Page 24 - Volume 16 Number 12

Twin Proficiency:Emer DescThe pressure vessel is breeched when a window cracks and gives way; the air is sucked from your lungs as the cabin fogs with condensation. An electrical fire flares and won’t extinguish. A passenger seizes with chest pains and you need to get him to medical help right away. An engine flames and the fire won’t go out. In any of these scenarios, a vital factor in survival is your knowledge of the Emergency Descent procedure.Emergency DescentThe FAA Airplane Flying Handbook tells us:An emergency descent is a maneuver for descending as rapidly as possible to a lower altitude or to the ground for an emergency landing. The need for this maneuver may result from an uncontrollable fire, a sudden loss of cabin pressurization, or any other situation demanding an immediate and rapid descent. The objective is to descend the airplane as soon and as rapidly as possible, within the structural limitations of the airplane. When initiating the descent, a bank of approximately 30 to 45° should be established to maintain positive load factors (“G” forces) on the airplane.The Pilot’s Operating Handbook (POH) or Approved Flight Manual (AFM) for your airplane has an Emergency Descent checklist in the Emergency Procedures section. The Emergency Descent is an extreme-performance maneuver, a deliberate act flown in a desperate time. The sequence of the procedure has you immediately:Reduce power to idlePush the propeller(s) fully forward, in propeller-driven aircraftExtend speed brakes, if equippedExtend the landing gearExtend APPROACH flaps, if the airplane has a pre-selectable approach flap position Pitch to a nose-low attitudeAttain and maintain the maximum indicated airspeed for the flap and gear configurationWhat are the considerations for each step?Reduce power to idle: If you need to get on the ground now, you need to chop the throttles or power levers and descend at idle power. Engine longevity is no longer an operating consideration in piston airplanes. In some emergency descent scenarios you’ll shut the engine down (engine fire in flight); in others, pull the throttles or power levers all the way back.22 • TWIN & TURBINEg