ATA 23 Communications

LEGEND

Procedures Required

(O) – An operational procedure
(M) or (M#) – A maintenance procedure
(O)(M) or (O)(M#) – Both operational and maintenance procedures

Repair Interval Categories

Category A

Items in this category shall be repaired within the time interval specified in the "Remarks or Exceptions" column of the air operator's approved MEL. Whenever the proviso in the "Remarks or Exceptions" column of the MMEL states cycles or flight time, the time interval begins with the next flight. Whenever the time interval is listed as flight days, the time interval begins on the flight day following the day of discovery.

Time Limited Dispatch - Some MMEL's for aircraft that are equipped with FADEC engines have relief that is subject to time limited dispatch expressed as a specific number of engine hours, and will start in accordance with the times established by the engine manufacturer or as indicated in the remarks column of the MMEL. Time limited relief cannot be extended.

Category B

Items in this category shall be repaired within 3 consecutive calendar days excluding the day of discovery.

Category C

Items in this category shall be repaired within 10 consecutive calendar days, excluding the day of discovery.

Category D

Items in this category shall be repaired within 120 consecutive calendar days, excluding the day of discovery. To be considered for placement in Category D, the item must be of an optional nature, or excess equipment which an air operator may, at his/her discretion, deactivate, remove from or install on an aircraft.

To be approved for Category D, the item must meet the following criteria:

  1. the absence of the item does not adversely affect crew member's workload;
  2. the crew members do not rely on the function of that item on a routine or continuous basis; and,
  3. the crew members' training, subsequent habit patterns and procedures do not rely on the use of that item.

Category D relief will generally not be approved for equipment which is considered to increase the level of safety, even if that equipment is of an optional nature.

ITEM:  23-10-1  COMMUNICATION SYSTEMS (VHF, UHF, HF, SATCOMetc.)

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions

Communication Systems (VHF, UHF, HF, SATCOM, etc.)

VHF and UHF

Transport Category Aircraft

D - 2  

Any in excess of those required by regulations may be inoperative provided:

a) It is not powered by a standby or emergency bus, and

b) It is not required for emergency purposes.

Non-transport Category Aircraft

D - -   Any in excess of those required by regulations may be inoperative.
HF (and SATCOM) D - -   Any in excess of those required by regulations may be inoperative.
HF C - 1 (O)

May be inoperative while conducting operations that require two Long Range Communication Systems (LRCS) provided:

a) SATCOM Voice or Data Link operates normally,

b) Alternate procedures are established and used,

c) SATCOM coverage is available over the intended route of flight, and

d) If Inmarsat codes are not available while using SATCOM voice, prior coordination with the appropriate ATS facility is required.

NOTE:
SATCOM is to be used only as a backup to normal HF communications unless otherwise authorized by the appropriate ATS facilities.

DISCUSSION:

References:   AWM 525.1307(d), FAA PL 95 (Rev. 1, March 20, 2002), FAA PL 106 (Rev. 3, October 7, 2005), NAV CANADA AIC 27/07 (November 22, 2007)

The design standard for transport category airplanes requires ”two systems for two-way radio communications ...”; therefore, the number required for dispatch should normally be two.  Furthermore, the intent of the design standard is that no single failure should result in failure of all communications systems.  Therefore, during MMEL deliberations, radio power supplies and electrical system architecture will need to be considered (e.g. it may be inappropriate to dispatch if both radios are powered from the same bus).

For non-transport category airplanes the number required for dispatch should be shown as variable. Since the design standard does not require a communication system, the operational requirements would apply.

For transport category rotorcraft the number required for dispatch should be consistent with that design standard.

The proviso regarding the emergency power situation is consistent with the principle that equipment that is required to complete an emergency procedure cannot be inoperative.

As a basic principle, the minimum operative Communication Systems required for dispatch must not only be in conformance with the CARs, but also be appropriate to the intended route to be flown.  If VHF coverage is not available throughout the flight, then Long Range Communication Systems (LRCS) must be installed and operative.

LRCS is defined in CFR 14 Section 1.1 as “A system that uses satellite relay, data link, high frequency, or other approved communication system which extends beyond line-of-sight.”  Examples of such systems are HF-voice, HF-data link, SATCOM-voice, and SATCOM-data link.  Although SATCOM can be used as a backup for an HF system, its availability is not always possible due to a gap in satellite coverage.  NAV CANADA AIC 27/07 describes an area in the Edmonton FIR, referred to as “SATCOM shadow”, where coverage is not available.

FAA Differences: FAA is inconsistent in assignment of category.  The FAA may not address design standard requirements (i.e. two required for dispatch for a FAR 25 airplane); they show a variable number required for dispatch.  The FAA has also addressed sub-systems of the radios.  It is TCCA position that the pilot must make a judgment as to whether or not the radio can perform its intended function and sees no need at this time to address sub-systems.

ITEM:  23-10-2  CONTROLLER PILOT DATA LINK COMMUNICATIONS (CPDLC)

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions
Controller Pilot Data Link Communications (CPDLC) C - 0 (O) May be inoperative where routine procedures require its use provided alternate procedures are established and used.
D - 0   May be inoperative provided operating regulations don’t require its use.
CPDLC In-Coming Message Visual Alerting

 

C - 0 (M) May be inoperative when provided In-Coming Message Aural Alerting is operative.
D - 0 (M)

May be inoperative provided operating regulations and routine operations don’t require the use of CPDLC.

DISCUSSION:

References: NPA 2003-063 [CAR 725.124 (54), CAR 725.08 (4)] 

Operators shall ascertain that aircraft equipage conform to the regulatory requirements of the State in which operations are conducted.  CPDLC is an alternative to ATC clearances voice communications in designated airspace.  Canadian operating regulations do not require the use of CPDLC.

Appropriate MMEL relief for CPDLC sub-systems (i.e.CMU or ATSU, SATCOM, VDL, HFDL, CMDU or FMS, etc.) should be considered individually and in the context of their respective function and operating requirements.

The (O) procedures require the operator to establish appropriate procedures where CPDLC is required by routine procedures.

Where operating regulations or routine procedures require the use of CPDLC, category C relief is available for a defective visual alerting device.  The (M) procedure may be required to disable the defective visual alerting device and/or verify the status of the aural alerting device.  Category D relief is available for a defective visual alerting device only where neither operating regulations nor routine operating procedures require the use of CPDLC.

This relief for CPDLC and associated sub-systems will be revised when operating regulations mandate the use of CPDLC.

FAA Differences: FAA has not issued a PL on this subject.

ITEM:  23-20-1  SELECTIVE CALL (SELCAL) SYSTEM

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions
Selective Call (SELCAL) System C 1 0 (O) May be inoperative provided alternate procedures are established and used.
D 1 0   May be inoperative provided procedures do not require its use.
1) Channels C - 0 (O) May be inoperative provided alternate procedures are established and used.
D - 0   May be inoperative provided procedures do not require its use.

DISCUSSION:

References: FAA PL 117 (Original, 07 Oct. 2005)

The cat D allows extended relief for operations where the SELCAL is not used routinely.

FAA Differences:  FAA relief is identical to TCCA.

ITEM:  23-20-2  ACARS (ARINC COMMUNICATIONS ADDRESSING AND REPORTING SYSTEM) INCLUDING PRINTER

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions
ACARS (ARINC Communications Addressing and Reporting System) Including Printer C - 0 (O)

May be inoperative provided alternate procedures are established and used.

NOTE:
Any portion of the system that operates normally may be used.

D - 0  

May be inoperative provided routine procedures do not require its use.

NOTE:
Any portion of the system that operates normally may be used.

DISCUSSION:

References:  nil

In some MMELs the system and printer are written as separate items with identical wording.  The cat D allows extended relief for operations where the ACARSis not used routinely.  Similar relief could be used for Airborne Flight Information Systems.

FAA Differences: FAA relief is identical to TCCA

ITEM:  23-20-3  AUTOMATED FLIGHT INFORMATION REPORTING SYSTEM (AFIRS)

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions
Automated Flight Information Reporting System (AFIRS) C 1 0 (O) May be inoperative provided alternate procedures are established and used.
D 1 0  

May be inoperative provided procedures do not require its use.

NOTE:
Any portion of the system that operates normally may be used.

1) Global Voice SATCOM C 1 0 (O) May be inoperative provided alternate procedures are established and used.
D 1 0   May be inoperative provided procedures do not require its use.

a) Flight Deck Dialer Pad

C 1 0 (O) May be inoperative provided alternate procedures are established and used
D 1 0   May be inoperative provided procedures do not require its use.
b) Handset C 1 0 (O) May be inoperative provided alternate procedures are established and used.
D 1 0   May be inoperative provided procedures do not require its use.
2) Global Messaging C 1 0 (O) May be inoperative provided alternate procedures are established and used.
D 1 0  

May be inoperative provided procedures do not require its use.

NOTE:
Any portion of the system that operates normally may be used.

DISCUSSION:

References:  nil

FAA Differences: There is no FAA PL for AFIRS.

ITEM:  23-20-4  AUTOMATIC DEPENDENT SURVEILLANCE (ADS)

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions
Automatic Dependent Surveillance - Broadcast (ADS-B) C - 0 (O) May be inoperative where routine procedures require its use provided alternate procedures are established and used.
D - 0   May be inoperative provided operating regulations don’t require its use.
1) Processor Unit, Cockpit Display, Control Panel, Data link Transmitter, Data link Receiver C - 0 (O) May be inoperative where routine procedures require its use provided alternate procedures are established and used.
D - 0   May be inoperative provided operating regulations don’t require its use.
Automatic Dependent Surveillance - Contract (ADS-C) C - 0 (O) May be inoperative where routine procedures require its use provided alternate procedures are established and used.
D - 0   May be inoperative provided operating regulations don’t require its use.

DISCUSSION:

References:  FAA PL 105 (Original, 11 Oct. 2000), NPA 2003-063 [CAR 725.124 (54), CAR 725.08 (4)]

ADS services may be available as an omni-directional Broadcast signal (ADS-B) or on a Contract basis (ADS-C).  ADS-B and ADS-C both operate over a data link network but require distinctive equipment and serve radically different purposes.  ADS-B is an on-board traffic information system available in domestic airspace whereas ADS-C is a point-to-point data communication system for intent and position reporting typically in remote and oceanic airspace as an alternate to voice communications position reporting.

Operators shall ascertain that aircraft equipment conform to the regulatory requirements of the State in which operations are conducted.  Some States may have approved ADS-B as an alternate to TCASADS services are available in Canada in designated airspace, however, ADS is not required by Canadian operating regulations.

Appropriate MMEL relief for ADS sub-systems not identified in the table above (i.e.: CMU or ATSU, SATCOM, VDL, HFDL, Mode S Transponder, CMDU or FMS, etc.) should be considered individually and in the context of their respective function and operating requirements.

The intent of the (O) is for operators to develop and use alternate procedures.

FAA Differences:  TCCA provides relief for ADS-B and ADS-C.

ITEM:  23-30-1  PUBLIC ADDRESS SYSTEM

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions
Public Address System

1) Passenger Configuration

B 1 0 (O)

May be inoperative provided:

a) Alternate procedures are established and used,

b) Flight deck/cabin interphone system (two way) with associated calls (e.g. chimes) is verified operative, and

c) Megaphone(s) is/are readily available and operative.

NOTE:
Any station function(s) that operates normally may be used.

C - 0 (O)

May be inoperative provided:

a) It is not required by regulations and

b) Alternate, normal and emergency procedures, and/or operating restrictions are established and used.

NOTE:
Any station function(s) that operates normally may be used.

A 1 0 (O)

For aircraft being operated in compliance with the provisions of CASS 725.104(2), may be inoperative for three flight cycles provided:

a) Alternate communications procedures are established and used,

b) Flight deck/cabin interphone system (two way) with associated calls (e.g. chimes) is verified operative,

c) Megaphone(s) is/are readily available and operative,

d) The aircraft is not being operated from a maintenance base,

e) Self-extension relief is not applied to this item,

f) A second flight attendant is added to the crew at the first opportunity,

g) The aircraft is not being operated from a flight attendant base without adding a second flight attendant,

h) Where a second flight attendant is carried, that flight attendant shall be assigned to a flight attendant station, or, for aircraft that are equipped with only one flight attendant station, to an aisle passenger seat at an exit row, and

NOTE:
Proper distribution of flight attendants is maintained.

i) operations procedures are specified in the air operator’s company operations manual.

B - 0 (O)

For aircraft with 19 or fewer seats may be inoperative provided:

a) Alternate procedures are established and used, and

b) Required standard safety briefings are given to passengers using a means that will ensure the briefings are audible to each passenger.

A 1 0 (O)

May be inoperative for non-passenger carrying operations for one flight day provided:

a) Crew members are the only occupants of the aircraft, and

b) Alternate procedures are established and used.

2) Cargo Configuration (Courier/Supernumerary Address System) D 1 0   May be inoperative provided all crew members are on the flight deck.
3) Crew Rest Facility - Bunk C - - (O)

May be inoperative provided:

a) Flight deck and Cabin to Crew Rest Facility - Bunk interphone systems (two way) with associated calls (e.g. chimes) is verified operative,

b) Crew Rest Facility - Bunk drop down oxygen system is operative,

c) Alternate procedures are established and used, and

d) The Pilot-in-Command is advised that all crew have been briefed.

D - - (M)(O)

May be inoperative provided:

a) Associated Crew Rest Facility - Bunk is not occupied, and

b) Associated Crew Rest Facility - Bunk is placarded INOPERATIVE - DO NOT USE.

DISCUSSION:

References:   CAR 705.16(3)(c), CAR 705.16(3)(d), CAR 705.74, CAR 705.89, CASS 725.104, CAR 704.34, CASS 724.34, CAR 703.39, CASS 723.39,  FAA PL 9 (Rev. 7, 25 Nov. 2003)

Although megaphones are only required on aircraft types certified to carry 60 or more passengers, they are considered a condition for granting relief for the PA system on aircraft configured with 20 or more passenger seats.

For non-passenger carrying flights conducting operations in an air transport service pursuant to Airline Operations regulated by CAR 705, alternate procedures referred to in proviso b) must be in compliance with the requirements of CAR 705.16 (3)(c) and (d).

It is noted that relief without an operative megaphone has been permitted on large airplanes (e.g. DHC 7 Ice Reconnaissance) with only crew members on board.  Proposals of a “one of nature” will be reviewed by Cabin Safety Standards to ensure that an equivalent level of safety is maintained.

FAA Differences:  TCCA permits carriage of crew members in a non-passenger carrying operation with the PA System inoperative and no requirement for the interphone.

ITEM:  23-30-2  PRE-RECORDED ANNOUNCEMENT (PASSENGER BRIEFING SYSTEM)

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions
Pre-recorded Announcement (Passenger Briefing System) C 1 0 (O) May be inoperative provided alternate procedures are established and used.
All Cargo Operations D 1 0   May be inoperative provided all crew members are on the flight deck.

DISCUSSION:

References:   CAR 705.43

If the flight attendant(s) is (are) unable to provide the standard safety briefing in both official languages, pursuant to CAR 705.43, an acceptable alternate means of compliance could be to provide printed copies of the standard safety briefings or live demonstration.

FAA Differences: FAA relief is identical to TCCA.

ITEM:  23-30-3  ACTIVE NOISE AND VIBRATION SUPPRESSION SYSTEM

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions
Active Noise and/or Vibration Suppression System (ANVS System)   1 0    

DISCUSSION:

References:  nil

This was originally included as part of the Passenger Convenience Item but was moved here to harmonize with the FAA in terms of ATA assignment.  No category has been assigned because no aircraft safety related issues have been identified related with the non-availability of this equipment.

FAA Differences: FAA relief is identical to TCCA.

ITEM:  23-40-1  CREW MEMBER INTERPHONE SYSTEM

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions
Crew Member Interphone System
1) Passenger Configuration

a) Flight Deck/Cabin and Cabin/Cabin
 

B

-

1

(O)

May be inoperative provided:

a) An operative flight deck/cabin interphone system (two way) is at an operative flight attendant seat,

b) The public address system is verified operative, and

c) Alternate communications procedures are established and used.

NOTE:
Any station function(s) that operates normally may be used.

A - 1 (O)

For aircraft being operated in compliance with the provisions of 725.104(2), may be inoperative for three flight cycles provided:

a) Alternate procedures are established and used,

b) The public address system is operative,

c) The aircraft is not being operated from a maintenance base,

d) Self-extension relief is not applied to this item,

e) A second flight attendant is added to the crew at the first opportunity,

f) The aircraft is not being operated from a flight attendant base without adding a second flight attendant,

g) Where a second flight attendant is carried, that flight attendant shall be assigned to a flight attendant station, or, for aircraft that are equipped with only one flight attendant station, to an aisle passenger seat at an exit row, and

NOTE:
Proper distribution of flight attendants is maintained.

h) Operations procedures are specified in the air operator’s company operations manual.

A 1 0 (O)

May be inoperative for non-passenger carrying operations for one flight day provided:

a) Crew members are the only occupants of the aircraft, and

b) Alternate procedures are established and used.

b) Flight Deck to Ground

C 1 0 (O) May be inoperative provided alternate procedures are established and used.
D 1 0   May be inoperative provided procedures are not dependent on its use.

c) Flight Deck and/or Cabin/Crew Rest Facility - Bunk

C - - (O)

May be inoperative provided:

a) The public address system is operative,

b) Alternate procedures are established and used, and

c) The Pilot-in-Command is advised that all crew have been briefed.

D - - (M)(O)

May be inoperative provided:

a) Associated Crew Rest Facility - Bunk is not occupied, and

b) Associated Crew Rest Facility - Bunk is placarded INOPERATIVE - DO NOT USE

2) Cargo/Passenger Combi Configurations (cargo compartment located between flight deck and passenger compartment)   1 1   Crew member interphone system must be operative.
3) Cargo Configuration

a) Flight Deck/Cabin and Cabin/Cabin

D

1

0

 

May be inoperative provided all crew members are on the flight deck.

b) Flight Deck to Ground

 

C 1 0 (O) May be inoperative provided alternate procedures are established and used.
D 1 0   May be inoperative provided procedures are not dependent on its use.

DISCUSSION:

References:   CAR 705.73, CAR 705.16(3)(c), CAR 705.16(3)(d), CASS 725.104(2), FAA PL 9 (Rev. 7, 25 Nov. 2003)

The guidance requiring that the crew member interphone system be operative at all times is based on the physical separation of the cabin from the flight deck as a result of the security recommendations that the flight deck door remain closed and locked.  It is essential that flight crew members and flight attendants be able to communicate during critical phases of flight and during an in-flight emergency.

For non-passenger carrying flights conducting operations in an air transport service pursuant to Airline Operations regulated by CAR 705, alternate procedures referred to in proviso b) must be in compliance with the requirements of CAR 705.16 (3)(c) and (d).

The cat B assigned to the cabin/flight deck interphone is to better ensure the availability of this equipment that might be essential in an emergency situation.  The cat B must be used for all Part 25 airplanes and is consistent with the category assigned to the PA system, item 23-30-1.

FAA Differences:  To permit getting the aircraft to a repair facility, TCCA relief permits non-passenger carrying operation with the entire system inoperative and no requirement for the PA System to be operative.

ITEM:  23-40-2  ALERTING SYSTEM

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions
Alerting System
1) Passenger Configuration

a) Visual Alert (flight deck)

B

1

0

 

May be inoperative provided the flight deck aural alert is operative.

b) Visual Alert (cabin)

B 1 0  

May be inoperative provided:

a) The PA system is operative, and

b) Affected alert is not used for lavatory smoke detector alerting.

c) Aural Alert (cabin) B 1 0  

May be inoperative provided:

a) The PA system is operative, and

b) Affected alert is not used for lavatory smoke detector alerting.

2) Cargo Configuration

a) Visual Alert (flight deck)

B

1

0

 

May be inoperative provided the aural alert is operative.

b) Courier/Supernumerary Visual Alert B 1 0   May be inoperative provided Courier/Supernumerary address system is operative.
c) Courier/Supernumerary Aural Alert B 1 0   May be inoperative provided Courier/Supernumerary address system is operative.

DISCUSSION: 

References:   FAA PL 9 (Rev. 7, 25 Nov. 2003)

FAA Differences: FAA relief is similar to TCCA.

ITEM:  23-40-3  HANDSETS

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions
Handsets
1) Passenger Configuration

a) Flight Deck Handset

C

1

0

(O)

May be inoperative provided:

a) Flight deck to cabin communication operates normally, and

b) Alternate procedures are established and used.

May be inoperative provided routine procedures do not require its use.

D 1 0   May be inoperative provided routine procedures do not require its use.
b) Cabin Handset(s) B - - (O)

May be inoperative provided:

a) Fifty percent of cabin handsets operate normally,

b) On wide-body airplanes, one handset must operate normally at each pair of exit doors,

c) Operative handset(s) is located at an operative flight attendant seat, and

d) Alternate communications procedures between the affected flight attendant station(s) are established and used.

NOTES:
1. An operative handset at an inoperative flight attendant seat shall not be counted to satisfy the fifty percent requirement.

2. Any handset(s) function(s) that operates normally may be used.

c) Crew Rest Facility - Bunk Handset

B - - (O)

May be inoperative provided:

a) The public address system is operative,

b) Alternate procedures are established and used, and

c) The Pilot-in-Command is advised that all crew have been briefed.

D - - (M)(O)

May be inoperative provided:

a) Associated Crew Rest Facility - Bunk is not occupied, and

b) Associated Crew Rest Facility - Bunk is placarded INOPERATIVE - DO NOT USE.

2) Cargo/Combi Configuration

a) Flight Deck Handset

D 1 0    
b) Cargo Compartment Handsets D 2 0  

Handsets located in the cargo compartment may be inoperative or inaccessible provided compartment remains unoccupied.

NOTE:
This includes the handset at L1 (and R1 when R1 is located in the main deck cargo compartment)

DISCUSSION:

References:   FAA PL 9 (Rev. 7, 25 Nov. 2003)

FAA Differences:  TCCA permits relief for handsets located in the cargo compartment.

ITEM:  23-50-1  AUDIO CONTROL PANELS

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions
Audio Control Panels   - -   Must be operative for each person on flight deck duty including any person occupying the forward observer seat(s) in an official capacity.
Primary Observer Seat Panel B 1 0    
Primary Observer Seat Panel D 1 0   May be inoperative provided the seat is not required to be available in an official capacity for extended periods of time.
Secondary Observer Seat Panel D 1 0    

DISCUSSION:

References:   CAR 703.21, CAR 704.21, CAR 705.27, FAA PL 56 (Rev. 4, 15 Sep. 2004)

For the purposes of this item, ”official capacity” includes flight training, Transport Canada/company check rides, and crew member or passenger who has authority and valid reason to occupy.
The denial of relief reflects the need for flight deck crew communication while wearing smoke masks and or oxygen equipment (i.e. during an emergency).

It is noted that, at times, there may be components of the audio control panel inoperative; however, the panel is still adequate for flight.  MMELs at this time do not address sub-components (e.g. ADF ident function) and it is considered the captain’s decision to dispatch with necessary equipment operative.

FAA Differences:  FAA requires observer seat (or a passenger seat) to be available for their use at all times, TCCA does not have this passenger seat requirement.

ITEM:  23-50-2  FLIGHT DECK SPEAKERS

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions
Flight Deck Speakers C 2 0  

May be inoperative provided:

a) Procedures are not dependent on their use,

b) Headsets are installed and used by each person on flight deck duty,

c) All aural alerts, messages and other communication which are normally routed through the flight deck speakers must be audible through the headsets, and

d) A spare headset must be readily available for crew use.

DISCUSSION:

References:  nil

With smoke masks on, a typical installation has the pilot talk through the co-pilot’s speaker and the co-pilot through the pilot’s speaker. If there are emergency (e.g. smoke) procedures which require the crew to establish communication then relief for both cannot be granted, but depending on flight test results, relief for one might be possible.

FAA Differences: FAA relief is identical to TCCA.

ITEM:  23-50-3  BOOM MICROPHONES (INCLUDING HEADSET MIC)

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions
Boom Microphones
Installations with CVR and FDR

If CVR required to be capable of recording boom microphone.

A

-

0

 

May be inoperative for three flight days provided the FDR is operative.

If CVR not required to be capable of recording boom microphone.

D - 0   May be inoperative.
Installations with only CVR

If CVR required to be capable of recording boom microphone.
 

A

-

0

 

May be inoperative for three flight days.

If CVR not required to be capable of recording boom microphone. D - 0   May be inoperative.

DISCUSSION:

References:   CAR 605.33, CAR 605.34, CASS 625.33, FAA PL 58 (Rev. 3, 12 July 2001)

Although this relief was written in the context of a headset boom microphone, it could apply to any other boom microphone, e.g. goose neck, and the appropriate relief would apply.  The title clarifies what is meant by a boom mic.

FAA Differences:  FAA PL refers to specific operating rules, TCCA item significantly different to reflect the CARs.

ITEM:  23-70-1  COCKPIT VOICE RECORDER

System and Sequence No. Item Repair
Interval
Category
Number
Installed
Number
required
for
dispatch
Procedures
required
Remarks or Exceptions
Cockpit Voice Recorder

If CVR and FDR required by regulations:

A

1

0

 

May be inoperative provided:

a) The Flight Data Recorder is operative, and

b) Repairs are made within three flight days.

If only CVR required by regulations: A 1 0   May be inoperative provided repairs are made within three flight days
If CVR not required by regulations: D - 0    

DISCUSSION:

References:   CAR 605.33, CAR 605.34, CASS 625.33, FAA PL 29 (Rev. 4, 15 Sep. 2004)

The MMEL may need to contain all relief options.  The MEL must reflect the correct situation for each specific aircraft/operation.

FAA Differences: FAA relief is similar to TCCA.  The FAA PL refers specifically to air carrier.  TC relief includes cat D for equipment not required by regulations.

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