Method for detecting a malfunction in a first turbos haft engine of a twin-engine
helicopter and for controlling the second turbos haft engine, and a corresponding
device
1. Technical field of the invention
The invention relates to a method for regulating the turboshaft engines of a twin-engine
helicopter. In particular, the invention relates to a method for detecting a malfunction of a first
turboshaft engine, referred to as an inoperative engine, of a twin-engine helicopter, and for
controlling the second turboshaft engine, referred to as a healthy engine. The invention also
relates to a device for detecting a malfunction of a first turboshaft engine and for controlling a
second turboshaft engine of a twin-engine helicopter.
2. Technical background
A twin-engine helicopter is equipped with two turboshaft engines which operate in regimes
which are dependent on the flight conditions of the helicopter. It is known that a twin-engine
helicopter can have two main regimes, a regime known by the abbreviation AEO (all engines
operative) in which the two turboshaft engines operate normally in predetermined regimes,
and a regime known by the abbreviation OEI (one engine inoperative) in which one of the
turboshaft engines is inoperative. This OEI regime occurs following the loss of one engine.
When this event occurs, it is necessary for the good engine to accelerate rapidly so that it
can provide the maximum permissible power thereof in an emergency situation and thus
make it possible for the helicopter to cope with the perilous situation, then to be able to
continue the flight.
Throughout the following text, the malfunctioning turboshaft engine will be referred to by the
term "inoperative turboshaft engine" and the good engine will be referred to by the term
"healthy turboshaft engine".
The technical problem is thus posed of minimising the period which separates the detection
of the sudden loss of power of the inoperative turboshaft engine and achieving maximum
power in the emergency regime of the healthy turboshaft engine.
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The shorter this period, the safer the flight is. Furthermore, the shorter this period, the more
the helicopter can have a significant take-off mass. Minimising the period which separates
the detection of the loss of power of the inoperative engine from achieving the full power of
the healthy engine is thus beneficial in two ways.
Nowadays, it is known to detect the loss of power of the inoperative engine by comparing the
operating regimes of the two turbos haft engines. If a predetermined difference between the
two operating regimes is detected, the turboshaft engine having the worse regime is
declared to be inoperative. This loss of power is detected by the identification of a difference
between the speeds of the gas turbines which is greater than a predetermined threshold or a
difference between the torques of the two engines which is greater than a predetermined
threshold.
Once the loss of power is detected, the healthy engine is controlled in order to reach the
maximum regime thereof in the emergency regime, which consists in increasing the
maximum torque and speed stops of the gas turbine to the maximum permissible stops.
Subsequently, the fall in the rotational speed of the rotary wing of the helicopter following the
loss of the inoperative engine will lead, by means of the regulation of the speed of the rotary
wing by the healthy engine, to an increase in the setpoint value of the fuel flow rate.
The technical problem is posed of providing a better solution to further minimise the period
which separates the detection of the sudden loss of power of the inoperative turboshaft
engine and achieving maximum power in the emergency regime of the healthy turboshaft
engine.
3. Aims of the invention
The invention aims to provide an effective and economical solution to this technical problem.
In particular, the invention aims to provide, in at least one embodiment of the invention, a
method for detecting a malfunction of a first turboshaft engine, referred to as an inoperative
engine, of a twin-engine helicopter, and for controlling the second turboshaft engine, referred
to as a healthy engine, which minimises the period which separates the detection of the
malfunction of the inoperative engine from achieving the full power of the healthy engine.
3
The invention also aims to provide a device for detecting a malfunction of a first, inoperative
turboshaft engine of a twin-engine helicopter, and for controlling the second, healthy
turboshaft engine.
The invention also aims to provide a twin-engine helicopter which is equipped with such a
device.
4. Summary of the invention
For this purpose, the invention relates to a method for detecting a malfunction in a first
turboshaft engine, referred to as an inoperative engine, of a twin-engine helicopter having a
rotary wing, and for controlling a second turboshaft engine, referred to as a healthy engine,
each engine comprising protective stops regulated by a regulation device which define a
maximum power regime, characterised in that it comprises:
- a step of detecting an indication of failure of said inoperative engine,
a step of modifying said protective stops of said healthy engine into protective stops
which correspond to a single-engine regime, in the case of the detected indication of
failure,
- a step of confirming a failure of said inoperative engine,
- a step of controlling an immediate increase in the flow rate of fuel supply of said
healthy engine, in the event of a confirmed failure, so as to allow an acceleration of
the healthy engine without waiting for an automatic regulation of the healthy engine
after a fall in speed of said rotary wing resulting from the failure of the inoperative
engine.
A method according to the invention thus makes it possible to switch the healthy engine from
a twin-engine configuration to a single-engine configuration once an indication of failure is
detected. This step of changing configuration is carried out by modifying the protective steps
of the engine into protective steps which correspond to the single-engine regime. A
subsequent step of confirming failure is then implemented and influences the control of the
immediate increase of the flow rate of fuel supply of the healthy engine. This step of
confirming failure makes it possible to ensure that the helicopter is actually facing a real loss
of power, and this avoids ordering an untimely acceleration of the healthy engine, which can
otherwise cause overspeed of the rotor. If the failure is confirmed, the fuel flow rate of the
healthy engine is immediately increased, and this makes it possible to rapidly accelerate the
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healthy engine without waiting for an automatic regulation following the fall in the rotational
speed of the rotary wing of the helicopter.
A method according to the invention thus makes it possible to rapidly detect a failure of an
engine and to rapidly achieve the full power of the healthy engine after the detection of the
failure. Once an indication of failure is detected, the protections of the healthy engine are
modified and increased to the protective stops which correspond to the single-engine
regime. If the failure is confirmed, the fuel setpoint value is modified. Since the healthy
engine is then at full acceleration, as a result of the increase in the protective stops, full
power in the single-engine regime is reached rapidly.
A method according to the invention has phases for detecting the failure of the inoperative
engine and for controlling the healthy engine which overlap one another, and this makes it
possible to shorten the period between the detection of the malfunction of said inoperative
engine and obtaining the full power of said healthy engine.
In a known manner, each turboshaft engine comprises a gas generator provided with a
combustion chamber, a free turbine which is supplied with gas by the gas generator, and an
output shaft which is set into rotation by the free turbine. The protective stops of each
engine, which define the maximum power regime of said engine, typically correspond to
levels of speed of the gas generator, of engine torque and/or of temperature of the
combustion chamber. These protective stops are regulated by a regulation device known by
the abbreviation FADEC (full authority digital engine control). The step of modifying the
protective steps makes it possible to modify, and in practice to increase, the maximum
permissible limits of these different parameters - speed of the gas generator, engine torque,
temperature of the combustion chamber. These stops pass from the levels thereof which
correspond to a twin-engine operation to the levels thereof which correspond to a singleengine
operation.
Advantageously and according to the invention, the step of detecting an indication of failure
consists in:
retrieving, for each engine, at least one measurement of at least one parameter
which is representative of the operating regime of the engines,
- detecting a difference between said measurements which is greater, in terms of
absolute value, than a predetermined threshold.
5
This step makes it possible to retrieve measurements of at least one parameter which is
representative of the operating regime of each engine and to detect a difference between
these measurements which is greater, in terms of absolute value, than a predetermined
threshold. Such a parameter which is representative of the operating regime of the engines
can be a measured parameter or an estimated parameter. Said parameter can be for
example the rotational speed of the gas turbine of each engine, or the torque exerted by an
output shaft of each turboshaft engine which sets into motion a power transmission case, or
the temperature of the gases at the input of the free turbine of each turboshaft engine, or the
estimation of the level of dose rate, etc.
Advantageously and according to this variant, each detection of a difference between said
measurements is modulated by at least one variable, referred to as a modulation variable,
which is representative of normal variations in said measurements during a nominal
operating regime of the engines.
According to this advantageous variant, each measurement of a difference is modulated by
a modulation variable which makes it possible to take into account the normal variations in
the measurements during a nominal operating regime. This thus makes it possible to avoid
the untimely detections of failure which in reality are due to normal variations in the
measurements. These modulation variables thus make it possible to integrate the normal
variations in the measurements and thus reduce the threshold above which a difference
must be considered to be an indication of failure.
Advantageously and according to this variant, at least one modulation variable is selected
from the following group: type of engine regimes; type of effective balancing of the engines;
proximity of the measurements of the shaft and torque speeds of the engines to the
maximum permissible values for said engines; acceleration and deceleration rates of the
engines; period of transmission of said measurements of each parameter which is
representative of the operating regime of the engines.
Each of these modulation variables makes it possible to take into account, when determining
a difference between the measurements of a parameter which is representative of the
operating regime of the engines, conditions in which the measurement has been carried out,
and thus to modulate the measurement of the difference.
6
Advantageously, in a variant or in combination, a method according to the invention further
comprises a step of learning nominal differences between said measurements of at least
one parameter which is representative of the operating regime of the engines, during
stabilised regimes of said engines, said nominal differences which are determined in this
way constituting a modulation variable.
A learning step of this type makes it possible to create a learning base which supplies
differences between the measurements of a parameter which is representative of the
operating regime of the engines, which are not representative of a failure of one of the
engines. This learning base also supplies normal differences in normal operating conditions.
In other words, this learning base makes it possible to refine the detection threshold above
which a difference must be considered to be an indication of failure.
Advantageously and according to the invention, at least one parameter which is
representative of the operating regime of an engine is a rotational speed of said gas
generator or a torque which is exerted by said output shaft of said engine.
According to this advantageous variant, the step of detecting an indication of failure consists
in comparing the values of the speeds of the gas turbines and/or the torques exerted by the
output shafts.
Advantageously and according to the invention, the step of modifying the protective stops of
said healthy engine into protective stops which correspond to a single-engine regime
consists in increasing the torque exerted by said output shaft and in increasing the rotational
speed of said gas generator in order to achieve predetermined rated values which
correspond to a full-power single-engine regime.
Advantageously and according to the invention, the step of confirming a failure of said first
engine consists in verifying that multiple predetermined conditions which are representative
of a real loss of power are verified.
Advantageously and according to this variant, said predetermined conditions are as follows:
- a signed difference between the rotational speed of said gas generator of said
inoperative engine and the rotational speed of said gas generator of said healthy
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engine is greater than the difference measured in said step of detecting an index for
this parameter,
- a signed difference between the torque of said output shaft of said inoperative engine
and the torque of said output shaft of said healthy engine is greater than the
difference measured in said step of detecting an index,
a rotational speed of said free turbine of said inoperative engine is less than a
predetermined setpoint value which is subtracted from a predetermined offset.
- a time derivative of the rotational speed of said gas generator of said healthy engine
is greater than a predetermined threshold,
- a time derivative of the rotational speed of said gas generator of said inoperative
engine is less than a predetermined threshold.
All of the above-mentioned predetermined conditions make it possible to confirm the failure
of said inoperative engine. In other words, it makes it possible to differentiate between a real
loss of power on the inoperative engine and another cause which could have led to the
detection of an indication of failure by highlighting a difference which is greater than a
predetermined threshold.
Advantageously and according to the invention, said step of controlling an increase in the
flow rate of fuel supply of said healthy engine consists in switching a law of anticipation of
power, which links a measurement of the collective pitch of the blades of said helicopter to a
speed setpoint value of said gas generator, in the twin-engine configuration to a law of
anticipation in the single-engine configuration.
According to this variant, the increase in the fuel flow rate in the healthy engine consists in
switching a law of anticipation of power in the twin-engine configuration to a law of
anticipation in the single-engine configuration.
The invention also relates to a device for detecting a malfunction in a first turboshaft engine,
referred to as an inoperative engine, of a twin-engine helicopter, and for controlling a second
turboshaft engine, each engine comprising protective stops regulated by a regulation device
which define a maximum power regime, said healthy engine comprising:
- a module for detecting an indication of failure of said inoperative engine,
8
- a module for modifying said protective stops of said healthy engine into protective
stops which correspond to a single-engine regime, in the case of the detected
indication of failure,
- a module for confirming a failure of said inoperative engine,
- a module for controlling an increase in the flow rate of fuel supply of said healthy
engine in the case of confirmed failure.
A device according to the invention advantageously implements a method according to the
invention, and a method according to the invention is advantageously implemented by a
device according to the invention.
Throughout the text, module denotes a software element, a sub-assembly of a software
program, which can be compiled separately, either for independent use or to be assembled
with other modules of a program, or a hardware element, or a combination of a hardware
element and a software sub-program. A hardware element of this type can comprise an
application-specific integrated circuit (better known by the abbreviation ASIC) or a
programmable software circuit or any equivalent hardware. In a general manner, a module is
thus a (software and/or hardware) element which makes it possible to ensure a function.
The invention also relates to a helicopter comprising at least two turboshaft engines,
characterised in that it comprises a device according to the invention.
The invention also relates to a method for detecting a malfunction of a first turboshaft engine
of a twin-engine helicopter, and for controlling a second turboshaft engine, to a
corresponding device, and to a helicopter comprising such a device, characterised in
combination by all or some of the features mentioned above or below.
5. List of the drawings
Other aims, features and advantages of the invention will become apparent from reading the
following description which is provided purely on a non-limiting basis and relates to the
appended figures, in which:
- Fig. 1 is a schematic view of a twin-engine architecture for implementing the method
according to one embodiment of the invention,
- Fig. 2 is a schematic view of a method according to one embodiment of the invention.
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6. Detailed description of an embodiment of the invention
Fig. 1 is a schematic view of an example of architecture 100 of a twin-engine helicopter
which is adapted to the implementation of a method according to the invention. Each
turboshaft engine 4, 5 comprises respectively and conventionally a gas generator 41, 51 and
a free turbine 42, 52 which is supplied by the gas generator 41, 51 to provide power. The
output of the turbine engines is connected to a power transmission case 9. Each gas
generator 41, 51 further comprises a combustion chamber 40, 50 which is supplied with fuel
by a fuel distribution circuit which is not shown in the drawing for the sake of clarity.
Each turboshaft engine 4, 5 is coupled to drive means E 1, E2 and to emergency assistance
devices U1, U2.
Each means E1, E2 for setting into rotation the respective gas generator 41, 51 can be
formed by a starter which is powered respectively by a starter/generator device with which
the other turbine engine is equipped.
The drive means E1, E2, the emergency assistance devices U1, U2 and the controls of the
turbine engines 4, 5 are managed by a regulation device 8. This regulation device is adapted
to regulate the protective stops which define the maximum power regime of each engine.
Fig. 2 is a schematic view of a method according to one embodiment of the invention. A
method according to this embodiment of the invention comprises a step 10 of detecting an
indication of failure of the first turboshaft engine 4, referred to as an inoperative engine, by
measuring a difference which is greater than a predetermined threshold between values
supplied by this inoperative turboshaft engine 4 and the healthy engine 5, for at least one
parameter which is representative of the operating regime of the engines 4, 5.
Throughout the text, the terms "engine" and "turboshaft engine" are synonyms and are thus
used to denote a device for supplying power for a helicopter. The blocks 4, 5 from Fig. 2
respectively show the inoperative turboshaft engine and the healthy turboshaft engine,
including the power and control members. Fig. 2 is only intended to show the sequencing of
the steps of the method and the main interactions with the two turboshaft engines.
10
The method further comprises a step 11 of modifying and increasing the protective stops of
the healthy turboshaft engine 5 to protective steps which correspond to a full-power singleengine
regime. This modification of the stops is carried out in the case of an indication of
failure detected in step 10. These protective stops are the rotational speed of the gas
generator, the torque on the output shaft and the temperature of the combustion chamber.
The method further comprises a step 12 of confirming the failure of the inoperative
turboshaft engine 4 by measuring a difference which is greater than a predetermined
threshold between the values supplied by this inoperative turboshaft engine 4 and the
healthy turboshaft engine 5, for multiple parameters which are representative of the
operating regime of the engines.
Lastly, the method comprises a step 13 of controlling an increase in the flow rate of fuel
supply of the healthy turboshaft engine 5 in the case of confirmed failure.
Each step will now be described in greater detail.
The step 10 of detecting an indication of failure consists in retrieving, for each engine 4, 5, a
measurement of at least one parameter which is representative of the operating regime of
the engines and detecting a difference between said measurements which is greater, in
terms of absolute value, than a predetermined threshold. This parameter is for example the
rotational speed of the gas generator 41, 51 of each engine or the torque of the output shaft.
The measurement of the difference between the values is modulated by at least one
modulation variable 20 which is representative of normal variations in the measurements
during a nominal operating regime of the engines 4, 5. This variable 20 is for example
representative of the type of engine regimes, of the type of effective balancing of the
engines, of the proximity of the measurements of the shaft and torque speeds of the engines
to the maximum permissible values for said engines, of the acceleration and deceleration
rates of the engines or of the period of transmission of said measurements of each
parameter which is representative of the operating regime of the engines.
In step 10 of detecting an index, the difference between the values supplied by the engines
is thus calculated, then modulated by the modulation variable 20. If a difference greater than
11
a predetermined threshold is detected, then an indication of failure of the engine 4 is
detected.
For example, taking into consideration the rotational speed of the gas generator, and
according to one embodiment, the predetermined threshold above which a difference is
considered to be significant enough to characterise a failure, is 1 %. Taking into
consideration the engine torque, the predetermined threshold is fixed at 7 %.
The step 11 thus consists in controlling the full power of the engine 5 in such a way that it
reaches rated values of single-engine operation, in order to overcome the malfunction of the
engine 4. Conventionally, this control is intended to increase the rotational speed of the gas
turbine and the torque at the output of the turboshaft engine.
The step 12 consists in verifying that the engine 4 is in fact inoperative. For this purpose, the
following tests are carried out. It is verified that a signed difference between the rotational
speed of the gas generator 41 of the inoperative engine 4 and the rotational speed of the
gas generator 51 of the healthy engine 5 is greater than the difference measured in the step
10 of detecting an index when the parameter which is representative of the operating regime
of the engines is the rotational speed of the gas generators of the engines. It is also verified
that the signed difference between the torque of the output shaft of the inoperative engine 4
and the torque of the output shaft of the healthy engine 5 is greater than the difference
measured during the step of detecting an index when the parameter which is representative
of the operating regime of the engines is the torque of the engines. It is also verified that the
rotational speed of the free turbine 42 of the inoperative engine 4 is less than a
predetermined setpoint value which is subtracted from a predetermined offset (for example
said offset is fixed at 0.75 % of the speed of the free turbine, and the setpoint value is the
rated speed of the free turbine). It is also verified that the time derivative of the rotational
speed of the gas generator 51 of the healthy engine 5 is greater than a predetermined
threshold (for example, the predetermined threshold for the time derivative of the healthy
engine is fixed at 1 % of the speed of the gas generator per second). It is lastly verified that
the time derivative of the rotational speed of the gas generator 41 of the inoperative engine 4
is less than a predetermined threshold (for example, the predetermined threshold for the
time derivative of the inoperative engine is fixed at 5 % of the speed of the gas generator per
second).
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If all of the above-mentioned conditions are verified, the failure of the engine 4 is confirmed,
and a command going to the healthy engine 5 is initiated to increase the fuel flow rate of the
healthy engine 5.
According to one embodiment, this increase in the fuel flow rate is obtained by switching a
law of anticipation of power, which links a measurement of the collective pitch of the blades
of the twin-engine helicopter to a speed setpoint value of the gas generator 51 in the twinengine
configuration to a law of anticipation in the single-engine configuration. This switching
of laws of anticipation causes a jump in the setpoint of flow rate, suddenly accelerating the
healthy engine 5 whilst guaranteeing the protections of the engine 5 (maximum speed,
maximum torque, maximum temperature, no pumping, etc.).
A method according to the invention is advantageously implemented by a device for
detecting a malfunction of the first, inoperative turboshaft engine of a twin-engine helicopter,
and for controlling the second, healthy turboshaft engine comprising:
- a module for detecting an indication of failure of said inoperative engine,
- a module for modifying said protective stops of said healthy engine into protective
stops which correspond to a single-engine regime, in the case of the detected
indication of failure,
- a module for confirming a failure of said inoperative engine,
- a module for controlling an increase in the flow rate of fuel supply of said healthy
engine in the case of confirmed failure.
According to one advantageous embodiment, this device is received in the regulation device
8, and this regulation device 8 is used as a detection module, as a module for modifying the
stops, as a module for confirming failure, and as a control module.
According to one advantageous embodiment, the device comprises a computer program
product which can be downloaded from a communication network and/or registered on a
support which can be read by a computer and/or can be executed by a processor,
comprising program code instructions for implementing the method according to the
invention, when said program is executed on a computer. This computer program product is
for example intended to be executed by the regulation device 8.

Claims
1. Method for detecting a malfunction in a first turboshaft engine, referred to as an
inoperative engine (4), of a twin-engine helicopter having a rotary wing, and for controlling a
second turboshaft engine, referred to as a healthy engine (5), each engine (4, 5) comprising
protective stops regulated by a regulation device (8) which define a maximum power regime,
characterised in that it comprises:
a step (10) of detecting an indication of failure of said inoperative engine (4),
a step (11) of modifying said protective stops of said healthy engine (5) into
protective stops which correspond to a maximum power single-engine regime, in the case of
the detected indication of failure,
a step (12) of confirming a failure of said inoperative engine (4),
a step (13) of controlling an immediate increase in the flow rate of fuel supply of said
healthy engine (5), in the event of a confirmed failure, so as to allow an acceleration of the
healthy engine without waiting for an automatic regulation of the healthy engine after a fall in
speed of said rotary wing resulting from the failure of the inoperative engine.
2. Method according to claim 1, characterised in that said step (1 0) of detecting an
indication of failure consists in:
retrieving, for each engine, at least one measurement of at least one parameter
which is representative of the operating regime of the engines,
detecting a difference between said measurements which is greater, in terms of
absolute value, than a predetermined threshold.
3. Method according to claim 2, characterised in that each detection of a difference
between said measurements is modulated by at least one variable, referred to as a
modulation variable (20), which is representative of normal variations in said measurements
during a nominal operating regime of the engines (4, 5).
4. Method according to claim 3, characterised in that at least one modulation variable
(20) is selected from the following group: type of engine regimes (4, 5); type of effective
balancing of the engines (4, 5); proximity of the measurements of the shaft and torque
speeds of the engines (4, 5) to the maximum permissible values for said engines;
acceleration and deceleration rates of the engines (4, 5); period of transmission of said
14
measurements of each parameter which is representative of the operating regime of the
engines.
5. Method according to either claim 3 or claim 4, characterised in that it further
comprises a step of learning nominal differences between said measurements of at least
one parameter which is representative of the operating regime of the engines (4, 5), during
stabilised regimes of said engines, said nominal differences which are determined in this
way constituting a modulation variable (20).
6. Method according to any of claims 2 to 5, wherein each engine comprises a gas
generator powering a free turbine which sets into rotation an output shaft, characterised in
that at least one parameter which is representative of the operating regime of an engine (4,
5) is a rotational speed of said gas generator or a torque exerted by said output shaft of this
engine.
7. Method according to claim 6, characterised in that said step (11) of modifying the
protective stops of said engine (5) into stops corresponding to a single-engine regime
consists in increasing the torque exerted by said output shaft and in increasing the rotational
speed of said gas generator (51) in order to achieve predetermined rated values
corresponding to a maximum power single-engine regime.
8. Method according to any of claims 1 to 7, characterised in that said step (12) of
confirming a failure of said first engine consists in verifying that multiple predetermined
conditions which are representative of a real loss of power are verified.
9. Method according to claims 6 and 8 taken together, characterised in that said
predetermined conditions are as follows:
a signed difference between the rotational speed of said gas generator (41) of said
inoperative engine (4) and the rotational speed of said gas generator (51) of said healthy
engine (5) is greater than the difference measured in said step (10) of detecting an index for
this parameter,
a signed difference between the torque of said output shaft of said inoperative engine
(4) and the torque of said output shaft of said healthy engine (5) is greater than the
difference measured in said step (1 0) of detecting an index,
15
i ..
I
I
I
- a rotational speed of said free turbine (42) of said inoperative engine (4) is less than
a predetermined setpoint value which is subtracted from a predeter~ined offset, .
I .,. '
- a time derivative of the rotational speed of said gas gene~ator (51) of said healthy
engine (5) is greater than a predetermined threshold, , I
a time derivative of the rotational speed of said gas generatof (41) of said inoperative
engine (4) is less than a predetermined threshold. I
10. Method according to claim 9, characterised in that said stlp (13) of controlling an
increase in the flow rate of fuel supply of said healthy engine (5) colsists in switching law of.
anticipation power, .which links a measurement of the collective pitch of the blades of said • I . .
:;:~::::::,:~::,~:·::~,;~~:~11:::,::: gecocotoc, to the T oocttgornttoo to' l'w
11. pevice for detecting a malfunction in a first turboshaft engine, referred to as an
. . I
· inoperative engine, of a twin-engine helicopter having a rotary wing, and for controlling a
second turboshaft engine, referred to as a healthy engine, e~ch engine comprising
protective stops regulated by a regulation device which define a r(laximum power regime,
comprising: i
- a module for detecting an indication of failure of said inoperative engine,
- a module for increasing the protective stops of said healthy I engine into stops which
correspond to a single-engine regime, in the case of a detected indidation of failure, ,
a. module for confirming a failure of said inoperative engine, I ,
a module for controlling an immediate increase in the flow r$te of fuel supply of said
healthy engine, in the event of a confirmed failure, so as to alloi an acceleration of the
healthy engine without waiting for an automatic regulation of the healthy engine after a fall in
speed of said rotary wing resulting from the failure of the inoperativelengine.
I
I
12. Helicopter comprising at least two turboshaft engines, fharacterised in that it
comprises a device according to claim 11.