TM  1-1520-240-10 9-1-2            nals will be used to notify occupants of an emergency situation: 1.     Prepare  for  ditching,  or  crash  landing  —  3 short rings. 2.   Water contact — Sustained ring. Safety equipment, emergency exits, and entrance routes are shown in Figures 9-1-1 and 9-1-2. Emergency exit door handles are yellow and black striped. Safety equip- ment consists of seven first aid kits, three hand fire extin- guishers, one emergency escape axe, and three emer- gency exit lights. 9-1-5.  After-Emergency Action. After a malfunction of equipment has occurred, appropriate emergency actions have been taken, and the helicopter is on  the  ground,  an  entry  must  be  made  in  the  Remarks Section of DA Form 2408-13-1. 9-1-6.  Engine. 9-1-7.  Flight Characteristics. a.  If an engine failure occurs, no control problems exist unless power from the remaining engine is not suffi- cient to maintain the selected RRPM. If sufficient power is not available to maintain altitude, descend to an alti- tude  where  single-engine  (S/E)  flight  can  be  accom- plished (fig. 9-1-3 and 9-1-4 for S/E performance data). The  best  indications  of  engine  failure  are  decreased torque on the failed engine and a compensating increase in torque on the remaining engine, accompanied by a droop in RRPM, and a continuing decrease in N1 speed below 60 percent. An engine failure will have no effect on any of the helicopter systems as long as the RRPM is maintained above the minimum speed. On the ^714A   a 1% to 3% RRPM momentary transient can be anticipa- ted.  Then  RRPM  will  automatically  recover  to  the  se- lected RRPM. ^714A   Single engine failure is character- ized  by  an  engine  fail  caution  light,  change  in  engine noise, split in torque, momentary drop in the RRPM with the DECU recovering RRPM to 100% within maximum single engine torque limits. b. 712 When one engine fails, rotor speed can be expected to drop to as low as 93 percent. Safe RRPM can usually be regained by using engine beep trim and power available of the operating engine. c.  If sufficient power is not available, normal RRPM is regained by lowering the thrust control. Procedure to be followed after engine failure will be governed by the altitude and airspeed available for helicopter control and for maintaining sufficient RRPM for continued flight and landing.  The  height-velocity  diagram  (fig.  9-1-4  and 9-1-6)  present  the  airspeeds  and  wheel  heights  from which a safe landing can be made at various GW and temperatures following a S/E failure. d.  Decrease in thrust after engine failure will vary with altitude   and   airspeed   at   the   time   of   occurence.   For example, thrust must not be decreased when an engine or engines fail at a hover in-ground effect (HIGE): whereas, during  cruiseflight  conditions,  altitude  and  airspeed  are sufficient   for   a   significant   reduction   in   thrust,   thereby allowing rotor speed to be maintained in the safe operating range. Following an engine failure, cyclic control isadjusted as necessary to remain in hover over the desired point or to control airspeed and flight path in forward flight. Pedal pressure  is  applied  as  necessary  to  control  aircraft heading. e.  Airspeed should be maintained at the opti- mum  for existing conditions for continued flight (S/E failure) or for autorotational descent (dual-engine failure). As airspeed increases above 70 KIAS in autorotation, there is a corresponding increase in rate of descent (R/D). Airspeed up to 100 KIAS or Vne, whichever is slower, will increase glide distance but should be avoided at low altitude because the time available to decelerate is critical. At airspeeds below 70 KIAS. R/D in autorotation increases and glide distance decreases. Gliding the helicopter in autorota- tion out-of-trim will also increase R/D and decrease glide distance. 9-1-8.  Minimum Rate of Descent — Power Off. The power off minimum R/D is attained at an indicated airspeed  of  approximately  70  knots and 100% RRPM (fig. 9-1-7). 9-1-9.  Maximum Glide Distance — Power Off. The maximum glide distance is attained at an indicated airspeed of 100 knots or Vne, whichever is slower, and 100% RRPM (fig. 9-1-7).