Flight_Recorder Air France (AF) Flight 447, that took off from Rio de Janeiro, Brazil to Paris-Charles de Gaulle, France with 228 people (216 passengers and 12 crew members) suddenly disappeared over the Atlantic Ocean on June 01.

Swift search operations were launched by Brazil Navy and Air Force to locate the missing aircraft on June 01. As Brazil Navy ships have found the bodies of two men and debris of the aircraft on June 06, it is clear that the aircraft has crashed in the Atlantic Ocean. Further 15 more bodies were recovered from the sea, 600 miles off Brazil’s northeastern coast on June 07.

From the automated messages received from the aircraft just before the crash, information available are

  • 15 minutes before the crash, the aircraft passed through a zone of stormy weather with strong turbulence.
  • Subsequently in the aircraft
    • autopilot disengaged
    • onboard computer switched to an alternate power system due to electrical faults
    • experienced loss of air pressure
    • experienced total electrical failure

The world is awaiting eagerly to know

  • What actually happened to the aircraft ?
  • Why and How the aircraft crashed in the Atlantic Ocean ?
  • What happened to the passengers and crew ?

Answers to all the above questions are available in the Black Box of the aircraft that has crashed.

Black Box (Flight Recorder)

Honeywell Aerospace lists the types of Flight Recorder (Black Box) as:

  • Cockpit Voice Recorder (SSCVR):
    • Cockpit_Voice_Recorderhas Crash Survivable Memory Unit (CSMU) to record the most recent 30 minutes or 2 hours of audio, digital and timing information.
    • has optional Underwater Locator Beacon (ULB).
    • dimension: Height – 6.1 inch; Width – 4.8 inch; Length – 12.62 inch;
    • weight: 11.5 pounds.
    • designed for data recovery even if subjected to
      • Impact Shock – 3400 G, 6.5 milli seconds
      • Penetration Resistance – 500 lb weight drop from 10 feet
      • Static Crush – 5000 lbs, 5 minutes
      • High Temperature Fire - 1100°C, 30 minutes
      • Low Temperature Fire: 260°C, 10 hours
      • Deep Sea Pressure and Sea Water/Fluids Immersion: 20,000 feet, 30 days Flight_Data_Recorder
  • Flight Data Recorder (SSFDR): similar to SSCVR except
    • CSMU can record the most recent 25 hours of digital flight data and timing information.
    • dimension: Height – 5.75 inch; Width – 5.88 inch; Length – 12.62/19.62 inch;
    • weight: 11.5/13.5 pounds.
    • tri-axial accelerometer can measure vertical, lateral and longitudinal acceleration.
  • Advanced Recorder (AR):
    • available as
      • Cockpit Voice Recorder only (AR-CVR)
      • Flight Data Recorder only (AR-FDR)
      • Combined Digital Voice and Data Recorder (AR-DVDR)
    • has Underwater Locator Beacon (ULB). Advanced_Recorder
    • voice recording duration: 30, 60, 120 minutes.
    • data recording: 10, 25 hours.
    • dimension: Height – 6.1 inch; Width – 4.8 inch; Length – 9.49 inch;
    • weight: 8.8 pounds.
    • designed for data recovery even if subjected to
      • Impact Shock – 3400 G, 6.5 milli seconds
      • Penetration Resistance – 500 lb weight drop from 10 feet
      • Static Crush – 5000 lbs, 5 minutes
      • High Temperature Fire - 1100°C, 60 minutes
      • Low Temperature Fire: 260°C, 10 hours
      • Deep Sea Pressure and Sea Water/Fluids Immersion: 20,000 feet, 30 days

Where is the Black Box ?

The Black Box is believed to be in the Atlantic Ocean, northeast of the Fernando de Noronha islands off Brazil’s northern coast at a depth of anywhere between 2,835 and 13,120 feet.

How to locate the Black Box ? Emergency_Locator_Pingers

Black Box is fitted with Underwater Locator Beacon (ULB). It is also called as Emergency Locator Pingers (ELP).

Emergency Locator Pingers

  • a product of Benthos.
  • designed to
    • assist in the recovery and investigation of aircraft that have gone down in water
    • operate in the most extreme environments and can withstand very high levels of vibration, pressure, and temperature
  • on contact with sea or fresh water, transmits acoustic signal through a water activated built-in switch.
  • transmits an acoustic signal once every second for 30 days after activation, with the standard lithium battery or 90 days with an optional lithium battery.
  • the transmitted acoustic signal can be received and converted to an audible signal by Acoustic Pinger Receivers. Emergency_Locating_Beacon
  • the acoustic signal can be detected in one mile radius.
  • operating depth: up to 20,000 feet.
  • weight: 190 grams.
  • dimension: length-9.95 cm; diameter-3.3 cm.
  • generally mounted in the aft mid section of the aircraft
    • where sound absorbing materials are not present
    • where the maximum temperature shall not exceed 71°C
  • requires maintenance
    • periodic beacon cleaning necessary to keep it free from dust, grease and dirt
    • periodic beacon functional test must be carried out
    • battery need to be replaced as per the date stamped on the beacon label
  • has a 6 year user replaceable battery.

Acoustic Pinger Receivers locate_flight_recorder

  • can detect the acoustic signal from a mile away.
  • initially the acoustic signal is detected by a Portable Acoustic Pinger Receiver from the sea surface, from a ship to find out the approximate location of the aircraft.
  • or by a Stingray – Remotely Operated Vehicle (ROV) at varying depths as acoustic signal detection range is limited to one mile only.
  • then, exact location can be found out by a diver with a hand-held unit.

Activities to locate the Black Box (Flight Recorder)

  • Black Box has to be located within 30 days of the crash (before June 30).
  • Two French submarines, including one that explored the wreck of the Titanic and another, nuclear powered warship, are on their way to hunt for the Black Box.
  • France also has sent a ship carrying two mini-submarines capable of operating at depths of 6,000 metres to commence salvage operations.
  • The U.S. Navy is sending to Brazil, two high-tech Towed Pinger Locators which can detect emergency beacons to a depth of 20,000 feet (6,100 metres), to be used by French ships.

View some interesting video clips:

Read more

All above images of Flight Recorder are from Honeywell-MyAerospace and Pingers are from Teledyne Benthos.

Post in MarineBuzz on this day a year before:

An Evening with Chennai Indibloggers

Update: June 09

Brazil Navy on June 08, recovered the tail fin of Airbus A330, Air France Flight 447. As the Black Box is mounted in the tail section, the search for Black Box can be done more confidently. French submarine is expected to arrive in the search area to locate Black Box on June 10. Read more from France 24.

View an interesting video clip from Associated Press: Brazil: Jet Vertical Stabilizer Found, Key Clue.

Update: June 10

French nuclear submarine Emeraude has arrived off Brazil, to look for the black box (flight recorder) from Air France Flight 447. On detecting the acoustic signal from the black box, French scientific research vessel Pourquoi Pas will launch a mini-submarine — the same one that found the wreck of the Titanic — to retrieve the recorders.

In addition, French helicopter carrier Mistral, would act as a naval command and control vessel during the search operations. Read more from France 24.

Update: June 11

French nuclear submarine Emeraude, is on “Mission Impossible” to locate the black box some 700 miles off Brazil’s northeast coast. Read more from France 24.

View a video clip from CCTV: Hunt for Air France black box - 10 Jun 09


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