Standard Training Procedures

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Standard Training Procedures
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BO 105 / BK 117 / EC 145
Governor emergencies
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D i s c l a i m e r
The information given in this presentation
represents my personal view and deals with
general airmanship ! I will not take
responsibility in case of training
accidents. Allways the current Flight Manual of
the helicopter used for training has to be
regarded as the correct source of information.
The autor
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Standard Procedures
There are basically three different governor
emergencies !
Engine overspeed caused by driveshaft
failure Means the driveshaft between engine and
transmission has lost its connection and the
available power will produce a quick
acceleration and a very high N2-RPM on this engine
Engine overspeed caused by governor
malfunction Means the governor senses wrong
signals for the need of power and gives the Fuel
Control Unit the order to increase its fuel flow
which then will produce an acceleration of N2 /
NRO-RPM
Engine underspeed caused by governor
malfunction Means the governor senses wrong
signals for the need of power and gives the Fuel
Control Unit the order to decrease its fuel flow
which then will produce an deceleration of N2 on
this engine
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Lets talk about Engine overspeed caused by
driveshaft failure!
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Standard Procedures
Engine overspeed drive shaft failure !
How to identify a driveshaft failure ??
Remember from the ground course ? The power
output (N2) drives the shaft which is connected
to the free wheeling unit in the XMSN. So, if
this connection is interrupted, we will hear a
mechanical noise and the indication on the
triple tacho indicator will be this !
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Standard Procedures
Engine overspeed drive shaft failure !
How to identify a driveshaft failure ??
Remember from the ground course ? The power
output (N2) drives the shaft which is connected
to the freewheeling unit in the XMSN. So, if this
connection is interrupted, we will hear a
mechanical noise and i.e. the indication on the
triple tacho indicator will be this !
N 2 left engine
N 2 right engine
N 2 / N RO
N RO
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Standard Procedures
Engine overspeed drive shaft failure !
The most important instrument is the triple tacho
indicator but there will be more indications
! For the affected engine Tq will go to zero,
N1 will decrease because of lost resistance For
the normal engine Tq / TOT / N1 will increase
caused by its power increase to maintain NRO
For BK 117 C2 VAR NR and ENG SPLIT caution
lights come on
N 2 / N RO
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Standard Procedures
Engine overspeed drive shaft failure !
Now what to do ??
1. Adjust the remaining engine to stay within its
OEI power limits
NOTE If the engine is protected for overspeed,
the system may become active
provided the N2 RPM level to activate the
system has been reached (For the BK 117
C1 / C2 the engine will shut down at 123 N2,
the remaining engine is interlocked and
its overspeed protection then no more available)
2. Identify the affected engine and perform for
this engine the Emergency shutdown procedure
3. Land as soon as practicable
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Lets talk about Engine overspeed caused by
governor malfunction!
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Standard Procedures
Engine overspeed governor malfunction !
How to identify a engine overspeed ??
The triple tacho indicator will show you this !
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Standard Procedures
Engine overspeed governor malfunction !
How to identify a engine overspeed ??
The triple tacho indicator will show you this !
N 2 left engine
N 2 right engine
N 2 / N RO
N RO
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Standard Procedures
Engine overspeed governor malfunction !
The most important instrument is the triple tacho
indicator but there will be more indications
! ROTOR RPM warning may come on For the
affected engine Tq / TOT / N1 will increase
caused by higher fuel flow / resistance For the
normal engine Tq / TOT / N1 may decrease caused
by lower power requirement
For BK 117 C2 VAR NR and ENG SPLIT caution
lights may come on
N 2 / N RO
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Standard Procedures
Engine overspeed governor malfunction !
Now what to do ??
1. Collective lift as necessary to stop NRO / N2
increase
NOTE Try to maintain the affected
engine within its TOT / Tq limits (For
BK 117 C1 / C2 check / make sure that the VAR NR
caution is on)
2. Try to trim NRO to its normal value with
matched torque
If trimming is not successful
3. Identify which engine is affected (It is
the engine with the higher Torque)
4. Twist grip (or Power lever) of the affected
engine adjust to low power until the NRO
comes back to normal and the torques are matched
5. Land as soon as practicable
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Standard Procedures
Engine overspeed governor malfunction !
How to land ??
1. Adjust the collective slowly to stay with the
fixed power engine within limits during
flight to the destination
2. Perform a long final and a smooth shallow
approach
NOTE One can always decide to land in single
engine condition as long as the power
requirement is low. If this seems not to be
advisable the power can be always
readjusted in the short final to assist the
normal engine during landing (In
this case, take great care when lowering the
collective after landing and lower also the
respective twist grip or power lever to
avoid a high NRO during that collective movement)
3. After landing perform a normal shut down
procedure
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Lets talk about Engine underspeed caused by
governor malfunction!
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Standard Procedures
Engine underspeed governor malfunction !
How to identify a engine underspeed ??
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Standard Procedures
Engine underspeed governor malfunction !
How to identify a engine underspeed ??
The triple tacho indicator will show you this !
Or, depending on the excess of underspeed,
the triple tacho indicator will just remain at
its normal position
N 2 left engine
N 2 right engine
N 2 / N RO
N RO
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Standard Procedures
Engine underspeed governor malfunction !
The most important instrument is the triple tacho
indicator but there will be more indications
! ROTOR RPM warning may come on For the
affected engine Tq / TOT / N1 will decrease
caused by lower fuel flow For the normal engine
Tq / TOT / N1 may increase caused by higher power
requirement
For BK 117 C2 VAR NR and ENG SPLIT caution
lights may come on
N 2 / N RO
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Standard Procedures
Engine underspeed governor malfunction !
Now what to do ??
1. OEI flight condition establish and switch any
bleed air consumer off
NOTE Try to maintain the normal
engine within its TOT / Tq limits (For
BK 117 C1 / C2 check / make sure that VAR NR
caution is on)
2. Try to trim NRO to its normal value with
matched torque
If trimming is not successful
3. Identify which engine is affected and continue
flight if the affected engine still delivers
assisting power (It is the engine with the lower
Torque)
NOTE For BK 117 C1 / C2 release the
flight position limiter on twist grip (power
lever) and adjust
the affected engine to high power until the NRO
comes back to normal and the
torques are matched.
4. Land as soon as practicable
5. If the affected engine does not deliver
assisting power, perform a emergency shut
down of this engine
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Standard Procedures
Engine underspeed governor malfunction !
How to land ??
1. Adjust the collective slowly to stay with the
affected engine within limits during flight
to the destination
2. Perform a long final and a smooth shallow
approach
NOTE One can always decide to land in single
engine condition as long as the power
requirement is low. If this seems not to be
advisable the power can be always
readjusted in the short final to assist the
normal engine during landing (In
this case, take great care when lowering the
collective after landing and lower also the
respective twist grip or power lever to
avoid a high NRO during that collective movement)
3. After landing perform a normal shut down
procedure
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Standard Procedures
Governor malfunctions
Please identify the governor problem ??
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Standard Procedures
Governor malfunctions
Please identify the governor problem ??
Engine overspeed left engine!
TRQ 80
TRQ 5
N 2 / N RO
TOT 745C
TOT 605C
N 1 96,0
N 1 80,5
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Standard Procedures
Governor malfunctions
Please identify the governor problem ??
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Standard Procedures
Governor malfunctions
Please identify the governor problem ??
Drive shaft failure right engine!
TRQ 89
TRQ 0
N 2 / N RO
TOT 745C
TOT 605C
N 1 99,0
N 1 78,5
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Standard Procedures
Governor malfunctions
Please identify the governor problem ??
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Standard Procedures
Governor malfunctions
Please identify the governor problem ??
Engine underspeed right engine!
TRQ 80
TRQ 5
N 2 / N RO
TOT 745C
TOT 605C
N 1 96,0
N 1 80,5
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Standard Training Procedures
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Many happy landings and enjoy your governor
malfunction training !