HuskyDeac
Well-known member
Regarding how it went off radar:
From the Guardian;
"Over land, air traffic controllers can use two types of radar, primary, which detects objects by bouncing back a radio signal, and secondary , where the plane sends back an automatic response, identifying itself. Air traffic consultant Doug Maclean, of DKM Aviation, says: "Secondary surveillance radar sends out a coded question, the interrogation message will be received and sent back; that requires a degree of co-operation between plane and the ground. In the likes of the 9/11 incident, the aircraft would have received messages but hijackers had switched off the reply.
But over longer distances where radar coverage is limited – ie usually when planes are flying across oceans – they use another system, Automatic Dependent Surveillance. Here the aircraft transmits its own signal and gives its position via satellites. Maclean says: "Once you go outside primary radar coverage, which would normally be about 100 miles offshore maximum, you are relying on the plane to be transponding."
Malaysia Airlines has confirmed its plane had a system called ACARS, or the Aircraft Communications Addressing and Reporting System, which would also automatically alert engineers at base of any mechanical failure.
So when flight MH370 disappeared from plane tracking websites, it could mean the signals from the plane's transponder were stopped deliberately (by pilots or others), or there was a complete electrical failure, or the plane disintegrated. Where the Malaysian plane was flying, the signals are picked up by sites only once a minute and only at a plane's cruising height above 29,000 feet. So a dramatic loss of altitude could conceivably also see a plane drop off their radar but potentially continue to travel for some distance."
From the Guardian;
"Over land, air traffic controllers can use two types of radar, primary, which detects objects by bouncing back a radio signal, and secondary , where the plane sends back an automatic response, identifying itself. Air traffic consultant Doug Maclean, of DKM Aviation, says: "Secondary surveillance radar sends out a coded question, the interrogation message will be received and sent back; that requires a degree of co-operation between plane and the ground. In the likes of the 9/11 incident, the aircraft would have received messages but hijackers had switched off the reply.
But over longer distances where radar coverage is limited – ie usually when planes are flying across oceans – they use another system, Automatic Dependent Surveillance. Here the aircraft transmits its own signal and gives its position via satellites. Maclean says: "Once you go outside primary radar coverage, which would normally be about 100 miles offshore maximum, you are relying on the plane to be transponding."
Malaysia Airlines has confirmed its plane had a system called ACARS, or the Aircraft Communications Addressing and Reporting System, which would also automatically alert engineers at base of any mechanical failure.
So when flight MH370 disappeared from plane tracking websites, it could mean the signals from the plane's transponder were stopped deliberately (by pilots or others), or there was a complete electrical failure, or the plane disintegrated. Where the Malaysian plane was flying, the signals are picked up by sites only once a minute and only at a plane's cruising height above 29,000 feet. So a dramatic loss of altitude could conceivably also see a plane drop off their radar but potentially continue to travel for some distance."
