----- Original Message ----- From: Henry Biantoro To: Yap Hong Gie Sent: Wednesday, September 07, 2005 3:32 PM Subject: Mandala Flight RI-091 Broer Yap, Dibawah ini adalah analisa saya yang diterbitkan didalam Concord Review (salah satu produk Concord) mengenai kemungkinan-kemungkinan yang menyebabkan terjadinya kecelakaan pesawat Mandala RI-091 pada hari Senin 5 Januari, yang telah menewaskan salah seorang sahabat, saudara kita semua Wilson Kusumo. No prejudice has been expressed, the article below is only an analysis of probabilities. Salam, Henry Biantoro Crash Raises Doubts on Air Safety (07/09) Monday's crash of Mandala Flight RI-091 shortly after take-off from Medan's Polonia airport with the death of around 150 people has inevitably raised the question of air safety in Indonesia.Read more Below, Concord Consulting partner Henry Biantoro, a former Garuda Airways pilot, looks at what could have gone wrong. Whatever went wrong, there is concern that the high level of competition in the Indonesian airline industry is causing airlines to cut maintenance standards. Before the Medan crash, there were 13 air accidents this year, with a total of 54 fatalities, on top of at least a dozen in 2004. Concord recently was advised by a senior engineer from one of the world's top aircraft engine manufacturers that some airlines should be avoided altogether. He named one carrier that does not meet international safety standards. He mentioned that in one recent incident, a leaking tire on a plane required it to be jacked up for hours while mechanics went off to get the tire fixed - they had no spares! While a leaking tire is enough of a threat to safety in itself, the engineer raised the more ominous question: if they didn't have spare tires, what else didn't they have? The government has moved to improve the situation by setting new standards on the age and number of flying hours. That should get rid some of the aged aircraft that have been in evidence at Indonesia airports and in the skies. It will not immediately solve the problem of regular maintenance. High fuel costs have added to the cost constraints of carriers. Planes are being pushed to spend more time in the air, automatically increasing the load factors on engines and other parts. Our recommendation: stick with Garuda. While its safety record isn't perfect, it has far better maintenance - and even more important, training - standards, than any of its competitors. It is more expensive, but the extra cost is worth it. Flight RI-091 - What Happened? By Henry Biantoro No probable cause has been declared yet by either the airline or the National Committee on Transportation Safety (KNKT), and such a statement will take months if not years to be given to the public, if the findings are ever released. If the findings are made public, in many case care will have been taken to generalize the case and avoid blame of a particular party. What we can do in the meantime is analyze probabilities that may lead to an accident, Bear in mind that the possible causes of a crash are not limited to the following: Case One Both engines fail during takeoff This case is very unlikely to happen, but it is not impossible. In such a case there is nothing that the pilots could do to recover the engines during this stage of the flight. The only available procedure in any Aircraft Flight Manual is to manage the emergency and passengers' evacuation. Case Two The aircraft is overweight while one engine fails during takeoff All take-off performance data calculation of any aircraft is based on the position if one engine fails during take off. Those performance charts are very marginal in nature, not least because they rarely occur in real life. For example, the writer had flown for 27 years and has a total of 17,000 flying hours, but has not experienced a single engine failure incident. Because of the rarity of these occurrences, airline ground staff and inexperienced flight crew members tend to think that the limitations dictated by the Aircraft Flight Manual are too limiting because the aircraft manufacturer has provided too much of a margin for safety. They think they can play a little bit with the margin by carrying more payload than the dictated take-off limit. This can either be a corporate decision on the part of the airline or by individuals on the ground. In normal operation, this will create no problems, and continuing ability to breach recommended load limits will reinforce the habit of overloading aircraft. If one engine fails during take-off, the aircraft will not be able to maintain its calculated take-off path. Added to this is the 5-6% performance degradation caused by aging aircraft and engines. Case Three One engine fails during takeoff, flight crew are not well-trained Civil Aviation Safety regulations everywhere dictate that any aircraft flight crew member must undergo recurrent training and a proficiency check every six months. Among other exercises, the training consists of simulation of situations in which one engine fails during take-off, cruise and landing. Well-trained pilots consider this exercise as an abnormal operation rather that an emergency operation and nothing is critical as long as they follow the procedures and techniques as dictated by the Aircraft Flight Manual. But as mentioned above, pilots who are not well-trained will consider it a nightmare as the aircraft will fly against them. This is because of in-balance thrust produced by the living engine(s) will fly the aircraft towards the direction of the dead engine. In such a case, the pilots are busy with fighting with the force of the living engine and may tend to forget that the aircraft has to be piloted away from obstacles. Case Four Down-burst caused by approaching thunderstorm Immediately after the tragic crash of Mandala Flight RI-091, there was a thunderstorm in the airport vicinity. When a thunderstorm approaches, there is always a chance that a down-burst phenomenon also appears near the edge of the cumulo-nimbus cloud carrying heavy precipitation. When an aircraft hits a down-burst during its take-off path below 1,000 feet, there is nothing that the flight crew can do to recover the aircraft. The aircraft will totally lose its lift and fall out of the air as a big piece of metal. Therefore taking off while a thunderstorm is approaching is not recommended. The above four cases do not remove the possibility of other causes of accidents. Accident reports have proven that lack of crew coordination is the most common cause of accidents, meaning that crew training and sound standard operating procedures are the most important factors to maintain flight safety.
source: http://www.polarhome.com/pipermail/marinir/2005-September/000887.html
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