BlackBox

How do the officials investigate the aviation accidents?
How do the officials investigate the aviation accidents?
❖ When an aviation accident occurs, both recorders are immediately removed from the accident site and transported to some investigation department (NTSB headquarters in Washington D.C.) for processing.
Terms
Cockpit voice recorder (CVR) (驾驶舱 话音记录器) is a tape recorder installed on the flight decks of commercial transport aircraft and helicopters and some business airplanes to record crew conversation, radio transmissions and cockpit background noises in case required for incidence or accident investigation.
The Cockpit Voice Recorder
CVRs
❖ The CVR records the flight crew's voices, as well as other sounds inside the cockpit.
❖ CVRs typically monitor four channels: ＊the pilot’s microphones; ＊the copilot’s microphone; ＊radio communications with the aircraft; ＊the cockpit area microphone (CAM).
Example
❖ FDRs help investigators reconstruct the final moments before an accident.
❖ In the case of US air flight 427, which crashed in September 1994 killing all 132 people on board, the last minute of FDR data indicated that the aircraft began yawing and rolling to the left as it approached the airport in Pittsburgh, Pennsylvania. This information contributed to the investigators’ conclusion that the cause of the accident was probably a disabling rudder malfunction that resulted in a loss of control.
❖ CVRs record in 30-minute loop. After 30 minutes, the oldest data is overwritten with new data.
Example
❖ The CVR provides information indicating how the pilots reacted to the circumstances that led to the accident.
❖ An analysis of these recordings can help investigators determine whether the pilots reacted appropriately to the situation.
❖ CVR recordings can also help investigators determine if the pilots were misinformed by or misunderstood instructions from air traffic controllers, ignored crucial warnings, of were confused by weather condition or other phenomena.
❖ Combined with the conversation and noises recorded by the CVR, the
Investigator-in-Charge uses this information as one of many tools to help the Safety Board determine the Probable Cause of the accident.
❖ In addition, some FDRs can record the status of more than 1,000 other in-flight characteristics that can aid in the investigation. The items monitored can be anything from flap position to auto-pilot mode or even smoke alarms.
❖ Flight data recorders (FDRs) and cockpit voice recorders (CVRs), commonly known as black boxes. Both recorders are installed to help reconstruct the events leading to an aircraft accident.
❖ In the case of Flight 427, the CVR recording suggested that the rudder malfunction caught the flight crew by surprise. In other cases, the CVR may reveal that the flight crew was aware of the problem that led to the accident.
Terms
❖ Flight data recorder (FDR) (飞行数据记 录器) is a device that records various parameters of an aircraft’s flight performance for analysis in the event of an incident or accident.
❖ These various pieces of information are called parameters. FDRs typically record in a 25-hour loop. After 25 hours the oldest data is overwritten with new data.
Black Box
Contents
❖ Terms ❖ Functions of Black Box ❖ FDRs ❖ CVRs
Terms
❖ Black box is the flight recorder, as on a military or commercial aircraft, which documents preflight checks, in-flight procedures, and the landing.
The Flight Data Recorder
❖ The FDR onboard the aircraft records many different operating conditions of the flight.
❖ By regulation, newly manufactured aircraft must monitor at least eighty-eight important parameters such as time, altitude, airspeed, heading, aircraft attitude and engine performance.
Functions of Black Box
❖ Large commercial aircraft and some smaller commercial, corporate, and private aircraft are required by the FAA to be equipped with two "black boxes" that record information about a flight.
❖ It is Orange-painted and crash-proofed. FDRs and CVRs preserve vital information, such as the airplane’s speed and altitude, and conversations between the pilot, copilot, and air traffic controllers.
Easy recognition
❖ Both FDRs and CVRs are painted bright orange and fitted with reflective strips to make them easierite.