什麼原因可能導致馬航飛機墜毀？
Traditionally regarded as one of the safest planes in the skies, the Boeing 777’s reputation will have been damaged by the second fatal crash in less than a year.
There are around 1,000 Boeing 777s in service, and the plane is a long haul workhorse, plying some of the longest routes.
It entered service in 1995 and the National Transportation Safety Board, which is responsible for monitoring US-made aircraft, has logged fewer than 60 incidents.
But the recent record has been more patchy with two major incidents - a crash at San Francisco airport last July, which claimed three lives, and the crash-landing of a British Airways 777 at Heathrow in January 2008.
But the Malaysian disaster is very different from both the BA incident and the crash involving a Asiana Airlines flight at San Francisco International Airport in July.
Both the BA and Asiana accidents occurred shortly before landing, while the Malaysia airlines plane disappeared off the radar during the early stages of the trip.
The accident at San Francisco in July was attributed to pilot error which led to the engines being set to idle because he believed the computer would maintain sufficient speed to keep the plane up in the air.
But initial reports suggest that Zaharie Ahmad Shah, the 53-year-old Malaysian airlines pilot, was hugely experienced - having joined the carrier in 1981 and with 18,365 hours in the cockpit under his belt.
The BA crash landing, which did not result in any fatalities, was finally found to have been caused by a blockage in the fuel line feeding the engine.
Simply put the aircraft had the aviation equivalent of a cardiac arrest because some of the fuel failed to melt and blocked the supply line at the end of a long flight from Beijing to London, during which the plane travelled through unusually cold airspace over Siberia.
This crash has echoes of the disaster in which 288 people on board an Air France Airbus 330. That plane, another long-haul workhorse, crashed into the Atlantic en-route from Rio de Janeiro in June 2009 killing 228 people.
A variety of explanations have been given for the Air France crash, with investigators finding that the plane’s speed sensors were giving an incorrect reading.
But with this crash involving a different aircraft, it will take several months before investigators can ascertain the cause.據英國《每日電訊報》報道，波音777飛機一直被認爲是最安全機型之一，但不到一年時間裏發生第二起致命墜毀必然會使其名聲受損。
波音777飛機在1995年投入使用，現在運行中的波音777飛機大約有1000架，而且它們通常承擔最遠距離的飛行，是長途運輸的主力。負責監控美國製造飛機的美國國家運輸安全委員會記錄的意外事件不到60件。
但是，最近的記錄卻因爲兩次重大事件顯得很突出——一件爲去年7月舊金山機場的墜機事件，導致三人死亡，另一件爲2008年1月在希思羅機場一架英國航空公司的波音777迫降事件。
然而，本次馬航事件與英國航空公司事件以及在舊金山國際機場發生的韓亞飛機墜毀事件不同。上兩次事件發生在降落前的很短時間內，而馬航飛機在航程開始不久就從雷達信號中消失了。
7月的舊金山機場事件歸因於飛行員的錯誤操作，飛行員認爲電腦能保持足夠的速度使飛機保持空中高度，因此使發動機處於閒置狀態。但是，初步報告表明53歲的馬航飛行員沙阿飛行經驗豐富——1981年進入馬航，飛行時間已達1.8365萬個小時。
英國航空公司的飛機迫降事件，沒有造成人員死亡，失事原因最終確定爲連接引擎的燃油管線堵塞。
假設把這次飛機失事的原因比作心臟驟停，原因是在北京到倫敦飛行的最後，經過了西伯利亞不同尋常的寒冷上空，一部分燃料沒有融化堵住了供應管道。
本次馬航事件讓人聯想到當年載有288名乘客的法航空客330墜毀事件。這架長途飛行的客機在2009年6月從里約熱內盧起飛後在途中墜入大西洋，造成228人死亡。
對於法航飛機墜毀事件的原因，有多個解釋，但調查發現飛機的速度傳感器給出了錯誤的讀數。但是本次馬航事件的飛機與前面所述飛機不同，可能需要幾個月的調查才能確定其原因。
