Aviation Technical English for aircraft maintenance engineers (Авиационный технический английский язык для студентов-авитехников)

69 battery master switch and ensure that the landing gear position indicators show that the gear is down and locked. Normally, the landing gear should be retracted after lift-off when the airplane has reached an altitude where, in the event of an engine failure or other emergency requiring an aborted takeoff, the airplane could no longer be landed on the runway. This procedure, however, may not be applied to all situations. The operating loads placed on the landing gear at higher airspeeds may cause structural damage due to the forces of the airstream. Limiting speeds, therefore, are established for gear operation to protect the gear components from becoming overstressed during flight. When the plane is approaching the runway for landing, the landing gear is extended by placing the gear selector switch in the GEAR DOWN position. As the landing gear extends, the airspeed will decrease and the pitch attitude may increase. During the several seconds it takes for the gear to extend, the pilot should be attentive to any abnormal sounds or feel. The pilot should confirm that the landing gear has extended and locked by the normal sound and feel of the system operation as well as by the gear position indicators in the cockpit. *https://www.flightliteracy.com/retractable-landing-gear-part-one/ (09.01.2020). THE OILTANK Oil tanks are made of sheet metal, suitably baffled and strengthened internally to prevent damage due to the oil surging during manoeuvres. The tank is placed wherever possible at a higher level than the engine to give a gravity feed to the pressure pump, and forms a reservoir of oil large enough for the engine’s requirements, plus an air space. The air space allows: a) The increased oil return when starting the engine. When the engine is stopped after a previous run, the walls of the crankcase are saturated with oil which will drain into the sump. The oil will remain there until the engine is started, when the scavenge pump will return it to the tank. b) The expansion of the oil, and therefore its greater volume as the oil absorbs heat from the bearings. c) «Frothing» due to aeration of the oil.