NAVWEPS OD-ROT-80  APPLICATION OF AERODYNAMICS  TO SPECIFIC PROBLEMS OF FLYING  inadequate distance and the refusal speed is  less than the minimum speed necessary to  continue a safe takeoff with one engine inoper-  ative. If engine failure occurs below refusal  speed,  the takeoff must be refused  and adequate  distance remains to effect  a stop on the runway.  If engine failure occurs above refusal speed  but below the minimum speed necessary to  continue takeoff with one engine inoperative,  an accident is inevitable.  Within this range  of speeds, the airplane cannot effect a safe  takeoff at L ’ s with one engine inoperative or  a safe  stop on the remaining runway.  For this  reason, the pilot  must properly plan the  takeoff and insure that the runway available  is equal to or greater than the critical field  length.  If the runway available is less than  the critical field length, there must be sufficient  justification for the particular operation be-  cause of the hazardous consequences  of engine  failure between the refusal speed and the  minimum speed necessary  to continue takeoff  with one engine inoperative. Otherwise, the  gross weight of the airplane should be reduced  in attempt to decrease  the critical field length  to equal the available runway.  speed, the distance necessary  to continue take-  off with one engine inoperative is equal to the  stopping distance. The critical engine failure  speed is generally referred to as the “I ’ ,”  speed and it is a function of the same factors  which determine the takeoff performance,  e.g.,  density altitude, gross weight, temperature,  humidity, etc.  (3) &t&l  jield kngrh: The runway length  necessary  to accelerate  with all engines opera-  tive to the critical engine failure speed (VJ  then continue accelerating to the takeoff and  initial  climb speed (VJ  with  one engine  inoperative and achieve safe takeoff or refuse  takeoff.  By this definition,  critical field  length describes the minimum length of run-  way necessary  for safe operation of the multi-  engine airplane. Obviously, the critical field  length is a function of the same factors affect-  ing the takeoff distance of the airplane.  The conditions of Vi, V,, and critical field  length are illustrated by figure 6.13.  The  first illustration of figure 6.13 depicts the  case where the runway length is equal to the  rritical jield kngth. In this case, the airplane  could accelerate  to Vi with all engines opera-  tive then either continue takeoff safely with  one engine inoperative or refuse takeoff and  decelerate  to a stop on the remaining runway.  For this condition, an engine failure occurring  at lefs than I ’ , speed dictates that takeoff must  be refused because  inadequate distance remains  to effect a safe takeoff at V, speed.  However,  at or below V, speed, adequate distance re-  mains to bring the airplane to a stop.  If  engine failure occurs at some speed greater  than Vi speed, takeoff should be continued  because  adequate distance remains to accelerate  to V, speed and effect a safe takeoff with one  engine inoperative.  If engine failure occurs  beyond Vi speed, inadequate distance remains  to brake the airplane to a stop on the runway,  The second illustration of figure 6.13 depicts  the case where the ranway length is 1~s than  the titical field length. In this case, the term  of “V,”  speed is not applicable because of  From the standpoint of public relations  and the maintaining of friendly public support  for Naval Aviation, great care must be taken  to prevent sonic booms in populated areas.  While the ordinary sonic boom does not carry  any potential of physical damage, the disturb-  ance must be avoided because  of the undesirable  annoyance and apprehension. As supersonic  flight becomes more commonplace and an  ordinary consequence  of flying operations, the  prevention of sonic booms in populated areas  becomes  a difficult and perplexing job.  When the airplane is in supersonic flight,  the local pressure  and velocity changes on the  airplane surfaces are coincident with  the  formation of shock waves.  The pressure  jump  through the shock waves in the immediate  vicinity of the airplane surfaces  is determined  SONIC “BOOMS’ 