Advanced Aircraft Systems Lesson 13

Aircraft Icing Types:

Structural, Engine Inlet, Fuel

Structural icing

icing adhering to airfoils, fuselage, windows, or components

Engine inlet icing

Of particular concern due to the possibility of engine flameout or damage​

Fuel icing

jet fuel is kerosene based and susceptible to water absorption.  Ensuring the water doesn’t freeze into crystals is important to supplying a steady flow of fuel to the engines and APU.​

Aerodynamically 30% loss of lift from

Sandpaper grade icing on wing

**Weight** Insignificant concern compared to

lost lift/added drag​

Icing on Antennae can

Reduce transmissions

Blockages​

pitot tube, static ports, fuel vents​

Surface shedding damage​ can cause

engine ingestion and ice strikes on fuselage and tail​

What are the two types of Ice formations?

Contact, Ingestion

Contact Ice formation is when an aircraft surface

is below 0℃​ and OAT 0℃ to -40℃​

Ingestion Ice formation is when

Low press inlet can freeze/thaw moisture ​and +10℃ to -40℃​

what are the three ice types?

Clear, Rime, Mixed

Clear ice are supercooled drops in

Freezing rain​ and cumuliform clouds​. They Spread back​ and are very adhesive and heavy​

Rime ice are

Opaque/milky white​, easily removed with deicing equipment, and aerodynamically alters the wing camber​

Mixed ice is the

worst of both clear and rime ice

Structural Icing Protections include

Pre-Departure and Inflight

Pre-departure Icing Protections include

Pre-flight check ensures clean aircraft​ and De-icing/Anti-Icing as needed​

Inflight Icing Protections include

Multiple systems like boots, heated surfaces, and liquid weeding system

How many types of De-icing fluids are there?

3 (Type I, Type II, Type IV)

What is type l fluid?

Best for de-icing, heated​

What is type ll fluid?

Thicker and shears off on takeoff​

What is type IV fluid?

Superior to II and III and longest lasting​

What is a holdover time?

Estimated time the fluid prevents frozen accumulation​ and varies with precipitation intensity​

Deicing removes

accumulated ice​ and use can be based on accumulation levels

Anti-icing is a

Preventative measure

Leading Edge Boots use

Pneumatic low press air and a vacuum​

How Do leading edge boots work?

Inflate to shed ice and vacuum back to airfoil

Can Leading edge boots handle severe icing?

No

Another word for weeping wing?

Liquid ice protection system

Liquid ice protection system uses glycol to

force through leading edge pinholes​. It has no aerodynamic interference​. No engine bleed draw penalty​. And has Added weight to carry glycol​

What uses hot, high pressure bleed air and is the most modern and used on commercial jets?

Bleed air Thermal Anti-icing.

Electrically heated systems are limited to

smaller surface areas​, and rotate from blade to blade on props​, and have multiple components that are heated electrically​

What are the Electrically heated components?

Windshield​, anti-ice and bird strike protection, pilot probes/some static ports​, and stall sensors/AoA vanes​

True or false: Turbine engines are more susceptible to carburetor icing?

False, Turbine engines aren’t as susceptible to icing like carburetor icing but they have their own concerns.​

Engine Inlet Anti- ice use

Anti-icing to prevent internal damage​

What are the three protected areas on an engine inlet?

Cowling leading edge​, Senser probes (EPR)​, and Fan blades​

Risks for the Cowling include

Ingesting ice chunks can cause damage​

Risks for the EPR include

EPR iced over would give erroneous engine indications​

Risks for the fan blades include

Vibration indications monitored for damage or ice

Another word for Inertial Separators

Ice vanes

Inertial separators process includes:

* Turbo Prop Issue​
* Ice is shed from prop​
* Ingestion threat to engine​
* Ice vane opens to shed ice before it enters compressor​
* Reduces thrust available so takeoff​
* power needs considered​

Fuel system icing protection has kerosene

based Jet fuel absorbs water​, and at cold temps at altitude crystalize water

Fuel System Icing Protection protective measures include:

Chemical Anti-ice additives​, fuel lines heated (heat exchangers)​, heated fuel filters, and fuel temperature indicator​

Other components that are heated in a fuel system are

Fuel vents​ and fuel tanks (rarely)​

Automatic systems include probes to

monitor for ice accumulation​, it auto activates engine/wing ice protection​, recognizes engine failure and provide ice protection​, is significant pilot workload reduction​, and available on some (i.e. B-777) but not all aircraft (i.e. B-737NG)​

engines are susceptible to

flame out in heavy rain​ and multiple igniters are selectable​ with heavy rain

components to a windshield include

Heavy duty, speed resistant wipers​, rain repellent chemicals​, and sheds water to increase visibility​

What are the three types of alerting systems?

Visual, audible, and kinesthetic

What is an indication of a warning level?

The color red, immediate crew action is required, and tied to the master warning and bell

What is an indication of a caution level?

the color yellow, and serious issues needing attention as time permits

What is an indication of a status (advisory) level?

colors of green, blue, or white and not necessarily abnormal but require monitoring

Examples of visual warnings:

* Eye Level Attention Grabber​
* Annunciator Panel directs focus to a system​
* Depicts system status through serious warnings​
* (this is the most prominent type of warning)

Examples of audible warnings:

* Status advisory​
* Caution ‘attention grabber’​
* Impending emergency​
* Occasionally repeat at faster intervals or louder​
* Number of chimes may be alert related​

How many chimes alert for a warning level?

Three

How many chimes alert for a caution or advisory level?

one

True or false: Audible warnings often have to be cancelled by the pilot?

True

What are example of kinesthetic warning signs?

* Sense or touch or ‘feel’​
* Usually combined with audible warning​

What does EICAS stand for?

Engine Indicating and Crew Alerting System

The EICAS is found on

most advanced Boeing aircraft​s

The EICAS is comprised of

a Primary display and a secondary display

What does the primary display do on the EICAS?

its the most important engine/system data​ and has N1, EPR, EGT​, and is color coded for Warnings and Cautions​

\n What does the secondary display do on the EICAS?

it is the supporting system data and alerts for fuel flow, engine vibration, and gear/flap position

True or false: The ECAM and EICAS do not assist pilots by displaying a checklist needed to deal with malfunctions?

False, they do help by detecting and presenting a checklist needed to deal with the detected malfunction

What does ECAM stand for?

Electronic Centralized Aircraft Monitoring

Where is the ECAM found?

Found on many Airbus aircraft​

What does the ECAM do?

it has a dual display similar to EICAS and can advise corrective actions​