什么原因可能导致马航飞机坠毁？

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.

据英国《每日电讯报》报道，波音777飞机一直被认为是最安全机型之一，但不到一年时间里发生第二起致命坠毁必然会使其名声受损。

波音777飞机在1995年投入使用，现在运行中的波音777飞机大约有1000架，而且它们通常承担最远距离的飞行，是长途运输的主力。负责监控美国制造飞机的美国国家运输安全委员会记录的意外事件不到60件。

但是，最近的记录却因为两次重大事件显得很突出——一件为去年7月旧金山机场的坠机事件，导致三人死亡，另一件为2008年1月在希思罗机场一架英国航空公司的波音777迫降事件。

然而，本次马航事件与英国航空公司事件以及在旧金山国际机场发生的韩亚飞机坠毁事件不同。上两次事件发生在降落前的很短时间内，而马航飞机在航程开始不久就从雷达信号中消失了。

7月的旧金山机场事件归因于飞行员的错误操作，飞行员认为电脑能保持足够的速度使飞机保持空中高度，因此使发动机处于闲置状态。但是，初步报告表明53岁的马航飞行员沙阿飞行经验丰富——1981年进入马航，飞行时间已达1.8365万个小时。

英国航空公司的飞机迫降事件，没有造成人员死亡，失事原因最终确定为连接引擎的燃油管线堵塞。

假设把这次飞机失事的原因比作心脏骤停，原因是在北京到伦敦飞行的最后，经过了西伯利亚不同寻常的寒冷上空，一部分燃料没有融化堵住了供应管道。

本次马航事件让人联想到当年载有288名乘客的法航空客330坠毁事件。这架长途飞行的客机在2009年6月从里约热内卢起飞后在途中坠入大西洋，造成228人死亡。

对于法航飞机坠毁事件的原因，有多个解释，但调查发现飞机的速度传感器给出了错误的读数。但是本次马航事件的飞机与前面所述飞机不同，可能需要几个月的调查才能确定其原因。