TM 1-1510-223-10 9-8            NOTE Brake deice on the affected side will not be avail- able with bleed air valve switch off. 4.  Cabin pressurization — Check. b.   Excessive Differential Pressure. If cabin differen- tial pressure exceeds 6.5 PSI, perform the following: 1.  Cabin altitude and rate-of-climb controller — Select higher setting. If condition persists: 2.  LEFT  ENVIRO  &  PNEU  BLEED  AIR  valve switch — PNEU ONLY (L BL AIR OFF annun- ciator illuminated). If condition still persists: 3.  RIGHT ENVIRO & PNEU BLEED AIR valve switch — PNEU ONLY (R BL AIR OFF annun- ciator illuminated). If condition still persists: 4.   Descend immediately. If unable to descend: 5.   Oxygen masks — On and 100%. 6.  CABIN PRESS switch — DUMP. 7.  ENVIRO & PNEU BLEED AIR valve switches — ON, if cabin heating is required. 9-22.   LOSS  OF  PRESSURIZATION  (ABOVE  10,000 FEET). If cabin pressurization is lost when operating above 10,000 feet or the ALT WARN warning annunciator illumi- nates, perform the following: 1.   Crew oxygen masks — On and 100%. 2.   Descend as required. NOTE Proper EFIS operation has been demonstrated at cabin altitudes of up to 12,500 feet. 9-23.   CABIN DOOR CAUTION ANNUNCIATOR ILLU- MINATED. Remain clear of cabin door and perform the following: 1.  ENVIRO & PNEU BLEED AIR valve switches — PNEU ONLY. 2.   Descend below 14,000 feet as soon as practi- cable. 3.   Oxygen — As required. 9-24.   PROPELLER FAILURE (OVER 1802 RPM). If an overspeed condition occurs that cannot be con- trolled with the propeller lever, or by reducing power, per- form the following: 1.   POWER lever (affected engine) — IDLE. 2.   PROP lever — FEATHER. 3.   CONDITION lever — As required. 4.  Engine cleanup — As required. 9-25.   FIRE. a.   Engine Fire. The following procedures shall be tak- en in the event of engine fire. (1)    Engine/nacelle fire during start or ground op- erations. If engine/nacelle fire is identified during start or ground operation, perform the following: 1.   PROP levers — FEATHER. 2.   CONDITION levers — FUEL CUTOFF. 3.   FIRE PULL handle — Pull. CAUTION If fire extinguisher has been used to extinguish an  engine  fire,  do  not  attempt  to  restart,  until maintenance personnel have inspected the air- craft and released it for flight. 4.   PUSH TO EXTINGUISH switch — Push. 5.   MASTER SWITCH — OFF. (2)    Engine fire in flight (FIRE PULL handle light illuminated). If an engine fire is suspected in flight, per- form the following: 1.   POWER lever — IDLE. 2.   If FIRE PULL handle light is extinguished: Advance power. 3.   If FIRE PULL handle light is still illuminated: Engine fire in flight procedures (identified) — Perform. (3)    Engine fire in flight (identified). If an engine fire occurs in flight, perform the following: CAUTION Due to the possibilities of fire warning malfunc- tions, the fire should be visually identified before the engine is secured and the extinguisher actu- ated. 1.   POWER lever — IDLE. 2.   PROP lever — FEATHER.