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) call of the ground squirrel requires the ability of the animal to first recognize that there is danger present and then to react. This type of behaviour is also seen in some birds. It is important to note that by making an alarm call to signal members of the flock one is providing the predator with an acoustical cue to the location of a possible prey. The benefit here is if the members of the flock are genetically related to one another. If this is true, even if the bird that signalled the flock were to die its fitness would