Merpati Nusantara Airlines Flight 5601

Merpati Nusantara Airlines Flight 5601 (MNA5601/MZ5601) was a domestic scheduled passenger flight, that departed Achmad Yani International Airport, Semarang, Indonesia bound for Husein Sastranegara International Airport, Bandung, Indonesia. On 18 October 1992, the two-year-old CASA/IPTN CN-235-10 was on approach to Bandung when it crashed into Mount Puntang, near Mount Papandayan, West Java, Indonesia at 1:30 pm in bad weather. The aircraft exploded on impact killing all twenty seven passengers and four crew on board.

Flight 5601 is the worst ever civilian aviation disaster involving a CASA/IPTN CN-235, the deadliest in the company's history, the deadliest in Garut history, and the second deadliest aviation accident in Indonesia in 1992, after a plane flew into a mountain in eastern Indonesia which claimed 70 lives.

The crash sparked large controversy and trust issues in every Indonesian built aircraft. This is because the plane was produced and designed by Bacharudin Jusuf Habibie, a former Indonesian president who at the time held the position of State Minister of Science and Technology. He denied that the cause of the accident was because of design flaws. An Indonesian investigator team and the National Transportation Safety Committee confirmed that the cause of the crash wasn't because of design flaws, but due to pilot error aggravated by bad weather conditions.

Flight
The plane was on approach to Husein Sastranegara Airport in Bandung, carrying twenty seven passengers and four crew. The Captain, a female, 29 year old Fierda Basaria Panggabean made first contact to Jakarta control tower in Soekarno-Hatta International Airport in Cengkareng informing the tower about the flight. Flight 5601 was at 12500 ft above mean sea level. Sumardi, the person in charge in ACO (Approach Control Office), told Flight 5601 that the weather in Bandung wasn't in very good condition with moderate precipitation and some thunder. Broken clouds and visibility limited from 4 to 5 km. Fierda later decreased the plane's altitude from 12500 to 8000 ft. Fierda already asked Jakarta Control Tower about the descent. Fierda decided to do a visual approach to the airport. Sumardi, the ACO, told Fierda to contact the tower if she saw the runway and Fierda agreed.
 * Flight 5601:"Merpati five six zero one. We are from Semarang"
 * ATC:"Merpati five six zero one, maintain one two five"

But this contact was never made by the aircraft, and the aircraft disappeared from Jakarta's radar. The plane went missing over the mountains. A search and rescue team was assembled by the National Search and Rescue Agency, consisting of Cisurupan military, one platoon from Yon 303 Cikajang Garut, Garut police and National Air Force Army consisting of ten people. Local residents and villagers also helped the operation. The plane was later discovered to be "disintegrated" in what onlookers described it as "totally incinerated". The tail and one of the propellers were the only parts left intact from the impact. The plane's wreckage was found 60 km southeast of Bandung in Barukaso Pasir Uji, Cipaganti village, Cisurupan regency, Garut. Fierda's body was found still gripping the yoke of the plane and made a nose up input. The wreckage of the plane was found to be in climbing position, possibly Fierda didn't realise that the plane would impacted terrain until the last moment, when the terrain was seen by her. She had initiated a pull-up which was too late. None of the twenty seven passengers and four crew made out alive. Body parts were strewn over the area. The body of a baby was found 20 m from the wreckage, with the legs burnt due to a post-impact fire. A child's body, nine year old Meka Fitriyani, was found in her mother's arms. Most of the bodies were found in burnt condition and with large burn injuries due to a post-impact fire. As the plane crashed, the fuel ignited and exploded causing a massive fire at the crash site. The post-fire was so intense in fact it burned the vegetation in the surrounding area and ignited some bush fire. The wreckage was still smoking when it was found by authorities and remained smoking even on Monday dusk. The plane's wreckage was strewn over a small area and situated in mountainous terrain, which is surrounded by two steep hills. This caused difficulties in order to retrieve the bodies. Therefore, the evacuation process proceed by foot. It took three hours to reach the crash site. On Monday at dusk, one day after the crash, around twenty seven bodies had been found and recovered by authorities. Eight of them had been identified including the body of the co-pilot, First Officer Adnan S. Paago. The bodies were then transported to a local regional hospital in Garut, the Guntur regional hospital. There they would be stored and later transported to Hasan Sadikin Hospital in Bandung for repatriations. The evacuation process was observed and monitored by at the time Transportation Minister Azwar Anas and Garut's mayor Momon Gandasasmita.

Passengers and crew
The aircraft was carrying thirty one passengers and crew, consisting of twenty seven passengers and four crew members. All of them were Indonesian. The Captain was 29 year old Fierda Basaria Panggabean. She had logged 6.000 hours of flight experience. The co-pilot was First Officer Adnan S. Paago from Jakarta. Cabin crew members were Rita Rusliati and Ketty. Most passengers were travelling from Semarang. Some of them reside in Tangerang, Jakarta and parts of West Java.

Aircraft
Flight 5601 used a CN235. The CN235 rolled out in September 1983 which was attended by President Soeharto and named by him as Tetuko, Gatotkaca's childhood name. The CN235 was manufactured by a joint venture of an Indonesian aviation company Indonesian Aerospace in Bandung and Spain's CASA. The engines and avionics instruments were not manufactured by Indonesia, while everything else were made in Indonesia. The cockpit, nose, and inner wing were produced by Spain, while the outer wing and the tail section were manufactured by Indonesia. In its specification, it could handle a total of 35-40 people with a top speed of 244 kn.

Investigation
Before investigators started analysis of the black box from the crash site, the Captain of the plane, Fierda Basaria, was the first one to blame as the cause of the accident. As such, this angered her father, Wilson. Wilson stated that the public shouldn't blame his daughter as she was the Captain of the ill-fated flight, and blamed the Minister of Research and Technology BJ Habibie. Because Habibie was the designer and also the producer of the CN235 aircraft, Wilson directly blamed that BJ Habibie made several mistakes in his design, indicating a design flaw in the aircraft.

However, BJ Habibie instantly denied that a flaw was found in the aircraft. He insisted that the aircraft was 'airworthy' and had taken several tests to prove it. In the latter, he blamed Captain Fierda Basaria as the cause of the crash, as the black box analysis indicated that the main cause of the crash was because Fierda's action. Radar data retrieved from the control tower supported this theory, and concluded that she followed the wrong procedure. Outraged, Wilson plans to sue Indonesian Aerospace via his lawyer. His lawyer ready to sued the manufacturer, as he claimed that they had 'damaged the images of Fierda Basaria' and insisted that their plane was 'rain-proof' and 'thunder-proof'.

Analysis from the crash site proved that Flight 5601 didn't follow its assigned route. Head Staff of Search and Rescue Operation Lieutenant Colonel Iut Wiandra said Flight 5601 encountered thick clouds, leaving the crew with two options: turning to the left or the right while flying over the side of the cloud. Fierda chose to fly to the left, heading to the south, towards Garut. Fierda's cautious action proved fatal. The thick clouds that Flight 5601 attempted to avoid would intercept the aircraft. Weather reports received from Husein Tower stated that the weather on the route that Fierda use was in bad condition, with cumulonimbus clouds spotted and heavy thunder in the sky.

Merpati's CN235 Flight Instructor claimed that he was confused by Fierda's decision to lower the plane's altitude to 2833 m and rely on Visual Flight Rules (VFR). He stated that if she wanted a safe flight, she should have stayed with the Instrument Flight Rules (IFR). With IFR, Flight 5601 would only have to maintain its altitude of 11000 ft and let the control tower direct it. The aircraft then allowed to lowered their altitude to 8500 ft when it reached a radius of 25 mi from the landing point. Later on they were allowed to continue their approach in Visual Flight Rules.

Indeed, Fierda disobeyed the rules. Shockingly, a technician from Husein Tower revealed that most pilots that fly in the route always did the same as Fierda, and said that they always do this until the accident because nothing ever happened to them. This time Fierda was unlucky, and in this situation she was at fault, since it was not easy to change her way to fly. According to Frans Sumolang, Former Director of Merpati, when a plane follows VFR, it should stay in VFR. Changing from VFR to IFR could cause errors in the navigation calculations. Moreover, to change back to IFR, Flight 5601 needs to climb 3300 ft first.

A pilot claimed that the aircraft involved in the accident, CN235, was an easy-to-control plane and well equipped. He stated that the aircraft was equipped with an instrument navigation model EFIS ( Electronics Flight Integrated System) with a large screen in the cockpit. Most indicators on the plane, including the altitude, speed and their position could be seen on the screen. If one of the indicators malfunctioned, a backup indicator could be used by the pilots.

Communication problems in-flight
There were speculations that the communication in Flight 5601 wasn't functiong properly. This theory surfaced because in the last 10–15 minutes of the tragedy, Flight 5601 didn't make any contact with Husein Tower nor with Soekarno-Hatta Tower. This was immediately denied by the technician in Husein Tower. He stated that while in VFR, most pilots were "having fun" with their job and most likely didn't want to talk with control tower, except if an emergency occurred.

Mid-air engine failure
A mid-air engine failure could have occurred in Flight 5601. This was what Fierda's family thought to the cause of the crash. Based on its direction and travel time, Iut Wiandra from BASARNAS forecasted that Flight 5601 were cruising in 120 knots, far beyond the normal 180 knots.

Robert Ropolewski from Aviation Week published their main report of CN235 on 27 April 1987. He spoke highly of the aircraft's quality. In his statement, he stated that the aircraft was safe, comfortable, and charming. However, rumors spread that the plane he was using was a CN235 from Spain. BJ Habibie later answered it with ease and stated that both CN235, either from Indonesia or Spain, have the same performance level.

A pilot, later identified as Toto Subandoro, claimed that the plane could only reached a top speed of 215 kn, and the real top speed of the aircraft rarely reached. The average speed of the aircraft was 180 kn. If its speed were pushed for over 215 knots, the plane would shake. Fierda had double engine failure before the accident. First in Ngurah Rai International Airport and the second one in Halim Perdana Kusuma Airport. On the last one, one of its engine failed just shortly after takeoff. Fierda turned back to Halim and landed safely. Subandoro also claimed that he had an engine trouble once and landed safely.

Fatal mechanical failure
Another pilot stated that the flaps in CN235 were not functioning properly. Flaps, which were used to generate lift, didn't work in optimum condition. Thus, most of the pilots should maintain a high speed while landing, which was very dangerous. As such, the aircraft needs a runway over 1 km long. They didn't have a choice. If they maintain a low speed, the plane would enter a stall condition.

In Merpati Nusantara Airlines, the aircraft, CN235 had a bad reputation. Aircraft spareparts delay often occurred. This causing a chaotic operation management in Merpati. There was a CN235 that had a failure on its CTHS (Control Tork Holding System). This component was produced in Spain, and its cover was produced in Bandung, Indonesia. In order to get the spareparts that they need, Merpati needs to wait for 6 months. If the spareparts delivered right away, in just two days the plane could go fly again to the sky. Because of this Merpati only operates 8 of its CN235, while the rest were claimed to be the 'backup'.

However, the head of Merpati stated that the spareparts delay and the tragedy of Flight 5601 was totally different and stated that if the plane was flying at the time, the plane was airworthy.

Bad weather
There was another speculation that actually stated that Fierda's deliberately decreased her speed to 'soften' turbulence that had occurred on Flight 5601. Another thing was that the wreckage of the plane was found at an altitude of 6120 ft meaning that it was quite impossible that Fierda decreased her altitude that low and hard to prove. The incident happened in a mountain with a thick fog, and sudden updraft and downdraft could occurred any moment in the mountain. It was suspected that Flight 5601 was struck by a downdraft which caused her altitude to decreased a few hundred meters. But so far, not a single evidence found.

Aftermath
After the crash, a memorial was erected by Garut Government to remember the accident. The surviving propellers from Flight 5601 was evacuated and placed in front of the city hall of Garut, remembering all victims of the tragedy in Mount Puntang.