What Are Black Boxes?

Cockpit Voice Recorders (CVR) and Flight Data Recorders (FDR) are the two so-called "black boxes" required to be installed on many turbine-powered business aircraft. These boxes, actually bright orange, are designed to capture data that investigators can use to help determine the why of a mishap. The units  work on a continuous loop: after a certain number of hours, both units self-rewind to start over again, erasing the previous recordings. 

The CVR records conversations of the pilot(s), ATC communications, checklist items, and other sounds emanating from the cockpit, such as: when flaps, trim tabs and landing gear are in motion; programmed altitude, ground proximity and speed callouts; safety belt sign activation; and caution and warning alarms. Smaller aircraft may require only a CVR and larger aircraft  require both a CVR and  an FDR.  

Cockpit recorders are required on U.S. civil registered, multiengine, turbine-powered airplanes or rotorcraft with a passenger seating configuration of 10 or more seats. A CVR is also required when there are six or more passenger seats and the aircraft requires two pilots. Cockpit voice recorders (and FDRs) are not required on single-engine jets or turboprops, or any piston-engine aircraft. Nevertheless, passengers should know that many operators of smaller business aircraft have opted to install CVRs even when they are not required and despite their high cost. 

Some CVRs have an erasable feature in the cockpit. According to regulations, "any time during the operation of the recorder, information recorded more than 15 minutes earlier may be erased or otherwise obliterated." Pilots generally support erasable CVRs as a privacy issue. But the National Transportation Safety Board (NTSB), the federal accident investigation agency, and others argue that the erasable feature conflicts with safety goals because it allows "critical audio" to be wiped before investigators see it. 

Currently, CVRs must retain information for two hours, operating continuously from the instant the aircraft begins its takeoff until it has completed the landing roll.  However, larger business jets manufactured after Feb. 2, 2027 and with 29 or fewer passenger seats will have to be equipped with CVRs designed to retain 25 hours of continuous information. The 25-hour requirement will apply to midsize and smaller multi-engine aircraft manufactured after Feb. 2, 2029. Since May 16, 2025, multi-engine aircraft with 30 or more passenger seats have had to be equipped with 25-hour CVRs. 

Flight recorders capture altitude, airspeed, acceleration, heading, control column position, engine thrust, landing gear settings, and hundreds of other parameters, along with the time of every radio transmission to and from air traffic control.

Airline and air taxi multi-engine, turbine-powered airplanes or rotorcraft having a passenger seating configuration of 10 or more passenger seats must have an FDR. Business jets that are flown privately and have nine or less passenger seats do not legally require an FDR. 

Data from CVRs and FDRs are intended to provide accident investigation and safety information. Data can be used in court cases, although there are strict limitations. If an accident or incident results in the termination of a flight, operators must keep CVR and FDR information for at least 60 days or longer if requested by investigation authorities.