APPENDIX 5. DEFINITIONS For the purposes of this AC, the following definitions apply:
Airborne Electronic Hardware (AEH). Examples include line replaceable units, circuit board assemblies, application specific integrated circuits, and programmable logic devices.
Aircraft-supplied Data. Data supplied by or via aircraft systems.
Aircraft-supplied Electrical Power. Any electrical power supplied by or via aircraft systems and used by the engine or propeller control system.
Alternate Mode. Any control mode that is not the primary mode.
Analysis. A specific and detailed qualitative or quantitative evaluation of the engine relative to the requirements of § 33.75 and other applicable requirements of the EECS. Examples include:
fault tree analysis (FTA), failure mode and effects analysis (FMEA), Markov analysis, similarity analysis and loss of thrust control or loss of power control analysis.
Automatic Power Reserve (APR) System. The entire automatic system used only during takeoff, including all devices both mechanical and electrical that sense engine failure, transmit signals, actuate fuel controls or power levers on operating engines, including power sources, to achieve the scheduled power increase and furnish cockpit information on system operation.
Automatic Takeoff Thrust Control System (ATTCS). The entire automatic system used on takeoff, including all devices, both mechanical and electrical, that sense engine failure, transmit signals, actuate fuel controls or power levers, or increase engine power by other means on operating engines to achieve scheduled thrust or power increases and to furnish cockpit information on system operation.
Backup Mode. The backup system control mode. The alternate channel in a dual-channel system with identical channels is not a backup mode. Any additional backup means provided differing from the two channels are backup modes under the definition.
Backup System. A part of the engine or propeller control system where the operating characteristics or capabilities of the engine control are sufficiently different from the primary system that the operating characteristics or capabilities of the aircraft, crew workload, or what constitutes appropriate crew procedures may be significantly impacted or changed.
Control Mode. Each defined operational state of the engine control system in which the crew can exercise satisfactory engine control that may involve evaluation in the aircraft.
Covered Fault. A fault that is detected or accommodated or both.
Demand Control Pump. A fuel pump whose output is variable and not directly proportional to engine rotor speed.
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Destructive Event. Any malfunction or failure of the EEC system that may result in a condition in which the engine, or any of its components, causes physical damage to the airplane structure or its occupants that may affect continued safe operation of the airplane. Examples include engine separation from its mounts, uncontrolled fire, inability to shutdown the engine, generation of toxic products, or uncontained high-energy debris.
Dispatchable Configuration. All control system configurations approved for flight dispatch.
Electronic Engine Control System (EECS). An engine control system in which the primary functions are provided using electronics. It includes all the components (e.g. electrical, electronic, hydromechanical and pneumatic) necessary for the control of the engine and may incorporate other control functions where desired. Components of the system provided by the installer may be considered part of the system.
Engine Control System (ECS). Any system or device that controls, limits, or monitors active engine operation.
Engine Dedicated Power Source. An electric power source providing electrical power generated and supplied solely for use by a single engine control system.
Engine/Propeller Control System (ECS/PCS). Any system that is an integrated engine and propeller control system. The system then contains elements of both ECS and PCS.
Erroneous data. Data that appears to be valid, but is incorrect.
Error. An omission or incorrect action by a person, a mistake in requirements, in design, or in implementation. An error may result in a failure, but an error is not a failure in and of itself.
Failure. An occurrence that affects the operation of a component, part, or element such that it can no longer function as intended (this includes both loss of function and malfunction). Note:
errors may cause failures, but are not considered to be failures.
Failure Condition. A condition with a direct, consequential engine-level effect caused or contributed to by one or more failures. Examples include any unwanted limitation of thrust to idle or total loss of a signal.
Failure Mode. The cause of the failure or the manner in which an item or function can fail.
Examples include failures due to corrosion or fatigue, opens and shorts in circuits, and malfunctions of electronic components.
Fault. A manifestation of an error in a component, part, element, or system that may lead to a failure.
Fault (or) Failure Accommodation. The capability to mitigate, either wholly or in part, the effects of a fault or failure.
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Full Authority Digital Engine Control (FADEC). An engine control system in which the primary functions are provided using digital electronics and in which the electronic engine control (EEC) unit has full-range authority over the engine power or thrust.
Full-up Configuration. An EECS that has no known faults or failures present that affect the loss of thrust (or power) control rate.
Local Events. Failures of aircraft systems and components, other than the EECS, that may affect the installed environment of the EEC unit.
Loss of Power Control (LOPC). A ECS failure event resulting in the inability to attain at least 85% of rated power or to modulate power under normal operating conditions.
Loss of Thrust Control (LOTC). An ECS failure event on a turbine engine that results in the inability to attain at least 90% of rated thrust or to modulate thrust under normal operating conditions.
Minor Power Loss (MPL). A reciprocating engine ECS failure event resulting in the ability to attain less than 95%, but still greater than 85%, of rated power.
Primary Mode. The mode for controlling the engine under normal operation; often referred to as the ‘normal mode.
Primary System. The part of the ECS/PCS normally used for controlling the engine/propeller operation.
Programmable Logic Device (PLD). An electronic component that is altered to perform an installation specific function. PLDs include, but are not limited to, Programmable Array Logic (PAL) components, General Array Logic (GAL) components, Field Programmable Gate Array (FPGA) components, and Erasable Programmable Logic Devices (EPLDs). These devices are a subset of AEH.
Propeller Control System (PCS). Any system or device that is part of the propeller type design that controls, limits, or monitors propeller operation.
Redundancy. Multiple independent methods incorporated within a system to accomplish a given function.
Time-Limited Operations (TLO). The duration of reciprocating engine flight operations permitted with the EEC system in a degraded condition.
Uncovered Fault. A fault or failure for which either no detection mechanism exists or, if detected, no accommodation exists.
Unsafe Condition. For the purposes of this AC, any malfunction or failure of a reciprocating engine EECS that could result in a destructive event or EECS LOPC and MPL rate in excess of A5-3
those specified in Tables A3-1 and A3-2 of this AC. This definition is intended to apply to reciprocating engine EECS.
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