After 71 days, the silence of MH370's ELT is getting louder

The latest was on the Emergency Locator Transmitter (ELT), which was claimed had never been discussed since the disappearance and since it never transmit any signals, there were speculations saying that the aircraft did not go into the Southern Indian Ocean and was still intact.

An ELT is an emergency beacon used in aircraft to alert rescue authorities and to indicate the location and the identity of an aircraft in distress.

In an exclusive interview with Bernama, former MAS chief pilot, Datuk Nik Ahmad Huzlan Nik Hussain said, even though it was weird that MH370's ELT did not give any signal at all, one must understand that it would trigger its signal depending on the impact

"The angle of impact is very important for it to trigger. The reason why they have certain impact indicator is so that when the aircraft is doing a hard landing on an airport's runway, the ELT will not trigger.

"If the ELT is really sensitive, every time an aircraft makes a hard landing, the ELT will trigger. So it has a pre-determine value for it to trigger," he explained.

He noted that in the case of Air France (AF) 447, the ELT was not triggered as the aircraft crashed at a low speed, about 100 kilometres per hour, and did not give enough trigger point for the ELT.

The ELT is designed to self-activate by certain triggers such as an impact or contact with water, similar to the black box's locator device.

"Although it (Air France 447) hit the water, it then sunk, signal was not transmitted. Water will hamper the range, the trajectory, the power of the ELT. So the transmission range of the ELT may be limited due to the water," he said, stressing that it was the Aircraft Communications Addressing and Reporting System (ACARS) that gave the signal.

According to Nik Ahmad Huzlan, before AF447 crashed into the Atlantic Ocean, various signals were sent by ACARS as it had detected one faulty after another, which has led to the aircraft's final resting place.

The former chief pilot further explain that the ELT was not related to the aircraft's transponder, saying that it stood alone and that the battery could last for only 48 hours after it triggered due to its strong signal and ability to be detected from far, unlike ping.

The ELT, when triggered, would transmit its signals to three frequencies that could be picked up by any aircraft or vessels that were monitoring via satellite.

"First one is the 243-MHz frequency for the ships, through which any ships that are passing through can hear it on their radio. The second one is the 121.5-MHz frequency, which is for the aircraft, he said.

"And another one will be sent to the satellite on 406-MHz frequency. So there are three frequencies and none of them are able to be detected," he added.

Commenting on the four pings detected in the Southern Indian Ocean on April 5 and April 8, he said that the reason there were no more pings detected after that was due to the black box's battery life nearly expiring at that time.

"So the four pings detected were from the black box. But why is it so hard to find the wreckage? It is because the signals are not strong enough to triangulate the search area. If it is strong and can be detected at every corner of the search area, intersection point can be created," he said, adding that the search would be a lot easier.

Asked if it was possible for the aircraft, presumably in the Southern Indian Ocean, to still be intact, Nik Ahmad Huzlan said it was possible because the aircraft was heavy and not designed to float.

"The water can enter through the undercarriage, engine and, bear in mind, the engine is heavy. So water can enter and sink the aircraft. The longest an aircraft can float on the water is five minutes," he said.

Meanwhile, on the need of revisiting and recalculating the analysis by the United Kingdom's INMARSAT and Air Accidents Investigation Branch (AAIB), Nik Ahmad Huzlan said it had to be done although there was no issue on doppler's effect analysis on satellite pings.

"I am holding on to several things. First, the range circle of the aircraft's capability based on the available fuel. Second, is finding the dawn, because whoever is flying MH370 at that time will look for sunrise area.