TM 1-1510-225-10 5-18 DUE  TO  A  CRACK  IN  THE  WINDSHIELD, PRESSURIZED    FLIGHT    IS    PROHIBITED.   CONDUCT     FLIGHTS     WITH     BLEED     AIR VALVES    IN    ENVIR    OFF    POSITION    AND CABIN PRESS SWITCH IN DUMP POSITION. d.  Internal    Crack    on    Ground.        Inner    ply cracking is not a structural consideration for replacement  prior  to  next  flight,  but  one  of  possible glass flaking which could interfere with pilot vision. 5-40.  CRACKED CABIN WINDOW. If crack(s) in cabin window ply(s) occurs in-flight, perform    the    Cracked    Cabin    Window    emergency procedure   in   Chapter   9.      If   a   cabin   window   has developed a crack, the aircraft shall not be flown, once landed, without proper ferry flight authorization. If  cracking,  chipping,  or  stress  crazing  that  can be  felt  with  the  fingernail  occurs  in  either  ply  of  the cabin   window,   the   window   should   be   replaced   in accordance with the approved maintenance instructions. If,    for    some    reason,    the    window    cannot    be replaced  prior  to  the  next  flight,  unpressurized  flight may be conducted, provided the following placards are installed in the aircraft. The  following  placard  must  be  placed  in  clear view of the pilot: PRESSURIZED     FLIGHT     IS     PROHIBITED DUE TO A DAMAGED WINDOW.   CONDUCT FLIGHT WITH THE CABIN PRESS SWITCH IN THE DUMP POSITION. The following placard must be placed next to the pressurization control: UNPRESSURIZED FLIGHT ONLY PERMITTED. If  a  crack  is  found  in  both  the  inner  and  outer plies    of    the    cabin    window,    the    window    must    be replaced   PRIOR   TO   FURTHER   FLIGHT   OF   THE AIRCRAFT, unless proper ferry flight authorization has been obtained. Section VIII.  OTHER LIMITATIONS 5-41.  INTENTIONAL ENGINE OUT SPEED. Intentional  in-flight  engine  cuts  below  the  safe one   engine   inoperative   speed   (V_sse,  104  KIAS)  are prohibited. 5-42.  LANDING ON UNPREPARED RUNWAY. CAUTION Except in an emergency, propellers should be moved out of reverse below 40 knots to minimize     propeller     blade     erosion,     and during crosswind to minimize stress imposed on propellers, engines,  and airframe.      Care   must   be   exercised   when reversing  on  runways  with  loose  sand  or dust   on   the   surface.      Flying   gravel   will damage    propeller    blades    and    dust    may impair  the  pilot's  forward  visibility  at  low aircraft speeds.  The aircraft has demonstrated landings on hard, smooth   runways.      Hard   braking,   i.e.,   skidding   tires while  operating  on  other  than  smooth  runways,  can result in damage to the landing gear.  When landing on other  than  dry  surfaces,  use  discretionary  propeller reverse to stop the aircraft on the available runway. Section IX.  REQUIRED EQUIPMENT FOR VARIOUS CONDITIONS OF FLIGHT 5-43.  REQUIRED EQUIPMENT LISTING. The Required Equipment List (REL) is approved by  the  Directorate  of  Evaluation  and  Standardization (DES)  USAAVNC,  Fort  Rucker.    It  is  fully  coordinated with the Master Minimum Equipment List (MMEL) and AR 95-1.   It  is  the  governing  document  for  flight  with inoperative    components    and    items    of    equipment.   Changes or modification to the REL are not authorized unless  approved  by  DES  and  distributed  by  the  Fixed Wing Product Manager’s Office (FWPMO).