Missing IAF AN-32 Plane did not even have Basic Search Equipment to locate it in case of a Crash

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When an Air Force transport plane, an AN-32, took off from Chennai 18 days ago on a flight to Port Blair, it was not carrying essential equipment that would have helped locate it in the event of a crash at sea.

We have learned that the black box of the Indian Air Force An-32, which had 29 people onboard, was not fitted with an Underwater Locator Beacon making a search operation for wreckage of the aircraft extremely difficult.

The underwater locator beacon is designed to emit an electronic signal at a particular frequency for at least a month after it is automatically activated during a crash and is used on all civilian aircraft.

The lack of this basic kit raises serious questions on why the Indian Air Force was operating an aircraft over maritime areas without installing systems which would have allowed wreckage to have been located underwater in the event of such a crash. IAF was actually in the process of testing underwater locator transmitter on its fleet of An-32s and has now decided to immediately install these units on all An-32s which it operates over water.

What the An-32 which went down was fitted with were two types of emergency locator transmitters or ELTs, designed to send out digitally encoded pings to be picked up by satellites which can then triangulate the position of the plane to within 1 nautical mile. The ELTs activate when the plane hits land or water with force in a pre-assigned range. However, these only function on the surface of water for a period of 70 hours after which their batteries die out. They also cease transmitting a distress signal if they sank.

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Defence Minister Manohar Parrikar on board P-8 Poseidon during search of missing An-32 along with Chief of IAF and Navy

In addition to the systems described, the AN-32 was fitted with four life rafts, each fitted with a single Personal Locator Beacon (PLB) which would transmit if it came in contact with water. However, these systems are designed to operate on the surface of the sea and assuming passengers and crew on the aircraft were able to board the life-rafts in the event of an emergency water landing. It is unclear if the PLBs would be able to broadcast a signal of any worthwhile strength from deep underwater. It is also unclear how long their batteries would last.

In the absence of an underwater locator beacon, search specialists on ships and submarines will now try to detect the wreckage underwater by going active on their sonar consoles, in other words, radiating a strong sonar (sound) signal which would reflect off any metallic object underwater revealing its position. But this is a long and arduous process comparable to pointing a flash light on a dark night in the middle of a jungle in the hope that you end up spotting something.

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Defence Minister Manohar Parrikar on board P-8 Poseidon during search of missing An-32

In the case of the AF-447, the Air France jetliner which crashed off the coast of Brazil in 2009, it took investigators two years using this method before they could detect the bulk of the debris of the aircraft in which 228 people lost their lives.

Speaking to the Times of India, NIOT director Satheesh C Shenoi said that the deep sea search would begin around 169 miles off the Chennai coast.

“We are diverting Sagar Nidhi directly to the search location and she is expected to reach any time after 2pm. She has to search an area of 220 nautical miles, which may even begin in the night,”  Shenoi said

The missing AN 32 aircraft, which had flown multiple times over the Bay of Bengal carrying military personnel and equipment, did not have an underwater locator system, making it difficult for rescuers to pinpoint the position of the plane.

In fact, none of the upgraded AN32 aircraft, the main workhorse of the military, has an underwater locator, unlike the modern transport planes like C130J or C17.

The missing aircraft came with two Emergency Locator Transmitter (ELT) — a stationary ARTEX C406-1 ELT manufactured by ACR Electronics/Artex Products, the US, and a French-made portable KANNAD 406AS ELT manufactured by Orolia

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A picture of an An-32 that previously crash landed at Chandigarh Airport on September 20,2014

In an emergency, the pilot has to activate the ELT beacon manually. The integrated ELT gets activated when the impact is about 2.3 G or 4.5 feet per second

However, ELT would not get activated automatically since radio waves are not transmitted in the water. There is no signal from ELT under water for this reason, IAF sources said

The sources said trials were already on to procure underwater ELTs for the aircraft and, as an emergency measure, effort is to have some kind of an underwater ELT on any aircraft that flies over water

Also, the AN-32 aircraft does not have the Automatic Dependent Surveillance – Broadcast

This system relies on navigational satellites to automatically transmit an aircraft’s journey in real time and it can be switched on and off based on operational needs

Defence Minister Manohar Parrikar had said overdue action, as per the Standard Operating Procedures, started at 1230 hours, one hour after the scheduled arrival at Port Blair and nearly three-and-a-half hours after the plane went out of ground radar cover area.

It was only at 1225 hours that Maritime Rescue and Coordination Centre, Chennai reported that an IAF AN-32 (AF-330) was not in contact. The weather at the time when the plane went missing was overcast with multi-layered clouds and embedded convection

The pilot had asked for deviation to the right to avoid a thundershower cloud before disappearing.