Examples of Aircraft Aural Warnings Stage of Operation  Warning System  Warning Signal  Cause of Warning Signal Activation  Corrective action Takeoff  Flight control  Intermittent  Throttles are advanced and any of the  Correct the aircraft to  horn  following conditions exist:  proper takeoff conditions  1. Speed brakes are not down 2. Flaps are not in takeoff range 3. Auxiliary power exhaust door is open 4. Stabilizer is not in the takeoff setting In flight  Mach warning  Clacker  Equivalent airspeed or mach number  Decrease aircraft speed  exceeds limits  In flight  Pressurization  Intermittent  If cabin pressure becomes equal to  Correct the condition horn  atmospheric pressure at the specific altitude (altitude at time of occurrence) Landing  Landing gear  Continuous  Landing gear is not down and locked when  Raise flaps; advance  horn  flaps are less than full up and throttle is throttle retarded to idle  Any stage  Fire warning  Continuous  Any overheat condition or fire in any engine or 1. Lower the heat in the bell  nacelle, or main wheel or nose wheel well,  the area where in the APU engine, or any compartment having fire F/W was activated warning system installed 2. Signal may be silenced Whenever the fire warning system is tested  pushing the F/W bell cutout switch or the  APU cutout switch Any stage  Communications  High chime  Any time captain’s call button is pressed at Release button; if button  external power panel forward or rearward  remains locked in, pull  cabin attendant’s panel button out Figure 10-130.  Aircraft aural warnings.  Figure 10-131.  A typical mechanical 8-day aircraft clock.  Figure 10-132.  A typical aircraft electronic clock.  10-80 12 6 8 DAYS 9 3 + °C UP D SET B 1 hr up DIM F. T. TIME E.T. ZERO DAVTRON M811B s t o p RUN mounted to absorb low-frequency, high-amplitude shocks.  The mounts absorb most of the vertical and horizontal  vibration but permit the instruments to operate under  conditions of minor vibration. Bonding straps are used to  ensure electrical continuity from the panel to the airframe.  [Figure 10-133] Instrument panels are usually made from sheet aluminum  alloy and are painted a dark, nonglare color. They sometimes  contain subpanels for easier access to the backs of instruments  during maintenance. Instrument panels are usually shock- Instrument Installations and Markings Instrument Panels