Let’s unveil the blackboxes.

The first things that is asked when anyairplane crashes and the first things investigators looking into black boxes,which are made up of a flight data recorder (FDR) and cockpit voice recorder(CVR).

First of all, the black boxes are storedin the empennage of the aircraft.

Typically, memory boards inside it canstore two hours of audio data and 25 hours of flight data from the FDR.

The FDR has been designed to recordoperating data from the system of the aircraft, with sensors being wired tovarious parts of the aircraft to the flight data acquisition unit, which inturn is wired to the FDR. 

How about CVR?

Several microphones are built intocockpits in aircraft and these can track the conversations inside the cockpit.They also pick up any ambient noise, including bangs, knocks or thuds. Soundpicked up by them are sent to the CVR and stored.

In addition to possible technicalproblems, CVRs reveal how the pilots communicate with one another and otherssuch as cabin crew and controllers. The ability to communicate with one anotheris paramount in flight safety.

Communication enables information to beexchanged, mistakes to be pointed out and help solve problems. Unfortunately,in numerous accidents, CVR recordings revealed a frightening inability offlight crew members to communicate. Situational awareness deteriorates whencommunication breaks down. After a KLM 747 collided with a Pan Am 747 in 1977,more emphasis was placed on teamwork, joint decision making and encouragingco-pilots to respectively question their captains. This concept is now known asCrew Resource Management (CRM).

FDR and CVR work together to provide anaccurate description of the flight to help the later investigation. In order tofulfill this goal, they are made to withstand crash and fire to keep the dataintact.

Although it is called the black box, thecolor of it is usually bright orange and red. The bright color makes it standout easily. So it can be spotted and found in the wreckage of the plane,especially when it’s at night or in the forest.

The battery life of an airplane black boxis 30 days.

If the black box is on land, it won’tsend out signals.

The underwater locator beacon in theblack box allows it send out an ultrasonic pulse in the event of the aircraftbeing submerged underwater. The beacon is automatically activated when watertouches it. and ultrasonic signal will be sent out every one second for 30days.

This signal helps people to locate theblack box after the accident.

But the signal will become weaker andweaker while the battery runs out.

The sooner we find the boxes, the closerwe are to the truth. First 30 days after the accidents or incidents arecritical.

When investigators find the black box itis taken to a lab and the information from it can be downloaded and the finalevents of the aircraft recreated to get an idea of what caused the accident.This can sometimes take many weeks or months. In some cases, the black box isdented and burned when retrieved but usually, the memory boards can be removedand information got from them after cleaning them.

All in all, the black box is a veryvaluable tool in determining what went wrong and what caused the accident. Itoften provides clues which would otherwise be impossible to find.

See you next week.

Words and Expressions

1.    black box 黑匣子

2.    CVR: cockpit voice recorder 驾驶舱语音记录器

3.    FDR: flight data recorder 飞行数据记录器

4.    underwater locator beacon 水下信标