Compressor stall The airliner successfully made a forced landing in a forest clearing without loss of life. On January 15, 2009, US Airways Flight 1549, an Airbus A320, ditched in the Hudson River about five minutes after takeoff. The apparent cause was compressor stall in both CFM International CFM56-5B engines after flying through a flock of birds about 90 seconds after takeoff. This same aircraft may have suffered a compressor stall on the right engine two days earlier. After an incident in which an Airbus A321-200 experienced compressor stalls on both engines during initial climbout on December 15, 2008, an EASA Emergency
Flock (birds) of individuals in order the maximize benefits without incurring a large amount of costs. By living in a large flock, birds are also able to attack the predator with a stronger force compared to if the bird was on its own. In the black-capped chickadees it can be seen that flocks of birds can produce a mobbing call when it visualizes a possible predator. In response the black-capped chickadees within the flock surround the predator and attack it in a mob-like fashion in order to force the predator to leave. This is known as mobbing. This mobbing behaviour is quickly