ENABLING LEARNING ENABLING LEARNING OBJECTIVE (ELO) OBJECTIVE (ELO)

• ACTION: Identify Mark XII (Mode 4) ACTION: Identify Mark XII (Mode 4) IFF capabilities and limitations.IFF capabilities and limitations.

• CONDITION: Given a list of cockpit CONDITION: Given a list of cockpit Mode 4 equipment settings Mode 4 equipment settings

and and combat flight environment.combat flight environment.• STANDARD: IAW student reference STANDARD: IAW student reference

materials.materials.

MARK XII CAPABILITIESMARK XII CAPABILITIES• Returns a coded reply to (SIF) using Returns a coded reply to (SIF) using

modes 1, 2, 3/A and C and provides modes 1, 2, 3/A and C and provides Mode 4 identification friend or foe (IFF).Mode 4 identification friend or foe (IFF).

• Mode 4 is secure mode of identification.Mode 4 is secure mode of identification.• SIF Modes 1 and 2 used by military.SIF Modes 1 and 2 used by military.• Modes 3/A and C used by civilian and Modes 3/A and C used by civilian and

military ATC.military ATC.

MODE FUNCTION MODE FUNCTION (NORMAL POSITION)(NORMAL POSITION)

• Mode 4 Code Switch- Switch selects Mode 4 Code Switch- Switch selects the A or B Mode 4 Operational Key.the A or B Mode 4 Operational Key.– A Position selects current 24-hour crypto A Position selects current 24-hour crypto

periodperiod– B Position selects the next 24-hour period B Position selects the next 24-hour period

• Used when unable to land for re-keyingUsed when unable to land for re-keying• Crypto changes at 2400 hrs ZULUCrypto changes at 2400 hrs ZULU

APX-100APX-100

A-B CODE USEA-B CODE USE

• COMPATIBLE CODE - Interrogator’s COMPATIBLE CODE - Interrogator’s and aircraft key matches & provides and aircraft key matches & provides IFF.IFF.

• VALID CODEVALID CODE– Key is possible, but not the correct keyKey is possible, but not the correct key– VALID CODE CANNOT provide friendly IFFVALID CODE CANNOT provide friendly IFF

TRANSPONDER TRANSPONDER CHARACTERISTICSCHARACTERISTICS

• The investigation into the F-15 shootdown The investigation into the F-15 shootdown of Army Blackhawk helicopters of Army Blackhawk helicopters determined design characteristics which determined design characteristics which could present HAZARDOUS could present HAZARDOUS OPERATIONAL IMPLICATIONS.OPERATIONAL IMPLICATIONS.

• Associated with the use of the Associated with the use of the AUDIO/LIGHT/OUT SWITCHAUDIO/LIGHT/OUT SWITCH

• ANTENNA SELECT SWITCHANTENNA SELECT SWITCH

AUDIO/OUT/LIGHT SWITCHAUDIO/OUT/LIGHT SWITCH

• Controls the ALERT INDICATORS for Controls the ALERT INDICATORS for MODE 4 OPERATIONS.MODE 4 OPERATIONS.

• AUDIO POSITION enables AUDIO AUDIO POSITION enables AUDIO TONE and REPLY LIGHTTONE and REPLY LIGHT– COMPATIBLE CODES. A COMPATIBLE CODES. A Green reply light Green reply light

indicates Friendly IFF responseindicates Friendly IFF response– VALID CODES. A Non Response will be VALID CODES. A Non Response will be

indicated by a indicated by a 400 Hz Tone400 Hz Tone

APX-100APX-100

MODE FUNCTION MODE FUNCTION (STANDBY POSITION)(STANDBY POSITION)

• Only when COMPATIBLE CODES are Only when COMPATIBLE CODES are used by the interrogator.used by the interrogator.

• IFF CAUTION LIGHT illuminatesIFF CAUTION LIGHT illuminates

AUDIO SWITCH AUDIO SWITCH ((OUT POSITIONOUT POSITION))

• Disables Disables – Mode 4 REPLY LIGHTMode 4 REPLY LIGHT– Mode 4 AUDIO TONEMode 4 AUDIO TONE– PRESS-TO-TEST Mode 4 REPLY LIGHTPRESS-TO-TEST Mode 4 REPLY LIGHT– IFF CAUTION LIGHTIFF CAUTION LIGHT

AUDIO SWITCHAUDIO SWITCHLIGHT POSITIONLIGHT POSITION

• Mode 4 REPLY LIGHT enabledMode 4 REPLY LIGHT enabled• MODE 4 AUDIO tone is disabledMODE 4 AUDIO tone is disabled– IFF RESPONSE. The green REPLY LIGHT will IFF RESPONSE. The green REPLY LIGHT will

illuminate to indicate IFF was givenilluminate to indicate IFF was given– NON RESPONSE to IFF will not be indicated by NON RESPONSE to IFF will not be indicated by

the 400 Hz AUDIO TONEthe 400 Hz AUDIO TONE

NOTE: PLACE THE NOTE: PLACE THE AUDIO/LIGHT/OUT SWITCH AUDIO/LIGHT/OUT SWITCH

IN THE AUDIO POSITION IN THE AUDIO POSITION DURING FLIGHT DURING FLIGHT

OPERATIONS. DO NOT OPERATIONS. DO NOT USE THE OUT POSITIONUSE THE OUT POSITION

ANTENNA SELECT SWITCHANTENNA SELECT SWITCH(TOP, BOT, & DIV)(TOP, BOT, & DIV)

• TOP - The transponder will respond TOP - The transponder will respond to interrogations from that antennato interrogations from that antenna

• BOTTOM (BOT) - Responses BOTTOM (BOT) - Responses allowed from the bottom antennaallowed from the bottom antenna

• DIVERSITY (DIV) - The transponder DIVERSITY (DIV) - The transponder will respond through the antenna will respond through the antenna receiving the STRONGEST SIGNALreceiving the STRONGEST SIGNAL

APX-100APX-100

DIV POSITIONDIV POSITION

• Place the TOP/BOT/DIV switch in the Place the TOP/BOT/DIV switch in the DIV position during flight operations.DIV position during flight operations.

• Do not use the TOP or BOT position.Do not use the TOP or BOT position.• This does not preclude using the This does not preclude using the

TOP or BOT switch position for TOP or BOT switch position for ground-based system checks.ground-based system checks.

APX-100APX-100

MODE 4 ON/OUT SWITCHMODE 4 ON/OUT SWITCH• MODE 4 ON/OUT SWITCH IN THE OUT POSTIONMODE 4 ON/OUT SWITCH IN THE OUT POSTION

– ALL AUDIO AND VISUAL INDICATIONS CEASE ( IN COCKPIT & IFF RESPONSES)ALL AUDIO AND VISUAL INDICATIONS CEASE ( IN COCKPIT & IFF RESPONSES)

– IFF CAUTION LIGHT ILLUMINATES WITH THE FREQUENCY OF “COMPATIBLE” IFF CAUTION LIGHT ILLUMINATES WITH THE FREQUENCY OF “COMPATIBLE” INTERROGATIONS.INTERROGATIONS.

IFF CAUTION LIGHTIFF CAUTION LIGHT

• ACTIVATED WHEN:ACTIVATED WHEN:– KIT 1A/C Not Keyed (steady IFF).KIT 1A/C Not Keyed (steady IFF).– TRANSPONDER SELF-TEST FAILURE TRANSPONDER SELF-TEST FAILURE

(STEADY).(STEADY).– COMPATIBLE INTERROGATION RECEIVED COMPATIBLE INTERROGATION RECEIVED

WHILE IN STANDBY POSITION (FLASHES WHILE IN STANDBY POSITION (FLASHES INTERMITTENTLY WITH INTERROGATIONS).INTERMITTENTLY WITH INTERROGATIONS).

IFF CAUTION LIGHT IFF CAUTION LIGHT (CONT’D)(CONT’D)

• ACTIVATED WHEN (CONT’D):ACTIVATED WHEN (CONT’D):– A MALFUNCTION OF THE TRANSMITTER.A MALFUNCTION OF THE TRANSMITTER.

• LOW POWERLOW POWER• INTERMITTENT IFF CAUT WITH EACH ATTEMPTED INTERMITTENT IFF CAUT WITH EACH ATTEMPTED

INTERROGATIONINTERROGATION– MODE 4 IS IN THE OUT POSITION.MODE 4 IS IN THE OUT POSITION.

• ALL AUDIO AND VISUAL INDICATIONS CEASE. ALL AUDIO AND VISUAL INDICATIONS CEASE. INTERMITTENT BLINKING.INTERMITTENT BLINKING.

TACTICAL OPERATIONSTACTICAL OPERATIONS

• CROSS-FLOTCROSS-FLOT– TRANSPONDER ON/OFF LINES.TRANSPONDER ON/OFF LINES.

• NORMAL/MODE 4 ON (BEACONING)NORMAL/MODE 4 ON (BEACONING)• OMNI-DIRECTIONAL SIGNAL GIVING AWAY OMNI-DIRECTIONAL SIGNAL GIVING AWAY

LOCATION AND MISSION.LOCATION AND MISSION.– FORMATION FLIGHTFORMATION FLIGHT

• ONLY ONE AIRCRAFT USES NORMALONLY ONE AIRCRAFT USES NORMAL• ALL OTHERS USE STBY TO PREVENT “TONE-ALL OTHERS USE STBY TO PREVENT “TONE-

BLANKING” or “REPLY GARBLING”BLANKING” or “REPLY GARBLING”

SUMMARY #1SUMMARY #1• Under what conditions will the IFF Under what conditions will the IFF

CAUTION LIGHT cycle ON/OFF, depending CAUTION LIGHT cycle ON/OFF, depending on the recurrence of Mode 4 IFF on the recurrence of Mode 4 IFF interrogations?interrogations?

SUMMARY # 2SUMMARY # 2• Under what condition/s should the APX-Under what condition/s should the APX-

100(v) be operated in the STANDBY 100(v) be operated in the STANDBY Position?Position?

SUMMARY # 3SUMMARY # 3

• With the APX-100(V) set to NORMAL and With the APX-100(V) set to NORMAL and Audio/Light/Out Switch in the LIGHT Audio/Light/Out Switch in the LIGHT POSITION, the receipt of a “valid code” POSITION, the receipt of a “valid code” would be indicated how?would be indicated how?

SUMMARY # 4SUMMARY # 4• With the APX-100(V) set to NORMAL and With the APX-100(V) set to NORMAL and

AUDIO positions, receipt of “compatible AUDIO positions, receipt of “compatible codes” Mode 4 interrogations would be codes” Mode 4 interrogations would be indicated by?indicated by?

SUMMARY # 5SUMMARY # 5• The design characteristics of the APX-The design characteristics of the APX-

100(V) transponder can present hazardous 100(V) transponder can present hazardous operational implications unless the operational implications unless the AUDIO/LIGHT/OUT switch and the ANT AUDIO/LIGHT/OUT switch and the ANT TOP/DIV/BOT switch are placed into which TOP/DIV/BOT switch are placed into which positions? positions?