2-7 o perator or maintainer. Details are immediately below and in Chapter 3 , Continued Airworthiness Requirements.
2.14.1 Operational Check. The flightcrew must perform operational checks before the first flight of the day. The extent of this check is reliant on the system failure analysis conducted at initial application. System failure analysis must take into consideration all failure modes and effects. This requirement is satisfied if the applicant can demonstrate built-in test equipment (BITE) that can notify the flightcrew of a CVR LRU failure. BITE checks are limited to the CVR LRU and do not detect failures of other CVR system components
(e.g., the CAM). These BITE check limitations must be noted in the ICA and AFM or RFM and supplements. Refer to § 23.1457, § 25.1457, § 27.1457, or § 29.1457, as applicable, for more information.
2.14.2 System Functional Check. Pursuant to § 23.1529, § 25.1529, § 27.1529, or § 29.1529, the applicant must develop ICA that include system functional checks that verify continued airworthiness of the entire CVR system, that may be part of a scheduled task, and should include:
1. Audio Quality: Verify the audio quality of all required input channels.
2. Duration: Verify the CVR recording duration meets the intended recording duration.
3. Self-Tests: Confirm that the CVR LRU BITE checks hidden functions related to fault notification.
4. Secondary Power: Ensure secondary or independent power sources perform as intended, including any automatic switching function.
5. Data Link: If installed, DLRs should be downloaded and the messages converted to a text-based format in English for legibility.
2.15 Removal and Replacement. The applicant must provide removal and replacement instructions for CVR system equipment and dedicated sensors and must include instructions for conducting a functional check of the equipment. Refer to § 23.1529, § 25.1529, § 27.1529, or § 29.1529, as applicable, for more information. Operators should have procedures to retain CVR data of a CVR that is removed for maintenance or installed on another aircraft. This ensures that data from accident or incident investigations are maintained.
2.16 ULD Installation and Maintenance.
Note: In this document, a ULD means an underwater locating device that operates at 37.5 kHz and is installed on or adjacent to the CVR. This is not to be confused with a low frequency underwater locating device (LF-ULD) that operates at
8.8 kHz and is attached to the airframe of the aircraft. An LF-ULD is designed to locate the wreckage; a ULD is designed to locate the CVR or FDR.
2.16.1 CVR Attachment Hardware. The ULD to CVR attachment hardware must be designed to minimize the possibility of the ULD separating from the CVR during crash impact. Refer
2-8 to the current versions of TSO-C123 and EUROCAE ED-112 for more information on ULD attachment hardware and test requirements.
2.16.2 ULD Battery Maintenance. Provide instructions for periodically replacing the ULD battery, conducting operational checks, and cleaning of the ULD. The battery replacement period must be consistent with the battery manufacturer’s life limit. Refer to § 23.1529, § 25.1529, § 27.1529, or § 29.1529, as applicable, for more information.
2.16.2.1 If the ULD battery is not accessible, the instructions should be for replacement of the ULD itself.
2.16.2.2 ULD operational checks should be performed with test equipment model numbers specified by the ULD manufacturer.
Note: For battery requirements in other performance specification documents, refer to the appropriate specifications for the battery type used for the ULD, such as TSO-C142b, Non-Rechargeable Lithium Cells and Batteries.
2.17 Installation Design. CVRs may be designed and tested to work with multiple ULD models with varying part numbers. Also, ULDs may be designed and tested to work with multiple CVR models with varying part numbers. In these cases, the CVR or ULD manufacturer should provide a list of compatible models and part numbers the device may be paired with to ensure only approved CVR and ULD devices and systems are installed together.
2.18 Electrical Wiring Interconnection System (EWIS). For installation on certain part 25 aircraft of a CVR system requiring alteration or modification of EWIS components, the operator must assess whether EWIS ICA is required as part of the substantiating data.
Under the requirements of §§ 25.1729 and 26.11, the manufacturer must provide these instructions, if required, to the operator or maintainer. As a minimum, they must include the procedures and intervals to inspect and maintain additional or modified EWIS components pertaining to the installation of the CVR system.
3-1 CHAPTER 3. CONTINUED AIRWORTHINESS REQUIREMENTS
3.1 Purpose of This Chapter. This chapter provides information for developing continued airworthiness requirements of a CVR system to ensure retention of intelligible recordings. During the certification process, a comprehensive system analysis must be conducted to identify functions that would not be readily apparent to flightcrew and maintenance personnel if they became defective. Applicants must provide the basic requirements for continued airworthiness of a CVR system as part of the data package submitted during type certificate (TC), amended TC, or Supplemental Type Certificate (STC) approval.
3.2 Continuous Airworthiness.
3.2.1 CVR System Inspection. Pursuant to § 23.1529, § 25.1529, § 27.1529, or § 29.1529, periodically inspect the CVR system in accordance with the manufacturer’s recommended procedures. In the absence of manufacturer’s instructions, the CVR system should be inspected at least every 24 months pursuant to International Civil Aviation Organization (ICAO) Annex 6, Part I, International Commercial Air Transport— Aeroplanes, Section 6.3.5.3 and Appendix 8, Flight Records, Section 7.2. The inspection interval may be changed in accordance with the operator’s reliability program. A typical maintenance program must include all the checks necessary at specified intervals to ensure the CVR system operates as certified.
3.2.2 Inspection Program. The program manager of an aircraft maintenance program should establish an Aircraft Inspection Program (AIP) for each make and model program aircraft and ensure each aircraft is inspected in accordance with that inspection program. The inspection program should include at least the following information:
1. Instructions and procedures for inspections, and include necessary tests and checks;
2. A schedule for performing the inspections that must be accomplished under the inspection program expressed in terms of the time in service, calendar-time, number of system operations, or any combination thereof; and
3. For equipment installed on transport category aircraft, the person or organization to which the airworthiness approval was granted shall make the related instructions for continued airworthiness (ICA) available to the operator of the aircraft to be incorporated in the Continuous Airworthiness Maintenance Program (CAMP). These ICAs cover in detail all the tasks required to ensure the continued serviceability of the flight recorder system. Refer to 14 CFR part 21, § 21.50.
3.2.3 Maintenance Program. The aircraft manufacturer or system designer/installer must provide the basic maintenance program recommendations (refer to §§ 121.367, 121.375, and 135.433). However, factors such as aircraft age, system design, and aircraft operation must be taken into account when developing the maintenance program. The following are typical parts found in a CVR system maintenance program:
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3.2.3.1 Operational Self-Test. Prior to the first flight of the day, flightcrew members should activate and monitor the recorder system self-test or built-in-test function.
3.2.3.2 Operational Check. The operational check typically verifies that there are no CVR system fault indications. A comprehensive self-test and automatic fault report may be accomplished in lieu of an Operational Self-Test.
3.2.3.3 System Functional Check. This check includes but is not limited to verification of backup power performance, automatic termination, fault indication operation, and intelligibility of audio recordings from all sources.
Pursuant to § 23.1457, § 25.1457, § 27.1457, or § 29.1457, sources can include:
1. Voice communications transmitted from or received in the airplane or rotorcraft by radio.
2. Voice communications of flight crewmembers on the flight deck.
3. Voice communications of flight crewmembers on the flight deck using the airplane or rotorcraft interphone system.
4. Voice or audio signals identifying navigation or approach aids introduced into a headset or speaker.
5. Voice communications of flight crewmembers using the passenger loudspeaker system, and the fourth channel, if installed.
3.2.3.4 Replay and Analysis. Replay and analysis of audio recordings should be conducted in accordance with manufacturer’s instructions. In the absence of specific instruction, the following procedures can be followed:
3.2.3.4.1 Intelligibility of all recorded channels should be checked during all phases of flight (such as taxi, takeoff, cruise, and landing). Ensure that audio signals from alerting or warning devices on the flight deck, both fully integrated with the aircraft audio system and nonintegrated, can be heard. CVR system audio playback should be intelligible and undistorted on each channel. Ideally, maintenance personnel should perform audio quality tests with engines running to verify background noise, such as a 400 hertz (Hz) hum, is not degrading recording quality. If the system cannot be adequately checked on the aircraft, it should be removed and a portion of the recording (preferably from a flight portion) should be checked.
3.2.3.4.2 The replay facility should determine adequacy of the quality of the recording on all channels. Information recorded on each channel, such as voice, warning, and alerts, should be identifiable. In addition to subjective listening tests, proper signal recording level should be confirmed (i.e., the recording level is not too quiet, too loud, or signal clipping is noted).
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3.2.3.4.3 Recording should be played back in an area where the privacy and confidentiality of the recorded voices are assured.
3.2.3.4.4 Dedicated tools to visualize the audio signal (e.g., over time, frequency domain, energy levels, etc.) may be employed to check if a part of the recording seems affected by an audio anomaly.
3.2.4 Underwater Locator Device (ULD) Subsystem Inspection.
3.2.4.1 Pursuant to § 23.1529, § 25.1529, § 27.1529, or § 29.1529, periodically inspect the ULD and the ULD battery in accordance with the manufacturer’s recommended procedures. In the absence of the manufacturer’s instructions, the ULD and ULD battery should be inspected at least every 24 months pursuant to ICAO Annex 6, Part I, Section 6.3.5.3 and Appendix 8, Section 7.2. The inspection interval can be changed in accordance with the operator’s reliability program.
3.2.4.2 The replacement period of the ULD battery should be consistent with the battery life limit determined by the manufacturer.
3.2.4.3 If the ULD battery is not accessible, the instructions should provide for replacement of the ULD itself. Historically, ULD batteries have been nonrechargeable and replaced at a specific time interval. If the battery or parts must be replaced, discard the batteries following manufacturer and local procedures.
3.2.5 Data Link Recorders (DLR). Pursuant to §§ 23.1457(a)(6), 25.1457(a)(6), 27.1457(a)(6),
29.1457(a)(6), 91.609(j), 121.359(k), 125.227(i), 129.24, and 135.151(h), data link communication (DLC) is not required on any aircraft. However, certain operating rules prescribe recording requirements if DLRs are installed. If DLC compatibility is installed, then periodically inspect the DLC in accordance with the manufacturer’s recommended procedures. In the absence of the manufacturer’s instructions, the DLR should be inspected at least every 24 months pursuant to ICAO Annex 6, Part I, Section 6.3.5.3 and Appendix 8, Section 7.2. The inspection interval can be changed in accordance with the operator’s reliability program.
3.2.6 Retention of Data. Pursuant to § 91.609(g), following an accident or occurrence requiring immediate notification of the National Transportation Safety Board (NTSB), recorded information must be retained for a minimum of 60 days or, if requested by the Administrator or the Board, for a longer period. This could be accomplished by inclusion in flightcrew checklists or company standard operating/emergency procedures and simply removing recorder power.
3.3 Configuration Control. CVR recording medium is not interchanged between aircraft without close supervision. Operators’ programs should include a requirement to erase stored data before installing a serviceable and previously used unit. Erasure of data should be included in any post-installation functional check.
3-4 Note: Data may need to be retained for up to 60 days or longer, if requested, following an accident or occurrence pursuant to § 91.609(g).
3.4 ICA. The operator must either follow the manufacturer’s provided ICAs as part of your maintenance program or develop your own. The ICA must identify all requirements that would have been established at certification and any others subsequently identified by the FAA, such as those applicable under an Airworthiness Directive (AD). Refer to § 23.1529, § 25.1529, § 27.1529, or § 29.1529, as applicable, for more information.
3.5 Storage. While most CVRs and ULDs are shipped and stored using manufacturer instructions, the operator should consider the CVR and the ULD, if attached, in your aircraft storage program. Some ULD batteries may require special temperature control if placed in extended storage while installed on the aircraft.
Appendix A A-1 APPENDIX A. DEFINITIONS, ACRONYMS, AND RELATED DOCUMENTS A.1 Definitions.
A.1.1 Applicants. The term “applicant” in this advisory circular (AC) is intended to describe type certificate (TC), amended TC, or Supplemental Type Certificate (STC) applicants seeking approval of a required cockpit voice recorder (CVR) system.
A.1.2 Data Link Communication (DLC). A DLC system is defined as the components installed on the aircraft that are necessary to provide the DLC function. The DLC function uses an approved message set, as determined by AC 20-140, Guidelines for Design Approval of Aircraft Data Link Communication Systems Supporting Air Traffic Services (ATS),
(e.g., Controller-Pilot Data Link Communication (CPDLC) application hosted in the flight management computer (FMC)), the datalink router (hosted in the Communication Management Unit (CMU)), the radios (e.g., very high frequency (VHF), high frequency (HF) Datalink, Satcom), and related antennas. Future Air Navigation System 1/A (FANS 1/A) and Aeronautical Telecommunications Network Baseline 1 (ATN B1) systems comprise DLC equipment. Refer to AC 20-140 for additional information. If required DLC is installed, it must be recorded on a data link recorder (DLR).
A.1.3 Operators. This AC uses the term “operator” to mean pilot in command (PIC), renter-pilot, operating certificate holder (CH), or air carrier CH. An operator must use an aircraft that complies with the CVR requirements of the applicable part (Title 14 of the Code of Federal Regulations (14 CFR) part 91, 121, 125, 129, or 135). The FAA has developed a series of flowcharts in Appendix B, Flowcharts, to assist in determining equipment requirements dependent on the applicable operating and aircraft certification rules. When using the charts in Appendix B, the operator should understand the initial certificate of airworthiness (IC of A) date also includes postdelivery equipment installations including a DLC system.
A.2 Acronyms.
14 CFR Title 14 of the Code of Federal Regulations AC Advisory Circular AD Airworthiness Directive AFM Airplane Flight Manual ATN B1 Aeronautical Telecommunication Network Baseline 1 BITE Built-In Test Equipment CAM Cockpit-Mounted Area Microphone CAMP Continuous Airworthiness Maintenance Program CB Circuit Breaker CFR Code of Federal Regulations
Appendix A A-2 CH Certificate Holder CMU Communication Management Unit CPDLC Controller-Pilot Data Link Communication CVR Cockpit Voice Recorder DLC Data Link Communication DLR Data Link Recorder ELA Electrical Load Analysis EUROCAE EUROCAE (formerly known as the European Organisation for Civil Aviation Equipment) EWIS Electrical Wiring Interconnection System FAA Federal Aviation Administration FANS 1/A Future Air Navigation System Version 1/A FDR Flight Data Recorder FMC Flight Management Computer FSDO Flight Standards District Office HF High Frequency ICA Instructions for Continued Airworthiness IC of A Initial Certificate of Airworthiness LF-ULD Low Frequency Underwater Locating Device LRU Line Replaceable Unit M/M/S Make, Model, and Series MPS Minimum Performance Standards MRO Maintenance, Repair, and Overhaul NTSB National Transportation Safety Board PIC Pilot In Command RFM Rotorcraft Flight Manual RIPS Recorder Independent Power Supply RTCA RTCA (formerly known as the Radio Technical Commission for Aeronautics) STC Supplemental Type Certificate TC Type Certificate TSO Technical Standard Order
Appendix A A-3 ULD Underwater Locating Device VHF Very High Frequency W&B Weight and Balance A.2.1 Related Documents.
A.2.1.1 Code of Federal Regulations (CFR). The following 14 CFR sections can be downloaded from the eCFR website at https://www.ecfr.gov/.
• Part 23, § 23.1457, Cockpit Voice Recorders.
• Part 25, § 25.1457, Cockpit Voice Recorders.
• Part 27, § 27.1457, Cockpit Voice Recorders.
• Part 29, § 29.1457, Cockpit Voice Recorders.
• Part 91, § 91.609, Flight Data Recorders and Cockpit Voice Recorders.
• Part 91, § 91.1045, Additional Equipment Requirements.
• Part 121, § 121.359, Cockpit Voice Recorders.
• Part 125, § 125.227, Cockpit Voice Recorders.
• Part 129, § 129.24, Cockpit Voice Recorders.
• Part 135, § 135.151, Cockpit Voice Recorders.
A.2.1.2 FAA ACs (current editions). A current list of ACs, including the following, can be found on the FAA website at https://www.faa.gov/regulations_policies/ advisory_circulars/ or in the Dynamic Regulatory System (DRS) at https://drs.faa.gov.
• AC 20-140, Guidelines for Design Approval of Aircraft Data Link Communication Systems Supporting Air Traffic Services (ATS).
• AC 20-141, Airworthiness and Operational Approval of Digital Flight Data Recorder Systems.
• AC 20-160, Onboard Recording of Controller Pilot Data Link Communication (CPDLC) in Crash Survivable Memory.
A.2.1.3 FAA Technical Standard Orders (TSO). A current list of TSOs, including the following, can be found in DRS at https://drs.faa.gov.
• TSO-C121b, Underwater Locating Devices (Acoustic) (Self-Powered), dated February 28, 2012.
• TSO-C123c, Cockpit Voice Recorder Equipment, dated December 19, 2013.
Appendix A A-4
• TSO-C155b, Recorder Independent Power Supply (RIPS), dated April 21, 2015.
• TS O-C177a, Data Link Recorder Equipment, dated December 19, 2013.
A.2.1.4 EUROCAE. Copies of EUROCAE Documents (ED) from EUROCAE can be ordered at 9-23 rue Paul Lafargue, “Le Triangle” building, 93200 Saint-Denis, France, or from their website at https://eshop.eurocae.net/.
• EUROCAE ED-93, Minimum Aviation System Performance Specification for CNS/ATM Message Recording Systems, dated November 1998.
• EUROCAE ED-112A, Minimum Operational Performance Specification for Crash Protected Airborne Recorder Systems, dated September 2013.
• EUROCAE ED-155, Minimum Operational Performance Specification for Lightweight Flight Recording Systems, dated July 2009.
A.2.1.5 International Civil Aviation Organization (ICAO). Current copies of the following ICAO documents can be obtained from the ICAO website at https://www.icao.int/publications/Pages/default.aspx.
• Annex 6, Part I, International Commercial Air Transport—Aeroplanes.
• Annex 6, Part II, International General Aviation—Aeroplanes.
• Annex 6, Part III, International Operations—Helicopters.
Appendix B APPENDIX B. FLOWCHARTS Figure B-1. Aircraft by Operating Rules Go to Start Operated under •Yes Figure B-2.
14 CFR part 91?
VO Go to Operated under -Yes- Figure B-3.
14 CFR part 121?
No Go to Operated under -Yes- Figure B-6.
14 CER part 125?
For part 129 operators of Operated under •Yes U.S.-registered aircraft, 14 CFR part 129? the CVR must follow part 121, 125, or 135.' Go to Operated under -Yes- Figure B-7.
14 CFR part 135?
' For part 129 operators of U.S.-registered aircraft operated solely outside of the United States in common carriage by a foreign person or a foreign air carrier, § 129.24 requires that the aircraft be equipped with an approved cockpit voice recorder (CVR) and record the information that would be required if the aircraft were operated under part 121, 125, or 135 and must be installed by the compliance times required by that operating part as applicable to the aircraft (refer to §§ 129.1(b) and 129.24).
B-1
Appendix B Figure B-2. Part 91 From Figure B-1.
Does the aircraft Is the aircraft a meet part 91 subpart K? No→ Does § 91.609 apply? Yes→ multiengine or Noturbine-powered aircraft?
§ 91.1045 $ 91.609(e) Les No Yes CVR not required. 6 or more pax seats?
CVR required. -No- § 91.609(a) $ 91.609(€) CVR required #Yes- Two pilots required? -No- $ 91.609(€) Date of Manufacture before 2010 Apr 7 must have a CVR installed by 2012 Apr 7. No CVR required.
§ 91.609(h) 2-hour CVR recorder required.
§ 91.609(i)(2) Adhere to §$ 23/25/27/29.1457, except for paras (a)(6) and (d)(5).
$ 91.609(i)(1) Part 25 *Aircraft- Aircraft or transport category? rotorcraft?
Rotorcraft No Yes Manufactured on or after Must record and after 2012 Apr 6?
meet § 25.1457(a). Record DLR if installed.
$ 91.609(j) B-2