Click to edit Master title styleKing Air Ground School

26 - Fire Protection

Overview

• Engine Fire Detection, IR Detection System– Not on E90

• Engine Fire Extinguishing – Halon based fire extinguishing– Not on U21 or E90

• Portable Extinguisher – at least one halon in the cockpit• Overheat protection for Bleed air• Emergency Portable Breathing Devices

Engine Fire Detection: Components

Sensors / Detectors

• Infrared photocells

Sensors / Detectors

• 3 Sensors in each engine compartment• Each sensor looking at a different zone in the engine

compartment– 1-forward of intake– 2-upper accessory case– 3-lower accessory case

Zone 1 Zone 2 Zone 3

Amplifier-Controller

• Amplifier-Controller translates sensor detection to cockpit annunciations

• Amplifier-Controller allows for testing the system

Illustration shows the relationship between sensor/detector and amplifier-controller

No fire detected

L Engine Fire Detected

Annunciators

• U21A “LH/RH FIRE WARNING” and “FAULT WARN”• U21H “FIRE L/R ENG” and “MASTER WARNING”

U21A U21H

Annunciators

• C12 T-handle – “#1/2 FIRE PULL” and “MASTER WARNING”• 200 “FIRE L/R ENG” and “L/R ENG FIRE-PUSH TO EXT” and

“MASTER WARNING”

C12 200

Test Switch

• U21 – 8 position switch “Test Switch Fire Detection”• C12 – 6 position switch “Fire Protection Test”• 200 – 7 position switch “Test Switch Fire Det & Fire Ext”• Only turn counter clockwise unless the test fails

U21 C12 200

Electrical

• Circuit Breaker in Cockpit – with CB pulled, detection won’t work

• Dual-fed bus – power must be on the aircraft in order to detect

U21 C12200

Engine Fire Detection: Operation

Test

• The three DET/DETR positions of the test switch– Position 1 tests the fwd intake sensor of both engines– Position 2 tests upper accessary case sensor of both engines– Position 3 tests lower accessory case sensor of both engines

Position 1

Position 2 Position 3

Test

• Sensors are tested by increasing the output voltage of each sensor

Test

• U21A and U21H– Both “LH/RH FIRE WARNING” / “FIRE L/R ENG” annunciators illuminate– “FAULT WARN” / “MASTER WARNING” is triggered– Audible warning horn

U21A

U21H

Test

• C12– Both T-handle “#1/2 FIRE PULL” annunciators illuminate– “MASTER WARNING” is triggered

C12

Test

• 200– Both “FIRE L/R ENG” annunciators illuminate– “MASTER WARNING” is triggered– “L/R ENG FIRE PUSH TO EXT” light on both sides

200

Fire Indication

• An actual fire has the same indications but will only be on the side of the fire

U21H C12 200

U21A

Referenced Procedures

• Engine Fire/Failure/Severe Damage• Evacuation/Engine Fire on the Ground

U21 C12

Engine Fire Detection: Abnormalities

Halon

Toxicity

• Not highly toxic but does cause issues in high concentrations (>10%)

• Typical side effects include giddiness and tingling of extremities

• Same chemical family as Freon

No extinguishin

g area

Aviation Uses

• 1301 used commonly for engine extinguishing• 1211 or blend commonly used for portable fire extinguishers

Engine Extinguishing Portable

Extinguishes Fire By:

• Chemically combining with atoms which are propagating the fire, preventing combustion reaction (primary)

• Displaces oxygen (secondary)• Cools the fire (secondary)

Engine Fire Extinguishing: Components

Fire Extinguishing Bottle

• One bottle per engine• Discharges through plumbing to nozzles into fire zones

Fire Extinguishing Bottle

• Pressure provides the motive flow for the halon• Fully discharges in .08 seconds

Zone 1 nozzles

Zone 2&3 nozzles

Pressure Gauges

• Pressure indicates quantity of halon available• Gauge visible from the wheel well• Ambient temperature determines the pressure limits

Looking up, LH Main

Aft

Squibs

• Pyrotechnic squib cartridge holds plug in place• “firing” the squib releases the plug• Halon flows to the discharge nozzles

Annunciations

• C12

Red “PUSH TO EXTINGUISH” indicates squib is armed

Indicates squib has discharged

Annunciations

• 200

Indicates a fire is detected

Indicates squib has discharged

Actuation

• C12• Pull appropriate T-Handle• Lift clear cover• Push the annunciator to discharge the bottle

Only fires the bottle that has been armed by the T-Handle

Actuation

• 200• Lift clear cover• Push the appropriate annunciator to discharge the bottle

One switch per side

Test Switch

• Two remaining positions of the rotary test switch

C12 200

Electrical

• Hot battery bus – bottles can be discharged with the batt master off

Engine Fire Extinguishing: Operation

Test

• EXTGH portion of rotary switch• Tests the circuitry to the squib and discharge light

– C12 “#1/2 EXTGH DISCH” and “SQUIB OK”

C12 #1 & 2

Test

• EXTGH portion of rotary switch• Tests the circuitry to the squib and discharge light

– 200 “D” and “OK”

200

Push to Extinguish

• Pull T-Handle• Lift clear cover• Press the “PUSH TO EXTINGUISH” button• Look for “#1/2 EXTGH DISCH” annunciator

C12 LH extinguish

Push to Extinguish

• Lift clear cover• Press the “L/R ENG FIRE PUSH TO EXT” button• Look for “D” annunciator

200 LH extinguish

Bleed Air Overheat Protection: Components

Bleed Air Supply Line

• Hot bleed air from engine is delivered to cabin• P3 air leaves the engine at 640⁰F• A broken line threatens smoke and fire

Heat Sense Line

• Pressurized, plastic line runs along side bleed air lines• 18psi originates at pneumatic controller• At 204⁰F the plastic line melts

Pressure Switch (C12/200)

• One for the LH and RH sense lines• Below 18psi, this switch closes to warn the pilot

Pressure switch located under co-pilot seat

Pressure Switch (U21)

• There are two pressure switches one for each side located just before the check valves.

Click icon to add picture Click icon to add picture Click icon to add picture

Annunciator Light (C12/200)

• “L/R BL AIR FAIL” and “MASTER WARNING”• The pressure switches illuminate these annunciators

respectively

C12 200

Annunciator Light (U21)

• “LH/ RH BLD AIR FAIL” and “MASTER WARNING”

U21 A

U21 H

Bleed Air Overheat Protection: Operation

Bleed Air Line Rupture C12/200

• The hot air melts the sense line (and anything else around it)• The low volume pressure in the sense line escapes• Pressure switch closes at18psi• “L/R BL AIR FAIL” annunciator Illumes with “MASTER

WARNING” • A loss of pressure in the sense line indicates a serious threat

C12 200

Bleed Air Line Rupture U21

• If a break in the bleed air line should occur the air pressure in the line would drop causing the pressure switch to open and the “LH or RH BLD AIR FAIL” to illume.

Referenced Procedures

C12U21

Duct Overtemp Protection: Components

Temperature Switch

• Senses air temperature

U21Between FO rudder peddles

C12/200RH Mid cabin

Annunciator

• “DUCT OVERTEMP”

U21H 200

C12U21A

Duct Overtemp Protection: Operation

Air Temp in Duct Rises

• Air in the ducting becomes too hot (potential for smoke)• Temperature switch closes circuit (225°F -300°F)• “DUCT OVERTEMP” annunciator illumes

U21H 200

C12U21A

Referenced Procedures

U21 C12

Portable Fire Extinguishers

• Halon 1211-1301 blend (2:1)• Located under pilot seat and an optional second one could be mounted in the

cabin

Portable Breathing Devices

PBE Part 25

• Part 25 required• Fixed (stationary, or built in) protective breathing equipment must be installed

for the use of the flightcrew, and at least one portable protective breathing equipment shall be located at or near the flight deck for use by a flight crewmember. In addition, portable protective breathing equipment must be installed for the use of appropriate crewmembers for fighting fires in compartments accessible in flight other than the flight deck.

• EPOS - Model MR-10096AF

EPOS Components

1. OPEN CLOSURE FLAP OF STOWAGE POUCH.

2. GRASP STOWAGE POUCH W/ ONE HAND AND WITH OTHER HAND PULL RED TAPE STRIP OF BARRIER POUCH.

3. REMOVE THE EPOS UNIT FROM BOTH POUCHES.

4. PULL THE RED BALL WITH ONE HAND WHILE HOLDING THE OXYGEN CYLINDER WITH THE OTHER HAND.

EPOS Operation

7. REMOVE HOOD AFTER YOU ARE CLEAR OF HAZARD

5. SPREAD NECK SEAL OPEN WITH HANDS. PALMS ARE TO BE FACING EACH OTHER.

6. PULL THE EPOS OVER THE HEAD.

EPOS Operation

PBE Training Video