AMT 213 - GAS TURBINE ENGINE 2 (FINALS)

What type of power does an APU produce?

SHAFT HORSEPOWER

APUs are self-contained turboshaft engines having _________________.

55 TO 350 SHAFT HORSEPOWER RANGE

APUs are used to provide _______________ to aircraft systems.

PNEUMATIC AND ELECTRICAL POWER

APU is categorized as either _____________.

GROUND OR INFLIGHT CERTIFIED

The primary uses of APU are:

• MAIN ENGINE STARTING

• MAIN ENGINES NOT OPERATING

• IN-FLIGHT EMERGENCIES

• GROUND POWER SUPPORT NOT AVAILABLE

• MAIN ENGINE DE-LOADING OF BLEED AIR DEMANDS

APUs were originally develop for the ___________ for large reciprocating engine and early turbojet powered aircraft.

ELECTRICAL REQUIREMENTS

____________ with piston engine and a direct drive generator to provide electrical energy to the main engine's stater motor.

GPU CARTS

____________ replaced the piston engines on GPU carts.

TURBOSHAFT ENGINES

APUs basic operation, construction, systems, inspection, and maintenance are ____________ to other turbine engines.

VERY SIMILAR

APU construction is divided into three main sections:

• INTAKE / COMPRESSION

• COMBUSTION / TURBINE

• GEARBOX

The inlet or plenum consists of:

DUCTING FROM AN INTAKE DOOR / SCOOP LOCATED ON THE TOP OR SIDE OF AIRCRAFT FUSELAGE

The inlet or plenum has a ___________ to prevent FOD and ice to enter the engine.

SCREEN

Types of APU Compressors

• POWER COMPRESSOR

• LOAD COMPRESSOR

• SINGLE-ENTRY DOUBLE-SIDED COMPRESSOR

This type of APU Compressor is for engine operation.

POWER COMPRESSOR

This type of APU Compressor is to create bleed air.

LOAD COMPRESSOR

This type of APU Compressor is to accomplish both power and load functions with one unit.

SINGLE-ENTRY DOUBLE-SIDED COMPRESSOR

Most APUs use a ______________ compressor combination one or two stages to compress intake air for engine operation.

CENTRIFUGAL IMPELLER / RADIAL DIFFUSER

The centrifugal compressor configuration is used for several reasons:

• IT CREATES A LARGER PRESSURE RISE PER STAGE

• IT CREATES A SMALLER ENGINE AREA

• FOD AND SURGE/STALL RESISTANT THAN AXIAL FLOW COMPRESSOR

APU combustion chamber use either ______________.

• CAN TYPE COMBUSTOR

• ANNULAR TYPE COMBUSTOR

APU with _________________ uses a can type combustor

RADIAL INFLOW TURBINES

APU with ______________ often use an annular type of combustor.

AXIAL FLOW TURBINES

APU turbine configurations are often ____________

• SINGLE

• DUAL

This type of APU turbine provides horsepower to rotate both the compressor and the gear box section

SINGLE TURBINE CONFIGURATION

In this type of APU turbine, one turbine spins the compressor and the other powers the gearbox and its accessories

DUAL TURBINE CONFIGURATION

The ___________ is carried overboard using stainless-steel ducting located in the tail cone or the side of the empennage.

APU EXHAUST

In APU exhaust, a device known as __________ is a convergent duct located around the APU exhaust that aids in cooling the engine.

EDUCTOR

Gearbox installation in APU is normally located _________ of the combustion section.

OPPOSITE

The generators used on the APU varies in _____________.

• SIZE

• OUTPUT

APU generator is ______________ to units installed on the main engines

ALMOST ALWAYS IDENTICAL

APU units are normally located in the empennage of the aircraft either __________________.

IMBEDDED IN AN ACCESSORY BAY / SUSPENDED WITHIN THE TAIL CONE STRUCTURE

APU enclosure are commonly fabricated from high temperature stainless and perform several functions:

• TO PROVIDE A SEALED SPACE FOR ENGINE FIRE SUPPRESSION AND COOLING AIRFLOW

• TO REDUCE NOISE THROUGH THE USE SOUND ABSORBING MATERIALS

• TO PROVIDE BALLISTIC CONTAINMENT IN CASE OF CATASTROPHIC ENGINE FAILURE

In a tail cone installation, the APU is suspended within the structure using a _______________ to a forward firewall with vibrational lock mounts like aircraft's main engines.

STEEL MOUNT ASSEMBLY

The function of APU in transport aircraft is to provide _______________ on ground operations

PNEUMATIC AND ELECTRIC POWER

APU does not serve as back-up for main engine to support in producing __________.

THRUST

APU is a ____________ operating at constant power output.

TURBOSHAFT ENGINE

The APU systems are separated into four main categories:

• FUEL

• OIL

• STARTING

• IGNITION

APU Engine Systems (Fuel)

• MAIN FUEL TANK

• ELECTRICALLY SHUTOFF VALVE

• APU FUEL CONTROL UNIT

• ELECTRONIC ENGINE CONTROL

• FULL AUTHORITY DIGITAL ENGINE CONTROL

What does ETOPS mean?

EXTENDED-RANGE TWIN-ENGINE OPERATION PERFORMANCE STANDARDS

Servicing of APU consist of several tasks:

• STARTER MOTOR BRUSH

• OIL FILTER AND FUEL FILTER CHANGES

• CHIP DETECTOR INSPECTION

• GEARBOX OIL CHANGES

• SPECTROMETRIC OIL ANALYSIS

Requires partial disassembly and visual examination of the APU's compressor section and components

COLD SECTION INSPECTION

Requires the partial disassembly and visual examination of the turbine and combustion components.

HOT SECTION INSPECTION

Performed on APUs to locate cracks in cold and hot section components

NDT INSPECTION

The FCU contains a metal mesh fuel filter with a bypass capability of _____________.

7 TO 10 MICRONS

APU utilizes a ______________, containing most all of the oil system components and the oil supply in the gearbox.

WET SUMP OIL SYSTEM

Fuel System Main Components:

• MAIN FUEL TANK

• ELECTRICALLY SHUTOFF VALVE

• APU FUEL CONTROL UNIT

• ELECTRONIC ENGINE CONTROL

• FULL AUTHORITY DIGITAL ENGINE CONTROL

APU uses an ____________ to cool the oil.

AIR-TO-FLUID HEAT EXCHANGER

A gear type pump is utilized to supply oil for cooling and lubricating the bearings which creates a constant __________ to the oil nozzles.

40 PSI

What are commonly used on a air-to-fuel heat exchanger?

• INTAKE AIR

• RAM AIR

• GEARBOX MOUNTED COOLING FANS

The APU has a _______ used for starting.

STARTER MOTOR

APU starter motor is energized by the ____________ separate from main aircraft batteries.

28V BATTERY WITH A CHARGING UNIT

The starter motor often contains a ____________ to disengage the unit from the gearbox at approximately ____ rpm when the engine become self-sustaining.

• CENTRIFUGAL SPRAG TYPE CLUTCH

• 60%

APU ignition system consists of:

• HIGH ENERGY CAPACITIVE DISCHARGE EXCITER

• IGNITION LEAD

• IGNITER

The igniter plug in APU is a surface gap type with a discharge potential from ___________.

5000 TO 8000 VOLTS

In a typical APU start sequence, the ignition system is engage by the APU's EEC at __ rpm and disengage at ___ rpm.

• 10 %

• 95 %

APU is manually operated during:

• START

• SHUTDOWN

• FIRE SUPPRESSION DISCHARGE

The _________ of APU has an input connections EGT probes, oil, fuel, and pneumatic pressure switches, as well as RPM sensing monopoles or magnetic sensors.

EEC / FADEC

EEC on APU contains a Built in Test Equipment (BITE) to:

• RECORD FAULTS

• SELF-TROUBLESHOOT

• MONITOR SYSTEM OPERATIONS

BITE functions aids maintenance personnel in ____________ in APU.

DIAGNOSING A PROBLEM

New APU models with FADEC have the EEC combined with the FCU in a common housing attached to the _________.

APU GEARBOX

Crew input to the APU is given through an APU control panel in the _____________.

COCKPIT

Transport category aircraft often have a secondary control unit located on the ____________.

NOSE LANDING GEAR

The crew can monitor the APU start sequence through ____________ on the panel or in the EICAS or ECAM.

• RPM GAUGES

• EGT GAUGES

There is a separate switch in APU panel to open load control valve or APU bleed valve to deliver pneumatic power to the aircraft such as:

• MAIN ENGINE STARTING

• CABIN PRESSURIZING

• WATER SYSTEM PRESSURIZING

• CABIN COOLING

An APU's usefulness to the aircraft and operational safety dramatically increases when the APU is __________.

IN-FLIGHT CERTIFIED

In flight APUs usually require a lower starting altitude (_____________) to ensure enough primary/combustion and secondary cooling air for start but are then capable of operation up to ___________ altitude

• 15000 FT TO 17000 FT

• 40000 FT

In-flight certified APU is one of the requirements for aircraft with __________.

ETOPS CERTIFICATION

In-flight certified APU can shoulder the ___________.

ELECTRICAL AND PNEUMATIC LOAD FROM LOST ENGINE

In-flight certified APUs are often started during aircraft's _____________.

LANDING PHASE

Most APU maintenance is performed _________, meaning as failure or faults deem necessary

ON-CONDITION

In-service time is tracked by APU operational hours through the use of _________.

HOBBS OR HOURMETER

APUs require several cold and hot sections inspection prior to an __________.

OVERHAUL

APU removal requires:

• MINIMUM TIME

• PERSONNEL

• EQUIPMENT

APU hot section components are time limited and are often removed from engines to margin of safety anywhere from __________ of operation.

3000 to 9000 HOURS

Necessary accessories in the powerplant.

• GEARBOX

• FUEL CONTROL

• INTAKE COWLING

• THRUST REVERSER ASSEMBLY

• FIRE PROTECTION EQUIPMENT

• SENSORS

• GENERATORS

• DUCTING

• WIRING

• COWLING

• CONTROL CABLES AND RODS

• DRAINS

• FIREWALLS

Types of powerplant installations:

• WING MOUNTED

• FUSELAGE MOUNTED

A partition between the engine powerplant installation and the aircraft.

FIREWALL

Firewalls are typically sheet metal shields made from _____________.

STAINLESS STEEL / OTHER HIGH RESISTANCE METAL

Nacelle are built around the engine to ______________.

PROTECT THE ENGINE AND ACCESSORIES

Nacelle are built around the engine to protect the engine and accessories from the:

• OPERATING ENVIRONMENT

• PROVIDE STREAMLINED, AERODYNAMIC ENCLOSURE

• DESIGN TO ROUTE COOLING AIR EFFECTIVELY AROUND THE ENGINE

Fixed and movable parts that makes up the nacelle enclosure.

COWLINGS

Small access panels to a particular part of the powerplant that requires:

FREQUENT INSPECTION OR SERVICING

Designed to reduce noise associated with turbine engine operation.

ACOUSTIC PANEL

An acoustic panel is a noise absorbent liner around the _____________.

INSIDE WALL OF THE BYPASS DUCT

The absorbent liner is comprised of ______________ that inhibits the motion of sound waves.

POROUS FACE SHEETING

Two types of acoustic lining:

• STAINLESS STEEL / GLASS REINFORCED COMPOSITE

• SINTERED FIBROUS METALLIC SHEET

What does the stainless steel / glass reinforced composite consist of?

• ALUMINUM

• VINTROSOND

What does the sintered fibrous metallic sheet consist of?

STAINLESS STEEL

The engine mounts on most turbofan engines perform the same basic functions:

• SUPPORTS THE ENGINE

• TRANSMIT LOADS IMPOSED BY THE ENGINE TO THE AIRCRAFT STRUCTURE

Function of the vibration isolator engine mounts:

• SUPPORTS THE POWERPLANTS

• IOSLATE AIRPLANE STRUCTURE FROM ADVERSE ENGINE VIBRATION

Each powerplant is generally supported by:

FWD AND AFT VIBRATION ISOLATED MOUNTS

Vibration isolators consist of a ____________ permanently enclosed in a metal case.

RESILIENT MATERIAL

The resilient material within the vibration isolators ____________, thereby ___________ before it reaches the airplane structure.

• DEFORMS SLIGHTLY

• DAMPENING THE VIBRATIONS

Control cables and rods are used on many powerplant installation to ____________.

ACTIVATE ACCESSORIES

Minor design differences which prevent proper mating may cause the joint to ________.

LEAK / FAIL

Make sure that the fuel line does not chafe against the:

• CONTROL CABLE

• AIRFRAME STRUCTURE

• CONTACT THE ELECTRICAL WIRING CONDUIT

The fuel line is located _________ the wiring and clamp securely to the _________.

• BELOW

• AIRFRAME STRUCTURE

For fuel line installation, always incorporate at least one bend between such fittings to absorb __________ caused by _____ and ______.

• STRAIN

• VIBRATION

• TEMPERATURE CHANGES

Place support ___________ for metallic lines as follows close to bends as possible to reduce _______.

• CLAMPS / BRACKETS

• OVERHANG

Carefully inspect all lines and fittings at __________ to ensure airworthiness

REGULAR INTERVALS

Check metal lines for:

• LEAKS

• LOSS ANCHORAGE

• SCRATCHES

• KINKS