. NOTE: Some aircraft have two-position (OPEN-CLOSE) switches instead of the earlier three- position (OPEN-OFF-CLOSE) switches. With two-position switches, great care must be taken when operating the doors with the hand crank. Should the actuating motor come into operation, the man operating the hand crank may be injured. 70.	PARACHUTE EXITS Main entrance door	) Open door Tailgunner's entrance door	) normally then Emergency door under control cabin ) pull emergency Bomb doors	) release and ) push door out. From RareAviation.com A, P. 8099B. C.D.E. F-P.N. 71.	FIRE EXTINGUISHERS (1) There is no automatically operated fire- extinguisher. On Fortress III aircraft, four flame switch warning lights are fitted immediately above the instrument panel to indicate when a fire starts. (ii) Engine fire-extinguisher (not fitted on Fortress III).- Each release handle discharges a bottle of carbon dioxide which is sufficient for one engine. The selector valve should remain in position long enough to completely discharge the bottle after operating release handle. If fire occurs in another nacelle, reset the selector valve and discharge the other of the two bottles. (ill) Hand fire-extinguishers At back of 2nd pilot. At starboard side of navigator's compartment. At forward power turret On rear bulkhead of bomb bay At main entrance door At tail gunner's position. 72.	DINGHIES AND DITCHING (i) Two American type AL life rafts are provided. (ii) To release, pull dinghy release cables in roof of wireless compartment. (ill) lower flaps 30% for ditching. 73.	INCENDIARY BOMBS One in pilot's conqpartment, either on starboard or port wall aft of pilot's seats. One in compartment aft of radio compartment, either on port side aft of window, or on starboard side just forward of entrance door. 74.	CRASH AXES One in pilot's contentment. One in bomb aimera compartment. One in radio contentment. F. S/19 1 To No. 3 Engine To No.1 Engine Priming Pump To No. 3 Engine Pump To No-2 Engine Pump To No. I Engine Pump 354 -GALS. 1341 177 (^ALS 177 GALS. 8 mu AUXILIARY BOMB-BAY TANKS (No provision In Fortress Hr) o OUTER WING CELLS (Fitted in Fortress HI t in some Fortress!! aircraft) OUTER WING CELLS \ Fitted In Fortress HI s in some Fortress H aircraft) gals; To No- 4 Engine Pump NOTE-ALL FUEL CAPACITIES ARE GIVEN IN IMPERIAL GALLONS. TO CONVERT TO U.S. GALLONS, MULTIPLY BY 1-2 . 354 ;. GALS. CJ Fuel shut-off valves To No-2 Engine To No.4 Engine Main fuel lines | Fuel transfer pump Fuel transfer selector valves Fuel booster pumps Fuel transfer lines FUEL SYSTEM DIAGRAM1			FIG. A From RareAviation.com A.P! 2099 9,CtPtif Key to figs.1,1A, and 2, NOTE. The port aide of Fortress that an electro-hydraulic 1.	Propeller anti-icer master switch 2.	Floor panel 3.	Intercom station boxes 4.	Cabin heating and ventilating control 5.	Vacuum selector valve 6.	Heated clothing control 7.	Bomber call light switch 8.	Pass light (not in use) 9.	Panel light switch 10.	Panel light 11.	Ammeters 12.	generator switches 1J. Sesin light rheostat 14.	Resin light switch 15.	Bomb release button 16.	Throat microphone button 17.	Static -pressure selector valve 18.	Control wheel 19.	Aileron locking pin 20.	Rudder pedal 21.	Rudder pedal adjusting lever 22.	Navigation lights switch 23.	Alarm boll switch 24.	Formation lights switch 25.	Voltmeter selector switch IT cockpit is similar to the IIA except pump switch (item 108 on fig.1A) is fitted. 26.	Battery switches 27.	Voltmeter 28.	pitot heater switch 29.	Bomb jettison control 30.	Undercarriage warning horn cut-out switch 31.	Inverter selector switch 32.	Intercom call switch 33.	Oil dilution switches 34.	Engine starter switches 35.	Fire-extinguisher selector valve 36.	Fire extinguisher operating buttons 37.	Brake control handle 38.	Hydraulic valve 39.	Hydraulic handpump 40.	Priming pump 41.	Intercooler controls 101.	Oxygen automix control 102.	Oxygen demand regulator 103.	Oxygen emergency knob 104.	Resin light master and colour selector switch 105.	Formation lights switch 106.	Hydraulic pump switch (also on .	Fortress II) 107.	Oxygen bayonet NOTE. The starboard side of Fortress IIA only is shown. The Fortress II differs only in the absence of item 35. "	" III " in 	"	" " 35 and 36, and a demand oxygen regulator is fitted above the intercom station boxes. From RareAviation.com1 Key to figs.3 and 3A. Note. The instrument panel of Fortress II is largely similar to Fortress IIA, ru	but has certain features in common with Fortress III. These are indicated M	below. 18. Control wheel 20. Rudder pedals 37. Parking brake control 42.	Telltale lights switch 43.	Dimmer switch for undercarriage and tail wheel warning lights 44.	Alternating current voltmeter 45.	vacuum gauge 4-6. Vacuum warning light 47.	Bomb release warning light 48.	Steering director 49.	Minneapolis Honeywill PDI 50.	Radio compass indicator 51.	Compass light switch 52.	Flight panel switch 53.	IFF switches 54.	IFF detonator buttons 55.	Instrument flying panel 56.	Fluorescent light 57.	Bomber's call light 58.	Undercarriage warning light 59.	Tailwheel lock warning light 60.	Boost gauges 61.	Rpm indicator 62.	Flaps position indicator 63.	Fuel pressure gauges 64.	Oil pressure gauges 65.	Oil temperature gauges 66.	Deicer air pressure gauge 67.	Cylinder head temperature gauges 68.	Fuel quantity gauge-inboard feeder tank)Fortress 69.	"	"	"	" engine " ) IIA 70.	"	"	" outboard "	"	) only 71.	Central control board 72.	Rudder triiming- tab -wheel 73- Control stand 74.	Propeller feathering buttons 75.	Hydraulic pressure gauge 76.	Hydraulic pressure warning light 108.	Flame switch warning lights 109.	Windscreen hot air control 110.	DR compass (Fortress B III only) 111.	Outside air temperature gauges 112.	Air intake filter indicator lights (Fortress II and III) 113.	Air intake filter switch (Fortress II and III) 114.	Fluorescent lights rheostat 115.	Liquidometer fuel gauge and selector (Fortress II and III) 116.	Oarburettor air temperature gauges(Fortress IIL HI 117.	Turbo boost selector, or manifold pressure selector 118.	Radio push-button unit 119.	2nd pilots oxygen blinker flow indicator, warning light, and oxygen pressure gauge 120.	1st pilots oxygen blinker flow indicator, warning light, and oxygen pressure gauge. From RareAviation.com Key to fig.U. The control stand on Fortress III is identical with that for Fortress ILA. and II, except that item 97 is replaced by item 117, Fig.3A. 71.	Central control	board 72.	Rudder trimming	tab wheel 73.	Control stand 77.	Magneto switches 78.	Master ignition	switch 79.	Fuel booster pump switch 80.	Fuel shut-off valve switches 81.	Identification switchbox 82.	 Undercarriage control switch 83.	Landing light switches 84.	Flap control switches 85.	Cowling gill switches 86.	Mixture control levers 87.	Throttle control levers 88.	Propeller speed control levers 89.	Propeller speed controls locking lever 90.	Elevator trimming tab control wheels 91.	Tailwheel locking lever 92.	Minneapolis Honeywill automatic control unit 93.	Flying controls locking lever 9h.	Elevator trimming tab wheel friction control 95.	Throttle control locking lever 96.	Mixture control locking handle 97.	Turbo-supercharger regulator levers (fitted on Fortress IIA and II only; replaced on Fortress III by turbo-boost selector, item 117 on fig.3A), J up zo99 a,c,*>, c, f FS13 Af tO99 ,C,O/ Key to fig.5. IJhe floor panel is Identical on all marks 1.	Propeller anti-icer control switch 2.	Floor panel 98,	Aileron trimming tab	control 99.	Wing de-icer control 100.	Pilots seat 101.	Propeller anti-icer rheostats.