Pratyush wrote:The beacon doesn't have to be seperate for over water applications. It can be a simple blackbox unit that has this functionality built-in to it. Like all civilian black box units have. In times of war this beacon can be switched off. To maintain security in case of the aircraft getting shot down.
This is IIRC, the 4th such instance in the last few years.
1) AN 32 enroute to ANC.
2) 2 seperate cost guard Dornier in bay of Bengal.
3) this is the fourth one.
The existence of a beacon would have made life easier for the recovery crews.
You are talking about an ELT, (emergency locator beacon) which is impact operated and the ones I know activate via a g switch usually set for 11g. This is normally carried by fixed wing aircraft and is a standalone unit that is easily retrofitted. It is also detachable and portable and can easily be carried by the survivors to help in vectoring rescuers to their location. The Indian forces may already be using such beacons.
once activated, it transmits on the emergency distress frequency and this signal is easily picked up by many orbiting satellites which send out alarm messages to ground stations. The location of the crash can be triangulated very quickly because multiple satellites receive the same distress signal. Water attenuates radio signals very strongly, especially at higher frequencies, so it may not be too effective in case of an accident over water where the wreckage has submerged.
The distress frequencies are 121.5 MHz for civilian use, 243.0 MHz for military use, and these frequencies are monitored worldwide on a 24X7 basis
IN helos use an SLB, (sonar locator beacon) that transmits sonar signals underwater to help rescue/recovery. The batteries usually do not last beyond a couple of days.
Not personally aware if the IA helos carry an ELT.
For sure, they will not carry an SLB when operating so far inland.
Coast Guard Dorniers carry an ELT as part of their standard fit.