The similarities between the crash of SilkAir flight MI 185 and the disappearance of Malaysian Airlines flight MH 370 point to deliberate and skilled human intervention

On the 17th day after the strange disappearance of the Malaysian Airlines flight MH 370, Malaysian Prime Minister Najib Razak announced that the plane may have crashed into the southern Indian Ocean. His announcement was based on the analysis of eight satellite “pings” sent by the aircraft between 1.11 a.m. and 8.11 a.m. Malaysian time to the satellite company Inmarsat and the UK CAA Air Accidents Investigation Branch. AAIB and Inmarsat concluded that the plane plunged into the Indian Ocean to the west of Perth, Australia. The investigators indicated that the flight was deliberately diverted west and all communication systems disabled.

‘Unlawful intervention’

The sequence of events that unfolded and news broadcast has an eerie similarity to another fatal tragedy that killed 104 persons 17 years back. SilkAir flight MI 185 dived into the Musi river in Sumatra, Indonesia. The difference was that the recorders on board were recovered as the point where the aircraft crashed was not deep, but the recorders had stopped functioning just prior to the point where the aircraft started the dive from 35,000ft. On August 25 1999, the Aircraft Accident Investigation Commission of Indonesia released a finding that “unlawful human intervention” may have been a factor in the SilkAir crash. However, they backtracked on this and covered up the truth when the final report came out. The National Transportation Safety Board of the U.S. (NTSB) brought out its own report disputing the AAIC’s report and stated that the accident pointed to pilot suicide by the captain.

On October 31 1999, EgyptAir flight 990 crashed into the Atlantic Ocean when the pilot flew the aircraft deliberately into the sea, killing all 217 on board. The Egyptian government denied it was a case of pilot suicide but the NTSB report clearly established that it was deliberate human intervention that caused the crash. Then we had the four 9/11 attacks where suicidal action by pilot terrorists killed several thousands. But one among them, United Airlines flight 93, may have a bearing on the MH 370 flight. In UA 93, passenger intervention prevented the hijackers from taking the aircraft down in a populated area.

Taking MI 185 and MH 370, what stands out are the initial sequences which are similar. The Cockpit Voice Recorder (CVR) had stopped in MI 185 before the co-pilot had reported his position to Jakarta radar control. In MH 370, the ACARs had stopped before the co-pilot reported “all right, goodnight” to Air Traffic Control. While the SilkAir co-pilot was highly experienced, the Malaysian co-pilot was new to Boeing 777. This was his first flight without a safety pilot on board. There is a likelihood that the Digital Flight Data Recorder (DFDR) was turned off on MH 370, soon after the CVR was turned off, as it happened in MI 185.

Both flights were cruising at 35,000ft before the crashes took place. In the MI 185 flight, the captain forgot to turn off the transponder which resulted in the final path of the aircraft being tracked by the Palembang Air Force radar all the way down to a point where radar signals were no longer visible. The radar tracked the near vertical descent of the SilkAir flight. An aircraft falling out of the sky cannot fly that profile unless manually forced to maintain that profile. This would have resulted in extreme forces on the controls and that can only be relieved by using the Stabiliser trimmers. What the investigators found was that the Stabiliser trim position indicated ZERO while the assumption of an electric trim motor malfunction would move it only to around 2 units. It was clearly evident that there was manual intervention and that was the reason Aircraft Accident Safety Commission concluded that there was “unlawful human intervention.”

Why did the co-pilot of the Silkair flight not intervene? Whether the co-pilot was present in the cockpit at that time or locked out of it will never be known as all recorders were switched off before the tragic dive. Ironically, the circuit breakers for the recorders are located just behind the captain’s seat. The force required to fly the profile and hold it down can only be done by an extremely experienced pilot and the captain was a former fighter pilot who was well trained in aerobatics.

Let us look at the data of MH 370 that was revealed in the initial days following the flight’s disappearance. The ACARs stopped at 1.07 a.m. and the co-pilot reported that everything was normal. A few minutes later, the aircraft made a sharp turn towards Kuala Lumpur (as reported by the Thai radar) and then a further turn toward the west across the Malaysian peninsula. There are reports that the aircraft climbed to as high as 45,000ft and later descended rapidly to 12,000ft. Thereafter it joined an airway that would have taken it towards the Andaman Islands.

Why would the aircraft climb to 45,000ft, that is 2,000ft above the maximum altitude for a Boeing 777? Only an experienced captain who has also carried out test flights would know that this manoeuvre is done during certification flights and there is no danger to the structure. What is more significant is that in the event of a depressurisation, the Time of Useful Consciousness (TUC) at 45,000ft is a mere 9-15 seconds. If the oxygen masks are not donned and used within that time, the person becomes brain dead. In the middle of the night, when most people are likely to be fast asleep, there is every possibility that the masks would not have been worn within 15 seconds. The aircraft could have been easily depressurised from the cockpit, where the pilot would have had access to unlimited oxygen. If warning systems were deactivated, everyone in the cabin would have been brain dead within a very short span of time. There would have been no threat of human intervention from the cabin like what happened in UA 93.

A rapid descent to 12,000ft normally takes places in the event of depressurisation. If this was done after ensuring that all on board are brain dead, it would have also misled the military radar into believing that the aircraft was carrying out an emergency descent and so they would not have interfered during this manoeuvre. Crossing over to the west and following the airway, maybe tucked in behind a scheduled flight on that route, would have further dulled the air force radar into complacency. Turning off the transponder would have ensured that the Traffic Collision Avoidance System was off and would have prevented detection of the aircraft on TCAS by any other aircraft flying in the sky.

Well-planned move



Assuming this, following the airway to the waypoint IGREX (a geographical position on the track) is an extremely well-planned move. The radars in Air Force station at Car Nicobar and the Navy station at Port Blair have a range of just 75 nautical miles (nm). IGREX is 152 nm from Port Blair and is out of range of the radar, even if it is functioning. Shockingly, the radars at Car Nicobar and Port Blair function only during the day and the MH 370 flight was travelling at night.

Taking that southern path from IGREX — maybe even a detour to fly low over the Maldives — and then to the final point for an end in the deep ocean would have ensured that no evidence was available except conjectures. This flight path could only have been flown deliberately and by someone who was highly experienced and skilled.

The three tragedies spoken of have resulted in the loss of lives of several passengers. It is time for the international aviation community and governments to realise that pilot suicide is a potential threat that needs urgent attention.

(Capt. A. Ranganathan is a former airline instructor pilot and aviation safety expert.)

Correction and clarification

A sentence read: “On October 31, 2009, EgyptAir flight 990 crashed into the Atlantic Ocean when the pilot flew the aircraft deliberately into the sea, killing all 217 on board.” The correct year is 1999.