Investigations by the authorities into the tragic crash of Russian-made Sukhoi Superjet 100 passenger aircraft may take years to wrap up, speculation is rife over the cause of the crash that killed the aircraft’s 45 crew members and passengers during the ill-fated May 9 flight. The Jakarta Post’s Nurfika Osman and Theresia Sufa explore the issue.

“The pilot intentionally flew the aircraft into thick clouds several times causing bad turbulence. The aircraft also descended close to the ground so that passengers could enjoy the view of the terrain from the sky above.”

“Overall, they wanted to prove how good the Superjet 100 was.”

These were the words spoken by Indonesian National Air Carrier Association (INACA) secretary-general Tengku Burhanuddin as he recalled his trip flying with the ill-fated aircraft only hours before it crashed on Mt. Salak, around 80 kilometers south of Jakarta, on May 9.

Burhanuddin was among dozens of aviation experts and executives who attended the morning session’s demonstration flight, aimed at luring local airliners to buy the aircraft.

He said that the passengers assumed the pilot was doing the maneuvers deliberately to demonstrate the plane’s ability to fly through thick clouds and turbulent conditions.

“The pilot seemed to push the aircraft to the limit. But it was a fantastic ride. I can honestly say that I still felt comfortable sitting in the passenger seat,” he recalled.

While the aircraft’s flight data and data recorder, or black box, have yet to be retrieved, aviation experts have voiced early predictions as to the cause of the tragedy, which occurred in a nation known as the “land of disaster”.

Answers to puzzling questions surrounding the crash are unlikely to be uncovered anytime soon, since investigations into the cause airplane disasters typically take years to complete.

Amid swirling speculation on the cause of the crash, the Russian media has focused on pilot error as the likely cause.

The pilots might have turned off an alert system in order to speak with passengers or to show them around the cockpit, RIA Novosti news agency reported on Friday.

The agency also said that the pilots might have “stopped paying attention” to the alert system as it was “nearly always on” in mountainous regions.

Indeed, the wreckage recovered from the slopes of Mt. Salak left a strong impression that the crash was the result of a head-on collision rather than side-swiping the mountain and then crashing.

The plane’s Terrain Awareness and Warning System (TAWS) should have informed the pilots if the plane was approaching an obstacle. But apparently this system failed to warn the pilot.

The route traveled for the demonstration flight is also known by local experts as an “aircraft graveyard”, given the number of accidents that have occurred along the flight path. Six aviation accidents have been recorded near Mt. Salak in the past 10 years, with a death toll of more than 25 people.

Extreme and unpredictable weather conditions, haze and mountainous terrain are often cited as the main hurdles in flying through the area.

“Even for experienced local pilots, flying around or near the area is not a walk in the park,” senior pilot Jeffrey Adrian of Garuda Indonesia Airways said.

Another question also concerns the pilot’s request to air-traffic controllers (ATC) for permission to descend to 6,000 feet when near the 7,000-foot-high Mt. Salak.

“Investigators need to look into this conversation. Why, or what, caused the pilot to request permission to go down to 6,000 feet from an altitude of 10,000 feet, when he was flying above a mountain that was 7,000 feet?” former Airforce chief Marshall (ret.) Chappy Hakim said.

“This is difficult to comprehend. Normally, if a pilot flying in a mountainous area faced thick clouds, he would request permission to increase altitude. Why did the pilot request to descend instead?”

Controllers approved the descend because the area where the aircraft was flying, eight nautical miles away from Mt. Salak, was considered safe, PT Angkasa Pura’s deputy senior general manager Mulya Abdi said.

Angkasa Pura oversees the ATC that directed the Sukhoi jet.

Mulya also said that the area in the airspace of Atang Sendjaja Air Force base was regularly used by training aircraft.

For the Sukhoi Superjet, traveling through the route might have sounded easy, since it was equipped with highly sophisticated technology produced by a Russian company in collaboration with European companies. The cockpit, which is almost identical to the Airbus is fitted with state-of-the-art avionics.

But several of the technology has apparently failed; the plane’s advanced emergency locator transmitters, for example, remained undetected during search and rescue missions.

“When we talk about advances in aviation technology, we should not discount the possibility of fatal accidents that are caused  either by recklessness or tiny mistakes when using the equipment,” Chappy said.

Contact between Sukhoi pilots and Soekarno-Hatta International Airport’s ATC

May 9
• 2:12 p.m: ATC approves the Sukhoi pilots to fly from Halim Perdanakusuma Airport in Jakarta towards Bogor, West Java.
• 2:21 p.m: Pilots request approval to descend from 10,000 to 6,000 feet, which ATC approves, given that the aircraft was located around 8 nautical mile from Mt. Salak.
• Third contact: Pilots request approval to maneuver.
• ATC loses contact with the aircraft around 20 minutes later.

The aftermath

May 10
• A search-and-rescue (SAR) team finds debris from the aircraft 1,500 feet above sea level on Mt. Salak, 80 kilometers south of Jakarta.

May 11
• Forty-five passengers confirmed to be on board. SAR team reaches crash site by land, collects 12 body bags of partial remains and personal effects.

May 12
• Russian team arrives at the SAR command post in Cijeruk, West Java.

May 13
• Police hospital reports receipt of 18 body bags for victim identification. National Transportation Safety Committee chairman Tatang Kurniadi says plane’s black box has been located, but has not yet been retrieved due to harsh terrain.

Sukhoi Superjet 100

The aircraft is a medium-haul regional jet under development since 2000. The aircraft is the first-passenger airliner manufactured by Russia’sSukhoi Civil Aircraft since the collapse of the Soviet Union. Aside from Russian government and companies, foreign stakeholders involved in the aircraft’s development include Italy’s Finnmeccanica, France’s Snecma and Thales, and German’s Liebherr. Russia’s Aeroflot operates seven Superjets and Armenia’s Armavia operates one. The aircraft is able to carry on its board 98 passengers, and operate at the range of 3,048 km for the basic version and 4,578 km for the long range version at the altitude up to 12,200 meters. In January 2011 the jet obtained a certificate by the Russian Certification Authority, and the European Aviation Safety Agency certification in February 2012. The first flight was conducted in May 2008.

According to the Russian Embassy in Jakarta, during the International Aviation and Space Salon MAKS-2011 in Zhukovsky, Russia, on Aug. 16, 2011, Sukhoi Civil Aircraft and Indonesian carrier PT Sky Aviation signed a contract for the purchase of 12 Sukhoi Superjet 100 valued in total of US$380.4 million.

Aviation accidents around Mt. Salak

Oct. 10, 2002
• Ultra-light Trikes aircraft crashes in Lido, killing one.

Oct. 29, 2003
• Air Force Sikorsky Twin-Pac helicopter crashes in Kemang, killing seven.

April 15, 2004
• Lido Aero Sport Red Baron GT 500 paraglider crashes in Cijeruk, killing two.

June 20, 2004
• Cessna 185 Skywagon crashed into Lake Lido in Cijeruk, killing five.

June 2008
• Air Force Casa 212 crashes into Mt. Salak at 4,200 feet above sea level, killing 18.

April 30, 2009
• Curug flying school training aircraft crashes in Tenjo, killing three.

Source: The Jakarta Post, Photo: Reuters

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