Flight Data Readouts: Cockpit Voice Recorder (CVR) Readouts

An Introduction to Cockpit Voice Recorders

As we covered in An Introduction to Flight Data Readouts, cockpit voice recorders are another mandated recording device used on aircraft. Cockpit voice recorders collect another portion of the information a readouts service can provide. Unlike flight data recorders which capture flight parameters, cockpit voice recorders are focused on crew interactions and cockpit noise.

What are Cockpit Voice Recorders, and What Do They Record?

Created in the late 1940s and refined in the early 1950s, cockpit voice recorders gained popularity in the aviation safety sphere during the late 1950s. Eventually, they were mandated globally in the late 1960s alongside flight data recorders. Early CVR iterations used analog wire recording but were soon replaced with analog magnetic tape. Current designs feature solid-state memory with digital recording techniques that protect against shock, vibration, and moisture.

Like flight data recorders, these bright orange avionics provide critical insights into the function of an aircraft. Using four recording channels, these compact devices record the cockpit environment through a cockpit area microphone (CAM). They also capture the audio streams as recorded by the microphones used by the flight crew, known as Pilot, Co-Pilot and 3^rd position.

As per ICAO provisions, most fixed-wing aircraft and helicopters must have a recorder with a recording duration of at least 2 hours. This ensures that enough pertinent audio is available for an in-depth investigation in the case of an accident. Sometimes, smaller and older aircraft can utilize recorders that only store 30 minutes of audio. But most international regulatory bodies require CVRs to record at least 2 hours of audio.

In some cases, other regional regulatory bodies require CVRs to record for longer durations. For example, EASA framework requires new aircraft over a certain weight to carry CVRs that have 25-hour recording times. This same sentiment is echoed by the FAA, which just announced its plan to construct a regulatory framework that will require 25-hour CVRs on aircraft.

Data Link Communication and Recording (DLR)

Despite their name, cockpit voice recorders do not only capture audio in the cockpit. They are also equipped to capture data link communication, known to many as a data link recorder or DLR. Since January 1^st, 2007, it has been required that all airplanes using data link communications must record data link messages.

It is important to note that data link recordings must align with the recording length of the CVR and are correlated to the recorded cockpit audio. These messages to the ground, combined with the recordings from the CVR, can give further insight into what is taking place on an aircraft at any given time.

What Information is Shared in a CVR Readout?

A CVR readout refers to only the audio recorded by the CVR itself. When providing a CVR readout service, a few different items are tracked and represented in the readout. Following EASA and UK approvals and conforming to ICAO and FAA recommendations, Flight Data Systems provides the following in their readouts service:

• CVR Data Stored as per CAT.GEN.MPA.195: EASA regulation CAT.GEN.MPA.195 has specific requirements regarding how flight recorder recordings are handled. Flight Data Systems’ readout service ensures that the CVR data is stored to this standard.
• Audio Analysis: A CVR can record cockpit conversations, radio transmissions, flight deck sounds, flight crew interactions, and warnings and alerts. The Flight Data Systems team analyzes this audio acquired by the CVR, and the observed findings are presented in the CVR readout report. This report provides an analysis of the conversations about other recorded information, timeline reconstructions, and the identification of critical events during the flight.
• Intelligibility Checks: An essential part of the flight recorder system service is confirming that the recorded audio information is intelligible. This is known as an intelligibility check and is conducted during Flight Data Systems readouts service.
• Recording Quality Check: When conducting a yearly service on a flight data system, it is essential to ensure that the recorded audio quality is up to the required quality standards and is intelligible.
• Four Recorder Channels: The Flight Data Systems team analyzes all four recorder channels to ensure everything functions correctly.
• Rotor Speed Encoder (RSE): Flight Data Systems readout service can provide the rotor speed encoder data from a rotorcraft as a part of their CVR readout service. A rotor speed encoder includes information regarding whether the rotorcraft’s rotors are moving at the correct speeds.

These tracked elements together provide the required information for those seeking to satisfy EASA, UK CAA, ICAO, and FAA regulations. They give a holistic understanding of how the cockpit voice recorder functions and insight into inter-crew relations. This data, coupled with flight data recorder readouts, can provide a clear picture of how an aircraft is functioning.

About Flight Data Systems

Since 1990, Flight Data Systems (FDS) has provided services and solutions to benefit the entire flight data ecosystem. As industry-leading flight data experts, we offer a holistic flight data ecosystem from flight data acquisition, storage, download, and analysis. Our solutions are trusted by over 300 operators worldwide in military and government, business aviation, commercial airlines, and rotorcraft segments.

About Our Readouts Service

Our readouts service provides 3500+ readouts yearly and touts over 440 fixed-wing and rotorcraft aircraft databases. Our full-service flight data analysis solution offers superior support and service and a 5-day turn-around time (TAT). Build the foundation of your flight data safety analysis program on our high-quality readout services.