1. Are Black Boxes Really Black?
What is commonly called the ‘black box’ is in fact two orange-coloured boxes, one is the Flight Data Recorder (FDR), the other is the Cockpit Voice Recorder (CVR). As the names suggest, CVR stores the last two hours of voice recording from the cockpit and the pilots’ headset microphones on four channels. The CVR also records ambient noises such as the turning on and off of switches, thuds and other noises.
Modern-day FDRs record the operating data from the plane’s systems. Sensors placed in different parts of the plane are connected to the Flight Data Acquisition Unit, which sends the data to the FDR. Hence, any change in the plane, any switch turning on or off of a switch, all the data is recorded. The FDR captures 88 different types of data, for the last 25 hours till the recorder loses power.
Parameters recorded commonly include:
- Pressure altitude
- Vertical acceleration
- Magnetic heading
- Control-column position
- Rudder-pedal position
- Control-wheel position
- Horizontal stabiliser
- Fuel flow
Data from both the components are stored in memory boards inside a Crash Survivable Memory Unit.