mickyman
If the airliner went down in one of the deepest parts
of the Atlantic - what effect will pressure have on the
'black boxes' and could the data survive in such conditions?
Specifications
Flight Data Recorder
Time recorded = 25 hour continuous
Number of parameters = 18 - 1000+
Impact tolerance = 3400Gs / 6.5 ms
Fire resistance = 1100 degC / 30 min
Water pressure resistance submerged = 20,000 ft
Underwater locator beacon = 37.5 KHz; battery has shelf life of 6 years or more, with 30-day operation capability upon activation
Cockpit Voice Recorder
Time recorded = 30 min continuous, 2 hours for solid state digital units
Number of channels = 4
Impact tolerance = 3400Gs / 6.5 ms
Fire resistance = 1100 degC / 30 min
Water pressure resistance submerged = 20,000 ft
Underwater locator beacon = 37.5 KHz; battery has shelf life of 6 years or more, with 30-day operation capability upon activation
Source:
www.ntsb.gov
The ULB, also known as the "pinger" usually have the following specifications to satisfy TSO-C121
Underwater Locator Beacon (ULB)
Operating Frequency:37.5 kHz ± 1 kHz
Operating Depth:Surface to 20,000 feet
Pulse Length:Not less than 9 milliseconds
Pulse Repetition Rate:Not less than 0.9 pulse per second
Useful Life:Six years
Operating Life:30 days (minimum)
Acoustic Output, Initial:1060 dynes/cm2 rms pressure at 1 meter (160.5 dB)Acoustic Output, After 30 days:700 dynes/cm2 rms pressure at 1 meter (157.0 dB)
Operating Temperature:28º F to 100º F
Actuation:Fresh or salt water, surface to 20,000 feet
Radiation Pattern:Rated output over 80 percent of sphere
Hope this helps
