Malfunction Analysis Flashcards
Things to know and malfunctions
- Blackhawk fuel system is built to operate on NEGATIVE pressure, because if a break occurs the fuel will stop.
- Only turn on fuel boost pumps over 5000ft PA, because at that altitude and higher is when they will be needed… otherwise the negative pressure is designed for the helo (seals, gaskets, etc.). Operation continuously below 5000ft PA could cause damage
- TGT rises above 500C after shutdown, place AIR SCE HT/STRT switch as required, tun ENGINE IGNITION switch off, and press starter to motor engine for 30 seconds or until TGT decreases below 500C
- W) Moving to LOCKOUT on the engine (warning) does not restrict MAX FUEL FLOW limitations (HMU) or NG limitations. If these limits are happening, LOCKOUT will not help you, but could kill the engine.
- C) when operating an engine in Lockout, engine responds faster and TGT limits are gone… care must be taken to not to over-tempt the engine.
What can effect HMU fuel given to engine
- Load Demand Spindle (collective)
- Power Demand Spindle (PCL)
- DEC
879*C TGT is when DEC starts to care and will stop the HMU metering the fuel and if you pull more collective you can droop the rotor (wants to keep the engine temp down)
DEC purely cares about NP speed in ALL flight regimes, but the TGT limit can influence it at high temps.
10minute limit is a DUAL engine limiting value, but the DEC will allow a single operating engine to get into the 2.5 minute limit
< 55% NG is engine out red x
NP oscillations - single engine airspeed, then back up with the checklist
Greater than 5% difference in torque is a torque split…
HMU controls airflow - if collective pushed down to decrease altitude, bleed valve opens and turns anti-ice light on in the cockpit (keeps airflow inside the engine from over pressurizing and causing compressor stall, stops from engine needing to re-spool when collective re-applied… like a turbo waste gate)
- W) single engine failure; before responding, verify the engine is out, AND THEN which engine is actually out!
- if required, jettison external stores if required to maintain rotor
- if power available, land as soon as possible
- if no power avail, land as soon as possible
- Lightening strike takes out all power and no MFD/ESIS - retard PCL’s and land as soon as possible
- Hot engine oil - establish single engine airspeed, retard PCL; if oil pressure below minimums and temp above maximums, emergency engine shutdown.
- compressor stall, ESEA, Engine PCL retard, then to FLY If it doesn’t stall again. Then, if compressor stall happens again, shut down (in combat, may be a wise idea to just go to idle or lower PCL setting to keep the engine)
- rotor reduction without a reduction in torque on either engine, this is a main transmission failure
- engine oil pressure low - ESEA, retard the PCL. If temp is still above max, or pressure is below minimums, emergency engine shutdown
ENGINE OIL BYPASS - establish single engine airspeed, retard PCL, land as soon as PRACTICABLE.
HIGH SIDE failure - ESEA, retard PCL (10% below other engine), if engine will not retard, emergency shutdown and land ASAPossible, otherwise if retard works, land as soon as practicable
Fuel
Fuel low - 172lbs left, land as soon as practicable (pilot’s error)… 15 minutes left typically
“4” fuel pumps per side really..
More EP stuff
Only we can shut off the Primary servos
Transfer valve allows backup pump to bypass the low pressure of a failing pump (or leak) to fill that pressure. If a leak is in the servos, BACKUP RSVR LOW caution comes on and you need to turn off those servos
“Boost” servos are like power steering
Pri Servo 1/2 Fail - by itself, a jam/hard-over and must isolate and turn off that servo
