sobota, 14 lutego 2015

The weirdest plane crashes- they shouldn't have happened-Birgenair 301.

I think everyone would say that plane crashes are horrific. But what adds to them being more horrific is a weird cause, for example plane crash caused by a ..... wasp, sticky tape or changing two numbers.
Well, I decided to write about some of them. At first a stuning cause.
Birgenair 301 The killer wasp
It was February 6th 1996. A Boeing 757-200 was preparing for takeoff in Peurto Plata, Dominicana.
The 757 was owned by Birgenair, a Turkish airline from Instanbul taking German vacationers to Frankfurt via Gander and Berlin. Along with Germans, 9 Poles were aboard. The crew consisted 11 Turkish and two people from Dominicana. There was a total amount of 189 people on board. The captain was Ahmet Erdem, a 62 year old veteran, the co-pilot was Aykut Gergin, a 34 year old novice to the Boeing 757. There was also a relief pilot, Muhlis Evrenesoğlu (51).
Birgenair tcgen.jpg
From Wikipedia
At 11:42 the plane taxied onto the runway and took off. During the takeoff roll  captain Erdem noted that his Speed indicator isn't working. He told the First officer to give him the speed readings, he didn't decide to abort it. The 757 became airborne at 23:43. The next two minutes of the flight were normal, until the captain noted "there is something wrong there are some problems". He soon reminded "okay there is something crazy do you see it, there is something crazy there at this." pointing at the speed indicator. After telling the first officer about the developing crisis, Gergin suggested to check the circuit breakers. For a minute they were trying to find a cause of the malfunction, while numerous alarms warned the crew. The captains airspeed indicator showed a low speed, while the first officers indicated a speed of around 350 knots. The autopilot wanting to decrease the speed increased the pitch and reduced the power. Moments later the stick shaker alert activated. The autopilot disengaged itself leaving the crew confused. Due to the high pitch the engines stopped, they couldn't get the needed airflow to keep them running. The situation got even worse, with the pilots puzzled about what to do. they were trying to prevent  a crash., however they efforts were all in vain. Everyone on board perished in the accident. An investigation was sent to investigate the crash.

Crash Animation from Wikicommons.
The investigators concluded that the cause of this disaster was:
"The crew's failure to recognize the activation of the stick shaker as a warning of imminent entrance to the stall, and the failure of the crew to execute the procedures for recovery from the onset of loss of control."
However this isn't all to the story. The cause of the stall was an action of the autopilot. The autopilot having its brain and knowing how to deal with problems decided that the plane is flying too fast and in order to slow it down pitched the airplane up and decreased the power. The cause of the abnormal readings was a pitot tube blockage. Investigators said that the blockage was most probably caused by a wasp nesting inside the component. Birgenair initially explained that: "was not on the ground for 20 days, but only for 12 days prior ill-fated flight. The pitot-tubes were covered prior to an engine test run which took place 2 days prior to the ill-fated flight. It was known by the Birgenair mechanics that the airplane should be returned to Turkey in a ferry flight within the next 3 days. If therefore the pitot-tubes had not been covered after the engine test run for 2 days, according to the Boeing procedures, set forth in the Boeing Maintenance Manual. This might be justified".
The next thing, pilots. The captain was very confused about the speed, he still didn't exactlly know it, while the Boeing was approaching a stall speed. Iventally the other crewman decided, aware of the situation didn't want to question the captains decisions. He is the most experienced pilot in the airline, he knows what he is doing. Such thinking may have led the crew to keeping quiet. Now, from the technical point the cause was maintance error and pilot error, however the crash wouldn't have happened if the wasp didn't nest in the pitot tube. Quite upsetting, that the airplane with nearly two hundred people was brought down by a tiny insect, but also that we as humans couldn't prevent it. As always the crash had been caused by human error, again human beings have designed planes. That I why they are always to blame even in the tiniest bit.
This year another 757 crashed due to a similar problem, the pitot tube on Aeroperu 603 was blocked by sticky tape. This gave pilots wrong indication of their sped altitude and heading causing them to crash into the Pacific Ocean killing all 70 people on board.
The next crash is probably going to be Avianca 11 or some crashed caused by lateralisation problems.


In memory of all killed in both accidents.