CHAPTER 13. Abnormal and Emergency Procedures

Electrical Fires

The initial indication of an electrical fi re is usually a slight amount of smoke and the distinct odor of burning insulation, which may not be noticeable in a WSC open fl ight deck. Once an electrical fi re is detected, the pilot should attempt to identify the faulty circuit by checking circuit breakers, instruments, avionics, and lights. If the faulty circuit cannot be readily detected and isolated, and fl ight conditions permit, the battery master switch should be turned off to remove the possible source of the fi re. However, any materials that have been ignited may continue to burn.

If electrical power is absolutely essential for the fl ight, an attempt may be made to identify and isolate the faulty circuit by:

  • Turning the electrical master switch off.
  • Turning all individual electrical switches off.
  • Turning the master switch back on.
  • Selecting electrical switches that were on before the fi re indication one at a time, permitting a short time lapse after each switch is turned on to check for signs of odor, smoke, or sparks.

This procedure, however, has the effect of recreating the original problem. The most prudent course of action is to land as soon as possible.

The electrical fi re could expand into a larger fi re in the carriage. A fi re in the cabin presents the pilot with two immediate demands: attacking the fi re and getting the aircraft safely on the ground as quickly as possible.

System Malfunctions

Electrical System

The loss of electrical power can deprive the pilot of communications and navigation systems, but for day/VFR conditions this is not a life threatening situation because most engines ignition systems are on a separate electrical system and not dependent on the battery for keeping the engine running. However, losing communications does present some challenges especially if operating at a controlled tower airport in which procedures in the Airmanís Information Manual (AIM) would be followed.

Pitot-Static System

The source of the pressure for operating the airspeed indicator, the vertical speed indicator, and the altimeter is the pitot-static system. Most WSC aircraft have pressure for the airspeed indicator. If this becomes plugged, the airspeed indicator may not read properly. If it is suspected that the airspeed indicator is not reading properly, use the feel of the aircraft and the trim position to determine speed. It is perfectly safe to fl y a WSC aircraft without an airspeed indicator if the pilot has developed a feel of the aircraft since the trim position speed is known and all other speeds can be determined based on the feel of the air and the pressure on the control bar.

Altitude and vertical speed utilize static pressure. Because there is typically no static line connecting these, they operate independently. Therefore, if one fails or becomes plugged, the other can act as a reference. For example, if the altimeter fails for any reason, the vertical speed indicator would provide the pilot with information on whether the aircraft was climbing, level, or descending. The global positioning system (GPS) (if equipped) could also provide altitude readings. If the vertical speed indicator failed, the altimeter could provide information on whether the aircraft was climbing, level, or descending by looking at the altitude reading over time.

 
 
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