A small sand bee, just 2.5 centimeters long, destroyed an airline in Turkey. On February 6, 1996, 18 minutes before midnight, Turkish Airlines Birgenair flight ALW 301 took off from Puerto Plata Airport (Dominican Republic).
The Boeing 757-225 destination is the Canadian city of Gander.
During takeoff, the captain suddenly noticed that his speedometer number was a bit abnormal, but he did not care, nor did he interrupt the takeoff, but let the co-pilot control the plane to continue flying.
But the plane reached an altitude of 1400 meters, and the captain noticed a big problem with the speed indicator, his watch showed 650 km/h, while the co-pilot's gauge showed 370 km/h.
The result is a difference in speed, causing the aircraft's autopilot to automatically shut down.
So the crew decided to slow down.
This has led to a series of mutual warnings about the aircraft being too low or too high, and it is difficult to make correct judgments.
Later, the captain subjectively thought that the speed of the aircraft was still too high and began to slow down.
However, due to the surge of the left engine, the flight situation continued to deteriorate, and the aircraft suddenly fell into a stall. The Boeing plane descended sharply, spinning around its axis.
Pilots can no longer regain control of the plane.
In addition, the hydraulic system failed due to engine failure, and the lack of clearance did not leave the pilot time to correct the flight.
As a result, the plane crashed into the Atlantic Ocean, killing all 189 people on board.
The speed of flight is determined using a special device, the pitot tube. Its work programme is based on the analysis of the pressure generated by the airflow.
During the investigation, it was found that the actual speed of the aircraft in the development of the emergency was 410 km / h.
Therefore, the gauges of the captain and co-pilot give the wrong speed value. This is because one of the three pitot tubes is clogged. However, the numbers are completely correct.
The presumable cause of the pitot blockage is a sand hive. These wasps sometimes build cylindrical nests of clay or clay.
Investigators determined that the plane had been at Puerto Plata Airport for 20 days before its last flight.
During this time, numerous sand bees nested in the aircraft's pitot tubes.
In addition to the clogging of the pitot tube, the wrong operation of the crew has also become the cause of the disaster.
They couldn't understand the contradictory readings of the speed indicator and allowed it to drop sharply, eventually leading to stalling.
Due to negative media coverage and the consequent decline in passenger traffic, Birgenair went bankrupt a few months after the disaster.
