Black box-USA Aircraft Group Corporation

Date: 2025/12/23

I. Core concepts

"Black box" is a general term for flight data recorder (FDR) and cockpit voice recorder (CVR). It is not black, but eye-catching international orange, with a reflective strip so that it can be quickly found at the scene of the accident. The name "black box" may come from its early design or symbolize that its internal working principle is "mysterious" to the public.

II. Two components

1. Flight Data Recorder (FDR)

· Function: Continuously record a large number of parameters of the aircraft system.

· Record parameters: Modern FDR can record more than 1,000 data, including:

· Basic flight status: airspeed, altitude, heading, vertical acceleration.

· Operating surface state: rudder surface, flap, seam wing position.

· Engine parameters: thrust, speed, temperature, fuel flow rate.

· Autonomous driving status, navigation information, warning information, etc.

· Record duration: save at least the data of the last 25 hours.

2. Cockpit Voice Recorder (CVR)

· Function: Record all the sounds in the cockpit.

· Sound source:

· Cockpit area microphone (capture ambient sound, alarm sound, switch sound).

· Calls of pilots, co-pilots and observers with headphones and microphones.

· Ground and air calls between pilots and air controllers and flight attendants.

· Recording time: save at least the last 2 hours of audio (the historical standard is 30 minutes, and the modern standard has been generally extended to 2 hours), and the old content is covered by loop recording.

III. Key technical characteristics (why is it so strong)

The black box is designed to withstand extreme conditions and is one of the most robust equipment on the plane:

· Impact resistance: It can withstand the impact of 3400g (gravitational acceleration).

· High temperature resistance: It can burn in flames at 1100°C for 60 minutes without being destroyed.

· Pressure resistance and immersion resistance: It can withstand the water pressure of 6,000 meters (about 20,000 feet) in the deep sea and is equipped with an underwater positioning beacon (ULB). Once it comes into contact with seawater, it will automatically emit an ultrasonic pulse signal of 37.5kHz for at least 30 days to help locate.

· Anti-static squeezing: can withstand continuous pressure.
IV. Installation location
It is usually installed in the tail of the aircraft. Statistics and accident analysis show that the tail of the plane has the highest survival rate in a plane crash, which can protect the recorder to the greatest extent.
V. Core use and importance
1. Accident investigation: This is the most important and critical purpose. By restoring flight data and cockpit dialogue, investigators can accurately analyze the cause chain of accidents (mechanical failure, human operation, environmental factors, etc.) like "time back".
2. Safety analysis: analyze the data in daily flight for flight quality monitoring (FOQA), actively discover potential risks, and improve pilot training, maintenance procedures and aircraft design.
3. Legal basis: provide objective evidence for accident liability determination, insurance claim settlement and legal litigation.
4. Improving aviation safety: The conclusions of each accident investigation have promoted the improvement of global aviation safety standards (such as improving operating procedures, aircraft design and maintenance procedures) to avoid the recurrence of similar accidents. The black box can be called the cornerstone of aviation safety progress with blood.
VI. Technological development and future trend
· Media evolution: from the early steel belt and foil to today's solid-state memory, the reliability, capacity and impact resistance have been greatly improved.
· Video recording: The industry is exploring the installation of cockpit image recorders to provide more intuitive visual information, but it has not been enforced due to privacy and cost.
· Real-time transmission: Conceptually, there is a "cloud box" scheme, that is, real-time transmission of key flight data through satellites. However, due to the huge amount of data, the extremely high cost, not all accidents occur in the transferable area, and the physical black box is very reliable at present, so it has not replaced the physical equipment. It may be an important supplement in the future.
· Throwable recorder: designed to automatically eject and float on the water in an emergency, which is easy to recycle, but it also has the risk of cost and false triggering.
Sum up
The black box is a silent and solid "witness". It does not interfere with the flight, but only faithfully records. When misfortune happens, it becomes the most critical tool to unravel the mystery, pursue the truth, and ultimately protect the safety of life in the future. Its existence deeply reflects the core spirit of the aviation industry of "learning from accidents and pursuing absolute safety".