TM  1-1520-240-10            9-1-17 9-1-12. 714A ENG 1 FAIL or ENG 2 FAIL. The ENG 1 or ENG 2 FAIL caution is illuminated whenev- er the engine failure logic within the DECU recognizes any of the following: 1.   Power  turbine  shaft  failure.  N2  is  greater than RRPM by more than 3%. 2.   N1 underspeed. 3.   Engine flameout. 4.   Over    temperature    start    abort    (Primary mode only). 5.   Primary  system  fail  freeze  (Primary  and Reversionary   mode   hard   faults,   FADEC caution is illuminated). 6.   During  normal  shutdown  as  the  N1  rpm goes below 48% the ENG 1 FAIL or ENG 2 FAIL caution is illuminated and then turned off 12 seconds after the N1 rpm drops below 40%. 9-1-13.  Single Engine Failure — Low Altitude/Low Airspeed and Cruise. If an engine fails under conditions that will permit S/E flight, thrust and  712    engine beep trim must be adjusted as required to maintain safe RRPM. Initial thrust reduc- tion will vary from no reduction at zero airspeed below 20 feet to a significant reduction at higher altitudes and air- speeds. Attempt to maintainat least 96 percent RRPM. If the helicopter is below the best S/E climb airspeed, forward cyclic must be applied to attain a nose-low attitu- de of up to 30_ in order to gain airspeed. As airspeed increases  to  30  knots,  adjust  the  pitch  attitude  of  the aircraft to accelerate to the best S/E airspeed. If an engine fails under conditions that will not permit S/E flight, the procedures will be essentially the same as for continued flight, except that cyclic pressures are applied to decelerate the helicopter for touchdown, rather than continued acceleration. During deceleration, just prior to touchdown, avoid rotating the aft landing gear into the ground. Continued flight is possible: 1.   Thrust control  — Adjust  as necessary to maintain RRPM. 2. 712 ENGINE BEEP TRIM switch —RPM INCREASE as required. 3.   External cargo — Jettison (if required). 4.   ALT switch — Disengage. 5.   Land as soon as practible. 6.   EMER ENG SHUTDOWN (when conditions permit). NOTE If S/E flight can be maintained, an attempt to restart the inoperative engine may be made if there is no evidence of fire or obvious me- chanical damage. Continued flight is not possible: Land as soon as possible. 9-1-14.  Engine Restart During Flight. WARNING Fire detector and extinguishing systems are  not  provided  for  the  APU.  Crewman must monitor APU area for fire. CAUTION If  abnormal  indications  are  present  during the restart, shut down the engine immediate- ly. 1.   APU — Start. 2. 712 ENG  COND  lever  (inoperative  en- gine) — STOP. 3. 714A ENG COND lever (inoperative en- gine) — STOP, then GND. 4.   FIRE PULL handle — In. 5.   All FUEL PUMP switches — ON. 6.   XFEED switch — As required. 7.   Starting engine — Perform. 8.   APU — OFF. 9-1-15. 712 Normal Engine Beep Trm System Failure (High Side) or N2 Governor Failure. Failure of the normal engine beep trim system to the high side may be recognized by increasing torque on the af- fected engine, decreasing torque on the unaffected en- gine, an increase in RRPM, and a lack of response of normal engine beep trim. These indications should be confirmed by observing all the engine instruments. Controling RRPM with the ECL must be done smoothly and with care. Engine response is much faster and it is possible  to  cause  the  RRPM  to  exceed  limitations  or decrease to the point that the generators will be discon- nected from the buses. If the thrust control is moved, it is necessary  to  control  RRPM  with  the  engine  condition lever and the No.1 and 2 ENGINE BEEP TRIM switch. If a malfunction to the high side occurs, perform the follow- ing: 1.   Thrust  control  —  Adjust  as  required  to maintain RRPM within limits.